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

Abstract

Objective: 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. Design: We conducted a randomised parallel group trial comparing a control group (n ¼ 29, age 61.879 y), who received currently advocated healthy eating dietary advice only, to an intervention group, who received healthy eating advice emphasising LGI carbohydrates (n ¼ 26, age 63.679.4 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 lowdensity lipoprotein cholesterol, low density lipoprotein cholesterol and triglycerides. Results: A significant lower dietary glycaemic index was achieved in the group assigned to an LGI diet compared to the healthy eating control group (7171 vs 8171); fibre intake was also higher in the LGI group (2071 vs 1571 g). All biochemical markers of glucose and lipid metabolism measured were similar after 12 weeks of the LGI diet or control diet. Discussion: 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.

Effect of non-oil-seed pulses on glycaemic control: a systematic review and meta-analysis of randomised controlled experimental trials in people with and without diabetes

“…Of these reports, 226 were excluded based on other criteria, leaving 41 trials (39 reports) that satisfied the inclusion criteria but did not meet the exclusion criteria, of which 11 trials (ten reports) investigated pulses alone, 19 trials (19 reports) investigated pulses in a low-GI dietary intervention, and 11 trials (ten reports) investigated pulses in a high-fibre dietary intervention. Tables 1, 2, and 3 show the characteristics of the 41 randomised controlled experimental trials included in each of the three meta-analyses: pulses alone [45][46][47][48][49][50][51][52][53][54], pulses in low-GI diets [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] and pulses in highfibre diets [55][56][57][58][59][60][61][62][63][64]. The 11 trials (ten reports) investigating pulses alone (Table 1) were predominantly crossover in design (seven trials, five of which had a washout period), studied a total of 253 participants (type 2 diabetes, n=21; normoglycaemia and/or hypercholesterolaemia, n=232) and had a mean sample size of 23.…”

“…In early studies, pulses were shown to result in exceptionally low glycaemic responses when fed to healthy volunteers [11], and in later experiments were demonstrated to possess a carbohydrate component that was more slowly digested than that of other foods such as cereals [12]. This property of slower absorption, which is common to α-glucosidase inhibitors, makes pulses an important means of lowering the GI of the diet, a characteristic that has been exploited extensively in studies of low-GI diets [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31], and would therefore be predicted to benefit glycaemic control and, by analogy with acarbose, CHD risk [8]. Based on limited clinical experimental evidence, the European (EASD) [32], Canadian (CDA) [33], and American (ADA) [34] diabetes associations recommend the consumption of dietary pulses as a means of optimising diabetes control through lowering the GI and increasing the dietary fibre content of the diet.…”

Glycaemic index methodology

“…GI) more often shows a significant association with disease risk (diabetes, CVD, cancer) than does the CHO content or GL of the diet. Very recently, several other papers and reviews addressed the impact of GI and GL on health aspects (Tavani et al 2003;Frost et al 2004;Kelly et al 2004;Opperman et al 2004). No benefits occurred in the Frost study, but according to the authors it cannot be excluded that potential effects may have been concealed due to drug therapy.…”

Glycemic Index for Sucrose, Corn Syrup and Honey Entrained Highbush Cranberry Juice

“…In this study, the GI values of HCJ were determined in accordance with the procedures that have been well-established in the GI literature [10,11,12]. Blood samples were taken from the finger using an automatic lancet (Safe-T-Pro, Germany) 15, 30, 45, 60, 90, and 120 min into the application, and each time the amount of glucose was determined by a glucometer.…”

“…The GI was calculated as the percent of glycemic area determined after the consumption of HCJ to the glycemic area produced by the glucose that was chosen as the standard [13]. The commonly-used GI classification system categorizes food into 3 groups, as low (<55), medium (55-69) or high GI (>70) [11]. The HCJ samples in this study were classified according to the GI results.…”