Biomedical subjects
Publications and source records attributed to J Yudkin.
The effects on the biochemistry and physiology of the human body of diets differing only in the ratio of the two major carbohydrates, starch and sugars are discussed and related to the epidemiology of coronary heart disease and diabetes.
Fourteen young male volunteers measured their habitual dietary intake for 2 weeks, then were told to increase their dietary sucrose while decreasing their other carbohydrates for 2 weeks and finally told to revert to their habitual diet while continuing to record their intake. Measurement of plasma constituents revealed a significant fall in HDL-cholesterol concentration after the period on the high sucrose diet, and a return to the higher concentrations after resumption of the habitual diet. Twenty-six young men whose habitual diet contained more than an average quantity of sucrose followed a similar regime, except that they were told to reduce their sucrose for 2 weeks and to compensate by increasing the intake of other carbohydrates. In the event, unlike the volunteers in the first experiment, they were found not to have made the compensatory change when lowering their sucrose intake. Measurement of their plasma constituents showed that the reduction in dietary sucrose resulted in a significant fall in the mean concentration of triglycerides. There was no significant change in the mean concentration of HDL cholesterol, although there was an increase in the concentration in 11 of the 26 subjects.
Explore the source record for details and available documents.
1. The claims that rats fed on diets with 'brown sugar' (unrefined muscovado) perform better in a number of ways than do rats fed on refined white sugar (sucrose) have been examined. 2. Male Wistar rats were fed on purified diets from weaning, in which the carbohydrate component was either maize starch or unrefined sugar or sucrose. The sugars produced no differences in growth rate, body composition, or the weights of liver or kidneys. Compared with sucrose, unrefined sugar produced an increase in blood cholesterol and in the activity of hepatic fatty acid synthetase, and a greater increase in blood triglyceride. In confirmation of earlier results, rats fed on either sugar had heavier livers and kidneys, increased activity of hepatic glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and a higher concentration of plasma triglyceride compared with rats fed on maize starch. 3. Female Sprague-Dawley rats were fed on the same three diets as the male rats, and mated when they weighed about 200 g. No difference was seen in their ability to mate, the progress of pregnancies, or the sizes of the litters. Does fed on unrefined sugar produced litters of higher viability than did does fed on starch or sucrose. Survival was between 85 and 100% with unrefined sugar and between 30 and 75% with starch or sucrose. 4. Unrefined muscovado sugar has thus been shown to contain a factor required by female rats for the proper viability of their pups. This may be the same 'Reproductive Factor R' as that described by Wiesner & Yudkin (1951). In certain circumstances, unrefined muscovado sugar might therefore contribute to the nutritional value of a human diet, although in what circumstances, in what respect and to what extent it might do so, is by no means clear.
Energy balance studies with weanling rats and mice were carried out to investigate the chronic effects of diets containing white sugar, unrefined sugar, and starch as sole carbohydrate on body composition and energetic efficiency. The results show no significant differences in energetic efficiency and in body composition of both rats and mice fed the different carbohydrate diets. However, there is a tendency for the sugar-fed animals to have higher metabolizable energy intakes, but rarely was this sufficient to increase body energy since there were corresponding increases in metabolic rate. These studies indicate that differences in energy balance between sugar and starch are small and that any increase in thermogenesis that occurred in some of the groups fed sugar-rich diets was in response to the higher energy intake rather than due to a lower efficiency of utilization of sucrose per se.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Two groups of rats were fed diets in which the carbohydrate components was either starch or sucrose. A third group was fed on a stock diet. Half of the animals in each group were made diabetic by injection of either streptozotocin, in two of the groups, or alloxan, in the third group. Both diabetes and sucrose-feeding increased renal gluconeogenesis as indicated by increased activities of fructose-1,6-diphosphatase and glucose-6-phosphatase. Sucrose-feeding increased fatty acid synthesis both in the liver and kidney. However, the effect of diabetes on fatty acid synthesis was different at the two tissue sites. Diabetes, whether induced by streptozotocin or alloxan, decreased fatty acid synthesis in the liver but increased the rate in the kidney. The latter response was obtained for each diet but was additive with the effect of sucrose. We conclude that the effect of diabetes on renal lipid metabolism may reflect, in part, the accelerated glucose flux. The response to both diabetes and sucrose-feeding is also possibly associated with the increased lipid required for the membrane synthesis reported previously.
Explore the source record for details and available documents.
In a controlled trial of a double-blind cross-over design, it has been shown that "Marvie', a non-calorigenic sweetener containing 58 per cent maltitol by weight, is an effective sweetener which has no influence on routine haematological and biochemical parameters. The dose that could be tolerated without undesirable symptoms was between 20 and 30 g per day. Above this dose, flatus production with abdominal discomfort could limit tolerance to this sweetening agent.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Rats were fed on diets containing either sucrose or starch as the carbohydrate component (55%) for eight months. Diabetes was induced in animals of both groups by injecting streptozotocin (50 mg/kg body weight). Diabetic rats failed to gain weight, had enlarged kidneys, polyuria and elevated blood glucose levels. Starch and sucrose fed rats gained weight normally and had normal blood glucose levels. Sucrose fed rats had enlarged kidneys. Regional thickening of the glomerular basement membrane was present in sucrose-fed and diabetic rats but not in starch-fed controls. Glomerular basement membrane isolated from pooled kidney cortices from rats in the different experimental groups were analysed for amino acid, disaccharide and hexosamine content. Hydroxylysine (9 to 20%), hydroxyproline (21 to 24%), disaccharide (27%) and hexosamine (26%) were increased in membranes insolated from the three experimental groups, compared with starch-fed non-diabetic controls. An increase in low molecular weight components of the glomerular basement membrane of sucrose-fed and diabetic rats was observed using electrophoresis in sodium dodecyl sulphate. Significantly higher (p < 0.001) glucosyltransferase activity was present in kidney supernatants prepared from sucrose-fed (1050 +/- 60 nmol/2h/kidney) compared to starch-fed rats (510 +/- 40 nmol/2h/kidney). Sucrose feeding induces changes similar to those found in diabetes and the induction of diabetes made little difference over the feeding of sucrose alone.