Folate Deficiency Triples Risk of Alzheimer’s and Other Dementia in Senior Citizens

New study supports others on importance of B vitamins in fighting dementia

	Rich sources of folate include leafy greens, dried beans and peas, fortified cereals and grain products, and some fruits and vegetables. USDA Photo by Peggy Greb

Feb. 5, 2008 - Folate deficiency is associated with a tripling in the risk of developing dementia among elderly people, says research published in the Journal of Neurology Neurosurgery and Psychiatry. This supports several studies published in SeniorJournal.com over the years suggesting that folate - also known as B9, seems to offer senior citizens protection from Alzheimer’s and other dementia.

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The South Korean researchers with the new findings tracked the development of dementia in 518 people over two years from 2001 to 2003. All participants were senior citizens (over the age of 65) and lived in one rural and one urban area in the south of the country.

Validated tests were carried out at the start and end of the two year period to find out if they had a dementing illness.

Similarly, blood tests were taken to assess levels of folate, also known as vitamin B-9, vitamin B12, and the protein homocysteine, and how these changed over time.

High levels of homocysteine have been associated with cardiovascular disease.

At the start of the two year period, almost one in five people had high levels of homocysteine, while 17% had low vitamin B12 levels and 3.5% were folate deficient.

The higher the levels of folate to begin with, the higher were vitamin B12 levels, and the lower those of homocysteine.

By the end of the study, 45 people had developed dementia.

Of these, 34 had Alzheimer’s disease, seven had vascular dementia, and four had “other” types of dementia.

Dementia was more likely in those who were older, relatively poorly educated, inactive, and had deposits of the protein ApoE.

The onset of dementia was significantly more likely in those whose folate levels then fell further over the two years, while their homocysteine levels rose.

People who were folate deficient to begin with, were almost 3.5 times more likely to develop dementia.

The authors suggest that changes in micronutrients could be linked with the other typical signs that precede dementia, including weight loss and low blood pressure.

While weight loss is unlikely to alter micronutrients levels in the blood, it may indicate dietary changes in the quality of quantity of food intake.

Folate and folic acid, another form of the compound, are essential for the creation of new cells in the body.

The compound occurs naturally in leafy vegetables such as spinach, turnip greens, lettuces, dried beans and peas and in certain fruits.

A study published last year in The Lancet showed an improvement in short-term memory, mental agility and verbal fluency among persons over 50 who took a daily dose of 800 micrograms (mcg) of folic acid. The US recommended daily dose is 400 mcg.

The Journal of Neurology, Neurosurgery and Psychiatry is a publication of the British Medical Association.

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Previous Study of Folate and Dementia

Folate and B12 May Influence Cognition in Seniors

"Our findings support the often-expressed idea that many seniors would benefit from more folate, but the research shows that we must look at the effects this would have on seniors with age-related vitamin B12 deficiency, who may be more numerous than once realized. There are also indications that too much folic acid and too little B12 is a general phenomenon that affects other systems in the body, and might be a factor in some other diseases."

Feb. 9, 2007 - Folate and vitamin B12, two important nutrients for the development of healthy nerves and blood cells, may work together to protect cognitive function among seniors, reports a new epidemiological study from the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University (USDA HNRCA).

According to Martha Savaria Morris, PhD, epidemiologist at the USDA HNRCA, "we found a strong relationship between high folate status and good cognitive function among people 60 and older who also had adequate levels of vitamin B12."

The study, published in the January 2007 issue of the American Journal of Clinical Nutrition, also determined that low vitamin B12 status was associated with increased cognitive impairment.

Using data collected from the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2002, Morris and colleagues found that people with normal vitamin B12 status and high serum folate, which is a measure of folate in the blood, had higher scores on a test of cognitive function.

"People with normal vitamin B12 status performed better if their serum folate was high," explains Morris, corresponding author of the study. "But for people with low vitamin B12 status, high serum folate was associated with poor performance on the cognitive test." Seniors with low vitamin B12 status and high serum folate were also significantly more likely than seniors in other categories to have anemia, a condition caused by reduced amounts of hemoglobin in oxygen-carrying red blood cells, or by a deficiency in the number or volume of such cells.

"For seniors, low vitamin B12 status and high serum folate was the worst combination," says Morris. "Specifically, anemia and cognitive impairment were observed nearly five times as often for people with this combination than among people with normal vitamin B12 and normal folate."

Vitamin B12 deficiency, which affects many seniors due to age-related decreases in absorption, can impact the production of DNA needed for new cells, as well as neurological function.

Vitamin B12 is normally consumed in meat, fish, poultry, eggs, and dairy products, and folate is found in leafy green vegetables, citrus fruits, and beans. Although folate occurs naturally in many foods, the U.S. Food and Drug Administration in 1998 required that all enriched cereal-grain products be fortified with folic acid, the synthetic form of folate, in order to help prevent birth defects in infants.

Morris notes that the study's results are inconsistent with the idea that high folate status delays detection of vitamin B12 by masking one of its key signs: anemia.

"When folate fortification was considered, opponents raised the possibility that because more folate might mask anemia, many cases of vitamin B12 deficiency would go undetected, causing people with the condition to suffer neuropsychiatric consequences.

"But in our study, the people with low vitamin B12 who also had high serum folate were more likely to exhibit anemia and cognitive impairment than subjects with low vitamin B12 status and normal serum folate. So although having high serum folate had an impact on cognitive function in our study, it did not cure anemia, as opponents of food fortification have suggested."

Depressed? "B" Sure to Get Enough Folate By Rosalie Marion Bliss, USDA, Agricultural Research Service April 7, 2004 - Evidence is mounting of a connection between various stages of depression and low blood levels of the B vitamin folate, according to research funded by the Agricultural Research Service. Epidemiologist Martha Savaria Morris and colleagues studied data based on a questionnaire given to 3,000 people aged 15 to 39 years. The data showed that individuals with either major or mild forms of depression had lower blood levels of folate than did those who had never been depressed. The researchers noted that low folate levels are known to be common in psychiatric patients and may hamper the effectiveness of antidepressant therapy.

Senior author Jacob Selhub, PhD, director of the Vitamin Metabolism Laboratory at the USDA HNRCA and professor at the Friedman School, says, "Our findings support the often-expressed idea that many seniors would benefit from more folate, but the research shows that we must look at the effects this would have on seniors with age-related vitamin B12 deficiency, who may be more numerous than once realized.

"There are also indications that too much folic acid and too little B12 is a general phenomenon that affects other systems in the body, and might be a factor in some other diseases."

As with any epidemiological study, Morris cautions that the results show association and not causation. She also notes that because the study only measured levels of total folate in the blood, it is uncertain whether the results were due to unmetabolized folic acid in the body.

"We encourage further studies of these relationships and their underlying mechanisms," write Morris and her colleagues at Tufts.

"We hope our findings both inform the continuing debate about folic acid fortification and influence future efforts to detect and treat low vitamin B12 status among seniors."

Editor’s Notes:

Morris MS, Jacques PF, Rosenberg IH, Selhub J. American Journal of Clinical Nutrition. 2007 (January); 85:193-200. "Folate and vitamin B-12 status in relation to anemia, macrocytosis, and cognitive impairment in older Americans in the age of folic acid fortification."

If you are interested in learning more about these topics, or speaking with a faculty member at the Friedman School of Nutrition Science and Policy at Tufts University, or another Tufts health sciences researcher, please contact Siobhan Gallagher at 617-636-6586.

The Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University is the only independent school of nutrition in the United States. The school's eight centers, which focus on questions relating to famine, hunger, poverty, and communications, are renowned for the application of scientific research to national and international policy. For two decades, the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University has studied the relationship between good nutrition and good health in aging populations. Tufts research scientists work with federal agencies to establish the USDA Dietary Guidelines, the Dietary Reference Intakes, and other significant public policies.