I’m often asked about my attitude to nutrient supplementation. Do we ‘need’ to supplement, is how it’s often put to me. My answer is that it is probably entirely possible to get all what we need to prevent overt nutritional deficiency diseases such as scurvy and beri-beri. However, less obvious deficiency states may occur quite easily that might impact on an individual’s ability to be optimally nourished and therefore enjoy optimal health. Also, there is evidence that, in the UK at least, the nutritional content of the diet has declined considerably over the last few decades. So, bearing all this in mind, I am generally warm to the idea of using nutritional supplementation, especially as an adjunct to (rather than a replacement for) a healthy diet.
However, not everyone is as enthusiastic as I with regard to the practice of nutritional supplementation. I often hear people contend that there is no evidence for it, and that taking supplements only serves to make expensive urine.
This attitude may come, at last in part, from a lack of evidence in the form of randomised controlled trials ” considered the gold standard of scientific studies. But, the reality is that very few such trials seeking to elucidate the benefits (or otherwise) of multivitamins and minerals or single nutrients have been done. So, let us not ‘conclude’ that nutritional supplementation doesn’t work when it has not, it seems, been adequately studied.
And furthermore, even when such studies are done, they are not without limitation. One major issue here is that many health conditions have considerable ‘latency’ ” which basically means they develop gradually over many, may years. Because of this, any benefits of nutritional supplementation may not materialise for many, many years. So studies may not be conducted for long enough for any benefits to come to fruition.
Also, there are certain ‘methodological’ issues to consider, which include the dose of nutrients and the form they come in. Using too little of a nutrient, particularly in a form than is not particularly utilisable by the body, may produce results that don’t say much about what benefits may be had by having decent doses of more ‘bioavailable’ nutrients.
Despite these limitations, there is indeed some evidence that nutritional supplementation can have benefits for health. Just such a study was published this month in the American Journal of Clinical Nutrition . In this study, the effect of nutrient supplementation was assessed on the brain function of about 800 Australian and Indonesian children. For a period of a year, each child was given a daily drink containing:
1. the nutrients iron, zinc, folate, and vitamins A, B6, B12, and C
2. the omega-3 fats DHA and EPA
3. both the nutrients and the omega-3 fats
4. no additional nutrients (placebo)
The cognitive function of the children was assessed at the outset of the study, as well as at 6 months and the conclusion of the study (1 year).
Omega-3 supplementation was found not to enhance brain function, though the nutrient (vitamin and mineral) supplementation was. Those supplemented in this way saw significant increases in scores on tests of verbal learning and memory.
It is perhaps worth noting that the dosage of omega-3 used in this study (actually 88 mg per day of DHA and 22 mg per day of EPA) are much lower than the dosages generally believed to have benefits for the brain. So, not only does this study support the concept of nutritional supplementation, it aptly demonstrates one of the potential limitations of trials of nutritional supplementation too.
Osendarp SJM, et al. Effect of a 12-mo micronutrient intervention on learning and memory in well-nourished and marginally nourished school-aged children: 2 parallel, randomized, placebo-controlled studies in Australia and Indonesia. Am J Clin Nutr 2007; 86(4): 1082-93.