scispace - formally typeset
Search or ask a question
Author

Anton C. Beynen

Bio: Anton C. Beynen is an academic researcher from Utrecht University. The author has contributed to research in topics: Cholesterol & Fatty acid synthesis. The author has an hindex of 38, co-authored 147 publications receiving 4387 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: It is concluded that dietary SDAP levels up to 6% increase both average daily gain (ADG) and feed intake (ADFI) in the first 2 weeks after weaning in a dose-dependent fashion and reduces post-weaning intestinal disease by preventing attachment of pathogens.

225 citations

Journal ArticleDOI
TL;DR: A rapid method for sampling of buttock fat without anesthesia is described and with this method one can obtain biopsies from a large number of subjects and determine objectively the long-term fatty acid composition of their diet.

207 citations

Book ChapterDOI
TL;DR: In hyperresponders, compared with hyporesponders, there is a higher hepatic efflux of cholesterol in low-density lipoproteins (LDL), or its precursors, after cholesterol consumption, which may be caused by insufficient inhibition of cholesterol biosynthesis and/or the high capacity of cholesterol absorption in thehyperresponders.
Abstract: The feeding of cholesterol-rich diets to random-bred animals results in marked interindividual differences in the response of serum cholesterol. Certain animals show only small responses (hyporesponders), whereas others develop high degrees of hypercholesterolemia (hyperresponders). Inbred strains of rabbits, rats, and mice differing in their sensitivity to dietary cholesterol are available. In these animals, and also in monkeys, the responsiveness to high-cholesterol diets has a strong genetic basis. The existence of hyper- and hyporesponders also holds in humans, though not as pronounced as in laboratory animals. Repeated trials with the same subjects have shown that persons exist with a consistently low or high response to increased intakes of cholesterol. However, "spontaneous," diet-independent within-person variations in the level of serum cholesterol markedly inflate the between-person variation in the response of serum cholesterol; both variations are of the same order of magnitude. Hypo- and hyperresponsiveness to dietary cholesterol extends to other hypercholesterolemic components of the diet. In humans and rabbits hyperresponsiveness to dietary cholesterol is associated with responsiveness to dietary saturated fatty acids. The mechanisms underlying hypo- and hyperresponsiveness to dietary cholesterol have not yet been unraveled. On the basis of available data, we propose that in hyperresponders, compared with hyporesponders, there is a higher hepatic efflux of cholesterol in low-density lipoproteins (LDL), or its precursors, after cholesterol consumption. This may be caused by insufficient inhibition of cholesterol biosynthesis and/or the high capacity of cholesterol absorption in the hyperresponders. The stimulation of LDL production accounts for the increase in LDL cholesterol in serum. The number of hepatic LDL receptors, which may be already decreased in hyperresponders, will decrease further through down-regulation. The receptor-mediated LDL clearance decreases, but the absolute amount of LDL cholesterol taken up by the cells via the receptor and by the receptor-independent pathway increases because of the increased level of LDL cholesterol. In this way a new equilibrium is reached in which LDL production equals LDL catabolism. The phenomenon of hypo- and hyperresponsiveness may have implications for counseling subjects who attempt to lower their serum cholesterol by diet. However, identification of true hyper- and hyporesponders is greatly hampered by within-person fluctuations of the level of serum cholesterol. No simple test is available to discriminate hypo- from hyperresponders.(ABSTRACT TRUNCATED AT 400 WORDS)

185 citations

Journal ArticleDOI
TL;DR: It is suggested that HCMC reduces macronutrient digestion by raising the viscosity of small intestinal contents, which is associated with enhanced bacterial fermentation due to accumulation of undigested material.
Abstract: The question addressed was whether the viscosity per se of dietary non-starch polysaccharides influences macronutrient digestion in broiler chickens. Water-soluble carboxymethylcellulose preparations of low (LCMC) or high viscosity (HCMC) were fed to broiler chickens (n = 10/group) from 21 to 35 d of age. The HCMC preparations reduced weight gain and raised water intake compared with LCMC. After the HCMC diet was fed, viscosity of the supernatant of small intestinal contents was significantly raised. The HCMC preparations raised the group mean ATP concentration in the digesta of duodenum plus jejunum, indicating that bacterial activity was increased. Consumption of HCMC depressed apparent fecal digestibility of lipids and nitrogen and also apparent ileal digestibility of starch. The dietary HCMC tended (P = 0.077) to reduce plasma triglyceride concentrations. After HCMC consumption, the weights of the small intestine and colon, without or with contents, were elevated. The data indicate that high viscosity of digesta in broiler chickens is associated with a reduced macronutrient digestion and impaired growth performance. Because the carboxymethylcellulose preparations were nonfermentable by fresh feces, we suggest that HCMC reduces macronutrient digestion by raising the viscosity of small intestinal contents, which is associated with enhanced bacterial fermentation due to accumulation of undigested material.

151 citations

Journal ArticleDOI
TL;DR: In this article, the characteristics of people whose serum cholesterol level is unusually susceptible to consumption of cholesterol were investigated, and a positive correlation with serum high density lipoprotein2 (HDL2) cholesterol was found with the reaction of endogenous cholesterol synthesis rate to an increased intake of cholesterol.
Abstract: The characteristics of people whose serum cholesterol level is unusually susceptible to consumption of cholesterol were investigated. Thirty-two volunteers from the general population of Wageningen, the Netherlands, each participated in three controlled dietary trials in 1982. A low-cholesterol diet was fed during the first half and a high-cholesterol diet during the second half of each trial, and the change (response) of serum cholesterol was measured. The responses in the three trials were averaged to give each subject's mean responsiveness. Fecal excretion of cholesterol and its metabolites were measured in the second trial, and body cholesterol synthesis was calculated. Responsiveness showed a positive correlation with serum high density lipoprotein2 (HDL2) cholesterol (r = 0.41, p less than 0.05) and with serum total cholesterol level on a high-cholesterol diet (r = 0.31, p = 0.09). A negative relation was found with habitual cholesterol consumption (r = -0.62, p less than 0.01), with body mass index (r = -0.50, p less than 0.01), and with the rate of endogenous cholesterol synthesis (r = -0.40, p less than 0.05), but not with the reaction of endogenous cholesterol synthesis rate to an increased intake of cholesterol. No relation was found with age, sex, total caloric needs, or the ratio of primary to secondary fecal steroids. Upon multiple regression analysis, only habitual cholesterol intake and serum total and HDL2 cholesterol levels contributed significantly to the explanation of variance in responsiveness. Thus, a low habitual cholesterol intake, a high serum HDL2 cholesterol level, or a low body weight do not make one less susceptible to dietary cholesterol-induced hypercholesterolemia.

150 citations


Cited by
More filters
Journal ArticleDOI
30 Oct 2009-Cell
TL;DR: The authors showed that colonisation of mice with a segmented filamentous bacterium (SFB) is sufficient to induce the appearance of CD4+ T helper cells that produce IL-17 and IL-22 (Th17 cells) in the lamina propria.

3,860 citations

Journal ArticleDOI
TL;DR: Resistant starch is a prebiotic, but knowledge of its other interactions with the microflora is limited and the contribution of RS to fermentation and colonic physiology seems to be greater than that of NSP.
Abstract: Resistant starch (RS) is starch and products of its small intestinal digestion that enter the large bowel. It occurs for various reasons including chemical structure, cooking of food, chemical modification, and food mastication. Human colonic bacteria ferment RS and nonstarch polysaccharides (NSP; major components of dietary fiber) to short-chain fatty acids (SCFA), mainly acetate, propionate, and butyrate. SCFA stimulate colonic blood flow and fluid and electrolyte uptake. Butyrate is a preferred substrate for colonocytes and appears to promote a normal phenotype in these cells. Fermentation of some RS types favors butyrate production. Measurement of colonic fermentation in humans is difficult, and indirect measures (e.g., fecal samples) or animal models have been used. Of the latter, rodents appear to be of limited value, and pigs or dogs are preferable. RS is less effective than NSP in stool bulking, but epidemiological data suggest that it is more protective against colorectal cancer, possibly via butyrate. RS is a prebiotic, but knowledge of its other interactions with the microflora is limited. The contribution of RS to fermentation and colonic physiology seems to be greater than that of NSP. However, the lack of a generally accepted analytical procedure that accommodates the major influences on RS means this is yet to be established.

2,702 citations

Journal ArticleDOI
TL;DR: The effects of dietary fats on total:HDL cholesterol may differ markedly from their effects on LDL, and the effects of fats on these risk markers should not in themselves be considered to reflect changes in risk but should be confirmed by prospective observational studies or clinical trials.

2,548 citations

Journal ArticleDOI
TL;DR: The present document has been written by a group of both academic and industry experts and aims to validate and expand the original idea of the prebiotic concept, defined as the selective stimulation of growth and/or activity of one or a limited number of microbial genus(era)/species in the gut microbiota that confer(s) health benefits to the host.
Abstract: The different compartments of the gastrointestinal tract are inhabited by populations of micro-organisms. By far the most important predominant populations are in the colon where a true symbiosis with the host exists that is a key for well-being and health. For such a microbiota, 'normobiosis' characterises a composition of the gut 'ecosystem' in which micro-organisms with potential health benefits predominate in number over potentially harmful ones, in contrast to 'dysbiosis', in which one or a few potentially harmful micro-organisms are dominant, thus creating a disease-prone situation. The present document has been written by a group of both academic and industry experts (in the ILSI Europe Prebiotic Expert Group and Prebiotic Task Force, respectively). It does not aim to propose a new definition of a prebiotic nor to identify which food products are classified as prebiotic but rather to validate and expand the original idea of the prebiotic concept (that can be translated in 'prebiotic effects'), defined as: 'The selective stimulation of growth and/or activity(ies) of one or a limited number of microbial genus(era)/species in the gut microbiota that confer(s) health benefits to the host.' Thanks to the methodological and fundamental research of microbiologists, immense progress has very recently been made in our understanding of the gut microbiota. A large number of human intervention studies have been performed that have demonstrated that dietary consumption of certain food products can result in statistically significant changes in the composition of the gut microbiota in line with the prebiotic concept. Thus the prebiotic effect is now a well-established scientific fact. The more data are accumulating, the more it will be recognised that such changes in the microbiota's composition, especially increase in bifidobacteria, can be regarded as a marker of intestinal health. The review is divided in chapters that cover the major areas of nutrition research where a prebiotic effect has tentatively been investigated for potential health benefits. The prebiotic effect has been shown to associate with modulation of biomarkers and activity(ies) of the immune system. Confirming the studies in adults, it has been demonstrated that, in infant nutrition, the prebiotic effect includes a significant change of gut microbiota composition, especially an increase of faecal concentrations of bifidobacteria. This concomitantly improves stool quality (pH, SCFA, frequency and consistency), reduces the risk of gastroenteritis and infections, improves general well-being and reduces the incidence of allergic symptoms such as atopic eczema. Changes in the gut microbiota composition are classically considered as one of the many factors involved in the pathogenesis of either inflammatory bowel disease or irritable bowel syndrome. The use of particular food products with a prebiotic effect has thus been tested in clinical trials with the objective to improve the clinical activity and well-being of patients with such disorders. Promising beneficial effects have been demonstrated in some preliminary studies, including changes in gut microbiota composition (especially increase in bifidobacteria concentration). Often associated with toxic load and/or miscellaneous risk factors, colon cancer is another pathology for which a possible role of gut microbiota composition has been hypothesised. Numerous experimental studies have reported reduction in incidence of tumours and cancers after feeding specific food products with a prebiotic effect. Some of these studies (including one human trial) have also reported that, in such conditions, gut microbiota composition was modified (especially due to increased concentration of bifidobacteria). Dietary intake of particular food products with a prebiotic effect has been shown, especially in adolescents, but also tentatively in postmenopausal women, to increase Ca absorption as well as bone Ca accretion and bone mineral density. Recent data, both from experimental models and from human studies, support the beneficial effects of particular food products with prebiotic properties on energy homaeostasis, satiety regulation and body weight gain. Together, with data in obese animals and patients, these studies support the hypothesis that gut microbiota composition (especially the number of bifidobacteria) may contribute to modulate metabolic processes associated with syndrome X, especially obesity and diabetes type 2. It is plausible, even though not exclusive, that these effects are linked to the microbiota-induced changes and it is feasible to conclude that their mechanisms fit into the prebiotic effect. However, the role of such changes in these health benefits remains to be definitively proven. As a result of the research activity that followed the publication of the prebiotic concept 15 years ago, it has become clear that products that cause a selective modification in the gut microbiota's composition and/or activity(ies) and thus strengthens normobiosis could either induce beneficial physiological effects in the colon and also in extra-intestinal compartments or contribute towards reducing the risk of dysbiosis and associated intestinal and systemic pathologies.

1,786 citations

27 Oct 1991
TL;DR: In this article, the effects of lead poisoning on the developing developing developing nervous system were investigated, including neurological, neurobehavioral, and developmental effects in children, and toxicity.
Abstract: Essentiality Toxicity Carcinogenicity Lead(Pb) Exposure Toxicokinetics Toxicity Neurologic, Neurobehavioral, and Developmental Effects in Children Mechanisms of Effects on the Developing Nervous System Peripheral Neuropathy Hematologic Effects Renal Toxicity Lead and Gout Effects on Cardiovascular System Immunotoxicity Bone Effects Reproductive Effects Birth Outcomes Carcinogenicity Other Effects Dose Response Treatment Organic Lead Compounds Mercury (Hg) Exposure Disposition and Toxicokinetics Metabolic Transformation Cellular Metabolism Toxicology Biological Indicators Treatment Nickel (Ni) Exposure Toxicokinetics Essentiality Toxicity Nickel Carbonyl Poisoning Dermatitis Indicators of Nickel Toxicity

1,727 citations