Understanding vitamin B12 deficiency



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Vitamin B12 deficiency can cause serious problems. This essential vitamin helps keep the body's nerve and blood cells healthy and helps make DNA — the genetic material in all cells.

Since our bodies do not make vitamin B12, it’s important to get it from food or supplements. B12 can be found in dairy products, meat and fish; however, many people do not absorb it adequately.

Older people and people who take certain medications, such as the proton-pump inhibitors for acid reflux or metformin for diabetes, seem to be at increased risk for this vitamin By Romy Block, MD, and Arielle Levitan, MDdeficiency. Also susceptible to a lack of absorption are people who have had gastric bypass surgery, suffer from gastrointestinal illnesses or follow a vegan or vegetarian diet.

The symptoms of vitamin B12 deficiency can be very disturbing. Because of this vitamin’s role in the nervous system, symptoms of deficiency include neurological complaints. People can suffer from memory loss, numbness and tingling, motor weakness, fatigue and attention-related issues. In our practices, we have seen people with symptoms resembling those in patients with multiple sclerosis or even Alzheimer’s disease whose only health problem has actually been a vitamin B12 deficiency.

The good news is that symptoms may improve with adequate replacement of B12, which can be in the form of supplements (usually combined with other B vitamins or as a multivitamin), nasal sprays or shots. We find that most mild deficiencies can be resolved with supplements, but people with severe deficiencies require shots, at least initially, to rebuild their levels. It can take several months to build up sufficient B12 levels and reverse any of the symptoms experienced with a deficiency.

At Vous Vitamin, we include vitamin B12 in our Power Up Situational Supplement, a blend of electrolytes and vitamins that provides an extra boost for a workout or taxing day. We also incorporate it into many of our personalized multivitamin formulations since the deficiency is so common.


Romy Block, MD, and Arielle Levitan, MDArielle Miller Levitan, MD, is a board-certified internal medicine physician and the cofounder of Vous Vitamin, LLC. She is the author of The Vitamin Solution: Two Doctors Clear Confusion About Vitamins and Your Health. She attended Stanford University and Northwestern University’s Feinberg School of Medicine, and has served as chief medical resident for the Northwestern University McGraw Medical Center’s Evanston Hospital Program and as a clinical instructor for its medical school. She has a special interest in women’s health and preventive medicine and currently practices general internal medicine on the North Shore of Chicago, where she teaches medical students on-site. She enjoys cooking, cardio tennis, running, being a soccer mom (sometimes) and spending time with her three kids and husband (also a doctor of internal medicine).

Romy Block, MD, is a board-certified specialist in endocrine and metabolism medicine, member of American Thyroid Association, and the cofounder of Vous Vitamin, LLC. She is the author of The Vitamin Solution: Two Doctors Clear Confusion About Vitamins and Your Health. She attended Tufts University and Tel Aviv University’s Sackler School of Medicine. She completed residency training in internal medicine at North Shore University Hospital—North Shore-LIJ and did a fellowship at New York University. She practices on the North Shore of Chicago, where she specializes in thyroid disorders and pituitary diseases. She enjoys travel, food and wine, working out with her personal trainer and spending time with her husband (a pulmonary and sleep specialist) and their three boys.