B12 Deficiency Linked to Cognitive Decline, Cancer and More
Research is showing that many older people could benefit from getting more vitamin B12 than they currently do. Some 10% to 15% of people over age 60 are outright deficient, and many more are borderline deficient. Their blood level of B12 is in what’s called a “low-normal” range, and if their doctor isn’t up on the latest research, they won’t be treated for B12 deficiency with supplemental B12. That’s a shame, because research now shows that low B12 can cause all sorts of problems, and that getting an optimal amount can boost brain power, deter depression, improve bone density, reduce cancer risk and halt hearing loss and eye disease.
Here’s what the latest research shows vitamin B12 does:
Stops brain shrinkage. One study found that older people with lower-than-average B12 levels were six times more likely to show signs of brain shrinkage, an early sign of impaired cognitive function and Alzheimer’s disease. Even B12 levels that are above the traditional cutoff for deficiency — and seemingly adequate — may impair cognition in older people. B12 is needed to maintain the fatty myelin sheath that wraps around and protects nerves, including nerve cells in the brain.
Protects your eyes. Harvard researchers found at least a 34% decreased risk of age-related macular degeneration for women aged 40 and older who supplemented with 1,000 micrograms of B12. They attribute it to lower levels of the amino acid homocysteine and better antioxidant effects. Both improved blood vessel function in the retina of the eye.
Keeps your hearing sharp. There may be a connection between B12 deficiency and hearing. One study found that low blood levels of vitamin B12 were linked to a higher risk of hearing loss in women in their 60s. Toxic homocysteine may damage the delicate cells that transmit sound waves in the inner ear.
Fights depression. A study from the National Institute of Aging found women with low B12 levels were more than twice as likely to develop depression as women with normal B12 status. B12 is needed for the production of important brain neurotransmitters such as serotonin, norepinephrine and melatonin, the “sleep” hormone.
Maintains strong bones. In the Framingham Offspring Osteoporosis Study, people with low B12 levels had lower-than-average bone mineral density. B12 may build stronger bones by aiding osteoblasts, the cells that build bone, and by lowering homocysteine, which weakens bone by interfering with collagen cross-linking, the molecular “stitching” that makes bones strong and flexible.
Sidetracks cancer. Harvard researchers found that women over age 65 who were supplementing with B vitamins (including 1,000 mcg of B12) were 25% less likely to develop invasive cancer of any kind and 38% less likely to develop breast cancer in particular. B12 may help prevent or repair the genetic damage that can cause cancer.
Older people often don’t absorb enough B12, even when they get enough in their diet. Some experts believe that blood B12 levels should be at least 350 picomoles/liter (or 44 picograms/mL.) It’s a good idea to have your blood level checked if you are over age 50. Symptoms of B12 deficiency include fatigue, depression, numbness and tingling of the arms and, most commonly, the legs, difficulty walking, memory loss, disorientation, tongue soreness, and appetite loss. Because so many older people are borderline deficient, more experts are recommending anyone age 50 or older get at least 100 to 400 mcg a day of B12.
The Anti-Aging Bottom Line: Your risk for deficiency increases as you get older, and the consequences for your health can be devastating. Taking a B12 supplement is good insurance against deficiency, and B12 supplements are also very well tolerated. It’s a good idea to ask your doctor to check your B12 levels to determine whether you may have a severe deficiency that warrants much higher levels of supplementation.