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Biomedical subjects

D J Jenkins

Publications and source records attributed to D J Jenkins.

At least 199 records · Page 11Linked to original sources
PubMed1982

Relationship between rate of digestion of foods and post-prandial glycaemia.

The amount of carbohydrate released at 1 and 5 h by digestion in vitro of 2 g carbohydrate portions of 14 foods by human digestive juices was compared with the area under the 2-h blood glucose response curve when 50 g carbohydrate portions were fed to groups of five to ten healthy volunteers. A significant relationship was found between the amounts of sugars and oligosaccharides liberated at 1 and 5 h and the food blood glucose area expressed as a percentage of the blood glucose area for 50 g glucose (r = 0.8627 and 0.8618, p less than 0.001). A significant relationship was also found between the glycaemic index and the food fibre content (p less than 0.02) and between the glycaemic index and the glucose trapping capacity of the foods (p less than 0.05). Legumes as a group liberated 56% less sugars and oligosaccharides (p less than 0.01) than the eight cereal foods over 5 h. It is suggested that such studies in vitro may help to identify food of use for diabetic patients, and at the same time throw further light on factors which affect post-prandial glycaemia.

Adult↗
PubMed1982

Slow release dietary carbohydrate improves second meal tolerance.

Breakfasts of lentils or wholemeal bread of identical carbohydrate content were taken by seven healthy volunteers. The lentils produced a significant 71% (p less than 0.001) reduction in the blood glucose area and flattened the plasma insulin and gastric inhibitory polypeptide responses by comparison with the bread. In addition, the lentil breakfast was followed by a significantly flatter blood glucose response to the standard bread lunch which followed 4 h later (by 38%, p less than 0.01). The blood glucose pattern was mimicked by feeding the bread breakfast slowly over the 4 h before lunch. Giving a bread breakfast containing a quarter of the carbohydrate reduced the breakfast glucose profile but resulted in a significantly impaired blood glucose response to lunch (168% of control, p less than 0.01). These results, together with breath hydrogen studies, performed on a separate group of four volunteers, indicate that the flattened response to lentils is not due to carbohydrate malabsorption. Slow release or "lente" carbohydrate foods such as lentils may form a useful part of the diets of those with impaired carbohydrate tolerance.

Adult↗
PubMed1982

Effect of processing on digestibility and the blood glucose response: a study of lentils.

To test the effect of processing on digestibility and the glycemic response to a leguminous seed, a group of eight healthy volunteers took a series of breakfast test meals containing either lentils which had been processed in four different ways or the same amount of carbohydrate as white bread. Lentils, boiled for 20 min, resulted in a flattened blood glucose response by comparison with bread. This was unaltered by blending the lentils to a paste or boiling them for an additional 40 minutes. However the blood glucose response was significantly enhanced by drying the boiled blended lentils for 12 h at 250 degrees F. In vitro digestion with human saliva showed the rate of sugars released from the food related positively to the blood glucose rise. Breath hydrogen studies indicated that carbohydrate malabsorption was too small to account for differences in the blood glucose response. These results emphasize the importance of processing in determining digestibility and hence the glycemic response to a food.

Blood Glucose↗
PubMed1982

The effect of fermented and unfermented milks on serum cholesterol.

Groups of 10 to 13 healthy volunteers were provided with 11 supplements of 2% butterfat milk (2% milk), whole milk, skim milk, yogurt, buttermilk, and sweet acidophilus milk daily for a 3-wk period. Despite increases in caloric intakes on all supplements, no significant increases were found in total, low-density, and high-density lipoprotein cholesterol. A significant weight gain was seen in subjects taking yogurt and acidophilus groups; these were the only two groups showing significant rises in triglyceride levels. These results in normal volunteers focus attention on the current practice of recommending only skim or 2% milk for hyperlipidemic individuals.

Adolescent↗
PubMed1981

Glycemic index of foods: a physiological basis for carbohydrate exchange.

The determine the effect of different foods on the blood glucose, 62 commonly eaten foods and sugars were fed individually to groups of 5 to 10 healthy fasting volunteers. Blood glucose levels were measured over 2 h, and expressed as a percentage of the area under the glucose response curve when the same amount of carbohydrate was taken as glucose. The largest rises were seen with vegetables (70 +/- 5%), followed by breakfast cereals (65 +/- 5%), cereals and biscuits (60 +/- 3%), fruit (50 +/- 5%), dairy products (35 +/- 1%), and dried legumes (31 +/- 3%). A significant negative relationship was seen between fat (p less than 0.01) and protein (p less than 0.001) and postprandial glucose rise but not with fiber or sugar content.

Adult↗
PubMed1981

Scope and specificity of acarbose in slowing carbohydrate absorption in man.

Fifty-gram carbohydrate tolerance tests were performed on healthy volunteers to test the activity and specificity of an alpha-glucoside hydrolase inhibitor, acarbose (BAY g 5421). Two hundred milligrams acarbose reduced the area under the blood glucose response curve by 89% (P less than 0.001) after sucrose by 80% (P less than 0.002) after starch, by 19% (N.S.) after maltose, with no effect on glucose. Breath hydrogen measurements indicated an almost complete malabsorption of the sucrose. At 50 mg acarbose, some reduction in blood glucose and insulin response to sucrose was still seen, but no significant hydrogen production. It is suggested that at lower doses, acarbose may prolong the time course over which carbohydrate is absorbed as does dietary fiber; as with fiber, it may be a useful adjunct to diabetic therapy.

Acarbose↗
PubMed1980

Effect of guar crispbread with cereal products and leguminous seeds on blood glucose concentrations of diabetics.

To compare the effect on blood glucose concentrations of guar incorporated into crispbreads with that of unprocessed high-fibre foods groups of four to six diabetics took a total of seven test breakfasts on separate days. By comparison with a breakfast of wholemeal bread and cheese, guar crispbread combined with bread reduced the area under the glucose response curve to 51% (p < 0.05); bread and soya beans reduced the area to 65% (p < 0.05); guar crispbread with soya beans to 25% (p < 0.002); and soya beans with lentils to 29% (p < 0.002). Porridge and cornflake breakfasts showed no difference. The favourable results with leguminous seeds may not make such meals more acceptable than meals of guar products, but a combination of leguminous seeds and guar may allow smaller and more acceptable amounts of both to be used.

Adult↗
PubMed1980

Exceptionally low blood glucose response to dried beans: comparison with other carbohydrate foods.

Normal volunteers took 50-g carbohydrate portions of eight varieties of dried legumes and 24 common foods drawn from grains, cereals and pasta, breakfast cereals, biscuits, and tuberous vegetables. Both the mean peak rise in blood glucose concentrations and mean area under the glucose curve of the subjects who ate beans were at least 45% lower than those of subjects who ate the other foods. These results suggest a potentially valuable role for dried leguminous seeds in carbohydrate exchanges for individuals with impaired carbohydrate tolerance.

Blood Glucose↗
PubMed1980

Rate of digestion of foods and postprandial glycaemia in normal and diabetic subjects.

Carbohydrate portions (2 g) of lentils, soya beans, and wholemeal bread were incubated for three hours with human digestive juices and the effect of digestibility on blood glucose examined. Lentils and soya beans released only 39% and 8% respectively of the sugars and oligosaccharides liberated from bread. In healthy volunteers 50 g carbohydrate portions of cooked lentils and soya beans raised blood glucose concentrations by only 42% (p < 0.001) and 14% (p < 0.001) of the bread value. There was a similar response in diabetics. These results suggest that rate of digestion might be a important factor determining the rise in blood glucose concentration after a meal and that supplementing chemical analysis with in-vitro and in-vivo food testing might permit identification of especially useful foods for diabetics.

Adult↗
PubMed1980

Improved glucose tolerance four hours after taking guar with glucose.

To gain some insights about the possible cumulative metabolic effect after a high-fibre meal, 6 subjects took two 80 g oral glucose loads, 4 h apart. Addition of 22.3 g guar to the first load decreased the rise in blood glucose and insulin after the second (guar-free) load by 50% (p less than 0.002) and 31% (p less than 0.02) respectively. This corresponded with decreased 3-hydroxybutyrate levels at the start of the glucose tolerance test after guar (by 20%, p less than 0.02). When no guar was added to the first glucose load, both 3-hydroxybutyrate and non-esterified fatty acids tended to rise before the second test. No significant effect was seen in the responses of the gut hormones, gastric inhibitory peptide and enteroglucagon. Spreading the intake of the first 80 g of glucose over the initial 4 h (2 subjects) similarly flattened the glycaemic but increased the insulin response. The effect of guar on carbohydrate and fat metabolism, therefore, lasts at least 4 h and may result in improved carbohydrate tolerance to subsequent guar-free meals.

Adult↗
PubMed1980

Dietary fiber and blood lipids: treatment of hypercholesterolemia with guar crispbread.

Eleven hyperlipidemic patients took an average of 13 g guar in crispbread form over 2- to 8-week periods. Eight weeks' treatment (seven patients) reduced total serum cholesterol by 13% (P less than 0.002) while high-density lipoprotein cholesterol was unchanged. A 13% nonsignificant reduction was also seen in serum triglyceride. Comparison of blood lipid changes over 2-week periods showed guar crispbread to be as effective as guar given in hydrated (eight patients) or semihydrated form (four patients). In addition total serum cholesterol was lowered significantly (11%, P less than 0.05) in five patients where cholestyramine was ineffective. Due to its acceptability, guar crispbread is likely to prove a useful cholesterol-lowering agent.

Adult↗
PubMed1980

Diabetic diets: high carbohydrate combined with high fiber.

The ideal level of carbohydrate intake for diabetics placed on high-fiber diets is unknown. Nineteen diabetics, therefore, took part in a total of twenty-four 5-day studies of fiber supplementation (guar) with carbohydrate intakes ranging from 22 to 61% of total calories. Where carbohydrate formed more than 40% of the calorie intake, there was a mean 64% reduction in glycosuria over the last 2 days on guar (P < 0.001, 14 studies, 11 patients). No significant reduction in glycosuria was seen in the 10 studies on lower carbohydrate intakes. This suggests that dietary fiber supplements in diabetes should be given against a background of higher rather than lower carbohydrate intake.

Adult↗
PubMed1980

Pectin and complications after gastric surgery: normalisation of postprandial glucose and endocrine responses.

Pectin has been shown to minimise the fall in blood glucose seen in patients who are troubled by hypoglycaemia attacks after gastric surgery. We therefore performed 50 g glucose tolerance tests with and without 14.5 g pectin on 11 post-gastric surgery patients. After pectin, the high postprandial levels of glucose, insulin, and enteroglucagon were significantly reduced as was the fall in blood glucose between 90 and 120 minutes. These effects of pectin may reflect slower uptake of glucose from the gastrointestinal tract and provide evidence to support the use of unabsorbable carbohydrate gelling agents in treating hypoglycaemia after gastric surgery.

Adult↗