B vitamins: a Whole Complex of benefits

Better Nutrition, April, 1999 by James F. Scheer, Patricia Andersen-Parrado

The B-complex family of vitamins -- especially folic acid, critical for preventing neural tube defects in babies, and other benefits -- are necessary for the overall health of your entire family.

While they may not be as well known as vitamins A or C, the B vitamins -- especially folate -- are certainly making a name for themselves these days. In fact, in 1998, the Food and Nutrition Board, the group within the National Academy of Sciences that sets the Recommended Dietary Allowances (RDAs), published revised RDAs, now called Dietary Reference Intakes (DRIs), for the B vitamins.

The B vitamins work together as a team, which is why it is generally recommended that we take a B-complex supplement, rather than individual B vitamins.

Here, get to know the whole "B" family -- the B-complex and other B-like vitamins -- and why they need to be on your "A" list of "must-have" nutrients.

Folic acid in the forefront

For healthy babies. How hungry are you? Starving, I hope, if you're going to manage to eat all the food it'll take to get the folic acid you need.

Imagine eating two heads of lettuce, three apples, five bananas, and seven carrots every clay in hopes that your intake of folic acid (folate) will reach the minimum requirement of 400 micrograms.

As most of us have heard and read lately, women of child-bearing age are now being urged to increase their folic-acid intake in order to help prevent neural tube defects in infants, such as anencephaly (a condition in which the brain never develops) and spina bifida (when a segment of the spinal nerve cord grows outside the bony spinal column).

Even if you could eat all of the aforementioned food in one day, you still might be short-changed in reaching your desired daily intake of folic acid. Why? Two reasons: (1) amounts of nutrients in vegetables and fruits vary according to the richness or poverty of the soil in which they're grown, and (2) research shows that folic acid derived from food may be less readily assimilated and utilized than that delivered in supplement form.

One such study, published in the British medical journal Lancet, found that folate supplementation and folate-fortified foods provided more bioavailable folate than did foods which are naturally high in folate, such as spinach, orange juice, and liver.

Folate for colon-cancer prevention. In a study on folic acid in relation to colon cancer prevention among women, Harvard University's Edward Giovannucci, M.D., Sc.D., and a team of colleagues found that folate from both foods and supplements helps to insure good health. However, again, supplementation seemed to have a more protective effect, according to the researchers.

Giovannucci, and associates, studied 88,756 women (The Nurses' Health Study), who were free of cancer in 1980, to determine if folic acid intake could, over time, reduce the incidence of colon cancer. They provided updated assessments on diet, including multivitamin supplement use from 1980 to 1994. During that time, 442 women developed colon cancer.

Their conclusions? The longer the women took folate, the lower their risk of developing colon cancer. Nurses whose intake of folic acid in 1980 was greater than the current recommended daily amount of 400 mcg were found to have a 31-percent lower risk of developing colon cancer than those who ingested only 200 mcg.

Giovannucci reported a cumulative value from folic acid -- no obvious protection in the first four years -- and a suggested 20-percent gain in benefits after five years. Women who took folic acid for 14 years were shown to decrease their risk of colon cancer by as much as 75 percent.

Folic acid for heart health. Mounting evidence indicates that folic acid can also help to prevent heart attacks by reducing blood levels of homocysteine, a chemical that, when elevated, may trigger hardening of the arteries and raise the risk of stroke, heart attack, or even dementia.

A study by researchers from Tufts University, Boston, Mass., published in The Journal of Nutrition, examined the eating habits of almost 900 elderly people participating in the Framingham Health Study. They found that those whose diets included the most fruits, vegetables, and folate-fortified breakfast cereals also had the lowest levels of homocysteine in their blood.

Lastly, certain groups, particularly alcoholics and those with chronic digestive problems, are at a higher risk of folic-acid deficiency, as larger amounts of this B vitamin are secreted than are absorbed.

Meet the rest of the B's Vitamin B-12

When most people hear "anemia," they immediately think of iron-deficiency; however, since vitamin B-12 is required for red-blood cell formation, a deficiency or absorption problems can lead to what's called "pernicious anemia."

Since vitamin B-12 is found almost exclusively in animal-derived foods (including eggs and dairy products), those who refrain from eating such foods must take a supplement and/or eat foods fortified with B-12.

Aging and vitamin B-12. Some research has shown that vitamin B-12 levels decline as we age. In his book, All About B Vitamins, Burt Berkson, M.D., Ph.D., proposes several reasons why this may be so: reduced intake, unhealthy diets, or poor absorption. If low levels of B-12 are related to absorption, he says that injections of B-12 or sublingual (under the tongue) supplements should help.