If you think you don’t need to take vitamin B12 supplements, you might need to think again. Most people get plenty of B12 from foods—meat, fish, dairy products, eggs, and fortified breakfast cereals—with no need for supplements. However, our body’s ability to absorb it from these sources is only as good as our gut. In order to absorb dietary B12 in the small intestine, we need adequate stomach acid, the enzyme pepsin, and a gastric protein called intrinsic factor.
Between 10 to 30 percent of people over 50 years old produce too little stomach acid, leading to decreased absorption of B12 from food. The percentage of people with this problem increases with advancing age. In addition, people who have pernicious anemia (a condition caused by autoimmunity to stomach cells that produce intrinsic factor), celiac disease and other illnesses of the small intestine, those who have undergone gastrointestinal surgery, and vegans/vegetarians are also at risk for vitamin B12 deficiency. Synthetic B12 supplements, which do not require stomach acid to be absorbed, might be a good option for older people and others at risk for deficiency. For most people with B12 deficiency, a monthly B12 injection is needed.
Adequate levels of vitamin B12 are necessary for proper brain health. Poor memory, dementia, depression, and neurological symptoms like numbness and tingling sensations can be symptoms of vitamin B12 deficiency. In fact, high-dose vitamin B12 could theoretically have saved Mary Todd Lincoln—who is thought to have had pernicious anemia—from the health issues that led to her stay in a mental hospital. Vitamin B12 is also one of several B vitamins that may help to protect from cognitive decline in older people with mild memory deficits and poor vitamin status.
Bottom line: B12 is essential for our health at all ages. A simple blood test can tell us whether we have sufficient levels of this critical vitamin. It may be exactly what our brains need to stay sharp as we age.
Yuko Hara, PhD, is Director of Aging and Alzheimer's Prevention at the Alzheimer's Drug Discovery Foundation. Dr. Hara was previously an Assistant Professor in Neuroscience at the Icahn School of Medicine at Mount Sinai, where she remains an adjunct faculty member. Her research focused on brain aging, specifically how estrogens and reproductive aging influence the aging brain's synapses and mitochondria. She earned a doctorate in neurology and neuroscience at Weill Graduate School of Medical Sciences of Cornell University and a bachelor's degree in biology from Cornell University, with additional study at Keio University in Japan. Dr. Hara has authored numerous peer-reviewed publications, including articles in PNAS and Journal of Neuroscience.
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