- High Folic Acid Intake Unlikely to Worsen B12 Deficiency

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Link: High Folic Acid Intake Unlikely to Worsen B12 Deficiency (http://www.medscape.com/viewarticle/744521)



Laurie Barclay, MD


June 14, 2011 — High intake of folic acid from fortified food and supplements is not likely to worsen the biochemical abnormalities linked to B12 deficiency, according to the results of a cross-sectional study reported online June 8 in the American Journal of Clinical Nutrition.

"In elderly individuals with low serum vitamin B12 (B12), those who have high serum folate have been reported to have greater abnormalities in biomarkers for B12 deficiency: low hemoglobin (Hgb), and elevated total homocysteine (tHcy) and methylmalonic acid (MMA), suggesting that folate exacerbates B12-related metabolic abnormalities," write James L. Mills, MD, MS., senior investigator in the Division of Epidemiology, Statistics and Prevention Research at the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, and colleagues. "We determined whether high serum folate in individuals with low serum B12 increases the deleterious effects of low B12 on biomarkers of B12 cellular function."

The study sample consisted of 2507 university students who were questioned about medical history and use of folic acid and B12 supplements and who gave blood samples for testing of serum and red cell folate, hemoglobin, plasma homocysteine, and MMA, holotranscobalamin (holoTC), and ferritin in serum.

Approximately 5% of the students sampled had low levels of B12 (< 148 pM), and these were subdivided based on folate concentration into group 1 (high folate level; > 30 nM) and group 2 (low/normal folate level; ≤ 30 nM). Group 1 had significantly higher mean intakes of folic acid and B12 from supplements and fortified food than did group 2.

Compared with participants in group 2, those in group 1 did not have greater abnormalities in any specific test result of B12 cellular function. In fact, they had significantly higher holoTC and red cell folate levels, significantly lower total homocysteine levels, and nonsignificantly lower (P = .057) MMA concentrations than group 2. Hemoglobin and ferritin levels were not significantly different between the groups.

"Our findings are reassuring for people who have low vitamin B12 levels," Dr. Mills said in a news release. "We found no evidence that folate could worsen their health problems. Consuming higher amounts of folate does not seem to interfere with the body's use of vitamin B12 in otherwise healthy individuals."

Limitations of this study include lack of food intake data and a relatively small number of participants (mostly women) in the low B12-high folate group.
(from http://www.medscape.com/viewarticle/744521 )

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This may be bad news for people who get a lot of folic acid in it's synthetic form. Many meat eaters often take folic acid due to the fact that they often have low levels, and in some countries, folic acid supplementation of flour is mandatory.

An excerpt:


The role of folate, a B vitamin, and its synthetic form, folic acid, in the development and progression of breast cancer is highly controversial. Although some studies have found it may offer protection against breast cancer, recent studies have suggested that taking high amounts of folic acid may increase the risk of developing breast cancer.
Dr. Young-In Kim, a physician and researcher at St. Michael's Hospital, said his lab has shown for the first time that folic acid supplements in doses 2.5 to five times the daily requirement "significantly promotes" the growth of existing pre-cancerous or cancerous cells in the mammary glands of rats. His research was published today in the online journal PLOS ONE.
"This is a critically important issue because breast cancer patients and survivors in North America are exposed to high levels of folic acid through folic acid fortification in food and widespread use of vitamin supplements after a cancer diagnosis," Dr. Kim said. "Cancer patients and survivors in North America have a high prevalence of multivitamin and supplement use, with breast cancer patients and survivors having the highest prevalence."
The amount of folic acid consumed in North America has increased dramatically in the past 15 years. Women are routinely advised to take folic acid supplements before becoming pregnant and while pregnant to prevent neural tube birth defects such as spina bifida. Since 1998, the Canadian and U.S. governments have required food manufacturers to add folic acid to white flour, enriched pasta and cornmeal products as a way of ensuring women receive enough of the B vitamin. In addition, up to 30 to 40 per cent of North Americans take folic acid supplements for possible but as yet unproven health benefits.



http://www.sciencedaily.com/releases/2014/01/140121183414.htm