Do we really need nutritional supplements — and would they even do us any good? If we believe the naysayers, nutritional supplements like vitamins and minerals are worthless; no clinical vitamin/mineral trial has ever shown any benefit. Besides, we′re told, we can get all our vitamins and minerals from a balanced diet.

Relying on our diets for all our nutritional needs is simply unrealistic. There might well be such a thing as a "complete balanced diet", but survey after survey has shown that hardly anyone follows dietary recommendations. If you get all your necessary nutrients from the food you eat you are truly an exception.

Yet, there are nutrients that we simply can′t do without. We need vitamins, minerals, essential fatty acids and essential amino acids because we either cannot make them at all or cannot make them in adequate amounts. If we don′t get them from food and drink — and every nutrition survey shows that we don′t — where else could get them but from supplements? So, how could supplementation be found to be useless?

The reason why nutrient trials usually give disappointing results is that they employ tools designed to evaluate pharmaceutical drugs. But nutrients aren′t drugs, and methods like randomized controlled trials (RCTs) — the "gold standard" of medical research — simply aren′t suited to the assessment of nutritional supplements (1).

The crucial difference between nutrients and drugs is that drugs are foreign to the body. Drugs interfere in metabolism and are useful only when this interference halts or slows a disease process. Nutrients, on the other hand, support metabolic functions; supplements are taken to ensure an adequate supply of essential nutrients. Put differently, drugs are used to treat disease whereas nutritional supplements are taken to prevent disease and optimize health. This makes all the difference when assessing drugs and supplements.

In randomized placebo-controlled trials a substance is compared to a placebo (treatment versus control group). Control groups are readily available for drug trials since the drug doesn′t occur in nature. In contrast, everyone has some — usually sub-optimal — level of essential nutrients, i.e. there can be no genuine control group. It is impossible to carry out true placebo-controlled nutrient studies.

Drugs interfere in physiological processes and usually act quickly. Drug trials can therefore be completed in a reasonably short time, Nutritional deficiencies, on the other hand, may take years or even decades to lead to symptoms. Clinical trials of that length of time would be prohibitively expensive.

Clinical trials of single drugs make sense since every drug has an effect of its own. Nutrients, on the other hand, work together; all essential nutrients have to be present in adequate amounts for optimal health. Clinical trials of individual nutrients are pointless.

Of course, there are numerous other differences between drugs and nutritional supplements. Most importantly, drugs have dangerous side effects and need to be monitored carefully. Nutrients, on the other hand, have wide safety margins.

All this is obvious, yet large sums of money are squandered on studying nutrients with tools developed for drug evaluation — with predictably inconclusive results. It is almost as if these trials are meant to fail.

It is actually quite hypocritical to demand that nutritional recommendations be backed by randomized controlled trials; most pharmaceutical therapies aren′t based on RCTs either! First, many drugs are prescribed for off-label use. Secondly, most people on prescription drugs take more than one medication. Neither off-label nor multi-drug prescription is supported by the supposed medical "gold standard". A cynic might say that the concept of randomized controlled trials is mainly used to dismiss non-pharmaceutical therapies as unscientific".

Of course, nutritional recommendations should be based on scientific evidence. Just remember that it is not the need for nutrients that is in question, but rather the amounts that we need for optimal health. We may not know yet what those optimal nutrient levels are but, given today′s diets, most people will surely benefit from nutritional supplements.

Sources

1. Shao A, Mackay D, A commentary on the nutrient-chronic disease relationship and the new paradigm of evidence-based nutrition, Nat Med J 2010;2(12):10-18.
   http://www.naturalmedicinejournal.com/pdf/NMJ_DEC10_LR2.pdf