Updated 29 August 2013

The problem with vitamins

On the one hand, the complementary health industry promotes vitamins, minerals and other supplements. On the other, it’s argued that supplements may be a waste of money, or risky.


If you were confused before about whether nutritional supplements are essential for your health or "just expensive urine", news over the past few weeks highlights exactly why that should be.

The good news: researchers have found "conclusive evidence" that vitamin D cuts the risk of breast cancer in women; another study has "clearly shown" that giving small children supplemental vitamin D helps prevent them from developing type 1 diabetes later on; and yet another has found that the vitamin could extend the lives of people with colon and rectal cancer.

The bad news: contrary to findings from earlier studies, it appears that rather than high vitamin D levels decreasing the risk of prostate cancer, they in fact elevate the risk of aggressive disease. But wait: researchers emphasise that these findings might have occurred by chance.

So the same vitamin can be both very good for you, and very bad for you.

What should we believe?
The truth is, the jury is still out. Both sides of the debate about the value of supplements are backed by good evidence.

For decades now, numerous studies have pointed to the benefits of getting an extra dose of calcium, folic acid, omega-3 fatty acids, probiotics, and more. And the evidence for supplementation of specific nutrients is mounting.

However, almost as many studies have showed that the supplementation of certain nutrients has little or no effect on disease. Others indicate that it could fuel disease under specific circumstances.

Hence the apparent contradictions implicit in the vitamin D studies. What makes this more interesting to South Africans is that that it has always been believed that, since our bodies produce their own vitamin D upon sun exposure, those of us living in sunny climes like South Africa, this is one vitamin we shouldn’t have to worry about. Now, it transpires, this isn’t true – indoor living and greater awareness about the dangers of sun exposure mean that most of us in fact don’t produce adequate levels of the vitamin.

Highly individualised
It's clear that the vitamin story is multifaceted, and as the body of research grows, so might the confusion. This makes the decision about whether to go the supplement route a tough one to make.

What we do know, is that most of us are nutritionally deficient. Unless you grow your own fresh produce, and eat it within a few hours of harvesting it, you won’t be getting all the nutrients you need. Fresh food that travels from the field, to cold storage, to the supermarket, and then spends some time in your fridge before you eat it, loses nutritive value along the way. Highly processed foods, part of many peoples’ diets, are often not as nutrient-dense as fresh foods. So, our need for supplementation may indeed be growing the further we get from the chain of production.

But we can't ignore the fact that supplementation may be risky. In March 2007, for example, a major review of studies showed that supplements of the antioxidants beta-carotene, vitamin A and vitamin E, taken alone or together with other supplements, increased mortality (death) significantly. Oh but wait: many of the reviewed studies included participants from affluent communities who might have taken excessive amounts of supplements on top of fairly adequate diets. So maybe we need to rethink that.

Health24’s position
We believe supplementation should be tailored to individual need. If you’re tuned into your health, you’re more likely to pick it up when you’re hitting a deficiency.

So take a look at yourself: if your hair and/or skin lacks lustre, your nails aren’t strong and glossy, you’re gaining or losing weight for no apparent reason, your energy levels are down, your mood is bleak, you’re feeling unexplained aches and pains, you’re forgetful, you’re often ill, or your digestion is all over the place, it might be time to consult a dietician who’ll be able to discuss your diet with you, point out the gaps, and possibly recommend where supplementation will be helpful.

We support the following guidelines by the Nutrition Information Centre of the University of Stellenbosch (NICUS):

1. Make sure you're consuming an adequate diet, which includes a variety of foods.

2. Consult an expert on the adequacy of your diet.

3. Avoid supplements with glamorous multi-claims, which cannot be substantiated when scrutinised.

4. Avoid single-nutrient supplements.

5. Check the composition of the supplement you plan to take or are taking. The label should have a list of all the vitamins and minerals in the product and also the amounts. Most labels will also specify the amounts of the vitamins and minerals as a percentage of the RDA (Recommended Dietary Allowance).

The RDA is defined as the intake that meets the nutrient needs of almost all (97-98%) individuals in that gender group, at the given life stage. It's important to recognise that the RDA applies to individuals and not to groups and is the goal for dietary intake by the individual.

Choosing a complete supplement that contains all the vitamins and minerals is also advisable.

6. Choose a multi-vitamin, multi-mineral supplement that contains up to 2-3 times the RDA. The percentage should therefore not exceed 300% of the RDA and the majority of percentages should be between 50% and 150% of the RDA.

Also bear in mind that the strongest or most concentrated formula is not always the best choice. Too much of certain vitamins and minerals in your multivitamin, multimineral supplement can be harmful. Be especially cautious of taking vitamin A, vitamin E and iron in excessive amounts.

As fortified foods are widely available nowadays, there is a risk of exceeding the upper tolerable level (UL) of certain vitamins and minerals if you are taking a multivitamin or a single dietary supplement every day, in addition to eating fortified foods. It's best to have a registered dietician review your diet and then provide individualised advice about taking dietary supplements.

Despite the complex composition of foods, some of which is known (more is unknown or is being studied), we often incorrectly assume that a balanced, varied diet can be replaced with pills of single or multiple known nutrients. It's vital to remember that taking supplements is not a substitute for a healthy, balanced diet and lifestyle. Supplements don't provide the necessary fibre and disease-fighting natural substances in food, such as the phytochemicals found in fruit and vegetables.

7. Reassess your need to take such supplements regularly and for prolonged periods.

8. Report to your doctor any adverse effects you think may be linked to the supplements.


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