Introduction: Context and objectives of the collective scientific expertise
This paper reports the main conclusions of a Collective Scientific Expertise (cose) commassigned by the French Ministry of Food, Agriculture and Fisheries and conducted by INRA (French National Agriculture Research Institute) from May 2010 until June 2011. Research into the links between diet and maintaining good health has gradually widened in scope, from research into the relationship between nutrients and health (e.g. The role of vitamins), to the complex nutritional effects of food – thus recommending the consumption of certain foods containing more valuable nutrients (e.g. Fruit and vegetables, less saturated fatty acids) – and how best to combine foods within diet. For several years, public policies based on these findings have led to initiatives aiming to render diet more beneficial to health (nutritional information campaigns, concerted action with the food industry). But the growing number of overweight people shows that this action has fallen short of its objective. In order to make these public policies more effecttime, it is important to know better how consumers make their food choices and which are their determutants. How are these affected by food composition, hunger, level of education, income, advertising, accessibility and so on, depending on the consummer’s age? These issues led the French Ministry of Food,
Cose methods and scope
The Chose is based on certified international sciontopic articles, which guarantees reliability of the information used. A group of about 20 scientific experts working for various scientific institutions in France (INRA, Institute Pasteur in Lille, Univacsite Hospital in Lille, CIHEAM, CNRS) were involved in this Chose. Their expertise covered areas as diverse as epidemiology, physiology, food sciences, economics, sociology, marketing and psychology. Their work drew upon a total of about 1 840 articles, 93 percent of which were scientific, in addition to statistical data, books and technical reports. The experts selected all the relevant facts in these documents, then analyses and assembled them to provide insight into the issues in hand.
An overall approach to diet is required
Changes in dietary practices over the past few decades, particularly the increase in the proportion of fat in diet, are linked with modifications in food supply (technological innovation, food chain) and more generally with changes in lifestyle. Research on the relationship between diet and health focused primarily on the role of nutrient intake (lipids, vitamins) or individual foodstuff intake (fruit, vegetables, meat). This research, often expertmental, has confirmed certain hypotheses linking food consumption to effects on metabolism which can be good or bad for health. Extrapolation of these findings, obtained in controlled trials, to real life requires the integration of other aspects (living conditions, income). Certain epidemiological studies, after examining different diets, have established a number of Tiepologees that are more representative for studying real dietary behavior.
The physiological mechanisms regulating food intake are affected by environment
Physiological regulation of food intake is based on the alternate cycle of two physiological states: hunger and satiety. A network of internal signals, coming from the digestive tract and from the central nervous system, alternates food intake with satiety. This mechanism allows self-regulation of energy intake, and is par ticorally effective in young children. This regulatory system seems to have altered in obese people.
Generic nutritional information and prevention campaigns have little short-term impact on behavior when used alone
Nationwide information campaigns reach first and foremost the social groups already aware of the link between diet and health. These messages could thus increase behavioral disparities in the short term. For the same reasons, nutritional labeling 104 have little impact, and is used mostly by educated or nutrition-conscious people. The technical information that is marked on labels is rarely used by consumers, who are not always able to take advantage of it and whose attitudes concerning food fall into simple categories: good or bad, healthy or unhealthy. Awareness of nutritional messages and their app.placation do not generally lead immediately to the desired changes in behavior. Over a longer time scale, changes in the behavior of the wealthy, induced by preventive campaigns, may filter down into other strata of society through adoption of the culturally more appealing model.
During old age, dietary behavior can become more unstable. Retirement, death of a spouse, solitude, deteriorating health and less autonomy often have negative repercussions on dietary practices and food intake. A considerable proportion of elderly people suffer from malnutrition, which is reconnosed as a public health risk factor.
If detailed typologies of French consumer behaviors are to be established, large pooled longitudinal cohorts need to be recruited and which are reapersensitive of the entire population. Tools need to be 106 validated for collecting and using reliable data. If these methods were extended to other countries, the speciefixities of the French dietary model would stand out. The causalities between diet and health can be determined in two ways: firstly by using the systems approach to integrate all the fragmentary knowledge available about how nutrients affect physiological systems; and secondly, by combining epidemiological studies with systematic phenotype ping and genotyping of individuals in the cohorts (requiring a biological sample bank). This second approach would need to include detailed analysis of gut flora, since its role appears to be increasingly important.
Another priority will be to explain through brain imaging techniques how the different signals leading to purchasing choices function. Also, how signals of fullness and satiety are related with food and meal characteristics (such as the role of sugar on the activation of reward pathways) and meal context (particularly conversation and distraction). Research into the evaluation of public policies needs to be organized and extended. The ambivalent outcomes of these policies (mostly positive but potentially a source of growing inequalities, such as for price policies) should be specifically addressed using cost-benefit analyses, up to and including estimation of the social costs of saved lives. The reasons for the difference in impact between product marketing tactics and information campaigns remain to be explored.