Vitamin B12 as Protection for the Aging Brain – The New York Times By JANE E. BRODY SEPT. 6, 2016
I’ve been told repeatedly by nutrition experts that the overuse of dietary supplements for “nutritional insurance” has given Americans the most expensive urine in the world.
I do take a daily supplement of vitamin D, based on considerable evidence of its multiple health benefits, especially for older people. However, based on advice from the National Academy of Medicine and an examination of accumulating research, I’m prompted to consider also taking a vitamin B12 supplement in hopes of protecting my aging brain.
Animal protein foods — meat, fish, milk, cheese and eggs — are the only reliable natural dietary sources of B12, and I do get ample amounts of several in my regular diet. But now at age 75, I wonder whether I’m still able to reap the full benefit of what I ingest.
You see, the ability to absorb B12 naturally present in foods depends on the presence of adequate stomach acid, the enzyme pepsin and a gastric protein called intrinsic factor to release the vitamin from the food protein it is attached to.
Only then can the vitamin be absorbed by the small intestine. As people age, acid-producing cells in the stomach may gradually cease to function, a condition called atrophic gastritis.
“Depression, dementia and mental impairment are often associated with” a deficiency of B12 and its companion B vitamin folate, “especially in the elderly,”
He described a 66-year-old woman hospitalized with severe depression, psychosis and a loss of energy and interest in life who had extremely low blood levels of B12 and whose symptoms were almost entirely reversed by injections of the vitamin.
European researchers have also shown that giving B12 to people deficient in the vitamin helped protect many of the areas of the brain damaged by Alzheimer’s disease.
Dr. Helga Refsum, a professor of nutrition at the University of Oslo, found reduced cerebral atrophy in those treated with high doses of the vitamin.
“A B12 vitamin deficiency as a cause of cognitive issues is more common than we think, especially among the elderly who live alone and don’t eat properly,” Dr. Rajarethinam said.
The academy estimates that between 10 percent and 30 percent of people older than 50 produce too little stomach acid to release B12 from its carrier protein in foods, and as the years advance, the percentage of low-acid producers rises.
The academy recommends that adults older than 50 get most of their daily requirement of B12 — 2.4 micrograms for people 14 and older, slightly more for women who are pregnant or nursing — from a synthetic form of the vitamin found in foods fortified with B12 or in a multivitamin supplement
Synthetic B12 is not attached to protein and thus bypasses the need for stomach acid.
Certain groups besides older people are also at risk of a B12 deficiency. They include
- vegetarians and vegans who consume little or no animal foods;
- people with disorders of the stomach and small intestine like celiac disease and Crohn’s disease;
- chronic users of proton-pump inhibitors to control acid reflux; and
- people whose digestive systems were surgically reduced for weight-loss or treatment for cancer or ulcerative colitis.
Among those most likely to be B12 deficient are the older patients in nursing homes whose diets are limited, and this deficiency may account in part for the symptoms of cognitive dysfunction so common among nursing home residents.
While a B12 deficiency can take years to develop, encroaching symptoms can be distressing and eventually devastating.
symptoms of B12 deficiency include
- tingling and numbness in the hands and feet,
- muscle weakness and loss of reflexes,
which may progress to
- confusion, depression, memory loss and dementia as the deficiency grows more severe.
- depression, memory loss and dementia as the deficiency grows more severe.
- memory loss and dementia as the deficiency grows more severe.
- dementia as the deficiency grows more severe.
as the deficiency grows more severe.
Early symptoms can be reversed by treatment with high doses of B12, usually given by injection. But symptoms related to nerve damage and dementia are more likely to be permanent.
experts at Kaiser Permanente in Oakland, Calif., suggest that chronic users of proton-pump inhibitors should have their B12 level tested every two years.
The Vegan Society recommends eating two to three servings a day of fortified foods to get at least three micrograms of B12.