Can Silicon Prevent Alzheimer’s Disease?
By Alan R. Gaby, MD
Healthnotes Newswire (May 5, 2005)—A high intake of the trace mineral silicon may reduce the risk of developing dementia or Alzheimer’s disease, reports a study in the American Journal of Clinical Nutrition (2005;81:897–902). While most nutritionists do not consider silicon an essential nutrient for humans, this study adds to the growing list of its reported benefits.
Although silicon has no known direct effect on brain function, it inhibits the absorption and increases the urinary excretion of aluminum, a toxic metal thought to play a role in the development of Alzheimer’s disease and other forms of dementia. Consequently, silicon might help preserve brain function by preventing the accumulation of aluminum.
Some 7,598 French women aged 75 years or older participated in the new study. At the beginning, an estimate was made of the amount of silica (silicon dioxide; one of the main forms of silicon in the diet) each participant consumed per day in their drinking water. Women with lower intakes of silica were found to perform worse on cognitive function tests, compared with women whose silica intake from drinking water was higher. A subset of approximately 20% of the participants was then followed for up to 7 years. During the follow-up period, women with lower intake of silica were at increased risk of developing Alzheimer’s disease; those who developed Alzheimer’s disease were nearly three times as likely to have a low silica intake from drinking water (4 mg per day or less).
While controlled trials are needed to confirm these preliminary results, the study suggests that increasing silicon intake may help prevent age-related mental decline and Alzheimer’s disease. Animal research and preliminary studies in humans suggest that silicon may also help prevent hardening of the arteries (atherosclerosis) and osteoporosis. In animals, silicon plays a role in promoting healthy connective tissue, including cartilage and bone, and inadequate silicon intake leads to osteoporosis. In humans, silicon appears to improve bone health by increasing bone formation and by enhancing the structural integrity of bone.
The richest dietary sources of silicon are the bran portions of grains such as wheat, oats, and rice. In contrast, refined grains contain little silicon. Unrefined soy products also contain relatively large amount of silicon. Silicon is also available as a nutritional supplement and as a component of some multivitamin-mineral products. Silicon is generally considered safe, although respiratory problems have occurred in industrial workers exposed to large amounts of silicon dust in the air.
Alan R. Gaby, MD, an expert in nutritional therapies, testified to the White House Commission on CAM upon request in December 2001. Dr. Gaby served as a member of the Ad-Hoc Advisory Panel of the National Institutes of Health Office of Alternative Medicine. He is the author of Preventing and Reversing Osteoporosis (Prima, 1994), and co-author of The Natural Pharmacy, 2nd Edition (Healthnotes, Three Rivers Press, 1999), the A–Z Guide to Drug-Herb-Vitamin Interactions (Healthnotes, Three Rivers Press, 1999), Clinical Essentials Volume 1 and 2 (Healthnotes, 2000), and The Patient’s Book of Natural Healing (Prima, 1999). A former professor at Bastyr University of Natural Health Sciences, in Kenmore, WA, where he served as the Endowed Professor of Nutrition, Dr. Gaby is the Chief Medical Editor for Healthnotes, Inc.
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