To B12 or Not to B12—And Why?
The ABCs of vitamins can be mind-boggling, but a few key nutrients are at the forefront of good health. Vitamin B12 is among them, mainly for the role it plays in a healthy nervous system. UR Medicine registered dietitian Rachel Reeves explains B12’s function, sources, and who may be at risk for deficiency.
Vitamin B12 is essential for the healthy function of our metabolism, formation of our red blood cells, and to keep our central nervous system working properly. Most people who eat a diet that includes meat, poultry and dairy will get enough B12 and, because our bodies are able to store B12 for a long time, won’t have a problem with B12 deficiency.
If you’re deficient in B12, it’s usually because your body isn’t absorbing it properly. Our stomachs produce a protein known as intrinsic factor, which aids in the absorption of B12. If your body doesn’t produce enough intrinsic factor, even if you take vitamin supplements, it may not take in and retain the B12 it needs.
Vitamin B12 is found naturally in a wide variety of animal foods. Plant foods have no vitamin B12 unless they are fortified. As a result, people who eat little or no foods that come from animals, such as vegans, are at greater risk for B12 deficiency. In addition to meat and other foods from animals, B12 is found in some fortified breakfast cereals, nutritional yeasts, and in fermented foods like tempeh (fermented soybeans).
People most at risk for B12 deficiency include those who:
Are elderly, as aging may affect the ability to absorb B12 from foods
Follow a vegetarian or vegan diet
Have had stomach surgery, such as gastric bypass, which can impact their ability to absorb nutrients
Have digestive disorders, such as celiac disease, Crohn's disease or pancreatic issues
A few symptoms may point to a possible B12 deficiency, such as:
Tingling or numbness in the feet or hands
Loss of balance, weakness or difficulty walking
Memory loss or disorientation
These symptoms may have other causes so the best way to find out if your body has enough B12 is through a blood test. If you’re concerned about B12 deficiency, check with your doctor.
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Rachel Reeves, RD, is a clinical dietitian in adult medicine in the Food and Nutrition Services Department at UR Medicine’s Strong Memorial Hospital. She has a personal interest in food anthropology, sports nutrition, and physiology.