Should You Take a Vitamin B12 Supplement?

Time​ Magazine

3 days ago

Everyone needs vitamin B12: It helps the body produce red blood cells and maintain healthy brain function, along with so many other things. But are you getting enough of it?
Here's what to know about vitamin B12 and whether you should consider upping your levels.
A boon for brain health
'Vitamin B12 is important for brain health because it helps protect nerve cells in the brain, which support memory and thinking skills,' says Michelle Routhenstein, a preventive cardiology dietitian and certified diabetes educator in New York. It's water-soluble, so the body does not store it in large amounts, and daily intake is essential.
The current federal recommendations are for adults to get 2.4 mcg of vitamin B12 per day. Great food sources of B12 include seafood like oysters, salmon and tuna, beef, and fortified products like nutritional yeast, plant-based milks, some breads and breakfast cereals, says Routhenstein.
But some recent research suggests that some people may need even more than that. Vitamin B12 deficiencies can impact your brain function even when your intake levels are considered normal, says Dr. Ari J. Green, a professor at the University of California, San Francisco's department of ophthalmology. In a recent study, Green and his colleagues found that people with B12 levels that were technically normal but on the lower end of the range had impaired brain function. 'We could detect neurological impairment at levels currently considered 'normal,' independently of other factors like years of education," particularly in older people, says Dr. Alexandra Beaudry-Richard, a resident at McGill University and co-author of the study. 'To us, this should reinvigorate a conversation about how much B12 is needed for optimal neurological function.'
Read More: Should You Take a Vitamin D Supplement?
Other studies have found that people with Alzheimer's disease and mild cognitive impairment tend to have lower B12 levels—and supplementation with B12 can reduce the rate of brain atrophy.
However, on the opposite end, the study showed signs of a possible detrimental effect on the brain when people had high B12 levels in their blood. 'This warrants further studies to evaluate what healthy B12 levels are on both ends of the spectrum,' says Dr. Ahmed Abdelhak, one of the study's authors and a clinical instructor in neurology at UCSF School of Medicine.
Should you take a B12 supplement?
You can (and should) get B12 from your diet, but some people may have a tough time getting adequate levels of the nutrient from food alone.
Older adults are more likely to develop vitamin B12 deficiencies because the vitamin requires stomach acid to be absorbed, and stomach acid production starts to decline with age. Routhenstein recommends people look closer into their B12 status starting around age 50 or if they are at higher risk of a B12 deficiency. This category includes vegans and vegetarians, people taking specific medications that interfere with B12 absorption such as metformin or proton pump inhibitors, and those who have gastrointestinal disorders like Crohn's, celiac, or atrophic gastritis.
You can get tested for a vitamin B12 deficiency at your annual physical. If you are deficient, your doctor might recommend supplementation.
Read More: 7 Surprising Symptoms of Lyme Disease
The UCSF study authors recommend checking levels starting at age 70, but you can get it checked on a standard blood test at any age through your primary care physician.
Dr. Ralph Green, a professor of pathology and lab medicine at the University of California, Davis—and another author on that recent study—says that checking B12 may also be valuable for people who have unexplained symptoms that have been linked to B12 deficiency. For those with declining gastric function, he says taking supplements is likely the best way to promote absorption, and the level of supplementation a person should consume depends on whether their absorption is normal or not.
Pregnant women, too, need higher B12 intake to support fetal brain development; if you're pregnant, consult with your ob-gyn about optimal B12 levels for you.
What kind of B12 supplement is best?
B12 in supplements and fortified foods can be more easily absorbed than from food, especially for older adults and those with absorption issues, says Routhenstein.
If your doctor has advised you to take a B12 supplement, it's best to ask them to recommend specific dosages and brands. But Routhenstein recommends following these general guidelines when selecting a B12 supplement.
Of course, no supplement is a cure-all, and there are other ways to support brain health, including maintaining a healthy diet and exercise regimen. Activities that stimulate multiple brain areas simultaneously are excellent at promoting cognitive longevity, Beaudry-Richard says.
Practicing a musical instrument, dancing, and studying a foreign language daily, for example, all recruit 'brain circuits responsible for vision, hearing, movement, emotions' and more. 'It's like a full-body workout for the brain,' she says.