|LE Magazine February 2001 |
In The News
Vitamin supplements reduce cataract incidence by 60%
In a study just published in the Archives of Ophthalmology [2000;118:1556-1563], researchers examined data from more than 3,000 people aged 43 to 86 years. Individuals who took a multivitamin or a supplement that contained vitamin C or E for more than 10 years had a 60% reduced risk of developing a cataract.
This study showed that the relationship between long-term supplement use and lower cataract incidence remained regardless of other known risk factors such as smoking, alcohol use, diabetes, age, weight and physical activity. Taking multivitamins or supplements for less than 10 years, however, did not appear to lower the risk of developing a cataract. The fact that short term vitamin supplement use did not reduce cataracts is not surprising since eye lens protein degradation develops over an extended period.
As the American population ages, the incidence of cataract is projected to triple in the next 50 years. Based on this new study, if more Americans consumed antioxidant vitamin supplements, the number of cataracts could be significantly reduced. According to the authors of the study, “There is evidence that certain dietary components, such as vitamins and minerals involved in protection against oxidative stress, may have a role in slowing cataract development.”
Selenium and cancer
Previous studies have shown that people with low blood levels of selenium have higher rates of cancer and that supplemental selenium reduces cancer incidence.
In a report published in the Journal of the National Cancer Institute [2000, Nov 1; 92(21): 1753-1763], the relationship between serum levels of selenium and the subsequent development of upper digestive tract cancers was measured. The results showed that those with the highest concentration of serum selenium had a 44% reduced risk of esophageal cancer and a 53% reduced risk for a type of stomach cancer called gastric cardia cancer.
This large human study, partially funded by the National Cancer Institute, had previously shown that people who received vitamin E, beta-carotene and selenium supplements had significantly lower cancer mortality from gastric and esophageal cancers than those who did not supplement. The purpose of measuring this sub-group of people was to ascertain the effects of blood selenium status over an extended period of time on the risk of developing upper digestive tract cancers. The findings indicated that people who develop these kinds of cancers are more likely to have low serum levels of selenium.
Melatonin inhibits prostate cancer cells
A recent study [Prostate 2000 Nov 1;45(3):238-44] shows that melatonin significantly slows and may even block the proliferation of prostate cancer cells.
The results were not ambiguous. “Melatonin exerts a direct oncostatic activity on human androgen-independent prostate cancer cells,” stated researchers at the Center for Enocrinological Oncology at the University of Milan, in Italy. They observed melatonin inhibit growth of this particular form of malignant disease in a carefully designed experiment.
The rationale for the test was simple. Previous studies had shown melatonin, a hormone produced in the pineal gland, has direct oncostatic, or growth-inhibiting effects on a variety of cancer cells types, particularly breast cancer. So, why not malignancy of the prostate? The significance of this disease, of course, is that it is so widespread; prostate cancer afflicts almost 200,000 males yearly, more than any other kind of neoplasm. 40,000 die from the disease. Any agent, therefore, that may help treat prostatic malignant disease would be extremely valuable.
In this particular study, investigators zeroed in on human androgen-independent DU 145 prostate cancer cells. They evaluated the effects of melatonin on cell proliferation and other growth parameters. With a hemocytometer, or a counter of cells in blood, the researchers counted the number of DU 145 cells at the outset and then again at the end of treatment, and compared the findings. Other forms of analysis were used to evaluate the effects of melatonin on the prostate cancer cells. The results were clear: In doses that are safe and non-toxic, melatonin, “significantly inhibited DU 145 cell proliferation,” the researchers observed. Melatonin also worked its way through prostate cancer cell membranes, into the cell nucleus and helped to interrupt a process called cell cycle distribution, a relentless pattern of unrestrained growth that leads to the formation of tumors. It will take further studies to tell just exactly what, if any role, melatonin may eventually play in the treatment of prostate cancer.—James O’Brien
Chromium for diabetics
“Chromium is good for diabetics and good for the lipid levels in the blood,” says Dr. Haim Rabinovitz, of the geriatric medical center at Shmuel Harofe Hospital in Tel Aviv, Israel. Supplements containing the metal lower both blood sugar (glucose) and cholesterol levels in elderly diabetics, according to a report Dr. Rabinovitz presented recently to the Gerontological Society of America. He and colleagues studied the effect of chromium supplements on 39 diabetics with an average age of 73. Although other studies have tracked these effects of chromium before, this was the first to look at the effect of the supplement on the elderly, said Rabinovitz.
Each one of the study participants took 200 micrograms of chromium twice a day for three weeks, along with their standard diabetes treatments. In addition, subjects followed a low-sugar diet restricted to 1,500 calories per day. By comparing blood sugar and cholesterol levels from before and after the study period, investigators found blood glucose dropped significantly—from an average of 189 to 150 milligrams/deciliter (mg/dl). In addition, average total cholesterol levels dropped from 225.26 to 211.42 mg/dl.
Chromium seems to work in diabetics by increasing the sensitivity of people’s cells to insulin—the hormone that clears the blood of sugar and routes it to cells for use as energy—so they are able to use it more effectively. In type II diabetes, cells do not respond to insulin. In type I diabetes, the body doesn’t produce enough insulin because special insulin-making cells in the pancreas are killed, likely due to an immune dysfunction. The danger of diabetes is that chronically high blood sugar levels can lead to medical complications such as heart attacks, heart disease, circulatory problems, kidney failure and blindness.
Because of the positive outcome of this study, Rabinovitz said he would recommend that physicians urge their elderly patients to take chromium supplements.—James O’Brien
Relief from rheumatoid arthritic pain
While NSAIDs (non-steroidal anti-inflammatory drugs) have long been used to fight the pain and inflammation associated with rheumatoid arthritis, their nasty side effects have made a more holistic alternative an eternal search. Luckily, scientific evidence has been weighing in for the use of fish oil and vitamin E to perform the same task as current anti-inflammatory drug therapies for rheumatoid arthritis. According to findings from researchers from the University of Buffalo, these two natural oils reduce levels of pro-inflammatory proteins that are evident in the disease [J Am Coll Nutr 1999 Dec;18(6):602-613].
The study, named the best scientific paper of year in October by the American College of Nutrition, revealed in a mouse model that a combined regimen of fish oil and vitamin E decreased the amount of inflammation-causing cytokines, which produce the related joint swelling and pain. The study authors report that the essential fatty acid and antioxidant vitamin duo may not be able to actually prevent rheumatoid arthritis from developing, although it may help to delay the onset of the disease and reduce the need for anti-inflammatory medication. Apparently, patients with rheumatoid arthritis typically take about 10 aspirins a day, so a reduction in that amount would be a welcome prospect.
While supplementation with omega-3 fatty acids from fish oils has been shown to provide benefits for the symptoms of rheumatoid arthritis, how they reduce inflammation has not been quite clear. The current research finally points to the role of fish oil, along with vitamin E, in effectively reducing concentrations of inflammatory cytokines. This also suggests that the oils may have some effect on the immune system, since cytokines are a key part of the immune system’s frontline defense of killer cells. The promise of these study results, suggest the researchers, is that they “may form the basis for future studies on selective nutritional interventions based on specific fatty acids and antioxidants in delaying the progress of autoimmune diseases, particularly in rheumatoid arthritis patients.”
According to some other study findings from the Albany Medical College, New York, dietary supplementation with omega-3 fatty acids “has been consistently shown to reduce both the number of tender joints on physical examination and the amount of morning stiffness in patients with rheumatoid arthritis” [AJCN 2000 Jan;71(1):349S-351S]. Findings indicated that omega-3 fatty acids yielded clinical benefits after 12 weeks of minimum daily intake of 3 grams of eicosapentaenoic and docosahexaenoic acids. The positive effect seemed to be the result of the fatty acids’ ability to reduce the release of leukotriene B4 and interleukin 1, which are both mediators of inflammation and believed to produce inflammation common to rheumatoid arthritis. Meanwhile, another study suggests that fish oils can also alter the expression of degradative factors called “aggrecanases,” which are responsible for destroying cartilage during arthritis [J Biol Chem 2000;275(2):721-724].
As for vitamin E, researchers have found that it is poorly concentrated in the joint fluid of rheumatic arthritis patients, perhaps due to depletion caused by the disease’s inflammatory process [Clin Sci 1992 Dec;83(6):657-664]. Other research has found that vitamin E may have analgesic properties more than anti-inflammatory ones, and may therefore complement the use of anti-inflammatory medication or fish oil. A British study of 42 patients, half of whom were treated with 600 milligrams of alpha-tocopherol twice daily and compared to a placebo group, found that the vitamin E patients had a small significant reduction in pain [Ann Rheum Dis 1997 Nov;56(11):649-655].—Angela Pirisi