20% of Americans may be lacking vitamin B12

August 15, 2000 in Vitamins, Minerals, Supplements

20% of Americans may be lacking vitamin B12

According to researchers from Framingham, Mass. nearly two-fifths of the American population may have marginal vitamin B12 status. A careful look at 3,000 men and women found 39 percent with blood B12 levels in the "low normal" range. While this is well above the currently accepted deficiency level, some people exhibit nerve symptoms in the higher range. Almost nine percent of the study population fell below the current deficiency level. The researchers believe there are many people with undetected vitamin B12 deficiency.

A vitamin B12 deficiency can cause a type of anemia marked by fewer but larger red blood cells. It can also cause walking and balance disturbances, a loss of vibration sensation, confusion, and, in advanced cases, dementia. The body requires B12 to make the protective coating surrounding the nerves, so inadequate B12 can expose nerves to damage. Most people can improve their B12 status by eating more fortified cereals and dairy products. This study found that these foods were nearly as effective as supplements containing B12 for getting people's blood levels above the danger zone.

The researchers looked at B12 levels in the adult population because most previous studies have focused on the elderly, who were thought to be at higher risk for deficiency. The youngest group (26- to 49-year-olds) had about the same B12 status as the oldest group (65 and up). Supplement use was linked with fewer adults being in the danger zone (plasma B12 below 185 pmol/L). Eating fortified cereals five or more times a week or being among the highest third for dairy intake reduced, by almost half, the percentage of volunteers who were classified as deficient. Oddly, the researchers found no association between plasma B12 levels and meat, poultry, and fish intake, even though these foods supply the bulk of B12 in the diet. The scientists feel that this is because the vitamin isn't getting absorbed. Many older adults don't secrete enough stomach acid to separate the vitamin from the meat proteins that tightly bind it. Fortified cereals are a different story. Tucker said the vitamin is sprayed on during processing and is "more like what we get in supplements."

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