Background – Inverse associations between fibre intake and cardiovascular risk factors are reported in many studies. In a randomised controlled trial we have previously shown that dietary fibre, in the form of a supplement, decreases cardiovascular risk factors in the postprandial period in overweight and obese individuals. The effects of dietary fibre in conjunction with a healthy diet on cardiovascular disease have not been studied in overweight and obese subjects.
Objectives – To evaluate the effects of dietary fibre with or without a healthy eating plan on blood lipids and glucose in overweight and obese individuals.
Design – A 12-week randomized controlled trial, including ad libitum diets and fibre supplements, was undertaken using four groups: (1) control, (2) control plus fiber supplement, (3) healthy diet and (4) healthy diet plus fibre supplement. Participants in groups 2 and 4 were given extra fibre in the form of supplements (36 grams psyllium husk per day). The healthy diet groups (3 and 4) followed a healthy eating plan based on the Australian Dietary Guidelines. Fasting blood triglyceride, total cholesterol, LDL-cholesterol, HDL-cholesterol and glucose were measured at the baseline, six and twelve weeks.
Outcomes – In total, 70 overweight and obese subjects were recruited and 57 (81%) completed the trial. In primary ‘intention to treat analysis’, total cholesterol and LDL-cholesterol were significantly different between all treatment groups and control group (P=0.000 for total cholesterol and LDL-cholesterol). In comparison with control group, total and LDL-cholesterol decreased by 3% and 9% respectively in the control plus fibre group (P=0.03 and P=0.002 for total cholesterol and LDL-cholesterol respectively), by 6% and 8% respectively in healthy diet group (P=0.001 and P=0.013 for total cholesterol and LDL-cholesterol respectively) and by 12% and 13% respectively in healthy diet plus fibre group (P=0.000 for total cholesterol and LDL-cholesterol). There were no differences in triglyceride, HDL-cholesterol and glucose between the groups.
Conclusion – These results suggest that consumption of additional fibre in the form of psyllium husk is as effective as a healthy dietary plan to improve fasting blood cholesterol and LDL-cholesterol in overweight and obese individuals.