A prospective randomised trial to determine the efficacy of a low glycaemic index diet given in addition to healthy eating and weight loss advice in patients with coronary heart disease. Retrospective analysis of the impact of a low glycaemic index diet on hospital stay following coronary artery bypass grafting: a hypothesis. Four-week low-glycemic index breakfast with a modest amount of soluble fibers in type 2 diabetic men. The effect of high- and low-glycemic index energy restricted diets on plasma lipid and glucose profiles in type 2 diabetic subjects with varying glycemic control. Low-glycemic index foods improve long-term glycemic control in NIDDM. Beneficial effect of low-glycemic index diet in overweight NIDDM subjects. Reducing cardiovascular disease risk with diet. Effect of a low-glycemic-index diet during pregnancy on obstetric outcomes. Influence on lifestyle measures and five-year coronary risk by a comprehensive lifestyle intervention programme in patients with coronary heart disease.
Recent epidemiological and prospective trial evidence suggests that consumption of a low glycaemic index (LGI) diet will reduce coronary risk. We hypothesise that introduction of an LGI diet will improve the metabolic profile of patients who have undergone coronary artery bypass grafting.
                We conducted a randomised parallel group trial comparing a control group (n=29, age 61.8+/-9 y), who received currently advocated healthy eating dietary advice only, to an intervention group, who received healthy eating advice emphasising LGI carbohydrates (n=26, age 63.6+/-9.4 y) over a 12-week period in free-living patients with coronary heart disease. Outcome measures included fasting glucose, insulin, total cholesterol, high-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, low density lipoprotein cholesterol and triglycerides.
                A significant lower dietary glycaemic index was achieved in the group assigned to an LGI diet compared to the healthy eating control group (71+/-1 vs 81+/-1); fibre intake was also higher in the LGI group (20+/-1 vs 15+/-1 g). All biochemical markers of glucose and lipid metabolism measured were similar after 12 weeks of the LGI diet or control diet.
                The LGI group achieved a significant LGI and a higher dietary fibre intake. However, there was no measurable significant effect of either the LGI diet or the health eating diet on lipid levels; this may have been hidden by concurrent drug therapy. Glucose tolerance and insulin resistance influence medical outcome in subjects with coronary artery disease, these metabolic parameters also influence general perioperative surgical outcome. We hypothesize that glucose tolerance and insulin resistance can be favourably modified by reducing the glycaemic index of the diet.
                The present study is a retrospective analysis of a low and high glycaemic index diet on glucose tolerance, insulin resistance and perioperative outcome, as assessed by the length of hospital stay following coronary artery bypass surgery. Thirty-five adults awaiting bypass surgery were randomized, for the 4 weeks prior to surgery, to either a low glycaemic index diet (17 subjects) or high glycaemic index diet (18 subjects). Glucose and insulin responses during a 75 g oral glucose tolerance test were assessed before and after dietary intervention and insulin-mediated glucose uptake was assessed in isolated adipocytes obtained at surgery.
                The patients who consumed a low glycaemic diet had improved glucose tolerance and significantly greater in vitro adipocyte insulin sensitivity at the time of surgery compared with the high glycaemic diet group (78.87 +/- 10.64% versus 41.11 +/- 7%, respectively). The total length of stay in the patients on the low glycaemic diet was less than patients consuming the high glycaemic diet (7.06 +/- 0.38 days versus 9.53 +/- 1.44 days, P < 0.5).
                This study provides further support that carbohydrate and fat metabolism influence cardiac outcome and provides new evidence that dietary modification prior to coronary artery bypass surgery can shorten hospital stay. Low-glycemic index diets are associated with a wide range of benefits when followed on a chronic basis. The chronic effects, however, of the substitution of 1 meal per day are not well known in diabetic subjects. Therefore, we aimed to evaluate whether the chronic use of a low-glycemic index breakfast (low-GIB) rich in low-GI carbohydrates and a modest amount of soluble fibers could have an effect on lipemia at a subsequent lunch, and improve glucose and lipid metabolism in men with type 2 diabetes. A total of 13 men with type 2 diabetes were randomly allocated in a double-blind cross-over design to a 4-week daily intake of a low-GI versus a high-GI breakfast separated by a 15-day washout interval. The low-GI breakfast was composed of whole grain bread and muesli containing 3 g beta-glucan from oats. Low-GIB induced lower postprandial plasma glucose peaks than the high-GIB at the beginning (baseline, P <.001) and after the 4-week intake (P <.001). The incremental area under the plasma glucose curve was also lower (P <.001, P <.01, baseline, and 4 weeks, respectively). There was no effect on fasting plasma glucose, insulin, fructosamine, or glycosylated hemoglobin (HbA(1c)). Fasting plasma cholesterol, as well as the incremental area under the cholesterol curve, were lower (P <.03, P <.02) after the 4-week low-GIB period than after the high-GIB period. Apolipoprotein B (apo B) was also decreased by the 4-week low-GIB. There was no effect of the low-GI breakfast on triacylglycerol excursions or glucose and insulin responses at the second meal. The high-GIB, however, tended to decrease the amount of mRNA of leptin in abdominal adipose tissue, but had no effect on peroxisome proliferator-activated receptor gamma (PPARgamma) and cholesterylester transfer protein (CETP) mRNA amounts. In conclusion, the intake of a low-GI breakfast containing a modest amount (3 g) of beta-glucan for 4 weeks allowed good glycemic control and induced low plasma cholesterol levels in men with type 2 diabetes. The decrease in plasma cholesterol associated with low-GI breakfast intake may reduce the risk of developing cardiovascular complications in subjects with type 2 diabetes.
                Copyright 2002, Elsevier Science (USA). All rights reserved. To determine whether glycemic index (GI) differentially affects improved glucose and lipid profiles observed during weight loss in overweight subjects previously diagnosed with type 2 diabetes with variable glucose tolerance.
                Twenty-three female and twenty-two male overweight subjects participated in 12 weeks of energy restriction (average BMI 33.2 kg/m2, age 56.7 years, glycated hemoglobin (GHb) 6.7%). After a four-week run-in on a high saturated fat (SFA) diet (1540 kcal/day, 17% SFA), the free-living subjects were randomly assigned to either a high- (75 GI units) or low- (43 GI units) GI diet (1440 kcal/day, 60% carbohydrate, 5% SFA) for eight weeks. Weight, serum lipids, plasma glucose and glycated hemoglobin were measured every four weeks. An oral glucose tolerance test (OGTT) was also performed at baseline, weeks 4 and 12. From the baseline OGTT results subjects were divided into three groups of low, median and high glucose tolerance.
                At baseline, BMI, age and glycated hemoglobin concentrations were not different between subjects allocated to the high- or low-GI diets. After four weeks, weight loss was 3.6+/-0.3 kg. Fasting glucose (-5.6%), glycated hemoglobin (-2.8%), area under the glucose curve (-13.0%) and triglyceride (-13.8%) concentrations were reduced (p < 0.02). Between weeks 4 and 12 reductions were observed in weight (-4.9%), fasting glucose (-4.6%), area under glucose curve (-10.1%), glycated hemoglobin (-7.2%), triglyceride (-7.5%) and LDL-C (-13.2%) concentrations. Weight loss was not different between low and high-GI diets. However, glycated hemoglobin was reduced twofold more in subjects consuming a low-GI diet as compared to subjects consuming a high-GI diet, but this was not statistically significant. LDL concentrations were also reduced more in subjects with low glucose tolerance on the low-GI diet (p = 0.02).
                Weight loss produces substantial improvements in glycemic control and lipoprotein metabolism. Lowering the glycemic index of high carbohydrate, low fat diets increases the fall in LDL cholesterol in subjects with type 2 diabetes with low glucose tolerance, but has little effect on glycemic control. To compare high- and low-glycemic index (GI) diets in the treatment of non-insulin-dependent diabetes mellitus (NIDDM).
                Sixteen subjects with well-controlled NIDDM and normal lipid profile, 10 of whom continued oral hypoglycemic medication, participated in the study. A diet that emphasized low-GI foods (e.g., porridge, pasta) was compared with a high-GI diet (e.g., processed cereals, potatoes). The GI of the low-GI diet was 15% lower than the high-GI diet (77 +/- 3 vs. 91 +/- 1) but otherwise similar in macronutrient composition and fiber, as determined by a 4-day weighed record. The diets were instituted under instruction from a dietitian who visited subjects at home on a weekly basis. Body weight was maintained within 1-2 kg.
                Glycemic control was improved on the low-GI diet compared with the high-GI diet (statistically significant findings, P less than 0.05). Mean glycosylated hemoglobin at the end of the low-GI diet was 11% lower (7.0 +/- 0.3%) than at the end of the high-GI diet (7.9 +/- 0.5%), and the 8-h plasma glucose profile was lower (area under the curve above fasting 128 +/- 23 vs. 148 +/- 22 mmol.h-1.L-1, respectively). Mean fasting plasma glucose, total cholesterol triglycerides, and lipoproteins did not show important differences.
                A low-GI diet gives a modest improvement in long-term glycemic control but not plasma lipids in normolipidemic well-controlled subjects with NIDDM. To determine whether low-glycemic index (GI) diets have clinical utility in overweight patients with non-insulin-dependent diabetes mellitus (NIDDM).
                Six patients with NIDDM were studied on both high- and low-GI diets of 6-wk duration with metabolic diets with a randomized crossover design. Both diets were of similar composition (57% carbohydrate, 23% fat, and 34 g/day dietary fiber), but the low-GI diet had a GI of 58 compared with 86 for the high-GI diet.
                Small and similar amounts of weight were lost on both diets: 2.5 kg on high-GI diet and 1.8 kg on low-GI diet. On the low-GI diet, the mean level of serum fructosamine, as an index of overall blood glucose control, was lower than on the high-GI diet by 8% (P less than 0.05), and total serum cholesterol was lower by 7% (P less than 0.01).
                In overweight patients with NIDDM, reducing diet GI improves overall blood glucose and lipid control. Past research efforts to determine the influence of the diet on cardiovascular (CV) health have focused on the individual roles of specific dietary components with debatable success. Awareness of the impact and complexity of nutrient interactions has expanded in recent years to include assessment of dietary patterns as they contribute to lower CV disease risk.
                In a series of multicenter studies, we compared a comprehensive, prepared meal plan, formulated to meet recommended intake levels of macro- and micronutrients, with a self-selected diet based on the exchange system. The three studies comprised adult participants with hypertension, hyperlipidemia, and type 2 diabetes (n = 560, 251, and 330, respectively). The first two studies (10 weeks) varied by the amount of contact with study personnel, and the third study assessed long-term effects over 52 weeks. Outcome measures included: blood pressure, lipid and lipoprotein levels, glycemic control, homocysteine, compliance, quality of life, and weight.
                The first study demonstrated significant improvements in all measures, with greater improvements with the prepared meal plan compared with the self-selected diet. The second study, designed to parallel the contact frequency that would occur in a real world clinical setting, also produced significant improvements in multiple CV risk factors. In the long-term study, in addition to sustained improvements in risk factors, significant weight loss was achieved and maintained over the 52 weeks.
                These trials demonstrate that regular consumption of a nutritionally complete diet offers multiple, concurrent clinical benefits for reducing CV disease risk and body weight. Pregnancy is a condition in which the glycemic index (GI) may be of particular relevance because maternal glucose is the main energy substrate for intrauterine growth.
                The aim was to compare the effects of low-GI and conventional dietary strategies on pregnancy outcomes in healthy women. Compliance and acceptability were also investigated.
                The subjects were assigned alternately to receive dietary counseling that encouraged either low-GI (LGI) carbohydrate foods or high-fiber, moderate-to-high GI (HGI) foods and were studied 5 times between <16 wk gestation and delivery. Of the 70 women who met the inclusion criteria, 62 completed the study (32 in the LGI and 30 in the HGI groups). Primary outcomes were measures of fetal size.
                The mean diet GI fell significantly in the LGI group but not in the HGI group. Compared with the LGI group, women in the HGI group gave birth to infants who were heavier (3408 +/- 78 compared with 3644 +/- 90 g; P = 0.051) and had a higher birth centile (48 +/- 5 compared with 69 +/- 5; P = 0.005), a higher ponderal index (2.62 +/- 0.04 compared with 2.74 +/- 0.04; P = 0.03), and a higher prevalence of large-for-gestational age (3.1% compared with 33.3%; P = 0.01). Women in the LGI group found the diet easier to follow.
                Because birth weight and ponderal index may predict chronic disease in later life, a low-GI diet may favorably influence long-term outcomes. Lifestyle measures of coronary heart disease (CHD) prevention have been overshadowed by the efficacy of drug treatments. This is particularly the case in the setting of secondary prevention where the benefits of lipid lowering, anti-platelet and anti-hypertensive drugs have been emphasised in numerous trials. Lifestyle measures address several CHD risk factors at once and are generally free of serious side effects.
                The objective of the present study was to determine whether a comprehensive programme of lifestyle modification could favourably influence dietary and exercise habits in addition to smoking cessation over two years. In addition, an attempt was made to evaluate if this programme could favourably influence the five-year CHD-risk in the male population included in the study.
                A total of 197 patients with proven coronary heart disease were included and randomised to a lifestyle intervention programme or to usual care. Follow-up was after a period of two years.
                Intervention comprised a low fat diet, regular exercise, smoking cessation, psychosocial support and education, delivered by nurses on the rationale for pharmacological and lifestyle measures. Usual care comprised follow-up in the routine outpatient clinic. Both groups were given the same comprehensive medication according to recent guidelines.
                Patients in the lifestyle intervention group reduced the intake of saturated fat, sugar and cholesterol (P<0.001), increased their exercise level (P<0.01) and stopped smoking (P<0.05) when compared with the usual care group. A sub-analysis of the influence of five-year CHD calculated risk in males resulted in a relative risk reduction of 22% (95% confidence intervals 9-35). Although significant, this result must be interpreted with caution due to poor statistical power and reproducibility of the method.
                In the presence of modern drug treatments for secondary cardiovascular disease prevention it remains possible through a favourable diet, exercise and smoking cessation to show an additional reduction in the five-year risk for CHD in males.
There is no evidence from RCTs to show an effect of low GI diets on coronary heart disease. Weak evidence for minor effects on some CHD risk factors was found. Many of the trials identified were short-term, of poor quality and did not have sufficient power to detect clinically important differences. The combined evidence from the studies suggests that any beneficial effect of low glycaemic index diets on CHD and its risk factors is small. There is a need for well designed, adequately powered, randomised controlled studies, of greater than 12 weeks duration to assess the true effects of low glycaemic index diets for CHD.