Saturday, May 23, 2009

Vitamin B12

Go to Health – Vitamin B12

Vitamin B12 plays a key role in the normal functioning of the brain and nervous system, and in the formation of our red blood cells. It is involved in the metabolism of every cell of the body, especially affecting the synthesis of DNA (our genetic material).

Vitamin B12 is bound to the protein in food from animals (fish, meat, poultry, eggs and dairy); mollusks like clams and oysters are especially high. B12 is not present in plant proteins. Fortified breakfast cereals are an important source of vitamin B12 for vegetarians. Hydrochloric acid in our stomach releases vitamin B12 from proteins during digestion. Once released, vitamin B12 combines with a protein called intrinsic factor (IF). This complex can then be absorbed by the intestinal tract.

Young people eating a variety of animal foods are rarely deficient in Vitamin B12, unless they have an underlying disorder of the stomach or small intestine (such as untreated celiac disease , or surgical removal of these organs). Vegans – who eat no animal protein - should take supplemental B12; pregnant and lactating women should of course be careful to eat well and take supplemental vitamins as prescribed.

Older adults can develop a condition known as atrophic gastritis with inflammation of the stomach, bacterial overgrowth, and a deficiency of the protein known as intrinsic factor. Without intrinsic factor, vitamin B12 cannot be absorbed. This condition can lead to an illness known as Pernicious Anemia, which is treated with Vitamin B12 and other B vitamins. Patients have anemia, fatigue, numbness and tingling in the hands and feet , difficulty in maintaining balance, depression, confusion, dementia, and soreness of the mouth or tongue. Any one with these symptoms should seek medical care, as they will need careful assessment and treatment.

Scientists are now seeing that low levels of B12 can cause problems even if Pernicious Anemia is not present. New studies are showing the benefits of high normal levels of this vitamin.

*Brain Power A recent study from Oxford University in England found that adults over age 60 who had higher vitamin B12 levels were 6 times less likely to experience brain shrinkage than those with lower levels on testing 5 years later. Testing involved brain scans and memory tests. None of the people in this study had what would be called vitamin B12 deficiency. The lead author in this study wrote:
‘Many factors that affect brain health are thought to be out of our control, but this study suggests that simply adjusting our diets to consume more vitamin B12 through eating meat, fish, fortified cereals or milk may be something we can easily adjust to prevent brain shrinkage and so perhaps save our memory.’ The study did not look at whether taking vitamin B12 supplements would have the same effect on memory.

*Link to 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 levels. This finding did not apply to men in a similar study from Spain.

*Bone strength: several studies show an association between B12 levels and bone strength. B12 seems to help osteoblasts , bone-building cells.

*Age-related Macular Degeneration: this is the leading cause of blindness in the elderly. A Harvard study showed women taking high doses of vitamins B6, B12 and folic acid were found to have significantly more protection from this eye disease than women on placebos. Epidemiologist and study author William G. Christen of Harvard Medical School said that if these findings are successfully replicated in future studies, "the combination of these vitamins might become the first prevention method of early stages of age-related macular degeneration other than avoiding cigarette smoking” He felt that the same results would also be true for men.

Hearing Loss: A study from the University of Georgia showed that hearing loss was associated with low concentrations of serum vitamin B-12 and red cell folate (folic acid – another B vitamin). Animal studies have also shown this correlation..

Based on these recent findings, many doctors are advising people reaching middle age, as well as vegetarians and vegans, to supplement with vitamin B12. A test is available to determine blood levels of the vitamin; levels considered normal have gone up in recent years. Levels below 200 pg per milliliter were considered low in past years, but now optimal levels may range from 500 to 1000 pg/ml. If you have this test, your doctor or nurse-practitioner will advise you about your results.

In cases of deficiency, vitamin B12 can be given by injection. However, people can also take oral B12 tablets that are dissolved under the tongue, so that the vitamin goes straight into the blood stream. Fortunately Vitamin B12 is a safe supplement, and it is becoming more popular among people aware of the aging process. Stay in touch with your body’s needs as the years go by.
Sadja Greenwood, MD –back issues on my blog

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