NUTRITION NEWS
NUTRITION NEWS
About-Face: JAMA Recommends Multivitamins
After 20 years, the Journal of the American Medical Association has completely reversed its policy and is now encouraging all adults to take at least one multivitamin per day. In a landmark article published in the Journal announced that all adults should take vitamin supplements to prevent chronic diseases."Most people do not consume an optimal amount of all vitamins by diet alone. It appears prudent for all adults to take vitamin supplements," state the articles by Robert H. Fletcher, MD, MSc, and Kathleen M. Fairfield, MD, DrPH, both affiliated with Harvard Medical School. The physicians reviewed studies published between 1966 and 2002 that investigate the links between vitamin intake and diseases such as cancer, osteoporosis, and coronary heart disease.
A large proportion of the population is at increased risk due to low vitamin levels. The high prevalence of these diseases indicates the standard diet in the U.S. fails to provide sufficient amounts of the vitamins studied. The authors examined the following nutrients: vitamins A, B6, B12, C, D, E, and K, folate, and the carotenoids including alpha- and beta-carotene, beta-cryptoxanthin, lycopene, lutein, and zeaxanthin.
They noted the association of low intakes of the B vitamins with elevated homocysteine levels and the increased risk of coronary heart disease; of low folate with neural tube defects, coronary heart disease, breast cancer, and colorectal cancer; of vitamin B6 deficiency with cheilosis, stomatitis, central nervous system effects, and neuropathy; of low B12 with macrocytic anemia and neurologic abnormalities; of low levels of vitamin E with prostate cancer; of low levels of various carotenoids with breast, prostate, and lung cancer; of low vitamin D with secondary hyperparathyroidism, bone loss, osteoporosis, and increased fracture risk; of low vitamin C with cancer; of low vitamin A with vision disorders and decreased immune function; and of low vitamin K with blood clotting disorders and with increased fracture risk.
Drs. Fletcher and Fairfield recommend that everybody, regardless of age or health status, take a daily multivitamin/mineral. The physicians go on to suggest that vegans, who may not get enough vitamins D and B12, also need to take a multivitamin. In addition, as people age, they become less able to absorb vitamins and minerals from their diet and should take a multiple vitamin, the physicians said.
Reference: Journal of the American Medical Association, 2002; 287:3116-26, 3127-29.
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Indian Remedy Reduces Cholesterol
Baylor College of Medicine molecular biologist Dr. David D. Moore and his colleagues studying guggul, a natural product used in traditional Indian medicine for more than 2,500 years, have found the secret to its cholesterol-lowering success.
The extract of the resin of the guggul tree blocks the action of a cell receptor called Farnesoid X Receptor (FXR). When FXR is too active, the body fails to convert cholesterol into bile-the main mechanism for excreting the fatty substance from the body. The researchers demonstrated that guggulsterone, the active agent in the extract, successfully blocks the activity of FXR.
In 1986, guggul was approved for sale by the Indian government as a cholesterol-lowering agent following research by government scientists and independent investigators. This natural herb is now also available in the U.S. as a supplement, containing the purified and standardized form of the guggul tree resin.
A considerable volume of research dating back to the 1960s has clearly validated the amazing benefits of guggul. According to internationally esteemed researcher and author Dr. James Braly, clinicians in the U.S. are now reporting encouraging results with their patients, further substantiating what the studies have shown.
Guggul has been clinically documented by the Indian Journal of Medical Research to reduce total cholesterol by 15%, and "bad" cholesterol (LDL) by 17%. It can also increase "good" cholesterol (HDL) by 12%, making it the only known herb documented to improve overall blood lipid profile.
Reference: Science, volume 296, issue 5573, 1703-06, May 31, 2002.
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Vitamin E Good For Arteries
In a recent study, Dr. James H. Dwyer of the University of Southern California, concludes that supplemental doses of 300 mg to 1,000 mg per day of vitamin E may help prevent stroke by slowing the progression of atherosclerosis.
At annual checkups, Dr. Dwyer and his colleagues used ultrasound to measure arterial wall thickness in the carotid arteries of 573 men and women who work at the same California company. All subjects were free of diagnosed cardiovascular disease when the study began in 1994.
The benefit was seen with the supplemented use of vitamin E in doses of at least 300 mg per day. The U.S. recommended dietary allowance for vitamin E is 15 mg per day for adults, and the tolerable upper intake level is 1,000 mg per day.
In addition to measuring the carotid arteries, Dr. Dwyer and his colleagues gathered information about the use of vitamin supplements and diet. This latest report is based on a three-year study of ultrasound screenings.
Dr. Dwyer said the study volunteers were divided into four groups based on the use of vitamin E. The subjects that had the highest intake of vitamin E had the lowest plaque build up. The doctor also observed that the benefit was limited to "vitamin E from supplements. We found no effect for dietary vitamin E."
Reference: Annual Conference on Cardiovascular Disease, Epidemiology, and Prevention, March 2001.
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Vitamin D Correlated In Colon Cancer Prevention
Dr. David Mangelsdorf, Professor of Pharmacology and a researcher at the Howard Hughes Medical Institute of the University of Texas Southwestern states, "Our findings suggest a new look at the relationship between nutrition and cancer, particularly how vitamin D protects against colon cancer."
Colon cancer is the second cause of cancer death in North America, after lung cancer. It is strongly linked to a diet heavy in red meat and animal fat. When a person eats fatty foods, the liver empties bile into the intestine, which makes it possible for the body to absorb fatty substances. After doing their job in the intestine, most bile acids are taken back into the liver. However, with lithocholic acid (LCA) this is not the case. LCA instead passes into the colon where it can promote cancer.
Dr. Mangelsdorf and his colleagues said they found at least part of the answer lies in the ability of vitamin D to rid the body of this toxic acid. "LCA is probably the most toxic compound that your body naturally makes, so you have to have a way to get rid of it. Normally, bile acids are made in the liver and stored in the gallbladder. When you eat a high-fat diet, your body makes more bile acids. Usually these acids are efficiently recycled, with the exception of LCA," Mangelsdorf said. "LCA does a variety of bad things. One of those bad things is induce changes in DNA."
Vitamin D seems to act as a sensor for high levels of LCA, and binds to it, triggering the increase of an acid-neutralizing enzyme. This is the way the body protects itself from colon cancer. Low levels of vitamin D may interrupt this healthy acid balance, thus increasing the risk of colon cancer.
Reference: Science, 2002; 296:1313-16.
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B Vitamins Reduce Risk Of Heart Disease
A growing body of scientific research shows a correlation between the risk of heart disease and high homocysteine levels. As reported in the American Journal of Clinical Nutrition, high homocysteine levels may indicate low vitamin intake. Researchers now believe that folic acid, and vitamins B6 and B12 work together to bring down homocysteine levels. Deficiencies of these three vitamins affect perhaps 25% to 30% of the adult population.
Both the elderly, and men rather than women are more likely to be deficient.In 1996, Canadian investigators reported that among more than 5,000 men and women who participated in a national nutrition survey, those with the lowest folic acid levels were 69% more likely to die of a coronary problem than those with the highest levels. This, along with other research has led to recommendations that people consume 400 mcg per day of folic acid, 1 mg per day of vitamin B12, and 3 mg per day of vitamin B6.
It is relatively easy to get additional folate-the form of folic acid found in foods-by eating green leafy vegetables, beans and citrus fruits. But the typical North American diet only provides 50 to 200 mcg per day of folate. In addition, the body does not always absorb folate well enough. However, the body does absorb folic acid added to foods, as well as in supplement form.
Reference: American Journal of Clinical Nutrition, volume 72, number 2, 315-23, August 2000.
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More Calcium Means Less Fat In Women
In a two-year study of 54 women ages 18 to 31, Purdue University researchers found that higher calcium intakes may reduce overall levels of body fat and slow weight gain for women in this age group.
"Our study is the first to show that, when overall calorie consumption is accounted for, calcium not only helps keep weight in check, but can be associated specifically with decreases in body fat," said Dr. Dorothy Teegarden, assistant professor of foods and nutrition at Purdue.
The women in the study were within normal weight ranges and followed no specific diet, Dr. Teegarden said. The researchers found that the women in the study who consumed less than 1,900 calories per day, and had a calcium intake of at least 780 mg per day, either had no increase in body fat, or lost body fat mass over the two-year period. The women who consumed less than 1,900 calories per day but averaged less than 780 mg per day of calcium gained body fat mass over the same period.
"Women who consumed an average of 1,000 mg of calcium per day, which is slightly below the recommended daily allowance for this age group, showed an overall decrease in body weight as high as six to seven pounds," Dr. Teegarden said.
The study showed that exercisers and non-exercisers benefited equally from high calcium intakes. Women who consumed more than 1,900 calories per day did not benefit. Dr. Teegarden said that if these findings are confirmed, it may prompt recommendations to increase calcium consumption, and lower overall calorie intake to prevent increases in body weight and body fat in young women.
Reference: Journal of the American College of Nutrition, 2000; 19:54-60.
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A recent study shows that people who supplement with more than 700 mg per day of vitamin C have a 62% lower risk of dying from heart disease than people with who take 60 mg per day or less. Supplementation with 2,000 mg per day of vitamin C has been found to reduce the risk of atherosclerosis.
An intake of 250 to 1,000 mg per day of vitamin C may be adequate for preventive purposes, but larger quantities are required in reversing heart disease. Although concerned about vitamin C sensitivity, most researchers now agree that vitamin C is entirely safe even in quantities of 10,000 mg per day or more.
Reference: American Journal of Epidemiology, volume 144, number 5, 501-11, September 1, 1996.
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Written by: EcoMall
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