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.

Conflict of interest statement

The authors declare no conflict of interest. The funders had no role in the design of the study, collection, analyses, interpretation of data, writing of the manuscript, and decision to publish.

Figures

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.