Vital vitamins: The key to good health

Vitamins are not only important to good health, they’re essential to life. They don’t contribute significantly to the body’s energy needs, but without them carbohydrates, fats and proteins can’t do their jobs. Vitamins turn food into energy, rejuvenate the forces of the immune system, nourishes soft tissues, organs and bones, and stimulate growth — among a host of other functions.

There are at least 13 vitamins that are vital in maintaining health and preventing disease, plus a number of other chemical substances — including bioflavonoids, biotin, carnitine, choline and folic acid, among others — that appear to be important to good health. Just how many other chemicals in foods are essential still isn’t known, which is why a varied and balanced diet is so important.

Many vitamins were first identified through observations of single-nutrient diseases, such as osteomalacia, the adult form of rickets, which causes bone deformities as a result of vitamin D deficiency; or scurvy, the scourge of ancient mariners, a vitamin C deficiency. We now know there are two types of vitamins: fat-soluble (A, D, E and K) and water-soluble (C and the eight Bs). Each performs specific tks in the body. Vitamin A, for example (from retinols in animal products, such as liver, salmon and egg yolks, and beta carotene in orange and yellow fruit and vegetables), helps keep vision sharp and skin healthy; it also promotes resistance against infections. Vitamin C (ascorbic acid) plays a key role in metabolizing essential minerals that ensure healthy bones and blood vessels. Citrus fruits are chock-full of C, but there are plenty of other good sources, including peppers and tomatoes, melons, broccoli and potatoes.

Vitamin D (cholecalciferol), which contributes to strong bones and teeth by promoting proper metabolization of calcium and phosphorous, is taken mostly from dairy products and fatty fish, and their oils and livers (as in cod-liver oil). The B vitamins — including B1 (thiamine), B2 (riboflavin), B3 (niacin), B6 (pyridoxine) and B12 (cobalamin) — perform a variety of important functions, including helping our bodies metabolize the nutrients in food.

Vitamin E (alpha-tocopherol) helps in the formation of red blood cells and muscle tissue, and is taken from whole-grain products and vegetable oils. Vitamin K (menadione) — from leafy green vegetables — contributes to healthy blood clotting.

Scientists have discovered that some vitamins also have an antioxidant effect, which may help reduce the risks of heart disease and some cancers. All body cells burn oxygen; in the process, they release unstable molecules called free radicals that can damage healthy cells, sometimes causing mutations that can lead to cancer and other diseases. Our immune systems generally sweep up free radicals before they do any harm, but as we age and the immune system weakens, more and more free radicals survive, and the incidence of degenerative conditions rises.

The best counter-measure is to increase your intake of antioxidants — molecules that latch onto free radicals and render them harmless. The major antioxidants — found in fatty fish, fresh fruits, vegetables and vegetable oils — are vitamins C and E, selenium, and beta carotene, which the body converts to vitamin A, but there are a number of other substances with antioxidant properties, including bioflavonoids (found in many fruits and vegetables) and various plant-derived phytochemicals.

In terms of cancer prevention, a host of studies have pointed to the benefits of including more vegetables and fruits in your diet, says Monica Vegelji, a registered dietician at The Toronto Hospital, “but so far the clinical trials are not as convincing as the epidemiological data. Population researchers, the epidemiologists, will tell you that if the population were to follow the nutrition recommendations outlined by Canada’s Food Guide and actually get their five to 10 fruits and vegetables every day, there’d be about 20 to 30 per cent less incidence of cancer.

“That’s a pretty dramatic finding. If there were a pill that came out that did the same thing, it would be front-page news. But somehow, because it’s only fruits and vegetables, people have a hard time swallowing it, if you’ll pardon the pun.”

In some cases, Vegelji says, the evidence produced in large trials is quite compelling. Studies done at Harvard University “seemed to indicate” vitamin E supplements (200 IU — International Units — daily) may lower the risk of heart disease. “But this is not proof. To prove something in a clinical trial with nutrition… well, it’s very difficult to control. So, while we can’t say we have concrete proof, we do have very compelling evidence.”

That’s good enough for Joe Schwarcz, Ph.D., who teaches chemistry at McGill University and Vanier College in Montreal. Schwarcz advocates taking vitamin supplements “at all ages. Especially because as people get older they naturally eat less, and the less they eat, the less likely they are to get all the vitamins and minerals they need. I think at the very least a one-a-day vitamin-mineral supplement is a good idea. Taking 200 IU of vitamin C and 200 IU of vitamin E as well is very supportable.”

Once thought to be a cold-preventative (it may improve symptoms slightly), vitamin C is now known as a potent antioxidant. “What we know is you really need vitamin C, beta carotene and vitamin E acting together as a team in order to support each other and act as antioxidants,” Schwarcz says. “It’s a synergistic effect. At 200 mgs/day, nobody’s taking any risk at all with vitamin C.”

As a chemist, and as a consultant and contributor to the bestseller Foods That Harm, Foods That Heal, Schwarcz is well aware that vitamin E is still a contentious issue. The Mayo Clinic Health Letter reported that “vitamin E shows promise in the fight against cardiovascular disease, but the final chapter isn’t written… More study is needed to establish the safety and benefits of vitamin E and other antioxidants.”

Schwarcz argues that studies will always be contradictory and inconclusive, and the risk “is essentially non-existent in taking those amounts [400 IU or less daily].”

And, when it comes to vitamin E as an anti-heart disease agent, supplements are essential. You can’t build an effective level of vitamin E in the bloodstream with a regular diet; you’d have to eat about five pounds of broccoli alone to measure up, or swallow a half-pound of butter.

Dieticians generally don’t recommend vitamin supplements, unless they’re required due to dietary restrictions; they prefer that you get your nutrition from a healthy, balanced diet. With vitamin C and beta carotene, it’s easy to get the good antioxidant effects described in studies through diet alone, Vegelji maintains, “simply by eating your five to 10 vegetables and fruits, and focusing on the dark red, orange and green vegetables and fruits, which are the highest in antioxidants, in folic acid, in beta carotene. That includes beets, and red peppers — an excellent source of vitamin C. One half of a green pepper has as much vitamin C as an orange, and C is even more concentrated in red peppers than in green.”

Vitamin E is another story. An Ontario survey found that many people are not getting even the RNI (Recommended Nutrient Intake) level of vitamin E, Vegelji notes, “and the amount to get the antioxidant effect is about 10 times that. Opinion now among dieticians and physicians is divided. One school says we don’t have concrete proof as to the long-term effects of taking lots of vitamin E, and until we get that proof we’re not going to recommend it.

“On the other hand, in all the trials we have so far for vitamin E with people taking 400 IU — which is more than 10 times the RNI — for a period of eight years, we haven’t seen any ill effects, and there’s some compelling evidence that there may be a benefit with regard to heart disease.”

Thus, Vegelji’s advice is to go with a supplement, but supplement conservatively: “I’d suggest taking a 400 IU supplement of vitamin E every other day. You may want to get on to, say, a Monday-Wednesday-Friday routine. And, because it’s fat-soluble, it’s stored in our own body fat. You won’t excrete it in your urine if you take an extra amount one day.”

If your caloric intake is very low, as it often is in the over-50 population, Vegelji also recommends a daily multiple vitamin.

If you’re concerned about getting enough vitamin E, check the label to see what nutrients various multiple vitamins contain. Since most only contain about 60 IU of vitamin E, you’ll have to supplement it with extra E to get up to the 200 IU/day level.

Vitamins A and D have a high toxicity level and should be taken conservatively. Most people, especially in the summer, when they’re outdoors more often, will get all the vitamin D they need right from the sun. The skin converts the sun’s rays to a usable form of vitamin D — and it doesn’t take much: Ten to 15 minutes’ worth of midday summer sun, hands and face only, will give you your daily requirement. “And you can’t get vitamin D toxicity from sunshine,” Vegelji says. “It’ll turn itself off, turn off the vitamin D synthesis. Aren’t we efficient? The human body is amazing.”

Vegelji also points out that calcium supplements are often available with magnesium and vitamin D rolled in, “which is a good idea,” she says, “because the magnesium and the vitamin D will actually improve the absorption of the calcium. If you’re concerned, check out each supplement with your pharmacist.”

With vitamin A, keep in mind that it’s really two nutrients in one, so you have a choice as to how you take it. As Patricia Hausman and Judith Benn Hurley point out in The Healing Foods (1991), “Animal foods contain retinol, or preformed vitamin A. Plant foods contain the nutrient in its precursor form [beta carotene], which is converted to vitamin A in the body.”

In terms of its anti-cancer effect, vitamin A has been linked to both forms, but, as Hausman and Hurley note, “carotene-rich foods have the longest list of credits. Why? Possibly because of the antioxidant properties that carotene has and retinol lacks.”

Hausman and Hurley also recommend carotene A over retinol A because, they say, it’s safer. An excess of carotene can lead to a yellow-orange discoloration in the skin, but it’s not toxic, and your skin will clear up once you cut back your carotene intake. On the other hand, “taken in large amounts, preformed A can lead to toxic symptoms — a syndrome that begins with peeling skin, headaches and digestive complaints.”

The bottom line on vitamins is that, taken in megadoses, they’re no longer “just” vitamins, they’re pharmacologically active substances — in other words, drugs. As June Engel, Ph.D., notes in her 1996 compendium, The Complete Canadian Health Guide, in large doses, some vitamins can produce harmful effects. It’s not just the fat-soluble vitamins, such as A and D, that are potentially harmful in megadoses — a danger Engel says is “widely acknowledged” — scientists have now shown that “even some water-soluble vitamins can be harmful in large doses.”

The recommended daily limit for vitamin B6, for example, is 200 mg/day; people taking as little as 250 mg/day could cause damage to nerves, leading to numbness in the limbs and extremities, loss of sensory perception and difficulty walking; and megadoses of vitamin C (more than a gram-and-a-half/day) can cause diarrhea and increase the risk of certain kinds of kidney stones.

Fortunately, such risks are relatively small. But, if you’re thinking of “megadosing” with vitamins to improve your overall health or treat a health condition, check with your pharmacist or dietician. Even a little vitamin goes a long way.