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No difference in body weight decrease between a low-glycemic-index and a high-glycemic-index diet but reduced LDL cholesterol after 10-wk ad libitum intake of the low-glycemic-index diet.
Sloth, B, Krog-Mikkelsen, I, Flint, A, Tetens, I, Björck, I, Vinoy, S, Elmståhl, H, Astrup, A, Lang, V, Raben, A
The American journal of clinical nutrition. 2004;(2):337-47
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Abstract
BACKGROUND The role of glycemic index (GI) in appetite and body-weight regulation is still not clear. OBJECTIVE The objective of the study was to investigate the long-term effects of a low-fat, high-carbohydrate diet with either low glycemic index (LGI) or high glycemic index (HGI) on ad libitum energy intake, body weight, and composition, as well as on risk factors for type 2 diabetes and ischemic heart disease in overweight healthy subjects. DESIGN The study was a 10-wk parallel, randomized, intervention trial with 2 matched groups. The LGI or HGI test foods, given as replacements for the subjects' usual carbohydrate-rich foods, were equal in total energy, energy density, dietary fiber, and macronutrient composition. Subjects were 45 (LGI diet: n = 23; HGI diet: n = 22) healthy overweight [body mass index (in kg/m(2)): 27.6 +/- 0.2] women aged 20-40 y. RESULTS Energy intake, mean (+/- SEM) body weight (LGI diet: -1.9 +/- 0.5 kg; HGI diet: -1.3 +/- 0.3 kg), and fat mass (LGI diet: -1.0 +/- 0.4 kg; HGI diet: -0.4 +/- 0.3 kg) decreased over time, but the differences between groups were not significant. No significant differences were observed between groups in fasting serum insulin, homeostasis model assessment for relative insulin resistance, homeostasis model assessment for beta cell function, triacylglycerol, nonesterified fatty acids, or HDL cholesterol. However, a 10% decrease in LDL cholesterol (P < 0.05) and a tendency to a larger decrease in total cholesterol (P = 0.06) were observed with consumption of the LGI diet as compared with the HGI diet. CONCLUSIONS This study does not support the contention that low-fat LGI diets are more beneficial than HGI diets with regard to appetite or body-weight regulation as evaluated over 10 wk. However, it confirms previous findings of a beneficial effect of LGI diets on risk factors for ischemic heart disease.
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Increasing fecal butyrate in ulcerative colitis patients by diet: controlled pilot study.
Hallert, C, Björck, I, Nyman, M, Pousette, A, Grännö, C, Svensson, H
Inflammatory bowel diseases. 2003;(2):116-21
Abstract
Topical butyrate has been shown to be effective in the treatment of ulcerative colitis (UC). Butyrate is derived from colonic fermentation of dietary fiber, and our aim was to study whether UC patients could safely increase the fecal butyrate level by dietary means. We enrolled 22 patients with quiescent UC (mean age, 44 years; 45% women; median time from last relapse, 1 year) in a controlled pilot trial lasting 3 months. The patients were instructed to add 60 g oat bran (corresponding to 20 g dietary fiber) to the daily diet, mainly as bread slices. Fecal short-chain fatty acids (SCFAs) including butyrate, disease activity, and gastrointestinal symptoms were recorded every 4 weeks. During the oat bran intervention the fecal butyrate concentration increased by 36% at 4 weeks (from 11 +/- 2 (mean +/- SEM) to 15 +/- 2 micromol/g feces) (p < 0.01). The mean butyrate concentration over the entire test period was 14 +/- 1 micromol/g feces (p < 0.05). Remaining fecal SCFA levels were unchanged. No patient showed signs of colitis relapse. Unlike controls, the patients showed no increase in gastrointestinal complaints during the trial. Yet patients reporting abdominal pain and reflux complaints at entry showed significant improvement at 12 weeks that returned to baseline 3 months later. This pilot study shows that patients with quiescent UC can safely take a diet rich in oat bran specifically to increase the fecal butyrate level. This may have clinical implications and warrants studies of the long-term benefits of using oat bran in the maintenance therapy in UC.
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Effects of a low-glycaemic index spaghetti meal on glucose tolerance and lipaemia at a subsequent meal in healthy subjects.
Liljeberg, H, Björck, I
European journal of clinical nutrition. 2000;(1):24-8
Abstract
OBJECTIVE The aim of the study was to evaluate the impact of a low glycaemic index (GI) breakfast on glucose tolerance and lipaemia at a subsequent lunch meal. DESIGN A low GI spaghetti meal and a high-GI white wheat bread (WWB) reference meal were served in the morning after an overnight fast in random order. Four hours after the breakfast, the subjects were given a second meal-a standardized high-GI lunch-and the blood glucose, insulin and lipid responses were measured after the lunch meal. SETTING The study was performed at the Department of Applied Nutrition and Food Chemistry, Lund University, Sweden. SUBJECTS Ten healthy volunteers, eight women and two men, aged 25-51 y, with normal body mass indices, were recruited. RESULTS Lowered glucose and insulin responses and reduced serum triglyceride (TG) level were found at the subsequent lunch meal when the low-GI spaghetti meal was given as a breakfast. No differences in total serum cholesterol or HDL cholesterol were seen after lunch, when preceded by the WWB reference breakfast or the spaghetti breakfast, respectively. CONCLUSIONS Improved glucose tolerance and lowered serum TG levels can appear in the course of a single day. As insulin resistance and raised postprandial TG concentration are known risk factors for cardiovascular disease, the present study adds evidence for a beneficial role of a low-GI diet. SPONSORSHIP Cerealia Foundation for Research and Development (project no. 232) and the Swedish Council for Forestry and Agricultural Research. European Journal of Clinical Nutrition (2000) 54, 24-28
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An examination of the possibility of lowering the glycemic index of oat and barley flakes by minimal processing.
Granfeldt, Y, Eliasson, AC, Björck, I
The Journal of nutrition. 2000;(9):2207-14
Abstract
Differences in glycemic responses to various starchy foods are related to differences in the rate of starch digestion and absorption. In this study, the importance of the degree of gelatinization and the product thickness for postprandial glycemic and insulinemic responses to rolled oats and barley were studied in healthy subjects (5 men and 5 women). Thick (1.0 mm) rolled oats were made from raw or preheated (roasted or steamed) kernels. In addition, thin (0.5 mm) rolled oats were made from roasted or roasted and steamed (processed under conditions simulating commercial production) oat kernels. Finally, steamed rolled barley kernels (0.5 or 1.0 mm) were prepared. All thin flakes elicited high glucose and insulin responses [glycemic index (GI), 88-118; insulinemic index (II), 84-102], not significantly different from white wheat bread (P: > 0.05). In contrast, all varieties of thick oat flakes gave significantly lower metabolic responses (GI, 70-78; II, 58-77) than the reference bread (P: < 0.05). Thick barley flakes, however, gave high glucose and insulin responses (GI, 94; II, 84), probably because the botanical structure underwent more destruction than the corresponding oat flakes. We conclude that minimal processing of oat and barley flakes had a relatively minor effect on GI features compared with the more extensive commercial processing. One exception was thick oat flakes, which in contrast to the corresponding barley flakes, had a low GI.