How much do you know about vitamins? Test your know-how in this brief quiz:
1. It's possible to obtain all the vitamins and minerals your body needs by eating the right foods and taking one multivitamin a day.
A: True B: False C: It depends.
2. Nonprescription vitamins and supplements are safer than prescription medications.
A: True B: False C: It depends.
3. Your doctor needs to know all the pills you're taking, whether they're by prescription or not.
A: True B: False C: It depends.
For the first two questions, the answer is C. The answer to number 3 is A.
Quest has reported on supplements such as L-carnitine, creatine and coenzyme Q10, all of which are being taken by people with neuromuscular diseases despite the lack of conclusive available evidence that they're actually helpful.
What about vitamins? Are they of any more use to people affected by neuromuscular diseases than to the general population? What should you take and how much? We asked a number of physicians who serve as directors of MDA clinics to help bring us up to speed on the current level of understanding about the world of vitamins.
ABCs of Vitamins |
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Vitamins are substances found in food and in some cases produced in the body that support essential processes within the body. They do so by serving as coenzymes, nonprotein compounds that assist enzymes in enabling vital reactions to take place, or as precursors (substances contributing to the development of other substances) of coenzymes.
The essential processes vitamins assist with include conversion of food to energy, building of red blood cells, manufacture of hormones, development of bones and teeth, regulation of blood sugar levels as well as blood pressure, maintenance of muscle tone, prevention of imbalances that may lead to mental illness, bolstering of the immune system, promotion of healing, and maintenance of hair, skin, eyes, nerves, nails and mucous membranes.
In other words, vitamins help us to live.
Some vitamins, such as vitamin B complex and vitamin C, are water-soluble. They're quickly eliminated and therefore not stored in the body. Thus, they need to be replaced regularly. Other vitamins, such as A, D, E and K, are fat-soluble and stored in the body. These vitamins are more likely to cause toxicity problems if taken in excessive doses.
A healthy, well-balanced diet should provide many of the vitamins and minerals a person needs. Few people are able to maintain such a diet, however. Even if they can, it's difficult to be certain that fruits and vegetables haven't been grown in mineral-depleted soil or lost much of their vitamin potency while being stored or prepared.
Many other factors, including emotional stress, physical exertion, infection, disease, use of prescription medications, use of illicit drugs and alcohol, trauma and aging, can interfere with adequate absorption of vitamins and necessitate a higher vitamin intake.
Vitamins should be kept in a cool, dry, dark place. Kept too long, they can lose potency and should be discarded.
Unlike prescription drugs, vitamins and supplements aren't regulated by the Food and Drug Administration (FDA). Manufacturers aren't required to prove the substances' safety or efficacy.
It's possible to suffer serious effects from a marked deficiency of a particular vitamin. Scurvy, arising from deficiency of vitamin C, causes such symptoms as weakness, muscle and joint pain, and loosening of the teeth.
RDIs: Everything You Need, Or Just a Starting Point? |
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The government has determined minimally required levels of vitamins and minerals for the typical adult. These levels, once called RDAs for recommended daily allowances, are now officially referred to as RDIs, reference daily intakes. (Some professionals still use the old abbreviation.)
The packaging of your multivitamin will tell you what percentage RDI is included for each vitamin or mineral. However, there's much debate and controversy about whether RDIs provide all you need or whether they're simply a starting point for a more complex vitamin regime.
Each physician or nutritionist has a set of beliefs about vitamin requirements. What's more, each vitamin plan must be tailored to an individual's needs.
"Nutrition is a very important part of anyone's care, so we do talk about diet and vitamins and supplements," says Lawrence Stern, director of the MDA clinic at the University of Arizona Health Sciences Center in Tucson, where people with any of the neuromuscular diseases in MDA's program can receive attention.
"We recommend that people be on a standard regimen, which is a good therapeutic multivitamin/mineral combination, something like Centrum," he says. "And then I usually recommend supplementation beyond that of vitamins C and E. Something like 500 to 1,000 milligrams of vitamin C a day and 400 to 800 international units of vitamin E probably isn't going to hurt you."
In specific cases, he'll recommend supplements such as coenzyme Q10, L-carnitine and creatine, depending on the neuromuscular disorder.
Robert McMichael, director of the MDA clinic at Neurology Associates in Arlington, Texas, isn't a huge advocate of coenzyme Q10, L-carnitine and creatine. But he believes they're mostly harmless and doesn't discourage his patients if they feel strongly about taking them. He also talks to them about traditional vitamins.
"I think a dose of up to 1,000 units a day of vitamin E and 500 to 1,000 milligrams of vitamin C is reasonable," says McMichael. In addition to being a neurologist who treats people with neuromuscular diseases, McMichael is himself affected by the limb-girdle form of muscular dystrophy.
Deborah F. Gelinas, co-director of the MDA clinic at California Pacific Medical Center in San Francisco, generally recommends vitamins C, E and B complex.
"In ALS, I recommend creatine as well as a few other supplements such as ginseng and soy isoflavone, vitamin E and coenzyme Q10. That's because those appear to have some benefit in the transgenic mouse model of the disease," says Gelinas.
Caveats and Concerns |
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"There are lots of consequences of vitamins and supplements," says Gelinas. "You can get very significant reactions with prescription medications. You can get clinical syndromes from taking too many vitamins. You can get prostatic hypertrophy, facial hair, kidney stones. You can actually get some kinds of encephalopathy [diseases affecting functioning of the brain] from excess of the fat-soluble vitamins."
Gelinas points out that multivitamins are offered in accordance with the guidelines of the FDA for minimum daily requirement, "so they're minimum, and they're safe. But patients who are exploring vitamin and supplement options are really talking about megadose therapy. When you're doing megadosing, you need to know what's safe and what's not safe and what are the side effects to watch out for."
"Vitamin B6 can be toxic to peripheral nerve, and I've seen several patients who developed sensory loss by taking it," says McMichael. "For example, somebody with Charcot-Marie-Tooth disease wouldn't want to be taking too much B6.
"Doses greater than 100 milligrams a day carry a risk of nerve damage, and the higher the dose, the more the risk is," he says. "In pharmacies, I've seen 200-milligram tablets of B6. However, the dose you would get in a multivitamin pill would be your RDA and would be far below the dose that would be toxic.
"If you take too much vitamin A, it can cause skin problems and cracking around the lips," McMichael says. "The maximum dose of vitamin A would be 20,000 or 30,000 units. And the better preparation would be to take as much as possible in beta-carotene form, or just take beta-carotene, period." Beta-carotene is a substance that's converted into vitamin A in the body.
It's possible to experience digestive difficulties such as a "sour mouth" effect from high doses of vitamin C, which is also called ascorbic acid.
"With regard to most other vitamins, I think it's unlikely you'll encounter ill effects," says McMichael. "But vitamin E does have a mild anticoagulant effect. So somebody taking a large dose of vitamin E and also taking aspirin or some other blood thinner would have more propensity to bruising or bleeding problems than somebody who does not.
"Also, in pregnancy, you should ask the obstetrician about what supplements should or shouldn't be taken," McMichael advises.
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