Vitamin B12
Vitamins + Supplements

Vitamin B12 Deficiency Can Be Sneaky, Harmful

What harm can having too little of a vitamin do? Consider this: Over the course of two months, a 62-year-old man developed numbness and a “pins and needles” sensation in his hands, had trouble walking, experienced severe joint pain, began turning yellow, and became progressively short of breath. The cause was lack of vitamin B12 in his bloodstream, according to a case report from Harvard-affiliated Massachusetts General Hospital published in The New England Journal of Medicine. It could have been worse—a severe vitamin B12 deficiency can lead to deep depression, paranoia and delusions, memory loss, incontinence, loss of taste and smell, and more.

The human body needs vitamin B12 to make red blood cells, nerves, DNA, and carry out other functions. The average adult should get 2.4 micrograms a day. Like most vitamins, B12 can’t be made by the body . Instead, it must be gotten from food or supplements.

And therein lies the problem: Some people don’t consume enough vitamin B12 to meet their needs, while others can’t absorb enough, no matter how much they take in. As a result, vitamin B12 deficiency is relatively common, especially among older people. The National Health and Nutrition Examination Survey estimated that 3.2% of adults over age 50 have a seriously low B12 level, and up to 20% may have a borderline deficiency.

Are you at risk?

There are many causes for vitamin B12 deficiency. Surprisingly, two of them are practices often undertaken to improve health: a vegetarian diet and weight-loss surgery.

Plants don’t make vitamin B12. The only foods that deliver it are meat, eggs, poultry, dairy products, and other foods from animals. Strict vegetarians and vegans are at high risk for developing a B12 deficiency if they don’t eat grains that have been fortified with the vitamin or take a vitamin supplement. People who have stomach stapling or other form of weight-loss surgery are also more likely to be low in vitamin B12 because the operation interferes with the body’s ability to extract vitamin B12 from food.

Conditions that interfere with food absorption, such celiac or Crohn’s disease, can cause B12 trouble. So can the use of commonly prescribed heartburn drugs, which reduce acid production in the stomach (acid is needed to absorb vitamin B12). The condition is more likely to occur in older people due to the cutback in stomach acid production that often occurs with aging.

Recognizing a B12 deficiency

Vitamin B12 deficiency can be slow to develop, causing symptoms to appear gradually and intensify over time. It can also come on relatively quickly. Given the array of symptoms it can cause, the condition can be overlooked or confused with something else. Symptoms may include:

  • strange sensations, numbness, or tingling in the hands, legs, or feet
  • difficulty walking (staggering, balance problems)
  • anemia
  • a swollen, inflamed tongue
  • yellowed skin (jaundice)
  • difficulty thinking and reasoning (cognitive difficulties), or memory loss
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