Leading scientists, researchers, and nutritionists recently gathered for a day-long confer-ence in London on the nutrient lycopene’s applications in promoting health and preventing disease. Conference presenters highlighted lycopene’s role in protecting the skin, reducing heart disease risk, and supporting prostate health.
Dr. Joseph Levy of Israel’s Ben-Gurion University presented evidence that lycopene and other tomato-derived carotenoids protect against ultraviolet (UV) radiation. Dr. Levy found that supplementing human subjects with a tomato paste containing lycopene helped protect against skin erythema, or sunburn. In another study, Dr. Levy demonstrated that tomato-based products are twice as protective as synthetic lycopene against UV-induced sunburn reactions. According to Dr. Levy, caro-tenoids like lycopene work by stimulating an “antioxidant response element” in the body that protects against carcinogens and other harmful compounds.
Prof. Michael Aviram of the Technion-Israel Institute of Technology presented evidence that lycopene is effective in preventing heart disease. Prof. Aviram believes carotenoids may act as inhibitors of cholesterol synthesis. Six healthy males who took 60 mg of lycopene daily for three months demonstrated significantly re-duced serum cholesterol levels by the study’s end. Prof. Aviram stated that the combination of natural antioxidants found in tomato paste may be superior to individual antioxidants in protecting LDL (low-density lipoprotein) against oxidation and thus reducing cardiovascular disease risk.
Neil Barber of King’s College Hospital in London discussed lycopene’s role in protecting prostate health. In a trial of 42 patients who had been diagnosed with prostate cancer but were not receiving treatment, subjects were given 10 mg of lycopene daily and their prostate-specific antigen (PSA) levels were measured each month. The subjects’ levels of PSA (a marker of prostate cancer progression) fell by 21% after supplementing with lycopene. Barber noted that lycopene administration may allow patients to play a proactive role in fighting prostate cancer.
Mixed vitamin E tocopherols may offer greater protection against Alzheimer’s disease than vitamin E alone, according to a recent report in the American Journal of Clinical Nutrition.*
The vitamin E family consists of four tocopherols and four tocotrienols. Alpha tocopherol is the most common form of vitamin E found in dietary supplements, while gamma tocopherol is the most prevalent form in food. Researchers have previously noted that vitamin E from food sources, but not from supplements, is associated with a reduced risk of Alzheimer’s.
In a six-year study examining community residents aged 65 and older, the participants completed food frequency questionnaires and underwent cognitive tests and clinical evaluation for Alzheimer’s disease. Higher intakes of vitamin E and alpha tocopherol equivalents were found to decrease the incidence of Alzheimer’s. With each 5 mg-per-day increase in dietary tocopherols, subjects had a 26-44% lower risk of developing Alzheimer’s. Alpha tocopherol and gamma tocopherol were independently associated with Alzheimer’s risk. Increased intake of vitamin E also provided protection against cognitive decline.
The study results underscore the importance of daily supplementation with vitamin E and indicate that mixed vitamin E tocopherols may offer greater protection against common diseases of aging such as Alzheimer’s than alpha tocopherol alone.
—Elizabeth Wagner, ND
* Morris MC, Evans DA, Tangney CC, et al. Relation of tocopherol forms to incident Alzheimer disease and to cognitive change. Am J Clin Nutr. 2005 Feb;81(2):508-14.
Italian researchers report that folate and vitamin B12 improve three cardiovascular risk factors in patients with pre-diabetes.*
Endothelial dysfunction, insulin resistance, and elevated homocysteine all increase risk for heart disease. Insulin resistance occurs with the cluster of disorders called metabolic syndrome, the precursor to diabetes. Researchers have long known that folate and vitamin B12 reduce cardiovascular disease risk by lowering homocysteine levels. The Italian study showed that in patients with metabolic syndrome, folate and B12 help reduce two other cardiovascular risk factors: endothelial dysfunction and insulin resistance.
In this double-blind study, 50 patients with metabolic syndrome were randomly assigned to either a placebo group or supplement group. Both groups took a placebo for one month. The placebo group then received the placebo for an additional month, while the supplement group received 5000 mcg of folate and 500 mcg of vitamin B12 daily. After just one month of folate and B12 supplementation, homocysteine levels decreased by nearly 30% in the supplemented group. Insulin levels decreased significantly in the supplement group as well, indicating an improvement in insulin resistance. Endothelial function also improved markedly in the supplemented group.
The finding that folate and vitamin B12 reduce three risk factors of cardiovascular disease in those with metabolic syndrome is of enormous importance, as these individuals are at much greater risk for both diabetes and cardiovascular disease. It also suggests that folate and vitamin B12 may help prevent diabetes by improving insulin resistance.
—Linda M. Smith, RN
* Setola E, Monti LD, Galluccio E, et al. Insulin resistance and endothelial function are improved after folate and vitamin B12 therapy in patients with metabolic syndrome: relationship between homocysteine levels and hyperinsulinemia. Eur J Endocrinol. 2004 Oct;151(4):483-9.
Green tea polyphenols inhibit markers of prostate cancer risk and progression in an animal model, according to scientists at the University of Wisconsin.*
Epidemiological evidence has found that abundant intake of green tea is associated with reduced risk of prostate cancer. The Wisconsin study findings further elucidate green tea’s protective role. In their study, researchers administered green tea polyphenols to transgenic mice for six months, while monitoring levels of insulin-like growth factor 1 (IGF-1) and IGF binding protein, as well as markers of cancer metastasis (spread) and angiogenesis (new blood vessel formation, which occurs in disease states such as cancer).
Mice receiving the green tea polyphenols demonstrated a substantial reduction in IGF-1 and an increase in IGF binding protein. Elevated levels of IGF-1 and decreased levels of IGF binding protein have been linked with a greater risk of prostate cancer development and progression. Green tea polyphenols also inhibited markers of metastasis and angiogenesis, which are involved in the spread and progression of cancer.
Through modulating numerous markers of cancer risk, progression, and metastasis, green tea polyphenols appear to offer broad-spectrum protection against prostate cancer. The dose of green tea polyphenols used in the mouse study is roughly equivalent to human consumption of six cups of green tea daily.
—Linda M. Smith, RN
* Adhami VM, Siddiqui IA, Ahmad N, Gupta S, Mukhtar H. Oral consumption of green tea polyphenols inhibits insulin-like growth factor-I-induced signaling in an autochthonous mouse model of prostate cancer. Cancer Res. 2004 Dec 1;64(23):8715-22