Life Extension Magazine®

Issue: Oct 2012

Zeaxanthin

By Life Extension.

Randomized, double-blind, placebo-controlled study of zeaxanthin and visual function in patients with atrophic age-related macular degeneration: the Zeaxanthin and Visual Function Study (ZVF) FDA IND #78, 973.

BACKGROUND: The purpose of this study is to evaluate whether dietary supplementation with the carotenoid zeaxanthin (Zx) raises macula pigment optical density (MPOD) and has unique visual benefits for patients with early atrophic macular degeneration having visual symptoms but lower-risk National Institute of Health/National Eye Institute/Age-Related Eye Disease Study characteristics. METHODS: This was a 1-year, n = 60 (57 men, 3 women), 4-visit, intention-to-treat, prospective, randomized controlled clinical trial of patients (74.9 years, standard deviation [SD] 10) with mild-to-moderate age-related macular degeneration (AMD) randomly assigned to 1 of 2 dietary supplement carotenoid pigment intervention groups: 8 mg Zx (n = 25) and 8 mg Zx plus 9 mg lutein (L) (n = 25) or 9 mg L ("Faux Placebo," control group, n = 10). Analysis was by Bartlett's test for equal variance, 3-way repeated factors analysis of variance, independent t test (P < 0.05) for variance and between/within group differences, and post-hoc Scheffé's tests. Estimated foveal heterochromic flicker photometry, 1° macular pigment optical density (MPOD QuantifEye®, low- and high-contrast visual acuity, foveal shape discrimination (Retina Foundation of the Southwest), 10° yellow kinetic visual fields (KVF), glare recovery, contrast sensitivity function (CSF), and 6° blue cone ChromaTest® color thresholds were obtained serially at 4, 8, and 12 months. RESULTS: Ninety percent of subjects completed ≥ 2 visits with an initial Age-Related Eye Disease Study report #18 retinopathy score of 1.4 (1.0 SD)/4.0 and pill intake compliance of 96% with no adverse effects. There were no intergroup differences in 3 major AMD risk factors: age, smoking, and body mass index as well as disease duration and Visual Function Questionnaire 25 composite score differences. Randomization resulted in equal MPOD variance and MPOD increasing in each of the 3 groups from 0.33 density units (du) (0.17 SD) baseline to 0.51 du (0.18 SD) at 12 m, (P = 0.03), but no between-group differences (Analysis of Variance; P = 0.47). In the Zx group, detailed high-contrast visual acuity improved by 1.5 lines, Retina Foundation of the Southwest shape discrimination sharpened from 0.97 to 0.57 (P = 0.06, 1-tail), and a larger percentage of Zx patients experienced clearing of their KVF central scotomas (P = 0.057). The "Faux Placebo" L group was superior in terms of low-contrast visual acuity, CSF, and glare recovery, whereas Zx showed a trend toward significance. CONCLUSION: In older male patients with AMD, Zx-induced foveal MPOD elevation mirrored that of L and provided complementary distinct visual benefits by improving foveal cone-based visual parameters, whereas L enhanced those parameters associated with gross detailed rod-based vision, with considerable overlap between the 2 carotenoids. The equally dosed (atypical dietary ratio) Zx plus L group fared worse in terms of raising MPOD, presumably because of duodenal, hepatic-lipoprotein or retinal carotenoid competition. These results make biological sense based on retinal distribution and Zx foveal predominance.

Optometry. 2011 Nov;82(11):667-80

Augmentation of macular pigment following supplementation with all three macular carotenoids: an exploratory study.

PURPOSE: At the macula, the carotenoids meso-zeaxanthin (MZ), lutein (L), and zeaxanthin (Z) are collectively referred to as macular pigment (MP). This study was designed to measure serum and macular responses to a macular carotenoid formulation. MATERIALS AND METHODS: Ten subjects were recruited into this study (five normal and five with early age-related macular degeneration [AMD]). Subjects were instructed to consume a formulation containing 7.3 mg of MZ, 3.7 mg of L, and 0.8 mg of Z everyday over an eight-week period. The spatial profile of MP optical density (i.e., MPOD at 0.25 degrees , 0.5 degrees , 1 degrees , and 1.75 degrees ) was measured using customized heterochromatic flicker photometry, and a blood sample was collected at each study visit in order to analyze serum concentrations of MZ, L, and Z. RESULTS: There was a significant increase in serum concentrations of MZ and L after two weeks of supplementation (p < 0.05). Baseline serum carotenoid analysis detected a small peak eluting at the same time as MZ in all subjects, with a mean +/- SD of 0.02 +/- 0.01 micromol/L. We report significant increases in MPOD at 0.25 degrees , 0.5 degrees , 1 degree , and average MPOD across its spatial profile after just two weeks of supplementation (p < 0.05, for all). Four subjects (one normal and three AMD) who had an atypical MPOD spatial profile (i.e., central dip) at baseline had the more typical MPOD spatial profile (i.e., highest MPOD at the center) after eight weeks of supplementation. CONCLUSION: We report significant increases in serum concentrations of MZ and L following supplementation with MZ, L, and Z and a significant increase in MPOD, including its spatial profile, after two weeks of supplementation. Also, this study has detected the possible presence of MZ in human serum pre-supplementation and the ability of the study carotenoid formulation to rebuild central MPOD in subjects who have atypical profiles at baseline.

Curr Eye Res. 2010 Apr;35(4):335-51

Dietary carotenoids, serum beta-carotene, and retinol and risk of lung cancer in the alpha-tocopherol, beta-carotene cohort study.

Findings from several beta-carotene supplementation trials were unexpected and conflicted with most observational studies. Carotenoids other than beta-carotene are found in a variety of fruits and vegetables and may play a role in this important malignancy, but previous findings regarding the five major carotenoids are inconsistent. The authors analyzed the associations between dietary beta-carotene, beta-carotene, lutein/zeaxanthin, lycopene, beta-cryptoxanthin, vitamin A, serum beta-carotene, and serum retinol and the lung cancer risk in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort of male smokers conducted in southwestern Finland between 1985 and 1993. Of the 27,084 male smokers aged 50-69 years who completed the 276-food item dietary questionnaire at baseline, 1,644 developed lung cancer during up to 14 years of follow-up. Cox proportional hazards models were used to estimate relative risks and 95% confidence intervals. Consumption of fruits and vegetables was associated with a lower lung cancer risk (relative risk = 0.73, 95% confidence interval: 0.62, 0.86, highest vs. lowest quintile). Lower risks of lung cancer were observed for the highest versus the lowest quintiles of lycopene (28%), lutein/zeaxanthin (17%), beta-cryptoxanthin (15%), total carotenoids (16%), serum beta-carotene (19%), and serum retinol (27%). These findings suggest that high fruit and vegetable consumption, particularly a diet rich in carotenoids, tomatoes, and tomato-based products, may reduce the risk of lung cancer.

Am J Epidemiol. 2002 Sep 15;156(6):536-47

Micronutrients and their relevance for the eye—function of lutein, zeaxanthin and omega-3 fatty acids.

Micronutrients play an important role in function and health maintenance for the eye. Especially lutein, zeaxanthin and omega-3 fatty acids perform remarkable functions: lutein together with zeaxanthin forms the macular pigment, these carotenoids filter out the damaging blue light component from the sunlight as well as the ultraviolet light which leads to improved contrast sensitivity and less problems with screen glare. Furthermore, the macular pigment has antioxidant and anti-inflammatory effects. The omega-3 fatty acids also possess anti-inflammatory effects and, when converted into neuroprotectin, they protect against oxidative induced apoptosis in the retina. They are also responsible for the fluidity and supply to the photoreceptor membrane. These properties are important for the prevention and treatment of degenerative eye diseases like age-related macular degeneration. However, older people are often not sufficiently supplied of micronutrients in their diet. Because the supply of nutrients can hardly be achieved by dietary change, the additional intake in the form of food supplements is useful in this age group. Scientific studies have shown the positive effects of supplementation with micronutrients such as lutein/zeaxanthin, vitamin C, vitamin E, zinc and omega-3 fatty acids, docosahexaenoic acid and eicosapentaenoic acid (DHA and EPA). Currently available nutritional products are based in part on the ingredients of the ARED study (Age Related Eye Disease Study). According to more recent studies formulations containing lutein and omega-3 fatty acids in physiologically meaningful doses without additional beta-carotene should be preferred. 10 to 20 mg of lutein and zeaxanthin represent a safe daily dose Regarding to the context above, beta-carotene in high doses plays a minor role to the eye and is especially critical for the health of smokers. This paper summarises the functions of the presented micronutrients in the eye and can assist ophthalmologists in advising their patients.

Klin Monbl Augenheilkd. 2011 Jun;228(6):537-43

Serum lutein response is greater from free lutein than from esterified lutein during 4 weeks of supplementation in healthy adults.

BACKGROUND: Current data suggest great variability in serum response following lutein ingestion from various sources. OBJECTIVE: To compare the relative serum response during supplementation with free lutein (fL) and lutein esters (Le). METHODS: 72 volunteers (23-52 years; body mass index [BMI] >20 and <30 kg/m2; baseline serum lutein <20 µg/dL [<352 nmol/L]) were identified. Subjects, matched for gender, age, and BMI, were randomly assigned to the fL or Le group. fL and Le capsules contained 12.2 mg of free lutein or 27 mg of lutein ester (equivalent to 13.5 mg free lutein), respectively. Fasting blood was obtained at baseline and after 7, 14, 21, and 28 days of supplementation. Supplements were consumed with standard portions of dry, ready-to-eat cereal and 2% cow's milk. RESULTS: Absolute changes in serum lutein, per mg daily dose, were significantly greater in fL vs. Le after 21 days (p = 0.0012) and remained so after 28 days (p = 0.0011) of supplementation. Serum lutein Area Under the Curve [AUC((day 0-28))] response was 17% greater for fL vs. Le (p = 0.0187). Regression models were used and determined that (1) baseline serum lutein levels and (2) the form of lutein ingested (fL > Le) influence the serum lutein response during supplementation, while subject age, gender, BMI, and serum lipids do not affect serum response. CONCLUSIONS: These results suggest that the relative serum lutein response will be significantly greater from supplements containing free lutein than from supplements containing lutein esters. These findings should be useful for future clinical trials exploring the effectiveness of lutein supplementation in the prevention of or protection against age-related macular degeneration and/or cataracts.

J Am Coll Nutr. 2010 Dec;29(6):575-85

Dietary supplementation with a natural carotenoid mixture decreases oxidative stress.

OBJECTIVE: To determine whether dietary supplementation with a natural carotenoid mixture counteracts the enhancement of oxidative stress induced by consumption of fish oil. DESIGN: A randomised double-blind crossover dietary intervention. SETTING: Hugh Sinclair Unit of Human Nutrition, School of Food Biosciences, The University of Reading, Whiteknights PO Box 226, Reading RG6 6AP, UK. SUBJECTS AND INTERVENTION: A total of 32 free-living healthy nonsmoking volunteers were recruited by posters and e-mails in The University of Reading. One volunteer withdrew during the study. The volunteers consumed a daily supplement comprising capsules containing fish oil (4 x 1 g) or fish oil (4 x 1 g) containing a natural carotenoid mixture (4 x 7.6 mg) for 3 weeks in a randomised crossover design separated by a 12 week washout phase. The carotenoid mixture provided a daily intake of beta-carotene (6.0 mg), alpha-carotene (1.4 mg), lycopene (4.5 mg), bixin (11.7 mg), lutein (4.4 mg) and paprika carotenoids (2.2 mg). Blood and urine samples were collected on days 0 and 21 of each dietary period. RESULTS: The carotenoid mixture reduced the fall in ex vivo oxidative stability of low-density lipoprotein (LDL) induced by the fish oil (P=0.045) and it reduced the extent of DNA damage assessed by the concentration of 8-hydroxy-2'-deoxyguanosine in urine (P=0.005). There was no effect on the oxidative stability of plasma ex vivo assessed by the oxygen radical absorbance capacity test. beta-Carotene, alpha-carotene, lycopene and lutein were increased in the plasma of subjects consuming the carotenoid mixture. Plasma triglyceride levels were reduced significantly more than the reduction for the fish oil control (P=0.035), but total cholesterol, HDL and LDL levels were not significantly changed by the consumption of the carotenoid mixture. CONCLUSIONS: Consumption of the natural carotenoid mixture lowered the increase in oxidative stress induced by the fish oil as assessed by ex vivo oxidative stability of LDL and DNA degradation product in urine. The carotenoid mixture also enhanced the plasma triglyceride-lowering effect of the fish oil. SPONSORSHIP: The study was supported by funding from the Greek Studentship Foundation and from Unilever Bestfoods plc. Carotenoids were contributed by Overseal Foods plc.

Eur J Clin Nutr. 2003 Sep;57(9):1135-40

Dietary carotenoid lutein protects against DNA damage and alterations of the redox status induced by cisplatin in human derived HepG2 cells.

Several epidemiological and experimental studies has been reported that lutein (LT) presents antioxidant properties. Aim of the present study was to investigate the protective effects of LT against oxidative stress and DNA damage induced by cisplatin (cDDP) in a human derived liver cell line (HepG2). Cell viability and DNA-damage was monitored by MTT and comet assays. Moreover, different biochemical parameters related to redox status (glutathione, cytochrome-c and intracellular ROS) were also evaluated. A clear DNA-damage was seen with cDDP (1.0µM) treatment. In combination with the carotenoid, reduction of DNA damage was observed after pre- and simultaneous treatment of the cells, but not when the carotenoid was added to the cells after the exposure to cDDP. Exposure of the cells to cDDP also caused significant changes of all biochemical parameters and in co-treatment of the cells with LT, the carotenoid reverted these alterations. The results indicate that cDDP induces pronounced oxidative stress in HepG2 cells that is related to DNA damage and that the supplementation with the antioxidant LT may protect these adverse effects caused by the exposure of the cells to platinum compound, which can be a good predict for chemoprevention.

Toxicol In Vitro. 2012 Mar;26(2):288-94

Cancer chemoprevention by carotenoids.

Carotenoids are natural fat-soluble pigments that provide bright coloration to plants and animals. Dietary intake of carotenoids is inversely associated with the risk of a variety of cancers in different tissues. Preclinical studies have shown that some carotenoids have potent antitumor effects both in vitro and in vivo, suggesting potential preventive and/or therapeutic roles for the compounds. Since chemoprevention is one of the most important strategies in the control of cancer development, molecular mechanism-based cancer chemoprevention using carotenoids seems to be an attractive approach. Various carotenoids, such as β-carotene, a-carotene, lycopene, lutein, zeaxanthin, β-cryptoxanthin, fucoxanthin, canthaxanthin and astaxanthin, have been proven to have anti-carcinogenic activity in several tissues, although high doses of β-carotene failed to exhibit chemopreventive activity in clinical trials. In this review, cancer prevention using carotenoids are reviewed and the possible mechanisms of action are described.

Molecules. 2012 Mar 14;17(3):3202-42

Dietary lutein inhibits mouse mammary tumor growth by regulating angiogenesis and apoptosis.

Even though we previously reported that dietary lutein can inhibit mammary tumor growth, the mechanism of this action was unknown. Here, we studied the action of dietary lutein through its possible regulation of apoptosis and angiogenesis. Female BALB/c mice were fed a semi-purified diet containing 0 (control), 0.002 or 0.02% lutein (n = 20/treatment) for 2 weeks prior to inoculation with 100,000 -SA mouse mammary tumor cells into the right mammary fat pad. Tumor volume was measured daily until day 50 postinoculation when all mice were killed. Angiogenesis and apoptosis activities in the tumors were measured by immunohistochemistry. Apoptosis and necrosis of blood lymphocytes were quantitated by flow cytometry using Annexin V-FITC and propidium iodide staining. The expression of the p53, Bax and Bcl-2 mRNA was measured by RT-PCR amplification. Lutein was not detectable in the plasma, liver or tumor of unsupplemented mice, but increased in a dose-dependent manner in lutein-supplemented mice. Mice fed lutein had tumors that were 30 to 40% smaller (p < 0.05) on day 50 post-inoculation compared to unsupplemented mice. Final tumor volume was lowest in mice fed 0.002% lutein. Mice fed lutein had higher apoptotic activity in the tumors but lower apoptotic activity in blood lymphocytes as compared to unsupplemented animals. These observations were supported by the observed increase in the expression of the proapoptotic genes, p53 and Bax, together with a decrease in the expression of the antiapoptotic gene, Bcl-2, and consequently an increase in the Bax:Bcl-2 ratio in tumors from lutein-fed mice. Furthermore, lutein-fed mice also had lower (p < 0.05) angiogenic activity in the tumors as compared to unsupplemented mice. The greatest beneficial effect on apoptosis and angiogenesis was observed with mice fed 0.002% lutein. Therefore, dietary lutein, especially at 0.002%, inhibited tumor growth by selectively modulating apoptosis, and by inhibiting angiogenesis.

Anticancer Res. 2003 Jul-Aug;23(4):3333-9

Dietary lutein/zeaxanthin partially reduces photoaging and photocarcinogenesis in chronically UVB-irradiated Skh-1 hairless mice.

Lutein and zeaxanthin are xanthophyll carotenoids with potent antioxidant properties protecting the skin from acute photodamage. This study extended the investigation to chronic photodamage and photocarcinogenesis. Mice received either a lutein/zeaxanthin-supplemented diet or a standard nonsupplemented diet. Dorsal skin of female Skh-1 hairless mice was exposed to UVB radiation with a cumulative dose of 16,000 mJ/cm(2) for photoaging and 30,200 mJ/cm(2) for photocarcinogenesis. Clinical evaluations were performed weekly, and the animals were sacrificed 24 h after the last UVB exposure. For photoaging experiments, skin fold thickness, suprapapillary plate thickness, mast cell counts and dermal desmosine content were evaluated. For photocarcinogenesis, samples of tumors larger than 2 mm were analyzed for histological characterization, hyperproliferation index, tumor multiplicity, total tumor volume and tumor-free survival time. Results of the photoaging experiment revealed that skin fold thickness and number of infiltrating mast cells following UVB irradiation were significantly less in lutein/zeaxanthin-treated mice when compared to irradiated animals fed the standard diet. The results of the photocarcinogenesis experiment were increased tumor-free survival time, reduced tumor multiplicity and total tumor volume in lutein/zeaxanthin-treated mice in comparison with control irradiated animals fed the standard diet. These data demonstrate that dietary lutein/zeaxanthin supplementation protects the skin against UVB-induced photoaging and photocarcinogenesis.

Skin Pharmacol Physiol. 2007;20(6):283-91

Role of glutathione in augmenting the anticancer activity of pyrroloquinoline quinone (PQQ).

Pyrroloquinoline quinone (PQQ), a bacterial redox co-factor and antioxidant, is highly reactive with nucleophilic compounds present in biological fluids. PQQ induced apoptosis in human promonocytic leukemia U937 cells and this was accompanied by depletion of the major cellular antioxidant glutathione and increase in intracellular reactive oxygen species (ROS). Treatment with glutathione (GSH) or N-acetyl-L-cysteine (NAC) did not spare PQQ toxicity but resulted in a 2-5-fold increase in PQQ-induced apoptosis in U937 cells. Cellular GSH levels increased following treatment by NAC alone but were severely depleted by co-treatment with NAC and PQQ. This was accompanied by an increase in intracellular ROS. Alternatively, depletion of glutathione also resulted in increased PQQ cytotoxicity. However, the cells underwent necrosis as evidenced by dual labeling with annexin V and propidium iodide. PQQ-induced cytotoxicity is thus critically regulated by the cellular redox status. An increase in GSH can augment apoptosis and its depletion can switch the mode of cell death to necrosis in the presence of PQQ. Our data suggest that modulation of intracellular GSH can be used as an effective strategy to potentiate cytotoxicity of quinones like PQQ.

Redox Rep. 2010;15(4):146-54

Pyrroloquinoline quinone inhibits the fibrillation of amyloid proteins.

Several neurodegenerative diseases involve the selective damage of neuron cells resulting from the accumulation of amyloid fibril formation. Considering that the formation of amyloid fibrils as well as their precursor oligomers is cytotoxic, the agents that prevent the formation of oligomers and/or fibrils might allow the development of a novel therapeutic approach to neurodegenerative diseases. Here, we show pyrroloquinoline quinone (PQQ) inhibits the amyloid fibril formation of the amyloid proteins, amyloid beta (1-42) and mouse prion protein. The fibril formation of mouse prion protein in the presence of PQQ was dramatically prevented. Similarly, the fibril formation of amyloid beta (1-42) also decreased. With further advanced pharmacological approaches, PQQ may become a leading anti-neurodegenerative compound in the treatment of neurodegenerative diseases.

Prion. 2010 Jan-Mar;4(1):26-31

The inhibitory effect of pyrroloquinoline quinone on the amyloid formation and cytotoxicity of truncated alpha-synuclein.

BACKGROUND: Parkinson's disease (PD) involves the selective damage of dopaminergic neuron cells resulting from the accumulation and fibril formation of alpha-synuclein. Recently, it has been shown that not only full-length alpha-synuclein, but also C-terminal truncated forms exist in the normal brain, as well as Lewy bodies, which are cytoplasmic inclusions in PD. It is known that truncated alpha-synuclein has a much higher ability to aggregate and fibrillate than full-length alpha-synuclein. Since the fibrils and precursor oligomers of alpha-synuclein are cytotoxic to the neuron, inhibitors that prevent the formation of oligomers and/or fibrils might open the way to a novel therapeutic approach to PD. However, no inhibitor for truncated alpha-synuclein has been reported yet. RESULTS: In this study, we first characterized the aggregation and cytotoxicity of C-truncated alpha-synuclein119 and alpha-synuclein133 which have been found in both the normal and the pathogenic brain. Alpha-synuclein119 aggregated more rapidly and enhanced significantly the fibril formation of alpha-synuclein. Although both of alpha-synuclein119 and alpha-synuclein133 showed a high cytotoxicity, alpha-synuclein133 showed a similar aggregation with full-length alpha-synuclein and no acceleration effect. We showed that PQQ dramatically inhibits the fibril formation of C-terminal truncated alpha-synuclein110119, and 133 as well as the mixtures of full-length alpha-synuclein with these truncated variants. Moreover, PQQ decreases the cytotoxicity of truncated alpha-synuclein. CONCLUSIONS: Our results demonstrate that PQQ inhibits the amyloid fibril formation and cytotoxicity of the C-truncated alpha-synuclein variants. We believe that PQQ is a strong candidate for a reagent compound in the treatment of PD.

Mol Neurodegener. 2010 May 20;5:20

Neuroprotection by pyrroloquinoline quinone (PQQ) in reversible middle cerebral artery occlusion in the adult rat.

Pyrroloquinoline quinone (PQQ) is a naturally occurring redox cofactor that acts as an essential nutrient, antioxidant, and redox modulator. It has previously been reported to reduce infarct size in 7-day-old rat pups with an in vivo cerebral hypoxia/ischemia model (Jensen et al., 1994). In this study, we tested whether improvement is found in both behavioral measures of protection and by histological measures of infarcted tissue at 72 h after reversible middle cerebral artery occlusion (rMCAo) in adult rats. Two-hour rMCAo was induced in adult rats using the intraluminal suture technique. PQQ (10, 3, and 1 mg/kg) was given once by intravenous injection at the initiation, or 3 h after the initiation, of 2 h rMCAo. Neurobehavioral deficits were evaluated daily for 3 days followed by infarct volumes measurements by 2,3,5-triphenyltetrazolium chloride (TTC) staining. PQQ at 10 mg/kg infused at the initiation, or 3 h after the initiation, of rMCAo was effective in reducing cerebral infarct volumes measured 72 h later. At 3 h after ischemia, a dose of 3 mg/kg significantly reduced infarct volume compared to vehicle-treated animals, but 1 mg/kg was ineffective. Neurobehavioral scores were also significantly better in the PQQ-treated group compared to the vehicle controls when PQQ was given at 10 and 3 mg/kg, but not at 1 mg/kg. Thus, PQQ is neuroprotective when given as a single administration at least 3 h after initiation of rMCAo. These data indicate that PQQ may be a useful neuroprotectant in stroke therapy.

Brain Res. 2006 Jun 13;1094(1):200-6

Altering pyrroloquinoline quinone nutritional status modulates mitochondrial, lipid, and energy metabolism in rats.

We have reported that pyrroloquinoline quinone (PQQ) improves reproduction, neonatal development, and mitochondrial function in animals by mechanisms that involve mitochondrial related cell signaling pathways. To extend these observations, the influence of PQQ on energy and lipid relationships and apparent protection against ischemia reperfusion injury are described herein. Sprague-Dawley rats were fed a nutritionally complete diet with PQQ added at either 0 (PQQ-) or 2 mg PQQ/Kg diet (PQQ+). Measurements included: 1) serum glucose and insulin, 2) total energy expenditure per metabolic body size (Wt(3/4)), 3) respiratory quotients (in the fed and fasted states), 4) changes in plasma lipids, 5) the relative mitochondrial amount in liver and heart, and 6) indices related to cardiac ischemia. For the latter, rats (PQQ- or PQQ+) were subjected to left anterior descending occlusions followed by 2 h of reperfusion to determine PQQ's influence on infarct size and myocardial tissue levels of malondialdehyde, an indicator of lipid peroxidation. Although no striking differences in serum glucose, insulin, and free fatty acid levels were observed, energy expenditure was lower in PQQ- vs. PQQ+ rats and energy expenditure (fed state) was correlated with the hepatic mitochondrial content. Elevations in plasma di- and triacylglyceride and -hydroxybutryic acid concentrations were also observed in PQQ- rats vs. PQQ+ rats. Moreover, PQQ administration (i.p. at 4.5 mg/kg BW for 3 days) resulted in a greater than 2-fold decrease in plasma triglycerides during a 6-hour fast than saline administration in a rat model of type 2 diabetes. Cardiac injury resulting from ischemia/reperfusion was more pronounced in PQQ- rats than in PQQ+ rats. Collectively, these data demonstrate that PQQ deficiency impacts a number of parameters related to normal mitochondrial function.

PLoS One. 2011;6(7):e21779

Pyrroloquinoline quinone prevents oxidative stress-induced neuronal death probably through changes in oxidative status of DJ-1.

Pyrroloquinoline quinone (PQQ) has been shown to play a role as an anti-oxidant in neuronal cells and prevent neuronal cell death in a rodent stroke model. DJ-1, a causative gene product for a familial form of Parkinson's disease, plays a role in anti-oxidative stress function by self-oxidation of DJ-1. In this study, the expression level and oxidation status of DJ-1 were examined in SHSY-5Y cells and primary cultured neurons treated with 6-hydroxydopamine (6-OHDA) or H(2)O(2) in the presence or absence of PQQ. The pI shift of DJ-1 to an acidic point, which was observed in SHSY-5Y cells treated with 6-OHDA, was inhibited by PQQ. TOF-MS analyses showed that while the level of a reduced form of DJ-1, one of the active forms of DJ-1, was decreased in SHSY-5Y cells treated with 6-OHDA or H(2)O(2), PQQ increased the level of the reduced form of DJ-1. These results suggest that PQQ prevents oxidative stress-induced changes in oxidative status of DJ-1. Therefore, the neuroprotective effects of PQQ on oxidative stress-induced neuronal death may be at least in part involved in increased level of an active form of DJ-1.

Biol Pharm Bull. 2008 Jul;31(7):1321-6

Pyrroloquinoline Quinone (PQQ) Prevents Cognitive Deficit Caused by Oxidative Stress in Rats.

The effects of pyrroloquinoline quinone (PQQ) and coenzyme Q(10) (Co Q(10)), either alone or together, on the learning ability and memory function of rats were investigated. Rats fed a PQQ-supplemented diet showed better learning ability than rats fed a CoQ(10)-supplemented diet at the early stage of the Morris water maze test. The combination of both compounds resulted in no significant improvement in the learning ability compared with the supplementation of PQQ alone. At the late stage of the test, rats fed PQQ-, CoQ(10)- and PQQ + CoQ(10)-supplemented diets showed similar improved learning abilities. When all the groups were subjected to hyperoxia as oxidative stress for 48 h, rats fed the PQQ- and CoQ(10) supplemented diets showed better memory function than the control rats. The concurrent diet markedly improved the memory deficit of the rats caused by oxidative stress. Although the vitamin E-deficient rats fed PQQ or CoQ(10) improved their learning function even when subjected to hyperoxia, their memory function was maintained by PQQ rather than by CoQ(10) after the stress. These results suggest that PQQ is potentially effective for preventing neurodegeneration caused by oxidative stress, and that its effect is independent of either antioxidant's interaction with vitamin E.

J Clin Biochem Nutr. 2008 Jan;42:29-34

The neuroprotective effect of pyrroloquinoline quinone on traumatic brain injury.

Pyrroloquinoline quinone (PQQ) is a water-soluble, anionic, quinonoid substance that has been established as an essential nutrient in animals. Owing to the inherent properties of PQQ as an antioxidant and redox modulator in various systems, PQQ is expected to be used in pharmacological applications in the near future. Although many recent studies have investigated its neuroprotective effects, the effect of PQQ on traumatic brain injury (TBI) has not been examined. In this study we employed Morris water maze (MWM) training, the results of which showed that PQQ led to improved behavioral performance in post-TBI animals. Considering that many experiments have suggested that β-1,4-galactosyltransferase I (β-1,4-GalT-I) and -V play significant roles in inflammation and the nervous system, in the present study we used Western blot analysis to study the effect of PQQ on the expression of β-1,4-GalT-I and -V. We found apparent expression upregulation of β-1,4-GalT-I and -V after PQQ was systemically administered. Lectin-fluorescent staining with RCA-I also revealed that PQQ contributed to expression upregulation of the galactosidase-1 (Gal -1), 4-galactosyltransferase N-acylsphingosine (4-GlcNAc) group in microglia and neurons of the cortex and hippocampal CA2 region. In summary, our experiment established that PQQ may play an important role in recovery post-TBI.

J Neurotrauma. 2012 Mar 20;29(5):851-64

Pyrroloquinoline quinone stimulates mitochondrial biogenesis through cAMP response element-binding protein phosphorylation and increased PGC-1alpha expression.

Bioactive compounds reported to stimulate mitochondrial biogenesis are linked to many health benefits such increased longevity, improved energy utilization, and protection from reactive oxygen species. Previously studies have shown that mice and rats fed diets lacking in pyrroloquinoline quinone (PQQ) have reduced mitochondrial content. Therefore, we hypothesized that PQQ can induce mitochondrial biogenesis in mouse hepatocytes. Exposure of mouse Hepa1-6 cells to 10-30 microm PQQ for 24-48 h resulted in increased citrate synthase and cytochrome c oxidase activity, Mitotracker staining, mitochondrial DNA content, and cellular oxygen respiration. The induction of this process occurred through the activation of cAMP response element-binding protein (CREB) and peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha), a pathway known to regulate mitochondrial biogenesis. PQQ exposure stimulated phosphorylation of CREB at serine 133, activated the promoter of PGC-1alpha, and increased PGC-1alpha mRNA and protein expression. PQQ did not stimulate mitochondrial biogenesis after small interfering RNA-mediated reduction in either PGC-1alpha or CREB expression. Consistent with activation of the PGC-1alpha pathway, PQQ increased nuclear respiratory factor activation (NRF-1 and NRF-2) and Tfam, TFB1M, and TFB2M mRNA expression. Moreover, PQQ protected cells from mitochondrial inhibition by rotenone, 3-nitropropionic acid, antimycin A, and sodium azide. The ability of PQQ to stimulate mitochondrial biogenesis accounts in part for action of this compound and suggests that PQQ may be beneficial in diseases associated with mitochondrial dysfunction.

J Biol Chem. 2010 Jan 1;285(1):142-52

Pyrroloquinoline quinone modulates mitochondrial quantity and function in mice.

When pyrroloquinoline quinone (PQQ) is added to an amino acid-based, but otherwise nutritionally complete basal diet, it improves growth-related variables in young mice. We examined PQQ and mitochondrial function based on observations that PQQ deficiency results in elevated plasma glucose concentrations in young mice, and PQQ addition stimulates mitochondrial complex 1 activity in vitro. PQQ-deficient weanling mice had a 20-30% reduction in the relative amount of mitochondria in liver; lower respiratory control ratios, and lower respiratory quotients than PQQ-supplemented mice (2 mg PQQ/kg diet). In mice from dams fed a conventional laboratory diet, but switched at weaning to the basal diet, plasma glucose, Ala, Gly, and Ser concentrations were elevated at 4 wk (PQQ- vs. PQQ+), but not at 8 wk. The relative mitochondrial content (ratio of mtDNA to nuclear DNA) also tended (P<0.18) to be lower (PQQ- vs. PQQ+) at 4 wk, but not at 8 wk. PQQ also counters the mitochondrial complex 1 inhibitor, diphenylene iodonium (DPI). Mice were gavaged with 0, 0.4, or 4 microg PQQ/g body weight (BW) daily for 14 d. At each PQQ level, DPI was injected (i.p.) at 0, 0.4, 0.8, or 1.6 microg DPI/g BW. The PQQ-deficient mice exposed to 0.4 or 4.0 microg DPI/g lost weight and had lower plasma glucose levels than PQQ-supplemented mice (P<0.05). In addition, fibroblasts took up (3)H-PQQ added to cell cultures, and cultured hepatocytes maintained mitochondrial PQQ concentrations similar to those observed in vivo. Collectively, these results indicate that dietary PQQ can influence mitochondrial amount and function, particularly in perinatal and weanling mice.

J Nutr. 2006 Feb;136(2):390-6

Ribose enhances retinoic acid-induced differentiation of HL-60 cells.

Ribose, a critical building block for nucleotides, plays an important role in energy metabolism, transcription, translation, and second messenger systems. This 5-carbon sugar, synthesized from glucose via the pentose phosphate pathway, has a rate-limiting step at glucose-6-phosphate dehydrogenase. Therefore, we hypothesized that when cells are required to proliferate or differentiate, as in an immune response, the requirement for D-ribose may be greater than what could be supplied by the synthetic pathway. We hypothesized that providing an exogenous source of D-ribose during cell differentiation will enhance the process of differentiation. We used a retinoic acid-induced HL-60 cell differentiation culture as a model of neutrophil maturation. The addition of 10 to 25 mmol/L D-ribose was shown to reduce cell proliferation and move the cell population toward apoptosis in a dose-dependent manner. The expression of a cell surface marker representing maturity (CD11b) significantly increased and a cell surface marker indicative of immaturity (CD117) significantly decreased. Functionally, the cells had a greater oxidative burst function dependent on time and dose. The mechanism by which ribose enhances HL-60 cell differentiation is not known; however, as adenosine triphosphate levels did not change, adenosine triphosphate is not thought to be involved. We conclude that in this cell culture model, ribose supplementation enhanced cellular differentiation and function. Thus, ribose might be conditionally essential during time of higher need as in an immune response.

Nutr Res. 2008 Nov;28(11):775-82

D-ribose improves cardiac contractility and hemodynamics, and reduces expression of c-fos in the hippocampus during sustained slow ventricular tachycardia in rats.

BACKGROUND: Moderate hypotension during hemodynamically stable ventricular tachycardia (VT), leads to cerebral ischemia. Supplementation of d-ribose has been shown to improve cardiac metabolism. We hypothesized that cerebral ischemia during slow VT may lead to the expression of immediate early genes related to neurodegeneration. This expression may be prevented by d-ribose substitution. METHODS: Slow VT was induced over 20 min by external left ventricular pacing after infusion of physiologic saline or d-ribose (450 mg/kg) in 44 rats. Different coloured microspheres were used for tissue blood flow measurements. Histochemistry of c-fos in cerebral tissue sections was performed. RESULTS: With the onset of VT, the mean arterial pressure (MAP) significantly dropped in both groups. However, the MAP in the d-ribose group was significantly higher (p<0.05) than in the control group (111+/-21 mm Hg vs. 80+/-40 mm Hg). The rate pressure product (RPP) during VT was significantly higher in the d-ribose group than in the control group (75,000 vs. 59,000, p<0.05). The occurrence of lethal VT was significantly higher in the control group and could be prevented by d-ribose. A stable activation of c-fos was observed in the control group. This ischemic stress response of the brain could not be seen after d-ribose infusion. CONCLUSION: d-ribose improves hemodynamic parameters, cardiac contractility and prevents the activation of pro-apoptotic c-fos, demonstrating a neuroprotective effect of d-ribose during slow VT.

Int J Cardiol. 2008 Mar 28;125(1):49-56

The use of D-ribose in chronic fatigue syndrome and fibromyalgia: a pilot study.

OBJECTIVES: Fibromyalgia (FMS) and chronic fatigue syndrome (CFS) are debilitating syndromes that are often associated with impaired cellular energy metabolism. As D-ribose has been shown to increase cellular energy synthesis in heart and skeletal muscle, this open-label uncontrolled pilot study was done to evaluate if D-ribose could improve symptoms in fibromyalgia and/or chronic fatigue syndrome patients. DESIGN: Forty-one (41) patients with a diagnosis of FMS and/or CFS were given D-ribose, a naturally occurring pentose carbohydrate, at a dose of 5 g t.i.d. for a total of 280 g. All patients completed questionnaires containing discrete visual analog scales and a global assessment pre- and post-D-ribose administration. RESULTS: D-ribose, which was well-tolerated, resulted in a significant improvement in all five visual analog scale (VAS) categories: energy; sleep; mental clarity; pain intensity; and well-being, as well as an improvement in patients' global assessment. Approximately 66% of patients experienced significant improvement while on D-ribose, with an average increase in energy on the VAS of 45% and an average improvement in overall well-being of 30% (p < 0.0001). CONCLUSIONS: D-ribose significantly reduced clinical symptoms in patients suffering from fibromyalgia and chronic fatigue syndrome.

J Altern Complement Med. 2006 Nov;12(9):857-62

Protective action of D-ribose against renal injury caused by ischemia and reperfusion in rats with transient hyperglycemia.

Hyperglycemia amplifies the inflammatory state after ischemia/reperfusion (I/R), and activated neutrophils have been implicated in the development of I/R-induced renal injuries. D-ribose is a naturally occurring monosaccharide found in all living cells. In this study, we examined whether D-ribose attenuates I/R-induced renal injury by reducing neutrophil activation in rats with transient hyperglycemia. Male Wistar rats were divided into sham (n = 24), control (n = 64), and D-ribose (n = 32) groups. Rats received intraperitoneal injection of glucose (3 g/kg) 30 min before induction of ischemia to induce transient hyperglycemia. Anesthetized rats underwent right nephrectomy and subsequent occlusion of the left renal artery and vein for 45 min. D-ribose (400 mg/kg) was intravenously administered 30 min before induction of ischemia. D-ribose significantly reduced the degree of the I/R-induced increases in renal concentrations of cytokine-induced neutrophil chemoattractant-1 (a chemotactic factor for the activation of neutrophils and chemotaxis to the site of injury) and myeloperoxidase (an indicator of neutrophils infiltration). D-ribose also reduced the I/R-induced increases in serum levels of blood urea nitrogen and creatinine, and improved histological changes, including acute tubular necrosis in the corticomedullary junction fields. These results indicate that D-ribose reduces the I/R-induced acute renal injury in rats with transient hyperglycemia, probably by reducing neutrophil activation. D-ribose might thus be useful for surgical procedures, such as renal transplant surgery, under hyperglycemia.

Tohoku J Exp Med. 2009 Nov;219(3):215-22

D-ribose attenuates ischemia/reperfusion-induced renal injury by reducing neutrophil activation in rats.

The ischemia/reperfusion (I/R) represents a common pathological mechanism that causes renal injuries. A monosaccharide D-allose has been shown to inhibit neutrophil activation, which is involved in the I/R-induced organ injuries. We therefore examined the role of D-ribose in the I/R-induced renal injury using a rat model. D-ribose, a monosaccharide found in all living cells, serves as a key component of adenosine-5'-triphosphate and nicotinamide adenine dinucleotide. Male Wistar rats were divided into the sham, control and D-ribose groups. In the control and D-ribose groups, rats were subjected to 45 min of left renal ischemia, followed by 24 h of reperfusion, while the I/R procedure was not performed in the sham group. Rats were intravenously administered D-ribose (sham group and D-ribose group, 400 mg/kg) or saline (control group) 30 min before ischemia. Blood urea nitrogen (BUN), serum creatinine and urinary N-acetyl beta-D-glucosaminidase (NAG) were measured as indicators of glomerular function and proximal tubular function. We also measured cytokine-induced neutrophil chemoattractant-1 (CINC-1) and myeloperoxidase concentrations to assess neutrophil activation and infiltration, respectively. The tissue sections were scored to evaluate the tubular injury. In the control group, BUN, creatinine, NAG, CINC-1, myeloperoxidase, histological severity score, and number of infiltrating neutrophils were increased following I/R insult, as compared with the sham group. Such increases in biochemical markers, severity score, and infiltrating neutrophils were significantly inhibited in the D-ribose group. Thus, D-ribose ameliorates the I/R-induced renal injury probably by inhibiting neutrophil activation, and may be useful in attenuating the renal injury associated with renal ischemia.

Tohoku J Exp Med. 2009 May;218(1):35-40

D-Ribose as a supplement for cardiac energy metabolism.

Metabolic support for the heart has been an attractive concept since the pioneering work of Sodi-Pallares et al. four decades ago.* Recently, interest has increased in the use of over-the-counter supplements and naturally occurring nutriceuticals for enhancement of cardiac and skeletal muscle performance. These include amino acids such as creatine, L-carnitine, and L-arginine, as well as vitamins and cofactors such as alpha-tocopherol and coenzyme Q. Like these other molecules, D-ribose is a naturally occurring compound. It is the sugar moiety of ATP and has also received interest as a metabolic supplement for the heart. The general hypothesis is that under certain pathologic cardiac conditions, nucleotides (particularly ATP, ADP, and AMP) are degraded and lost from the heart. The heart's ability to resynthesize ATP is then limited by the supply of D-ribose, which is a necessary component of the adenine nucleotide structure. In support of this hypothesis, recent reports have used D-ribose to increase tolerance to myocardial ischemia. Its use in patients with stable coronary artery disease improves time to exercise-induced angina and electrocardiographic changes. In conjunction with thallium imaging or dobutamine stress echocardiography, D-ribose supplementation has been used to enhance detection of hibernating myocardium. In this article, we review the biochemical basis for using supplemental D-ribose as metabolic support for the heart and discuss the experimental evidence for its benefit.

J Cardiovasc Pharmacol Ther. 2000 Oct;5(4):249-58

Assessment of Hematological and Biochemical parameters with extended D-Ribose ingestion.

D-ribose, a naturally occurring pentose carbohydrate, has been shown to replenish high- energy phosphates following myocardial ischemia and high intensity, repetitive exercise. Human studies have mainly involved short-term assessment, including potential toxicity. Reports describing adverse effects of D-ribose with prolonged ingestion have been lacking. Therefore, this study assessed the toxicity of extended consumption of D-ribose in healthy adults. Nineteen subjects ingested 20 grams/Day (10 grams, twice a Day) of ribose with serial measurements of biochemical and hematological parameters at Days 0, 7, and 14. No significant toxic changes over the 14-day assessment period occurred in complete blood count, albumin, alkaline phosphatase, gamma glutamyltransferase, alanine amiotransferase, and aspartate aminotransferase. However, D-ribose did produce an asymptomatic, mild hypoglycemia of short duration. Uric acid levels increased at Day 7, but decreased to baseline values by Day 14. D-ribose consumption for 14 days appears not to produce significant toxic changes in both hematological and biochemical parameters in healthy human volunteers.

J Int Soc Sports Nutr. 2008 Sep 15;5:13

The role of ribose on oxidative stress during hypoxic exercise: a pilot study.

Oxygen free radicals are produced during stress, are unstable, and potentially interact with other cellular components or molecules. This reactivity can influence cellular function, including a prolongation in tissue recovery following exercise. We tested the effect of ribose (d-ribose), a pentose carbohydrate, in a double-blinded, crossover study on markers of free radical production during hypoxic exercise. Seven healthy volunteers cycled at their lactate threshold for 25 minutes while inhaling 16% O(2) with a subsequent 60-minute resting period at room air. Subjects ingested either placebo or 7 g of ribose in 250 mL of water before and after the exercise session. Urinary malondialdehyde (MDA) and plasma reduced glutathione levels increased significantly during placebo ingestion (0.2 +/- 0.03 nM/mg and 0.26 +/- 0.29 microM, respectively) but were lower with ribose supplementation (0.04 +/- 0.03 nM/mg and 0.38 +/- 0.29 microM, respectively; P < .05). Uric acid levels were similar between groups (ribose vs. placebo, 4.55 +/- 0.06 mg/dL vs. 4.67 +/- 0.06 mg/dL). Ribose demonstrated a beneficial trend in lower MDA and reduced glutathione levels during hypoxic stress.

J Med Food. 2009 Jun;12(3):690-3

Effects of ribose on exercise-induced ischaemia in stable coronary artery disease.

There is no established treatment specifically aimed at protecting or restoring cardiac energy metabolism, which is greatly impaired by ischaemia. Even after reperfusion, myocardial content of ATP remains low for more than 72 h. Long-term post-ischaemic dysfunction and irreversibility of ischaemic damage have been associated with low ATP content. Evidence that the pentose sugar ribose stimulates ATP synthesis and improves cardiac function led us to test the possibility that ribose increases tolerance to myocardial ischaemia in patients with coronary artery disease (CAD). 20 men with documented severe CAD underwent two symptom-limited treadmill exercise tests on 2 consecutive days; we postulated that the ischaemia induced might bring about changes in ATP metabolism lasting for several days. Patients whose baseline tests showed reproducibility were randomly allocated 3 days of treatment with placebo or ribose 60 g daily in four doses by mouth. Exercise testing was repeated after treatment on day 5. At that time mean (95% confidence interval) treadmill walking time until 1 mm ST-segment depression was significantly greater in the ribose than in the placebo group (276 [220-331] vs 223 [188-259] s; p = 0.002). The groups did not differ significantly in time to moderate angina. In the ribose-treated group the changes from baseline to day 5 in both time to ST depression and time to moderate angina were significant (p less than 0.005), but these changes were not significant in the placebo group. In patients with CAD, administration of ribose by mouth for 3 days improved the heart's tolerance to ischaemia. The presumed effects on cardiac energy metabolism offer new possibilities for adjunctive medical treatment of myocardial ischaemia.

Lancet. 1992 Aug 29;340(8818):507-10

Prevalence and burden of overactive bladder in the United States.

CONTEXT: The National Overactive BLadder Evaluation (NOBLE) Program was initiated to better understand the prevalence and burden of overactive bladder in a broad spectrum of the United States population. OBJECTIVE: To estimate the prevalence of overactive bladder with and without urge incontinence in the US, assess variation in prevalence by sex and other factors, and measure individual burden. DESIGN: US national telephone survey using a clinically validated interview and a follow-up nested study comparing overactive bladder cases to sex- and age-matched controls. SETTING: noninstitutionalized US adult population. PARTICIPANTS: a sample of 5,204 adults >/=18 years of age and representative of the US population by sex, age, and geographical region. MAIN OUTCOME MEASURES: prevalence of overactive bladder with and without urge incontinence and risk factors for overactive bladder in the US. In the nested case-control study, SF-36, CES-D, and MOS sleep scores were used to assess impact. RESULTS: the overall prevalence of overactive bladder was similar between men (16.0%) and women (16.9%), but sex-specific prevalence differed substantially by severity of symptoms. In women, prevalence of urge incontinence increased with age from 2.0% to 19% with a marked increase after 44 years of age, and in men, increased with age from 0.3% to 8.9% with a marked increase after 64 years of age. Across all age groups, overactive bladder without urge incontinence was more common in men than in women. Overactive bladder with and without urge incontinence was associated with clinically and significantly lower SF-36 quality-of-life scores, higher CES-D depression scores, and poorer quality of sleep than matched controls. CONCLUSIONS: the NOBLE studies do not support the commonly held notion that women are considerably more likely than men to have urgency-related bladder control problems. The overall prevalence of overactive bladder does not differ by sex; however, the severity and nature of symptom expression does differ. Sex-specific anatomic differences may increase the probability that overactive bladder is expressed as urge incontinence among women compared with men. Nonetheless, overactive bladder, with and without incontinence, has a clinically significant impact on quality-of-life, quality-of-sleep, and mental health, in both men and women.

World J Urol. 2003 May;20(6):327-36

The overactive bladder and quality of life.

Overactive bladder (OAB) affects 16.6% of the U.S. population, or 33 million adults, in some form. Despite the prevalence of OAB, almost 60% of those affected seek no medical assistance for the condition either because of embarrassment or the misconception that it represents an inevitable function of aging. A recent surge of interest on the subject has uncovered the dramatic effect that OAB can have on social interactions, sleep, depression, sexual health, and overall health-related quality of life (HRQoL). The introduction of validated, condition-specific QOL questionnaires has enhanced our ability to measure these subjective dimensions of OAB, and to assess their response to therapeutic interventions.

Int J Fertil Womens Med. 2005 Jan-Feb;50(1):30-6

Protein-source tryptophan as an efficacious treatment for social anxiety disorder: a pilot study.

Until recently, intact protein that is rich in tryptophan was not seen as an alternative to pharmaceutical-grade tryptophan because protein also contains large neutral amino acids (LNAAs) that compete for transport sites across the blood-brain barrier. Recent evidence indicates that when deoiled gourd seed (a rich source of tryptophan with approximately 22 mg/g protein) is combined with glucose (a carbohydrate that reduces serum levels of competing LNAAs) a clinical effect similar to that of pharmaceutical-grade tryptophan is achieved. Objective and subjective measures of anxiety in those suffering from social phobia (also known as social anxiety disorder) were employed to measure changes in anxiety in response to a stimulus as part of a double-blind, placebo-controlled, crossover study with a wash-out period of 1 week between study sessions. Subjects were randomly assigned to start with either (i) protein-source tryptophan (deoiled gourd seed) in combination with carbohydrate or (ii) carbohydrate alone. One week after the initial session, subjects returned for a follow-up session and received the opposite treatment of that received at the first session. All 7 subjects who began the study completed the 2-week protocol. Protein-source tryptophan with carbohydrate, but not carbohydrate alone, resulted in significant improvement on an objective measure of anxiety. Protein-source tryptophan combined with a high glycemic carbohydrate is a potential anxiolytic to those suffering from social phobia.

Can J Physiol Pharmacol. 2007 Sep;85(9):928-32

Effect of pumpkin-seed oil on the level of free radical scavengers induced during adjuvant-arthritis in rats.

Pumpkin-seed oil (PSO), a natural supplement rich with antioxidant ingredients, was given to rats in which arthritis was induced using Freund's complete adjuvant. Its effect was compared with that of indomethacin, as a classical anti-inflammatory agent. Two experimental patterns were studied, an acute phase that was applied only with PSO and a chronic phase applied for both PSO and indomethacin. Compared to normal untreated rats, it was shown that the induction of arthritis caused a decrease in serum sulphhydryl groups, with an increase in serum ceruloplasmin in both phases. Blood glutathione was first elevated in the acute phase, then its level was reduced in the chronic phase. Serum N-acetyl-beta-D-glucosaminidase activity was elevated only at the acute phase, while plasma total proteins and albumin were reduced at the chronic phase. Liver glucose-6-phosphate dehydrogenase activity was markedly increased, while no changes were observed in the levels of liver lipid peroxides and glutathione. These changes in the studied parameters were attributed to the superoxides and free radicals during arthritic inflammation. Administration of PSO succeeded in modulating most of the altered parameters affected during arthritis, especially at the chronic phase. Also, a remarkable inhibition of paw oedema was observed. A similar pattern was obtained upon treatment with indomethacin except that indomethacin markedly elevated liver lipid peroxides levels. Concurrent administration of PSO with indomethacin caused no changes in the parameters studied compared to that induced by treatment with indomethacin alone.

Pharmacol Res. 1995 Jan;31(1):73-9

Increased incidence of fractures in middle-aged and elderly men with low intakes of phosphorus and zinc.

The aim of the study was to determine dietary risk factors for fracture in men aged 46-68 years. Six thousand five hundred and seventy-six men were randomly invited using the Municipal Registry to a diet and health study. The diet was assessed using a combined 7-day menu book for hot meals, beverages and dietary supplements and a quantitative food frequency questionnaire for other foods. The fracture incidence was 103/10,000 person-years during a mean follow-up of 2.4 years. Zinc and phosphorus intake were associated with fracture risk and showed a threshold effect. The zinc intake in the lowest decentile, 10 mg daily, was associated with almost a doubled risk of fracture compared with the fourth and fifth quintiles (RR = 0.47; 95% confidence interval, 27-82) of zinc intake adjusted for energy, previous fractures, lifestyle factors and co-morbidity. Energy-adjusted phosphorus intake in the lowest quintile, mean level 1357 mg, was associated with an increased fracture risk compared with subjects in the second quintile. Smoking, martial status and physical activity were independently associated with fracture risk. Calcium, retinol and vitamin D showed no associations with fracture risk. We conclude that inadequate intakes of zinc and phosphorus are important risk factors for fracture.

Osteoporos Int. 1998;8(4):333-40

Magnesium intake from food and supplements is associated with bone mineral density in healthy older white subjects.

OBJECTIVES: To determine whether magnesium intake from supplemental and dietary sources is associated with bone mineral density (BMD) in older men and women. DESIGN: Cross-sectional. SETTING: Memphis, Tennessee, and Pittsburgh, Pennsylvania. PARTICIPANTS: Two thousand thirty-eight older black and white men and women aged 70 to 79 at baseline enrolled in the Health, Aging and Body Composition Study. MEASUREMENTS: Dietary intake of magnesium was assessed using a semiquantitative food frequency questionnaire, and supplement data were collected based on a medication inventory. BMD of the whole body was obtained using a fan-beam densitometer. Additional covariates included age, body mass index (BMI), smoking status, alcohol use, physical activity, estrogen use, and supplemental calcium (Ca) and vitamin D use. RESULTS: In white, but not black, men and women, magnesium intake was positively associated with BMD of the whole body after adjustment for age, self-report of osteoporosis or fracture in adulthood, caloric intake, Ca and vitamin D intake, BMI, smoking status, alcohol intake, physical activity, thiazide diuretic use, and estrogen use in women (P=.05 for men and P=.005 for women). BMD was 0.04 g/cm2 higher in white women and 0.02 g/cm2 higher in white men in the highest than in the lowest quintile of magnesium intake. CONCLUSION: Greater magnesium intake was significantly related to higher BMD in white women and men. The lack of association observed in black women and men may be related to differences in Ca regulation or in nutrient reporting.

J Am Geriatr Soc. 2005 Nov;53(11):1875-80

Improvement in HDL cholesterol in postmenopausal women supplemented with pumpkin seed oil: pilot study.

OBJECTIVE: Pumpkin seed oil is rich in phytoestrogens and animal studies suggest that there is some benefit to supplementation in low estrogen conditions. This study is the first to evaluate the benefit of pumpkin seed oil in postmenopausal women. METHODS: This pilot study was randomized, double-blinded and placebo-controlled. Study participants included 35 women who had undergone natural menopause or had iatrogenically entered the climacteric due to surgery for benign pathology. Wheat germ oil (placebo; n = 14) and pumpkin seed oil (n = 21) were administered to eligible participants over a 12-week period at a dose of 2 g per day. Serum lipids, fasting plasma glucose and blood pressure were measured and an 18-point questionnaire regarding menopausal symptoms was administered; the atherogenic index was also calculated. Differences between groups, as well as before and after the period of supplementation, were evaluated with Student's t-test, Wilcoxon matched-pair signed-ranked test and Mann-Whitney test, as appropriate (Stata version 10.1). RESULTS: Women receiving pumpkin seed oil showed a significant increase in high density lipoprotein cholesterol concentrations (0.92 ± 0.23 mmol/l vs. 1.07 ± 0.27 mmol/l; p = 0.029) and decrease in diastolic blood pressure (81.1 ± 7.94 mmHg vs. 75.67 ± 11.93 mmHg; p < 0.046). There was also a significant improvement in the menopausal symptom scores (18.1 ± 9.0 vs. 13.2 ± 6.7; p < 0.030), with a decrease in severity of hot flushes, less headaches and less joint pains being the main contributors. Women in the group receiving wheat germ oil reported being more depressed and having more unloved feeling. CONCLUSION: This pilot study showed pumpkin seed oil had some benefits for postmenopausal women and provided strong evidence to support further studies.

Climacteric. 2011 Oct;14(5):558-64. Epub 2011 May 5

Phytosterol composition of nuts and seeds commonly consumed in the United States.

Phytosterols were quantified in nuts and seeds commonly consumed in the United States. Total lipid extracts were subjected to acid hydrolysis and then alkaline saponfication, and free sterols were analyzed as trimethylsilyl derivatives by capillary GC-FID and GC-MS. Delta5-Avenasterol was quantified after alkaline saponification plus direct analysis of the glucoside. Sesame seed and wheat germ had the highest total phytosterol content (400-413 mg/100 g) and Brazil nuts the lowest (95 mg/100 g). Of the products typically consumed as snack foods, pistachio and sunflower kernel were richest in phytosterols (270-289 mg/100 g). beta-Sitosterol, Delta5-avenasterol, and campesterol were predominant. Campestanol ranged from 1.0 to 12.7 mg/100 g. Only 13 mg/100 g beta-sitosterol was found in pumpkin seed kernel, although total sterol content was high (265 mg/100 g). Phytosterol concentrations were greater than reported in existing food composition databases, probably due to the inclusion of steryl glycosides, which represent a significant portion of total sterols in nuts and seeds.

J Agric Food Chem. 2005 Nov 30;53(24):9436-45

Micellar distribution of cholesterol and phytosterols after duodenal plant stanol ester infusion.

Properties of the intestinal digestion of the dietary phytosterols, cholesterol and cholestanol, and the mechanisms by which phytosterols inhibit the intestinal absorption of cholesterol in healthy human subjects are poorly known. We have studied the hydrolysis of dietary plant sterol and stanol esters and their subsequent micellar solubilization by determining their concentrations in micellar and oil phases of the jejunal contents. Two liquid formulas with low (formula 1) and high (formula 2) plant stanol concentrations were infused via a nasogastric tube to the descending duodenum of 8 healthy human subjects, and intestinal contents were sampled for gas-liquid chromatographic sterol analysis 60 cm more distally. During the duodenal transit, phytosterol esters were hydrolyzed. This was especially profound for sitostanol, as its esterified fraction per milligram of sitosterol decreased 80% (P < 0.001) in formula 1 and 61% (P < 0.001) in formula 2. Contrary to that, esterified fraction of cholesterol per milligram of sitosterol was increased fourfold (P < 0.001) in formula 1 and almost sixfold (P < 0.001) in formula 2, whereas that of cholestanol remained unchanged. Percentages of esterified sterols and stanols in total intestinal fluid samples were higher after the administration of formula 2 than of formula 1. Esterified cholesterol and stanols accumulated in the oil phase, and free stanols replaced cholesterol in the micellar phase. At high intestinal plant stanol concentrations, cholesterol looses its micellar solubility possibly by replacement of its free fraction in the micellar phase by hydrolyzed plant stanols, which leads to a decreased intestinal absorption of cholesterol.

Am J Physiol Gastrointest Liver Physiol. 2002 Jun;282(6):G1009-15