Archive

Health Bits and Pieces
By Michael Janson, M.D.
June 06, 2006

Exercise helps to preserve brain function and prevent dementias from Alzheimer’s disease and other causes, such as atherosclerosis.  In a study of 65-year olds who had normal cognitive function at the start of the study, those who exercised three times a week or more over the following six years had a 38-percent reduction in dementias compared to those who exercised less than three times a week.  Even as little as 15 minutes of walking provided significant benefits.  Exercise improves cerebral circulation and also helps to control blood sugar, thus reducing the production of damaging substances called advanced glycation end products (AGEs).  AGEs impair membrane function and damage the vascular lining. (Larson EB, et al., “Exercise is associated with reduced risk for incident dementia among persons 65 years of age and older,” Ann Intern Med. 2006 Jan 17;144(2):73-81.)

An earlier study lasting for 21 years showed that regular exercise reduced dementias by 50-60 percent, suggesting that the consistency of the activity over a long time is helpful, so it is never too soon to get started on a fitness program.  (Rovio S, et al., “Leisure-time physical activity at midlife and the risk of dementia and Alzheimer’s disease,” Lancet Neurol. 2005 Nov;4(11):705-11.)

Another way to support brain function is by eating fish.  Researchers evaluated 3718 men and women over 6 years.  They found that those who ate fish once a week had a 10-percent slower cognitive decline (gaining about 3 years of brain preservation).  Those who ate fish twice or more per week had a 13-percent slower decline in brain function, gaining about four years of healthier brain function.  This study did not show that the benefit was from the omega-3 oils in fish, although based on other data the researchers speculated that the result was likely due to the essential fatty acids.  Those who ate more fish consumed less saturated fat and trans fat.  (Morris MC, et al., “Fish consumption and cognitive decline with age in a large community study,” Arch Neurol. 2005 Dec;62(12):1849-53.)

High serum homocysteine (Hcy) levels are associated with an increased risk of memory loss.  Researchers tested the memory of 2189 adults over six years.  Subjects who developed memory loss were found to have higher Hcy levels and lower folate levels than those without memory loss.  If the subjects increased their folate level and reduced their Hcy during the course of the study, their memory scores improved by the end of the study.  (Nurk E, et al., “Plasma total homocysteine and memory in the elderly: The Hordaland Homocysteine study,” Ann Neurol. 2005 Dec;58(6):847-57.)

Other studies have shown a relationship between Hcy levels and the risk of developing Alzheimer’s disease and other forms of dementia.  In a study of 816 subjects followed for four years, those with high Hcy had twice the risk of dementia.  Low folate levels were an independent risk factor, unrelated to homocysteine.  Subjects with low folate levels had an almost doubled risk of both dementia and Alzheimer’s disease.  (Ravaglia G, et al., “Homocysteine and folate as risk factors for dementia and Alzheimer disease,” Am J Clin Nutr. 2005 Sep;82(3):636-43.)

Homocysteine elevation is also associated with an increased risk of strokes.  In a study of 1015 men, those with the highest Hcy levels had almost triple the risk of strokes compared with men with the lowest levels.  Again, men with the highest folate levels had a 60-65 percent reduction in stroke risk.  Hcy can be reduced by a high intake of fruits, vegetables (including mushrooms), whole grains, and supplements.  In addition to folic acid, supplements of vitamins B6 and B12 also lower homocysteine levels.  (Virtanen JK, et al., “Serum homocysteine, folate and risk of stroke: Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study,” Eur J Cardiovasc Prev Rehabil. 2005 Aug;12(4):369-75.)

Clinical and epidemiological evidence shows that soy and cruciferous vegetables (cabbage, broccoli, Brussels sprouts, and others) are healthful in many ways, including cancer prevention.  New laboratory tests of cancer cells show that compounds found in these foods enhance DNA repair, providing some explanation as to why these foods help to prevent cancer.  Genistein (from soy) and indole-3 carbinol (from the cabbage-family vegetables) administered to both breast and prostate cell lines increase the levels of two proteins (BRCA1 and BRCA2) that enhance DNA repair.  Combining the two phytochemicals works even better.  (Fan S, et al., “BRCA1 and BRCA2 as molecular targets for phytochemicals indole-3-carbinol and genistein in breast and prostate cancer cells,” Br J Cancer 2006 Feb 13;94(3):407-26.)  Oriental diets are high in these vegetables and soy, and this may partly explain the low rates of some cancers in these populations.

Michael Janson, M.D., is Past President of the American College for Advancement in Medicine and the author of four books, including Dr. Janson’s New Vitamin Revolution and the User’s Guide to Heart Healthy Supplements. He has a free monthly newsletter, Dr. Janson’s Healthy Living, available at his website, www.drjanson.com, which he regularly writes and publishes while also practicing medicine in New England and Florida.