Vegetarian — Vitamin B-12 deficient?

Originally Published: September 5, 1995 - Last Updated / Reviewed On: August 1, 2014
Share this
Alice,

My friend recently got a blood test back from her doctor and she was told she was deficient in Vitamin B12. She is a vegetarian. What can she do to supplement this vitamin if she does not eat meat?

Animal lover

Dear Animal Lover,

Vitamin B12 is important in the formation of nerve cells and red blood cells. Natural food sources of the vitamin are found primarily in meat and other animal products, which mean those who stick with a plant-based diet have to find their source elsewhere. Though there are some foods that your friend may want to add to her/his diet, vitamin supplements may also be something to consider. However, because of the serious symptoms and long-term risks involved with B12 deficiency, consulting with a health care provider and/or a registered dietitian may help as well.

Contrary to popular belief that B12 deficiency takes many years to develop, it actually may only take a matter of two to four years to become symptomatic. A recent meta-analysis found that the prevalence rate of B12 deficiency among non-pregnant young adults who followed a vegetarian diet (lacto- or lacto-ovo) was at about 32 percent and among vegans, ( those who eschew all animal products: meat, eggs, dairy, honey, leather, silk, etc.) prevalence was at 43 percent. Symptoms of B12 deficiency include anemia, fatigue, weakness, constipation, loss of appetite, and weight loss. Long-term effects may be neurological changes such as numbness and tingling in the hands and feet. Additional signs of B12 deficiency include difficulty in maintaining balance, depression, confusion, dementia, poor memory, and soreness of the mouth or tongue. But be advised that these can also be symptoms of many different ailments, so having a blood test from a doctor like your friend did can help with diagnosis.

The recommended daily allowance (RDA) of B12 for adults is 2.4 micrograms (µg) and there are actually two forms of B12, active (which the body can actually use) and inactive (a.k.a.,pseudovitamin B12). Now, for the good news: Both vegetarians and vegans have various options for obtaining sufficient amounts of vitamin B12. Some varieties of mushrooms, green and purple nori (seaweed), and some fermented foods like sauerkraut and tempeh (fermented soy beans) are recognized as plant-based sources active B12. Fortified foods like some cereals, soy products, or meat substitutes are options for both vegans and vegetarians. Milk, yogurt, and eggs are rich in vitamin B12 and may also be added to a vegetarian diet. And while it is possible to get sufficient amounts of the vitamin from these sources, many vegans and vegetarians don’t seem to eat enough of these products. As such, it might be a good idea to look into vitamin supplements that contain B12. Due to the low absorption rate of the vitamin through supplements, taking a 250 microgram (µg) dose is recommended. Seeking out the guidance of a registered dietitian may prove helpful for your friend to identify where B12–rich sources can be added in her/his diet.

Happy healthy eating!

Alice

For more information or to make an appointment, check out these recommended resources:

Medical Services (Morningside)

Student Health Services (CUMC)