What's Hot Archive
April 29, 2005
Long term vitamin E use associated with slower cataract development
The April 2005 issue of the American Medical Association journal, Archives of Opthalmology (http://archopht.ama-assn.org/) published the findings of researchers from Tufts and Harvard Universities in Boston that long term use of vitamin E supplements and an increased intake of the B vitamins thiamin and riboflavin are associated with a reduction in the progression of cataracts.
The researchers analzyed data from 408 participants in the Nurses' Health Study, who were between the ages 52 to 74. Nutrient intake was determined from food frequency questionnaires, including questionnaires which inquired about supplement use, that were completed by the participants over a 13 to 15 year period prior to their initial eye examinations. Follow-up eye examinations were conducted after five years to measure changes in lens opacities.
The association of cataract development with B vitamins thiamin, riboflavin and niacin, vitamins C and E, and the carotenoids was evaluated. Duration of vitamin E supplement use was found to be inversely associated with the increase in opacities observed after five years. Women whose intake of thiamin and riboflavin was the highest also experienced reduced progression of opacities. Niacin additionally appeared to have an effect, although it was smaller than that of the other B vitamins.
The findings concerning vitamin E are consistent with prior studies which documented an association between vitamin E supplement use and a lower risk of cataracts. Based on the current findings, the authors conservatively estimate that the long term use of vitamin E supplements would delay the progression of cataracts by five months per year compared to those who did not use supplements, a difference that would become substantial over a longer period of time.
April 27, 2005
Garlic ingredient delivers death to cancer cells
The February 2005 issue of the journal Molecular Cancer Therapeutics (http://mct.aacrjournals.org/) published the discovery of researchers at the Weizmann Institute of Science in Israel of a way to deliver allicin, a compound present in freshly crushed garlic, to cancer cells for their destruction. Allicin is formed by a reaction between the enzyme alliinase and alliin. The compound readily penetrates biological membranes to kill cancer cells, but the molecules are potent for only a short period of time, prompting the team to devise system for long term delivery.
The research team, led by Professor David Mirelman, attached alliinase to an antibody used in cancer treatment known as Rituximab, which marks tumors for destruction by the body's own immune system. When injected into mice implanted with human lymphoma cells, the drug bound itself to the target cancer cells. The researchers then injected alliin, which combined with the alliinase to form allicin on the cancerous cells' surface, resulting in the programmed cell death of almost all of the lymphoma cells within three days. A control group of mice who received Rituximab and alliinase alone experienced only a slight amount of cancer cell destruction.
Dr Mirelman calls the method "weaponizing" an antibody, because the antibody drug docks on the targeted cell and continuously reacts with the alliin molecules which are periodically injected. This allows a steady supply of allicin to reach the cancer cells and destroy them.
Dr Mirelman stated, "The medicinal value of garlic is no longer an ancient Chinese secret. Years of scientific research led to the identification and understanding of allicin's mode of activity and we are currently studying ways to target and deliver its toxic punch."
April 25, 2005
Tea inhibits diabetic cataract in animal model
A report that will be appearing in the May 4 2005 issue of the Journal of Agricultural and Food Chemistry, announced the findings of Joe A. Vinson, PhD and Juan Zhang of the University of Scranton that green and black tea both help prevent cataracts in diabetic rats. Dr Vinson, who is the lead author of the report, commented, "Most people, scientists included, believe that green tea has more health benefits than black tea." Previous research conducted by Dr Vinson found that green and black tea are equally effective at inhibiting atherosclerosis, which is one of cardiovascular disease's major risk factors.
The researchers induced type 1 diabetes in 25 rats, and dvided them to receive green tea, black tea, or no tea for three months. An additional eight rats without diabetes were used as controls. The amount of tea the animals received was equivalent to less than five cups of tea per day for a human. Blood samples were analyzed before and after the treatment period for glucose, sorbitol, protein, oxidative damage, glycation, cholesterol and triglycerides.
All diabetic animals were found to have significantly elevated glucose in the lenses of their eyes and in blood plasma at the study's conclusion. Cataract formation was significantly reduced in the lenses of the rats who receieved both green and black tea compared to the rats who did not receive tea. It was determined that green and black tea retarded the development of cataracts by lowering glucose, which affects pathways that increase diabetic complications, including cataracts. The reduction in glucose of 28 to 32 percent in rats who were given tea was comparable to the 29 percent reduction associated with tea drinking in a human diabetic study.
The authors recommend, "Teas should be investigated further for possible prevention therapy and adjunct therapy in human diabetes."
April 22, 2005
Selenium's role in prostate cancer prevention defined
In yet another important study reported on April 20 at the 96th Annual Meeting of the American Association for Cancer Research, Vladimir M Kolenko MD of Fox Chase Cancer Center in Philadelphia announced that his team is closer to defining selenium's role in prostate cancer cell suicide. They found that that the mineral helps cancerous cells overcome their resistance to self-inflicted cell death known as apoptosis induced by TRAIL, an agent under investigation as a new cancer drug that some malignant cells have demonstrated resistance to.
Dr Kolenko and colleagues tested a selenium metabolite known as methylseleninic acid (MSA) on androgen dependent and androgen independent prostate cancer cell lines treated with TRAIL, and assayed DNA fragmentation, a measure of apoptosis. Other androgen dependent and independent cancer cells were treated with methylselninic acid or TRAIL alone.
After 24 hours, treatment of prostate cancer cells with TRAIL alone did not result in a significant amount of cell death in either cells, and treatment with methylseleninic acid only induced a "notable" amount of apoptosis in the androgen independent cells. However, both androgen dependent and independent cancer cells treated with combined TRAIL and MSA were found to have undergone a significant amount of apoptosis. Dr Kolenko concluded, "Taken together our data reveal a potential mechanism for the synergistic effect of TRAIL and MSA on the induction of apoptosis in prostate cancer cells. The combination of TRAIL and MSA may be a novel strategy for the development of innovative therapeutic modalities targeting apoptosis-resistant forms of prostate cancer."
He added, "Selenium and vitamin E are the most promising dietary supplements considered for use in the reduction of prostate cancer risk. This enthusiasm is reflected in the initiation of the large National Cancer Institute sponsored trial - SELECT (Selenium and Vitamin E Chemoprevention Trial). "
April 20, 2005
Broccoli, red chili compounds inhibit cancer cell growth
At the annual meeting of the American Association for Cancer Research held April 16 to 20 in Anaheim, California, Sanjay K Srivastava of the University of Pittsburgh reported that capsaicin from red chilies and a compound derived from broccoli have an anticancer action in vitro.
Dr Srivastava's team treated human pancreatic cancer cells with capsaicin, an ingredient in chilies that has an antioxidant and anti-inflammatory action. They discovered that capsaicin disrupted the mitochondrial function of the cancerous cells which led to apoptosis (programmed cell death), while not affecting healthy cells. In a second study, the team tested the effects of phenethyl isothiocyanate, a compound found in cruciferous vegetables such as broccoli, on ovarian cancer cells. After twenty-four hours of exposure to isothiocyanate, the cancerous cells exhibited a reduction in the protein expression of epidermal growth factor, which is crucial for their growth. Isothiocyanate also inhibited Akt, which protects cancer cells from apoptosis. The amount of isothiocyanate used in the study could reasonably be obtained by adding cruciferous vegetables to the diet.
Dr Srivastava, who is an assistant professor at the University of Pittsburgh School of Medicine's department of pharmacology, noted, "In our studies, we decided to look at two particular cancers – ovarian and pancreatic – with low survival rates, to ascertain the contribution of diet and nutrition to the development of these cancers. We discovered that red chili pepper and broccoli appear to be effective inhibitors of the cancer process. The contribution of diet and nutrition to cancer risk, prevention and treatment has been a major focus of research in recent years because certain nutrients in vegetables and dietary agents appear to protect the body against diseases such as cancer."
April 18, 2005
Vitamin D levels predict successful lung surgery outcome
At the 96th Annual Meeting of the American Association for Cancer Research held in Anaheim, California this month, Wei Zhou of the Harvard School of Public Health presented the findings of a team led by Professor David Christiani MD, also of Harvard, that successful outcomes of early stage lung cancer surgery are dependent upon vitamin D levels. Vitamin D sources include food, supplements and sunlight which is greater during the summer.
The team investigated data from 456 patients who had received surgery for early stage non-small cell lung cancer. Outcome based on vitamin D intake as assessed from dietary questionnaire results, and outcome based on the season during which the surgery was performed as an indicator of the amount of vitamin D received from sunlight were separately calculated.
Dr Christiani and colleagues discovered that lung cancer patients who had their surgery during summer months were twice as likely to have survived in the five years following the operation compared to those who had their surgery during winter. Overall survival and disease-free survival were both greater in patients who had surgery during summer, with those whose surgery was during the spring or autumn falling between summer and winter in their survival rates. When data concerning seasonal outcome was combined with data concerning vitamin D levels, subjects with the highest vitamin D intake whose surgery occurred during the summer months experienced a three-fold greater disease-free survival and a four-fold improved overall survival compared to those whose surgery occurred during winter and who had the lowest vitamin D intake.
Dr Zhou cautioned, "This study in no way suggests that people should try to time their cancer surgeries for a particular season - that would obviously be impossible. But, if validated, it may mean that increasing a patient's use of vitamin D before such surgery could offer a survival benefit."
April 15, 2005
CoQ10 and vitamin E improve symptoms of movement disorder
The April 2005 issue of the American Medical Association journal Archives of Neurology (http://archneur.ama-assn.org/) published the findings of researchers in England that a combination of the antioxidant nutrients coenzyme Q10 and vitamin E appears to slow the progression of Friedreich ataxia, an inherited disease characterized by progressive difficulty in movement, loss of sensation, skeletal abnormalities and enlargement of the heart. A reduced energy supply may be an early event in the disease. Increased oxidative damage has also been observed, which may further increase with the progression of the disorder.
In the current study, ten patients with genetically confirmed Friedreich ataxia were administered 525 international units vitamin E and 200 milligrams coenzyme Q10 twice per day for over 47 months. Blood tests were conducted periodically during the trial to monitor the participants' serum levels of the nutrients. Neurologic assessments, electrocardiograms, and magnetic resonance spectroscopy of cardiac and skeletal muscle were also periodically conducted during the study and at its completion. Data from 77 patients with the Friedreich ataxia that allowed the researchers to predict the clinical course of the disease was used for comparison.
At the study's conclusion, it was determined that treatment with coenzyme Q10 and vitamin E improved mitochondrial energy synthesis. This was associated with a slowing of some features of the disease, such as kinetic scores, although posture and gait continued to deteriorate. Heart function also significantly improved. The authors recommend a larger randomized trial to confirm whether antioxidant treatment should be initiated to prevent the progression of Friedreich ataxia in its early stage.
April 13, 2005
Fish oil beats statins for lowering mortality risk
The April 11 2005 issue of Archives of Internal Medicine published a review of the effects of various lipid lowering regimens on overall mortality and mortality from coronary heart disease. Researchers from Basel Institute for Clinical Epidemiology and University Hospital in Basel, Switzerland reviewed 97 clinical trials published between 1965 and 2003 that included 137,140 men and women being treated and 138,976 control subjects. The current analysis compared the association with mortality risk of diet, lipid lowering drugs categorized as statins, fibrates and resins, and the nutritional supplements omega-3 fatty acids (commonly found in fish oils) and niacin.
While the fibrate class of drugs failed to influence overall mortality and mildly elevated noncardiac mortality, and while diet, resins and niacin appeared to provide insignificant benefits, statins and omega-3 fatty acids signifcantly lowered both overall and coronary heart disease mortality risk during the trial periods. The risk of overall mortality was reduced by 13 percent by statins and 23 percent by omega-3 fatty acids compared to the risk experienced by those who did not receive treatment. When the risk of mortality from heart disease alone was analyzed, the use of statin drugs and omega-3 fatty acids were found to lower the risk by 22 and 32 percent, respectively.
The superiority of omega-3 acids in lowering the risk of overall and cardiac mortality cannot be explained by an ability to reduce cholesterol, which averaged 2 percent in this meta-analysis compared to an average reduction of 20 percent acheived via the use of statins. The protection provided by omega-3 fatty acids against heart arrhythmias, along with their antithrombotic and anti-inflammatory properties may be responsible for the mortality risk reduction suggested by this review.
April 11, 2005
Fish and soy oil provide short as well as long term heart benefits
The April 2005 issue of the journal Chest (http://www.chestjournal.org/) has found that supplementation with soy or fish oil benefitted the heart in a matter of weeks. Fish oil and soy contain omega-3 fatty acids, which have been shown to provide cardiovascular benefits when consumed long term.
Researchers from Atlanta, Boston, and Cuernavaca, Mexico, divided 58 older patients to receive 2 grams fish oil or 2 grams soy oil for 11 weeks. Heart rate variability (HRV), which is a measure of cardiac autonomic function, was assessed every other day for two months prior to the study to established a baseline for each participant. Greater variability between beats reduces the risk of arrhythmia with its possibility of sudden death.
At the study's conclusion, both groups of participants experienced a significant increase in heart rate variability, but those who received fish oil experienced an increase after only 2.7 weeks compared to 8.1 weeks for the soy oil group. Lead author Fernando Holguin, MD, of Emory University School of Medicine in Atlanta, commented, "Our findings contradict the current belief in the medical community that increasing the intake of omega-3 fatty acids produces only long-term cardiac benefits. In fact, our study group showed improvements in heart function in as little as two weeks."
He added, "Reduced HRV predicts mortality and arrhythmic complications in patients who have had a heart attack, as well as those who are considered healthy. Taking a daily supplement of fish or soy oil may help reduce the risk of suffering an adverse cardiovascular event, such as arrhythmia or sudden death, specially in persons with known cardiovascular disease or at increased risk for it, such as those with lipid disorders, advanced age, hypertension, a history of smoking, and family history of heart disease."
April 8, 2005
Live longer on the Mediterranean diet
On April 7 2005, the British Medical Journal (http://bmj.bmjjournals.com/) published online the findings of researchers from the University of Athens Medical School that adherence to the Mediterranean diet is linked with a longer life. The diet is characterized by a greater than average intake of vegetables, fruit, legumes, and grains; a moderate to high intake of fish; reduced amounts of saturated fats and a greater intake of unsaturated fats, particularly from olive oil; a lower proportion of meat and dairy products; and a modest amount of alcoholic beverages, mainly consisting of wine.
The researchers analyzed data from 74,607 participants in the European Prospective Investigation into Cancer and nutrition study (EPIC). Subjects were 60 years of age or more, and were recruited from 1992 to 2000 at 23 centers in Denmark, France, Germany, Greece, Italy, the Nehterlands, Norway, Spain, Sweden and Great Britain. Information on diet, lifestyle, medical history and physician activity was obtained via questionnaires completed by the participants. Follow up continued through 2003.
Diets were assigned values from 0 to 9 according to their degree of adherence to the Mediterranean diet. A higher dietary score was associated with a lower death rate, particiularly in Greece and Spain. An increase of 2 points in dietary scores corresponded with an 8 percent reduction in mortality. According to this analysis, a man aged 60 with a high dietary score could expect to live a year longer than a similarly aged man who did not consume the Mediterranean diet.
In their discussion of the findings, the authors emphasize, "The important point is that a diet that can be operationalized does have a relation with mortality, and that realistically achievable changes in diet--for example, 3 or 4 point increments--are associated with a reduction of total mortality by 11% or 14%, respectively."
April 6, 2005
Cranberries improve blood vessel function
The 35th Congress of the International Union of Physiological Sciences held in San Diego was the site of a presentation by Kris Kruse-Elliott of the University of Wisconsin-Madison School of Veterinary Medicine on the ability of cranberries to improve the ability of blood vessels to relax in an animal model of familial high cholesterol, which causes atherosclerosis. Recent research has found that cranberries contain antioxidants, flavonoids and polyphenols that may be protective against heart disease. Dr Kruse Elliott presented her findings on April 3 2005.
One group of pigs bred to have high cholesterol were fed 150 grams per kilogram cranberry juice powder from whole cranberries for six months, while another group did not receive the powder. At the study's conclusion, it was found that the blood vessels of the pigs who received cranberries were more like those of normal pigs, while those who did not receive cranberry powder had significantly less vascular relaxation than normal or cranberry-fed pigs.
Dr Kruse-Elliott commented, "Since the abnormal functioning of blood vessels is an important component of heart disease, finding ways to improve vascular function in patients with high cholesterol and atherosclerosis is critical to helping protect these patients from consequences such as heart attack or stroke. The value of fruits and vegetables in our diet has recently been an area of intense research and studies like this help us to understand the specific mechanisms by which the nutrients we consume can protect against heart disease."
Dr Kruse-Elliott's plans "to determine what specific components of cranberries are most important to the improvements in vascular function that we observed, exactly how they modify blood vessel relaxation, and how they can be most easily consumed as part of the diet."
April 4, 2005
Garlic compound prevents pulmonary hypertension in animal model
On April 2 2005 at the Experimental Biology conference in San Diego, Dr David D Ku of the University of Alabama at Birmingham presented the findings that an active compound in garlic known as allicin prevents a severe form of pulmonary hypertension in rats. Primary pulmonary hypertension in humans is a potentially life-threatening condition that occurs when blood pressure in the the arteries that lead from the heart to the lungs is elevated above normal, often leading to right heart hypertrophy and heart failure. The findings confirm a previous study conducted by Dr Ku and colleagues which found that garlic protected rats from a less serious form of the disease.
Dr Ku and colleagues gave rats a dose of a compound known as monocrotaline, which induces vasoconstriction of the pulmonary arteries. Half the rats were supplemented with small amounts of allicin for three weeks, while the remainder received garlic from which allicin had been removed. Within three weeks, chronic pulmonary hypertension with signficantly increased pulmonary artery pressure had developed in the animals who did not receive allicin, demonstrating a protective effect for the compound which the researchers attribute to vasorelaxation.
In other research presented by Dr Ku at the Experimental Biology 2005 conference, garlic was shown protect coronary vascular function and reduce the severity of right heart hypertrophy. A technique developed by the team has enabled them to correlate varying concentrations of allicin with vasorelaxation and vasodepressor responses in isolated pulmonary arteries and in laboratory animals.
Although clinical studies have yet to be conducted to confirm the findings, Dr Ku believes that including garlic in one's diet intake seems reasonable, especially for people with pulmonary conditions. The human equivalent of the amount of allicin used in the study can be found in two cloves of garlic a day.
April 1, 2005
Aspirin as effective as warfarin for artery condition
The March 31 2005 issue of the New England Journal of Medicine (http://content.nejm.org/) reported that warfarin, an anticoagulant drug used for decades to prevent strokes in people with partial blockages of arteries in the brain known as intracranial stenosis, is no more effective than aspirin at treating the condition and has greater side side effects.
Marc I. Chimowitz, MB, of Emory University enrolled 569 patients at 59 U.S. medical centers for the current investigation, called the Warfarin Aspirin Symptomatic Intracranial Disease (WASID) trial. Participants, who had a greater than 50 percent blockage of a major intracranial artery and who had experienced a transient ischemic attack or stroke three months prior to enrollment, received warfarin or 1300 milligrams aspirin per day for 1.8 years.
At the conclusion of the study, 22 percent of the subjects had a subsequent ischemic stroke, hemorrhage, of death from other blood vessel causes. Major hemorrhage occurred in 8.3 of those who received warfarin compared to 3.2 percent of the aspirin group. The rate of all cause mortality experienced by those who received warfarin was more than double that of those who received aspirin, with a rate of 9.7 percent in those who received warfarin, compared to 4.3 percent. Heart attack of sudden death was experienced by 7.3 percent of those on warfarin compared to 2.9 percent of the aspirin takers.
John R. Marler, MD, the associate director for clinical trials at the National Institute of Neurological Disorders and Stroke (NINDS) who funded the study, stated, "This trial is good news. A simple low-cost drug works just as well as one that requires complicated and expensive monitoring and dose adjustments."
Dr Chimowitz estimates that replacing warfarin with aspirin when treating intracranial stenosis would save more than $20 million per year.
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