Folic acid is one of several B-complex vitamins. Certain enzymes in the body need this vitamin to function properly. Specifically, folic acid mediates biological processes that are necessary for proper brain functioning, and low levels of this vitamin have been associated with certain brain diseases. One active area of research is whether there is a link between folic acid deficiency and Alzheimer's disease.
Signs and Symptoms of Alzheimer's Disease
The brain degeneration caused by Alzheimer's disease causes progressively worse mental functioning and memory loss. This common form of dementia affects approximately 5 million people in the U.S., according to the University of Maryland Medical Center. The signs and symptoms of Alzheimer's disease include memory loss and difficulty concentrating, sleeping, understanding and speaking. Affected people may experience depression, anxiety, restlessness and changes in personality. Physical symptoms include incontinence, weight loss, twitching of muscles and seizures, and abnormal coordination and impaired movement.
Low Folic Acid Levels and Brain Degeneration
Low levels of folic acid in the blood are significantly associated with brain degeneration diseases, including Alzheimer's disease. A University of Kentucky study showing this link was published in the "American Journal of Clinical Nutrition" in April 2000. It found that low serum folate levels, an alternative form of folic acid, were significantly associated with injury to the frontal cortex of the brain in patients with Alzheimer's disease.
Folic Acid Supplementation
The link between low levels of folic acid in the blood and Alzheimer's disease-associated brain damage leads to the question of whether supplementation with folic acid helps to prevent the progression of Alzheimer's disease. The University of California San Diego conducted one such study and published the results in the "Journal of the American Medical Association" in October 2008. It found that taking folic acid supplements did not significantly slow Alzheimer's disease progression in patients with mild to moderate forms of the disease. Further studies are needed to determine if folic acid supplementation earlier in the disease may lead to more positive results.
Mechanism
Although scientists are not certain about how lower folic acid levels may cause a lower risk of Alzheimer's disease, a common hypothesis involves the protein homocysteine. People with Alzheimer's disease often have elevated levels of this protein in the blood, and high levels of homocysteine doubles a person's risk of developing Alzheimer's disease. Folic acid is necessary to remove homocysteine from the blood, and the University of Maryland Medical Center reports that 400 to 1,000 mcg of folic acid per day reduces homocysteine levels.
References
- Oregon State University: Folic Acid
- University of Maryland Medical Center: Alzheimer's Disease
- "Journal of the American Medical Association"; High-dose B Vitamin Supplementation and Cognitive Decline in Alzheimer Disease: A Randomized Controlled Trial; Paul Aisen, MD, et al; October 2008
- "American Journal of Clinical Nutrition"; Serum Folate and the Severity of Atrophy of the Neocortex in Alzheimer Disease: Findings From the Nun Study. David Snowden, PhD et al; April 2000
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