Blood pressure and diet in normotensive volunteers: absence of an effect of dietary fiber, protein, or fat.

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.

The effect of a natural high-fiber diet on serum lipids, fecal lipids, and colonic function.

In a cross-over experiment, 46 young healthy volunteers consumed in succession a high-fiber and a low-fiber diet for 3 weeks at two levels of dietary cholesterol. Half of the dietary fiber came from fruits and vegetables, and the rest from bread and other cereal products. On the high-fiber diet, concentrations of serum cholesterol decreased on average by 0.44 mmole/liter with high-cholesterol and 0.31 mmole/liter with low-cholesterol regimes; high density lipoprotein-cholesterole decreased by 0.1 mmole/liter; on average fecal weight increased by 115 g/day and mean transit time through the gut was decreased by 18 hr. Only part of the decrease in serum cholesterole may be due directly to the high intake of dietary fiber components. The remainder is due to differences in fat intake: during the high-fiber period subjects consumed less fat and cholesterol than had been planned.

Increase of serum cholesterol in man fed a bran diet.

The effects of wheat bran and other sources of dietary fibre on serum total and high density lipoprotein(HDL)-cholesterol were investigated in a group of 62 subjects, with rigid control of dietary intake. It was found that a high-fibre diet with vegetables and fruits as well as a low-fibre diet, to which isolated citrus pectin had been added to the same level as present in the vegetables and fruits diet, caused a small decrease in the concentration of serum cholesterol after 5 weeks. Surprisingly, addition of bran (on average 38 g/day) to a low-fibre diet caused an increase in the level of serum cholesterol by on average 0.34 mmol/l (P less than or equal to 0.005). The amount and type of dietary fibre had no substantial effect on the HDL-cholesterol concentration.

The prevention and treatment of overweight and obesity. Summary of the advisory report by the Health Council of The Netherlands.

This article presents the highlights of an advisory report on the prevention and treatment of overweight and obesity. The report, which was produced by the Health Council of The Netherlands, incorporates the most recent developments and projected scientific breakthroughs in this field. The prevalence of overweight and obesity has taken on epidemic proportions. In The Netherlands, as elsewhere, there is a steady rise in the number of individuals suffering from overweight or obesity. Since it is associated with serious health problems, obesity (and to a lesser extent overweight) leads to increased costs for the healthcare system. Food consumption surveys and studies on time trends in physical activity patterns have revealed that the increased prevalence of obesity is due to an increasing lack of exercise, combined with relative overconsumption. A healthy diet (including plenty of fruit, vegetables and cereal products) and at least one hour a day of moderate physical activity are recommended for the maintenance of energy balance and for the prevention of weight gain. While genetic factors play a part in the development of overweight and obesity, environmental factors appear to be of overriding importance. The so-called 'obesogenic environment' prompts individuals to eat more and to take less exercise. There are still no effective intervention strategies for the prevention of weight gain. However, the explosive increase in the prevalence of obesity and of its associated serious medical problems demands a common-sense approach involving preventive interventions, which are based on modern views of health promotion. These interventions require a broad coalition of actors, in which local and national authorities, industry, the healthcare system and the population at risk must each shoulder their own share of responsibility. The primary aim of obesity treatment should be a long-lasting weight loss of about 10%. Even this relatively small weight loss can produce significant health gains. Treatment methods must involve an integrated (lifestyle) approach, dependent on the amount of overweight involved and on the presence of comorbidity. Obesity should be treated chronically and prevention of weight regain must be part of any obesity treatment programme.

[Healthy eating in 1995]. / Gezond eten anno 1995.

The report 'Dietary Guidelines' of the Dutch Nutrition Council advises about the composition of a balanced diet, conductive to good health. Such a diet supplies all nutrients in the right amounts and has a preventive function towards those diseases of the affluent society which are nutrition related. The key principle of a healthy diet is 'variety'. Present day food habits make the recommendation 'moderation with (saturated) fat' a compelling second one. A logical follow-up when reducing the amount of fat in the diet is the recommendation of a generous amount of bread, potatoes, vegetables and fruit, in order to compensate fat reduction. For many consumers this means an increase in the consumption of these products.

The bifidogenic effect of inulin and oligofructose and its consequences for gut health.

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.