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Preventing Alzheimer's: A Role for Diet and Exercise
Africans living in Indianapolis are twice as likely to develop Alzheimer's disease as those living in Nigeria, suggesting environmental factors are at play. A ten-year study found that the Indianapolis residents also have higher rates of hypertension, diabetes, and high cholesterol, suggesting a link between Alzheimer's disease and vascular disorders. Nigerians typically eat less fat and protein than Americans.
Researchers are also looking into possible links between Alzheimer's disease and lifelong physical activity. One study measured changes in 26 activity levels in people with possible or likely Alzheimer's to those without. Compared to Alzheimer's patients, healthy people stayed involved in a broader variety of activities in adulthood. Those whose activity level fell below average had a four-fold increase in risk. It is too early to tell whether dementia develops in this context because people stop engaging in physical and intellectual exercises or whether early symptoms keep them from participating in enjoyable activities. One theory speculates that cardiovascular fitness minimizes the number of blood vessel breaks, which can kill brain cells.
Ogunniyi A, Baiyewu O, Gureje O, et al. Epidemiology of dementia in Nigeria: results from the Indianapolis-Ibadan study. Eur J Neurol 2000;7:485-90.
Friedland RP, Fritsch T, Smyth KA, et al. Patients with Alzheimer's disease have reduced activities in mid-life compared with healthy control-group members. Proc Natl Acad Sci 2001;98:3440-5.
Vegan Diet Eases Fibromyalgia
Fibromyalgia patients who adhered to a low-salt, raw, vegan diet for three months showed significant improvements in pain, joint stiffness, quality of sleep, and overall health compared to a control group that continued an omnivorous diet. Participants in the University of Kuopio study in Finland also experienced a significant decrease in body weight and lowered their cholesterol levels.
Kaartinen K, Lammi K, Hypen M, Nenonen M, Hanninen O, Rauma AD. Vegan diet alleviates fibromyalgia symptoms. Scand J Rheumatol 2000;29:308-13.
Animal Proteins Promote Osteoporosis
Elderly women who get most of their protein from animal products rather than plant sources have a higher risk for bone loss and hip fracture. A study published in the American Journal of Clinical Nutrition surveyed 1,035 women regarding their food choices, looking at intakes of protein, potassium, sodium, and other nutrients. Over time, the women with the highest intakes of animal protein had three times the amount of bone loss compared to those who consumed the most vegetable protein.
Animal products overload the body with acid, coming in part from the sulfur-containing amino acids found in meat. In an effort to buffer this acid, calcium is pulled from the bones, weakening them significantly. Vegetables fight this effect in two important ways: by adding less acid and neutralizing what's already there.
Sellmeyer DE, Stone KL, Sebastian A, Cummings SR. A high ratio of dietary animal to vegetable protein increases the rate of bone loss and the risk of fracture in postmenopausal women. Am J Clin Nutr 2001;73:5-6.
Diabetes Takes a Toll on Mental Health
People with Type 2 diabetes and high blood pressure experience a greater loss of cognitive function with age than their healthy counterparts. As reported in the journal Neurology, the initial decline tends not to be fast enough to be apparent in everyday activities but can show up on mental agility tests. It is unclear exactly how diabetes impairs the brain, although scientists believe it damages small blood vessels.
Researchers at PCRM and elsewhere have found that low-fat, vegan diets dramatically improve diabetes management and reduce complications.
Knopman D, Boland LL, Mosley T, et al. Cardiovascular risk factors and cognitive decline in middle-aged adults. Neurology 2001;56:42-8.
Low-Fat Diet Helps High-Cholesterol Kids
Children raised on typical American fare can easily develop high cholesterol levels. Until now, some physicians have been wary of putting youngsters on low-fat diets, fearing a negative effect on growth and brain development. However, a seven-year study from the National Heart, Lung, and Blood Institute of 663 children, aged eight to ten, showed that they thrived through adolescence on a diet low in saturated fat and cholesterol. Significant reductions in LDL cholesterol were measured while physical and cognitive development progressed normally.
The National Heart, Lung, and Blood Institute is part of the U.S. federal government's National Institutes of Health.
Trade Meat for Tofu and Save Your Heart
Simply trading meat for tofu in your favorite meals throughout the week can cut your risk for heart disease by lowering cholesterol and triglyceride levels and by slowing the rate at which LDL cholesterol is oxidized, a recent study shows.
Plant versions of estrogen, called phytoestrogens, found in soy products such as tofu, contain antioxidants that are believed to prevent cholesterol oxidation, making it less likely to deposit in arteries of the heart. Researchers also stress the importance of eating a variety of plant foods with plenty of vegetables and fruits for an optimal heart-protective diet.
Ashton EL, Dalais FS, Ball MJ. Effect of meat replacement by tofu on CHD risk factors including copper induced LDL oxidation. J Am Coll Nutr 2000;19:761-7.
Heart Bypass May Harm Brain Function
More than one-third of all bypass patients have measurable cognitive dysfunction that persists many years after surgery. A New England Journal of Medicine study found a 20-percent drop in mental ability in 53 percent of bypass patients at the time of discharge. Although mental functioning varied in the following years, by the fifth year, declines were still significant. It is believed that tiny blood clots form and go to the brain as the heart-lung machine pumps and oxygenates blood during surgery.
Diet changes are far safer. The research studies of Dean Ornish, M.D.; Caldwell Esselstyn, M.D.; and others have shown that artery blockages can be reversed without surgery when patients follow a vegetarian diet along with an otherwise healthy lifestyle.
ALTERNATIVES TO ANIMAL EXPERIMENTATION
Abolition of the LD-50: One Step Closer
The Organization for Economic Cooperation and Development (OECD) has announced that the heavily criticized Lethal Dose 50 (LD-50) acute toxicity test will be deleted from its manual of internationally accepted chemical test guidelines. The LD-50, which determines the dose of a chemical that kills half the animals tested, has been denounced for causing severe suffering in animals while producing unreliable results.
The abolition of the test is only a partial victory because the OECD's proposed replacement methods still require subjecting animals—albeit somewhat fewer than used in classical LD-50 tests—to high doses of toxic substances. In vitro tests using human cells have been shown to be more accurate at predicting what will harm humans.
Toxicogenomics: Modern Methods Replace Animal Tests
The testing of new drugs, chemicals, food additives, and cosmetics may soon rely on toxicogenomics, an exciting branch of study evolving from the humane genome project. The innovative approach goes straight to the source—human DNA—to sort out how cells react to certain chemicals, rather than relying on animal tests, which are notoriously poor predictors of toxicity in humans. Chips encoded with DNA are treated with a chemical to determine how individual genes are affected. It is hoped that this procedure will not only identify which substances are harmful, but offer new clues to how they do their dirty work.
Toxicogenomics may also allow researchers to rapidly evaluate new compounds for potential medicinal properties and let physicians tailor treatments and drugs to their patients' individual needs, based on their unique genetic make-up.