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H N Englyst

Publications and source records attributed to H N Englyst.

32 records · Page 2Linked to original sources
PubMed1987

Digestion of polysaccharides of potato in the small intestine of man.

Digestion and absorption from the small intestine of starch and nonstarch polysaccharides (NSP) (dietary fiber) from potato cooked and treated in various ways have been studied in ileostomy subjects. Test meals (300 g) of potato were fed following 24 h on a plant polysaccharide-free diet. Regardless of the treatment the potato had received, greater than 90% of NSP was recovered in ileostomy effluent. Starch from freshly cooked potato was well digested, only 3% being recovered; however, 12% from cooked and cooled potato escaped digestion in the small intestine. Digestibility of starch made resistant to alpha-amylase by cooling improved on reheating. Overall, 9, 18, and 14% of total carbohydrate fed was recovered from freshly cooked, cooled, and reheated potato, respectively. Digestibility of cooled potato was identical when eaten as large lumps or as finely sieved potato. In vitro studies with pancreatin also demonstrated incomplete digestion of cooled potato.

Adult↗
PubMed1986

The effect of age, sex and level of intake of dietary fibre from wheat on large-bowel function in thirty healthy subjects.

1. To evaluate the effect of age, sex and level of intake on the colonic response to wheat fibre, thirty healthy volunteers aged 17-62 years (nineteen men, eleven women) recruited from a local industry, were divided into four groups and given a controlled diet for two 3-week periods. The diet contained white bread during one period or one of four different amounts of bran-enriched wholemeal bread during the other (30, 60, 110, 170 g/d). 2. Wide variation was observed between subjects in stool weight on the basal diet and in response to wheat fibre. Stepwise regression analysis showed that the variation in stool weight was significantly related to sex (t 4.0, P less than 0.001) but not to age, height, weight or energy:fibre intakes on the basal diet. Stool weight in men (162 (SE 11) g/d) was approximately double that in women (83 (SE 11) g/d). Transit time and stool weight were closely related and the effect of sex on stool weight could be explained entirely by differences in transit. 3. The increase in stool weight with fibre was significantly related to dose (t 4.18, P less than 0.001) with approximately 1 g non-starch polysaccharides (the main component of dietary fibre) increasing stool weight by 5 g/d. Smaller increases in stool weight were seen in females, persons with initially low stool weights and small people. 4. Faecal carbohydrate excretion increased with the addition of bran mainly due to increased amounts of cellulose and pentose (arabinose + xylose), whilst digestibility of dietary non-starch polysaccharide fell from 77.6 (SE 2.3)% on the white bread diet to 65.6 (SE 2.4)% with the added bran (t 7.4, P less than 0.01, n26). 5. Faecal pH was more acid in men than in women and was related to methane production. Methane producers had higher faecal pH than non-producers (7.06 (SE 0.11) v. 6.65 (SE 0.1], lower stool weight (g/d; 93 (SE 12) v. 156 (SE 13] and slower transit times (h; 84.6 (SE 11.7) v. 48.6 (SE 6.6]. 6. These studies show that, when on similar diets, women have much lower stool weights and slower transit times than men. Furthermore, within the range of amounts of wheat fibre used in this and other published work, stool weight increases in linear proportion to the dose of fibre added to the diet. Methane excretion in breath is associated in this group of subjects with slow transit time and high faecal pH.

Adolescent↗
PubMed1986

Digestion of the carbohydrates of banana (Musa paradisiaca sapientum) in the human small intestine.

The digestion and absorption from the small bowel of the carbohydrate of banana has been studied by feeding ileostomy subjects banana from six batches of different ripeness and measuring the amounts excreted in the effluent. Starch content of bananas depended on the ripeness being 37% of dry weight in the least ripe and 3% in the most ripe. Excretion of carbohydrate from banana in ileostomy effluent ranged from 4-19 g/day and was directly related to the starch content (r = 0.99). Up to 90% of the starch could be accounted for in the effluent. Complete recovery of nonstarch polysaccharides [NSP (dietary fiber)] was obtained. The amount of banana starch not hydrolyzed and absorbed from the human small intestine and therefore passing into the colon may be up to 8 times more than the NSP present in this food and depends on the state of ripeness when the fruit is eaten.

Aged↗
PubMed1986

Starch utilization by the human large intestinal microflora.

High levels (2-565 units/g) of amylase activity were observed in human faeces. Over 92% of amylase activity in faeces obtained from healthy persons was extracellular, whereas only about 9% of activity was associated with particulate material and washed cells. Bacterial cell-bound amylases were considerably more efficient in breaking down starch, however, than were the soluble enzymes which occurred in cell-free faecal supernatant fluids. Cell population densities of anaerobic starch-hydrolysing bacteria in the stools of ten persons ranged from 1.1 X 10(10) to 3.3 X 10(12)/g of faeces. Identification of 120 starch-hydrolysing colonies isolated from the stools of six subjects showed that the predominant amylolytic bacteria belonged to the genera Bifidobacterium, Bacteroides, Fusobacterium and Butyrivibrio. Mixed populations of gut bacteria rapidly fermented starch with the production of volatile fatty acids and organic acids. Lactate was observed to be a major, though transient intermediate during starch fermentation by these cultures. Approximately 60% of starch utilized was converted to volatile fatty acids, which in the human colon would be potentially available for absorption.

Amylases↗
PubMed1986

Dietary fiber in the Japanese diet as investigated in connection with colon cancer risk.

The low risk of colon cancer among the Japanese suggests a high intake of dietary fiber. Composite diets for 1959, 1970, and 1979 were prepared using food consumption data from the National Nutrition Survey in Japan and analyzed for non-starch polysaccharides (NSP) at the Dunn Clinical Nutrition Centre in Cambridge. The results showed that average intake of NSP by Japanese in the above years did not exceed 13 g per day, which is as low as the corresponding intake by the Scandinavians and the British, whose risk of colon cancer is known to be high.

Colonic Neoplasms↗
PubMed1985

Digestion of the polysaccharides of some cereal foods in the human small intestine.

The digestion and absorption of dietary starch and nonstarch polysaccharides (NSP) in the small intestine of man from oats, cornflakes, and white bread has been determined by feeding seven ileostomists test meals containing these foods and estimating carbohydrate recovery in the effluent. NSP, the main constituent of dietary fiber, was almost completely recovered from all three test meals, including the water soluble beta-glucan which is the main NSP in oats. Less than 0.6% of the starch in oats was recovered as starch with a further 1.2% as dextrins and maltose. 4% of cornflake starch however was recovered, of which the main part was resistant to alpha-amylase digestion in vitro unless specially dispersed. Similarly with white bread 2.5% of ingested starch reached the terminal ileum of which the greater part was starch resistant to alpha-amylase in vitro. Overall 5.8% of the carbohydrate in white bread, 5.3% in cornflakes, and 11.7% in oats was recovered. This study supports the view that human digestive enzymes do not break down dietary NSP. It also identifies a fraction of starch, RS, present in processed food which resists breakdown by alpha-amylase both in vitro and in the small intestine of man.

Adult↗
PubMed1985

Dietary fibre in the Japanese diet.

The low risk of colon cancer among the Japanese suggests their high intake of dietary fibre. Composite diet mixtures for 1959, 1970, and 1979 were prepared utilising the food consumption data from the National Nutrition Survey in Japan and analysed for non-starch polysaccharides (NSP) at the Dunn Clinical Nutrition Centre in Cambridge. The results showed that average intake of NSP by a Japanese in the above years did not exceed 13 g per day, which is as low as the corresponding intake by the Scandinavians and the British whose risk of colon cancer is known to be high. Since all the materials were analysed by the same methods and at the same laboratory, the results are well comparable and indicate that the low risk of colon cancer among the Japanese cannot readily be explained by their intake of NSP alone.

Colonic Neoplasms↗
PubMed1983

The effects of breads containing similar amounts of phytate but different amounts of wheat bran on calcium, zinc and iron balance in man.

The capacity of wheat bran to impair mineral absorption independent of its phytate content was studied by metabolic balance studies in man. Three breads were prepared, equivalent to white, brown and wholemeal, by adding bran in different quantities to white flour. Calcium, iron, zinc and sodium phytate were added to the loaves to make the amounts equal in all breads. Six healthy volunteers were studied for three consecutive 24-d-periods during which they ate a controlled diet, typical of that normally consumed in the UK but with 200 g bread/d. Only the type of bread changed between each dietary period. The phytate contents (mmol) of 200 g of each of the breads after baking were: white 2.3, brown 2.1 and wholemeal 2.2; non-starch polysaccharide contents (g) were: white 3.3, brown 10.9 and wholemeal 18.7. The increased amount of bran in the breads increased stool output in the expected way but no change was seen in Ca, Zn and Fe balance. Blood levels of these minerals remained unchanged. It is concluded that wheat bran and, in particular, the cell-wall polysaccharides of bran, are unlikely to exert a significant effect on mineral absorption in man, in amounts customarily eaten, independently of the effect of phytate present in the bran.

Adult↗
PubMed1982

Nonstarch polysaccharide consumption in four Scandinavian populations.

Nonstarch polysaccharide (NSP) intake was measured in representative samples of 30 men aged 50-59 in 2 urban and 2 rural Scandinavian populations that exhibited a 3-4 fold difference in incidence of large bowel cancer. Intake was measured by chemical analysis of complete duplicate portions of all food eaten over one day by each individual. NSP intakes showed a rural-urban gradient, with 18.4 +/- 7.8 g/day in rural Finland and 18.0 +/- 6.4 g/day in rural Denmark versus 14.5 +/- 5.4 g/day in urban Finland and 13.2 +/- 4.8 g/day in urban Denmark. NSP intakes were also calculated (using food tables) from weighed food records kept over 4 days, one of which was the day on which the duplicate collection was made. Intakes were 2-2.5 g/day higher with this method than with direct chemical analysis, mainly because published tables of values have become outdated and inaccurate as a result of improved methods for measuring NSP in food. Individual variation from day to day in NSP intake was considerable. Average NSP intake and intake of some of its component sugars were inversely related to colon cancer incidence in this geographical comparison. To show a relationship at the individual level between diet and cancer risk in a prospective study would require detailed and accurate methods for the assessment of NSP consumption.

Colonic Neoplasms↗
PubMedDate not supplied

Improved method for measurement of dietary fiber as non-starch polysaccharides in plant foods.

A method is described that allows rapid estimation of total, soluble, and insoluble dietary fiber as the non-starch polysaccharides (NSP) in plant foods. It is a modification of an earlier, more complex procedure. Starch is completely removed enzymatically, and NSP is measured as the sum of its constituent sugars released by acid hydrolysis. The sugars may, in turn, be measured by gas chromatography (GC), giving values for individual monosaccharides, or more rapidly by colorimetry. Both GC and colorimetry are suitable for routine measurement of total, soluble, and insoluble dietary fiber in cereals, fruits, and vegetables. Values obtained are not affected by food processing so the dietary fiber content of various processed foods and mixed diets can be calculated simply from knowing the amount in the raw materials. The additional information obtained by GC analysis is valuable in the interpretation of physiological studies and in epidemiology where disease is related to type and amount of dietary fiber.

Acetylation↗