If scientists cannot explain the cause of a particular connection between food consumption and health outcome, they would do better to wait before seeking wide publicity
They should always ask themselves what their research findings really mean and whether they are biologically plausible. If they fail to do this, they will only be helping to confuse the public and damage the credibility of nutritional science, says Sander Kersten, Professor of Molecular Nutrition at Wageningen University, part of Wageningen UR.
Prof. Kersten is researching the effect of fat in foods at the cellular and molecular level. He refers to an example from his own field: the effect of unsaturated fatty acids in fish. ‘We have worked out why these fatty acids have a positive effect on human health. On the other hand, we also have fairly conclusive biological evidence that certain protective mechanisms in saturated fatty acids do not work effectively, causing them to accumulate in the cells and cause damage to the human body. This allows us as nutritionists to make confident claims about the differential effects of saturated and unsaturated fatty acids. However, if an important element is missing from our explanation, scepticism and reticence should be observed.’
In his inaugural address entitled Mechanisms of Dietary Fat, Kersten claims that there is no biological explanation for many of the effects that have been discovered. An American study that recently featured in the media claimed that eating chocolate frequently increased energy intake but lowered body weight. According to the press release, the study heralded an end to the commonly held belief that eating too much chocolate would make you fat. Prof. Kersten cites this as an example of how it should not be done. He wonders whether the scientists, information officers and press were perhaps a bit too quick off the mark. To his mind, this is a typical case of gross misinterpretation of very dubious data.
In his speech, Kersten explained how far nutritional scientific insight into the effects of fat had advanced over the past decades. Fat is not only a fuel that can either be used directly or stored before use. Kersten: ‘Fat regulates countless bodily mechanisms that affect metabolism and even our immune system. You could say it has a directing role. For example, we are currently examining one particular gene in the human body that is extremely sensitive to fatty acids. This gene controls a protective mechanism that combats the accumulation of fat in the body’s cells. It reacts differently to saturated and unsaturated fatty acids, which might explain why saturated fats are more harmful to cells.’ Kersten thinks that his discipline is responsible for informing people about how essential these mechanisms are.
Kersten sees 'customized nutrition' (giving people individual dietary advice) as one of the main challenges in his field. Much research erroneously claims that many so-called dietary interventions are ineffective. To his mind, the effect certainly exists, but is different in different people. Kersten: ‘Although the average effect may not be obvious, this doesn’t mean that nothing has happened. We are not all receptive to the same things. Some foods will affect different people in completely different ways.’