Vitamin B12 plays a vital role in keeping your brain and nervous system healthy, but new research suggests that many older adults might not be getting enough of it, even when their blood levels appear “normal”. Studies show that low or borderline B12 levels can affect memory, thinking skills, and balance, especially in adults over 65.
Researchers and neurologists are now calling for routine B12 testing in older adults, arguing that early detection could help prevent cognitive decline. Here’s what the latest science reveals about vitamin B12, how much you need, and when to consider supplements or dietary changes.
Why B12 matters 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. She’s a preventive cardiology dietitian and certified diabetes educator in New York.
The recommended daily intake for adults is 2.4 micrograms, according to federal guidelines. Foods rich in B12 include seafood such as salmon, tuna, and oysters, as well as beef, eggs, dairy products, and fortified plant-based milks or cereals. Despite those recommendations, new evidence suggests the standard range for “normal” blood levels may not be enough for everyone.
A team of researchers from the University of California, San Francisco (UCSF) and McGill University recently found that people with B12 levels on the lower end of the normal range showed signs of neurological impairment. “We could detect neurological impairment at levels currently considered ‘normal’, independently of other factors like years of education”, says Dr. Alexandra Beaudry-Richard, a co-author of the study.
Dr. Ari J. Green, a professor of neurology at UCSF, notes that B12 deficiency can affect the brain long before symptoms become obvious. Meanwhile, another study author, Dr. Ahmed Abdelhak, cautions that excessively high B12 levels may also have negative effects, suggesting that maintaining balance is key.
The researchers recommend that adults over 65, and especially those over 70, get their B12 levels checked regularly as part of routine bloodwork. Low or fluctuating levels, even within the so-called normal range, may increase the risk of cognitive decline or mild brain atrophy.
How to protect your B12 levels
While most people can meet their needs through diet, older adults often have difficulty absorbing B12 from food because the body produces less stomach acid with age. Certain medications, like metformin and proton pump inhibitors, can also interfere with absorption. Here’s what experts suggest:
- Don’t guess. Ask your doctor to include a vitamin B12 test in your next blood panel, especially if you’re over 50 or noticing unexplained fatigue, tingling, or memory issues.
- Focus on food first. Eat B12-rich foods regularly. Salmon, tuna, clams, eggs, and fortified breakfast cereals are among the best sources. Vegans and vegetarians should choose fortified products or supplements.
- Consider supplements wisely. If your doctor recommends supplementation, look for methylcobalamin, the most absorbable form of B12. Sublingual or liquid versions may improve absorption for those with digestive issues.
- Be consistent. B12 is stored in the liver, so you don’t need it daily, but you do need it regularly.
- Support your brain in other ways. Exercise, eat a nutrient-dense diet, and engage in mentally stimulating activities like learning a new language or playing an instrument.
Small changes in your diet or supplement routine could help keep your brain sharper, your energy higher, and your memory stronger for years to come.