The topic of vitamin supplements is currently a hot one. On the one hand, the more affluent populations in South Africa tend to take excessive doses of supplements, while on the other hand, the majority of our population are malnourished and deficient in essential vitamins and minerals.
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Then there is the question of using supplements to improve HIV/Aids outcomes, which is a burning issue in sub-Saharan Africa. This contrasts with international moves to reduce the doses of vitamins and minerals in commercial supplements.
What are we to believe – that vitamin and mineral supplements are good for us, or that they are bad?
No simple answer
There is really no simple answer to these questions. If you are basically well- or over-nourished, following a western diet and not exposed to certain stresses, you probably don’t need to take such supplements.
In fact, now that the SA Government has made vitamin and mineral fortification of wheat bread and maize flour mandatory, and every second processed food and beverage contains added vitamins and minerals, people following an affluent western diet could be ingesting excessive doses of nutrients such as vitamins A and D, iron and other heavy metals like zinc or selenium.
The two kinds of vitamins a) Water-soluble vitamins
Generally speaking, high doses of the so-called water-soluble vitamins (vitamin C and all the B vitamins) will not cause too much of a problem. Since they are water-soluble, the human body is capable of excreting these vitamins through the kidneys.
However, research results indicate that western diets tend to be deficient in certain B vitamins, especially folic acid. Although the fortification of bread and maize meal will help to alleviate this problem, there are certain periods in our lives when we need additional folic acid. For example, women who intend to fall pregnant should take an additional folic acid supplement in the pre-natal and natal period to ensure that their babies do not develop neural tube defects.
There is also evidence that supplementing folic acid, and vitamins B12 and B2 (riboflavin), can help to prevent increased homocysteine levels, which are associated with heart disease and possibly with the development of Alzheimer’s.
People who do not eat sufficient unprocessed grains and cereals, and vegetarians who do not eat meat or fish, are at risk of developing folic acid and B12 and B2 deficiencies.
Vitamin B12 is required to prevent megaloblastic or pernicious anaemia, which is relatively common in vegetarians and vegans.
Folic acid has also been identified as a potential anticarcinogen, so if you have a genetic risk of cancer, taking a folic acid supplement may be protective.
b) Fat-soluble vitamins
The fat-soluble vitamins A, D, E and F are quite a different story. Our bodies are capable of storing vitamins A and D, so that if you ingest excessive doses this can lead to conditions called hypervitaminosis A or D.
Unfortunately, hypervitaminosis can cause permanent damage to organs such as the liver and the skeleton. It is, therefore, a good idea not to take high doses of vitamins A and D if you have sun-exposure for about 30 minutes a day (our bodies manufacture vitamin D when the skin is exposed to sunlight) and if you already eat plenty of the following:
dark yellow and green fruits and vegetables (carrots, butternut, sweet potatoes, pumpkin, broccoli, spinach, pawpaw, mangoes, apricots, yellow peaches – these all contain beta-carotene which is converted into vitamin A in our bodies),
fortified bread and maize meal (contains vitamin A),
margarine (contains vitamin D).
If you need a vitamin and mineral supplement because of exposure to stress, rapid growth, strenuous physical activity at work or in sport, illnesses, etc, you should check that the vitamin A and D contents of the supplements do not exceed 100% of the Recommended Daily Allowance (RDA). If they do, you should only take one tablet three times a week.
Vitamin E or alpha-tocopherol is usually not a problem because most diets – even in the western world – are deficient in this vitamin. Most experts agree that adults of all ages would benefit from taking additional vitamin E on a regular basis.
The difference in our requirements for certain of the fat-soluble vitamins means that you may have to take different supplements for different purposes. You may only need to take a supplement which contains vitamins A and D three times a week as suggested above, but it may be prudent to take a vitamin E supplement every day.
Where supplements can play a vital role
There are many instances where vitamin and mineral supplement can play a vital role. The example of folic acid supplementation to prevent neural tube defects is such a case.
A recent study published by Fawzi and coworkers in the New England Journal of Medicine suggests that micronutrients such as vitamins and minerals can play an important role in maintaining immune function and neutralising oxidative stress.
The authors are of the opinion that “undernourished people infected with HIV could benefit from any measures to correct micronutrients deficiencies”.
The study was conducted in Tanzania with 1078 HIV-positive pregnant women, who took multivitamin supplements. Significantly fewer women progressed to the WHO stage 4 of this disease or died in a six-year follow-up period compared to women who were given no multivitamins.
Fawzi and coworkers recommend that patients with HIV may be able to delay the need for antiretroviral drugs by taking a daily multivitamin supplement. HIV/Aids is, therefore, a situation where the use of multivitamins can play an essential role.
The bottom line
We need to keep the following in mind when considering the use of multivitamin and mineral supplements:
If you are healthy, not exposed to extreme stresses, under the age of 50, and follow a balanced diet, you probably don’t need to take supplements.
If you are exposed to extreme stresses, are over 50, and have an identified deficiency (e.g. iron-deficiency anaemia or osteoporosis), taking one multivitamin and mineral supplement a day should be adequate.
If you are at risk of heart disease, certain cancers or osteoporosis, you could benefit from supplements – but don’t overdose on them.
If you are trying to fall pregnant or already are pregnant, you need to take folic acid daily and any other supplement, such as iron tablets, that your doctor may prescribe.
If you have HIV/Aids, then the use of a daily multivitamin may be of benefit.
Be sensible when you do take vitamin and mineral supplements. Consider taking one tablet a day, or if you are at risk of developing hypervitaminosis A or D, then take one tablet three times a week instead of daily.
Consider taking individual supplements, e.g. vitamin E, or folic acid, or calcium, rather than a complete supplement every day.
Moderation and a sensible approach should be applied when you take vitamin and mineral supplements. – (Dr I.V. van Heerden, DietDoc)
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