How Vitamin B12 Prevents Senility
What you don’t know about vitamin B12 can literally take your mind away. Unfortunately, it’s a well-kept secret that a deficiency of vitamin B12, which is alarmingly common, can lead to neurological damage, including disorientation, memory problems, and dementia. A recent survey found that sixty percent of a group of older people diagnosed with B12 deficiency had no idea that a shortage of the vitamin could be so devastating to the brain. “The lack of knowledge about vitamin B12 deficiency is astounding,” said Dr. Robert M. Schmidt, professor of preventive medicine at California Pacific Medical Center in San Francisco and a board member of the local American Society on Aging that conducted the survey.
The awful neurological consequences of a B12 deficit typically sneak up, originating in midlife, but do not become noticeable until twenty or thirty years later in the sixties or seventies. “A vitamin B12 deficiency develops very slowly over many years and oddly, often affects the brain and nervous system entirely and nothing else,” according to the late John Lindenbaum, M.D., an authority on vitamin B12 at New York’s Columbia Presbyterian Medical Center. He noted that a B12 deficiency is often not detected by conventional blood tests.
The cause is usually not a faulty diet. You can’t count on foods high in B12 to save you from a deficiency as you get older. The real culprit is a biological fact of life. As you age, you can lose your ability to absorb vitamin B12 from food. This condition, called atrophic gastritis, means your stomach progressively secretes less hydrochloric acid, pepsin, and intrinsic factor—a protein needed to absorb B12 from food—than when you were younger.
Atrophic gastritis is startlingly common. It becomes more prevalent with each passing year after middle age, and affects up to half of all Americans over age sixty, according to one study. But since it takes the body so long to exhaust stores of B12, deficiency symptoms can take years to appear. Yet, silently and without hints of trouble, the B12 you eat goes to waste and your nervous system eventually begins to feel and respond to B12 starvation. Gradually, lacking B12 nourishment, the outer layer of nerve fibers deteriorate, giving rise to neurologic abnormalities, including loss of balance, muscle weakness, incontinence, mood disturbances, dementia, and psychosis.
The signs of B12 deficiency are often described as “pseudo-senility” because they so closely mimic those of age-related intellectual decline. Numerous older people with failing memory and other unexplained mental disturbances have been diagnosed with irreversible “senility” or Alzheimer’s when in fact the cause was a very reversible deficiency of vitamin B12. A recent Israeli study found that up to 16 percent of older people with dementia actually had a B12 deficiency.
However, a lack of B12 may lead to full-blown Alzheimer’s disease. A recent British study by David Smith at Oxford University found that older people with abnormally low blood levels of vitamin B12 were four times more apt to develop Alzheimer’s disease. A probable reason: the link with homocysteine, a blood factor thought to damage blood vessels and have direct toxic effects on brain cells. B vitamins, including folic acid, B6 and B12, help suppress homocysteine. In the British study, those deficient in B12 also had the highest levels of dangerous homocysteine.
Keeping the lid on homocysteine also cuts your risk of “brain attack,” or strokes. B vitamins can help keep carotid arteries, that feed the brain, from closing.
BRAIN ALERT: The average American woman over age fifty gets only 43 to 48 percent of the recommended dose of B12 in her diet. Men of the same age get 62 to 75 percent, according to the U.S. Department of Health and Human Services.
Everyone over age fifty should take supplements of B12 to help prevent neurologic damage due to deficiencies caused by malabsorption or “atrophic gastritis.” —National Academy of Sciences
The important fact is the sooner you catch and correct a B12 deficiency, the greater the chances of full recovery. If the brain is deprived of 1312 for long periods, brain damage can become permanent. Dr. Robert Russell, Tufts University warns: “Always suspect a vitamin B12 deficiency if an older person develops unexplained neuropsychiatric problems.”
Better yet, don’t wait for a brain-busting B12 deficiency to occur. Take B12 supplements as insurance. They may not totally prevent a deficiency, but they sharply cut your risk. A recent study of 400 older people found that 40 percent of those not taking a vitamin supplement had low B12 compared with only 12 percent of those taking a daily supplement containing on average a mere 6 micrograms of B12. In other words, non-multivitamin-takers tripled their risk of B12 deficiency.
The B12 in supplements is a “crystalline” form which is much better absorbed than B12 in food, despite low levels of stomach acid due to atrophic gastritis. You can take B12 supplements at any age—they are extremely safe. But for sure, you should take B12 after age fifty (when atrophic gastritis could set in).
How much? Dr. Lindenbaum recommended that people past fifty take 500 to 1,000 micrograms of B12 a day. Dr. Robert Russell at Tufts University, also an expert on B12, says all older people should take B12 supplements. He advises 1,000 micrograms daily, even 2000 micrograms if necessary to overcome severe malabsorption or advanced atrophic gastritis. B12 is considered remarkably safe even at high doses. In fact, there have never been any reports of adverse effects from B12 at any dose. However, some experts set 3000 micrograms daily as the top safe dose.
High doses of vitamins and minerals could become toxic to the body and brain. Here is a guide to how much is safe:
After an extensive review of the medical research on vitamins and minerals, John Hathcock, Ph.D., formerly with the Food and Drug Administration, and now with the Council for Responsible Nutrition, compiled the following chart of supplement risks for adults:
Nutrient Daily Safe Dose* Lowest Dose Known to Cause Harm
Vitamin A 10,000 IU 21,600 IU
(retinol) (liver damage)
Beta carotene 25 mg none known
Vitamin D 800 IU 2000 IU
Vitamin E 1200 IU none known
Vitamin C Over 1,000 none known
Thiamin (B1) 50 mg none known
Riboflavin (B2) 200 mg none known
Nicotinic acid: 500 mg 1000 (500 mg slow
Nicotinamide: 1500 mg 3000 mg
Pyridoxine (B6) 200 mg 500 mg
Folic Acid 1000 micrograms none known
Vitamin B12 3000 micrograms none known
Calcium 1500 mg more than 2500 mg
Magnesium 700 mg none known
Chromium 1000 mcg none known
Iron 65 mg 100 mg
Selenium 200 mcg 910 mcg
Zinc 30 mg 60 mg
*No adverse effects have been noted at this level.
SOURCE: John N. Hathcock, Vitamin and Mineral Safety, Council of Responsible Nutrition, Washington, D.C. (Hathcock, J.N., American Journal of Clinical Nutrition, 66:427-37, 1997) Copyright: Council for Responsible Nutrition.