A Comparison of a Pulse-Based Diet and the Therapeutic Lifestyle Changes Diet in Combination with Exercise and Health Counselling on the Cardio-Metabolic Risk Profile in Women with Polycystic Ovary Syndrome: A Randomized Controlled Trial

Abstract

We compared the effects of a low-glycemic index pulse-based diet, containing lentils, beans, split peas, and chickpeas, to the Therapeutic Lifestyle Changes (TLC) diet on cardio-metabolic measures in women with polycystic ovary syndrome (PCOS). Ninety-five women (18⁻35 years) enrolled in a 16-week intervention; 30 women in the pulse-based and 31 in the TLC groups completed the study. Women participated in aerobic exercise training (minimum 5 days/week for 45 min/day) and were counselled (monthly) about PCOS and lifestyle modification. Women underwent longitudinal follow-up post-intervention. The pulse-based group had a greater reduction in total area under the curve for insulin response to a 75-g oral glucose tolerance test (mean change ± SD: -121.0 ± 229.9 vs. -27.4 ± 110.2 µIU/mL × min; p = 0.05); diastolic blood pressure (-3.6 ± 6.7 vs. -0.2 ± 6.7 mmHg, p = 0.05); triglyceride (-0.2 ± 0.6 vs. 0.0 ± 0.5 mmol/L, p = 0.04); low-density lipoprotein cholesterol (-0.2 ± 0.4 vs. -0.1 ± 0.4 mmol/L, p = 0.05); total cholesterol/high-density lipoprotein cholesterol (TC/HDL-C; -0.4 ± 0.4 vs. 0.1 ± 0.4, p < 0.001); and a greater increase in HDL-C (0.1 ± 0.2 vs. -0.1 ± 0.2 mmol/L, p < 0.01) than the TLC group. Decreased TC/HDL-C (p = 0.02) at six-month and increased HDL-C and decreased TC/HDL-C (p ≤ 0.02) at 12-month post-intervention were maintained in the pulse-based group. A pulse-based diet may be more effective than the TLC diet at improving cardio-metabolic disease risk factors in women with PCOS.

Trial registration: CinicalTrials.gov identifier, NCT01288638.

Keywords: dietary intake; glucose; insulin; lifestyle; lipid; metabolic syndrome; physical activity; pulse foods.

Figure 1

CONSORT flow diagram of the randomized controlled trial. In the “follow-up (16-week post-intervention)” section—“completed the intervention”—represented women who completed the 16-week lifestyle intervention;—“discontinued the intervention”—represented women who dropped out of the study before completing the 16-week lifestyle intervention. In the “analysis (16-week post-intervention)” section, the number of subjects that were analyzed in the pulse-based and TLC diet groups included women who completed the 16-week lifestyle intervention and women who dropped out of the study before completing the 16-week intervention period, but their last observation data which were collected at nine-weeks post-intervention were carried forward to 16-week time point according to the intention-to-treat principle.

Figure 2

Plasma insulin and glucose responses to a standard 75-g OGTT before and after 16-week of intervention in the pulse-based diet and TLC diet groups. Solid dark lines represent women in the pulse-diet group at baseline (n = 30). Solid light lines represent women in the TLC diet group at baseline (n = 29). Dotted dark lines represent women in the pulse-diet group after the intervention (n = 30). Dotted light lines represent women in the TLC diet group after the intervention (n = 29). Insulin time course in response to OGTT (A); glucose time course in response to OGTT (B); ratio of plasma insulin to glucose time course in response to OGTT (C). Groups were comparable at baseline. Data are expressed as mean ± SEM. Abbreviations: OGTT, oral glucose tolerance test.