The bifidogenic effect of inulin and oligofructose is now well established in various studies, not only in adult participants but also in other age groups. This bifidogenic shift in the composition of the colonic microbiota is likely the basis for the impact of these prebiotic compounds on various parameters of colonic function. Mainly from animal and in vitro studies and also from some human trials, there are indications, for instance, that inulin-type fructans may reduce the production of potentially toxic metabolites and may induce important immune-mediated effects. This review discusses how these changes in the composition and activity of the colonic microbiota may affect gut health in healthy people, including in those who may experience some form of gastrointestinal discomfort.

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Nutrition science has enriched our understanding of how to stay healthy by producing valuable knowledge about the interaction of nutrients, food, and the human body. Nutrition science also has raised societal awareness about the links between food consumption and well-being, and provided the basis for food regulations and dietary guidelines. Its collaborative and interdisciplinary research has accomplished much, scientifically and socially. Despite this, nutrition science appears to be in crisis and is currently confronted with a public reluctance to trust nutritional insights. Though deflating trust is a general phenomenon surrounding the scientific community, its impact on nutrition science is particularly strong because of the crucial role of nutrition in everyone’s daily life. We, a Dutch collective of nutritionists, medical doctors, philosophers and sociologists of science (http://www.nutritionintransition.nl), have diagnosed that nutrition science is meeting inherent boundaries. This hampers conceptual and methodological progress and the translation of novel insights into societal benefit and trust. In other words, nutrition science is facing limitations to its capability and credibility, impeding its societal value. We take up the challenge to halt the threatening erosion of nutrition science’s capability and credibility, and explore a way forward. We analyse limitations to capability and credibility, then argue that nutrition science is caught in a vicious circle, and end by offering some suggestions to transcend the limitations and escape the current deadlock. We invite nutritional experts as well as scholars from adjacent disciplines to engage in the discussion.

Diet is well known to have beneficial health properties that extend beyond traditionally accepted nutritional effects. The approach involved in elucidating these beneficial physiological effects is becoming more important, as reflected by increasing research being undertaken. With growing consumer awareness of foods and food constituents and their relationship to health, the key questions for regulators, scientists and the food industry continue to relate to: (1) how consumers could be protected and have confidence that the health claims on foods are well supported by the evidence; (2) how research on physiological effects of food (constituents) and their health benefits could be stimulated and supported; (3) how research findings could be used in the development of innovative new food products. The objectives of this paper are to provide a set of recommendations on the substantiation of health claims for foods, to develop further guidance on the choice of validated markers (or marker patterns) and what effects are considered to be beneficial to the health of the general public (or specific target groups). Finally, the case for developing a standardised approach for assessing the totality of the available scientific data and weighing the evidence is proposed.

In the course of four controlled experiments on the effect of specific dietary components on cardiovascular risk factors, the effects on blood pressure of various sources of dietary fiber, of type and amount of dietary fat, and of animal versus plant were measured in young normotensive volunteers. In each of the four experiments a group of 50 to 75 healthy student volunteers received a control diet for 11/2 to 21/2 wk. They were then randomized into subgroups which received various test diets for periods ranging from 4 to 12 wk. In each experimental one group received the control diet throughout the whole experimental period. Diets differed between groups in one dietary component only. All foodstuffs were weighed out individually according to each person's energy needs. Body weights and Na intake were controlled. Initial blood pressures were about 120 mm Hg systolic and 70 mm Hg diastolic. Both systolic and diastolic blood pressure decreased during the test period in all four experiments on almost every diet, including the control diets, by about 0 to 5 mm Hg. However, changes in blood pressure over the test period were never significantly different between the test groups and the control groups. Thus, none of the investigated dietary factors had a demonstrable effect on blood pressure in young normotensive persons.