A high rate of non-compliance confounds the study of whole grains and weight maintenance in a randomised intervention trial - the case for greater use of dietary biomarkers in nutrition intervention studies

TY - JOUR

T1 - A high rate of non-compliance confounds the study of whole grains and weight maintenance in a randomised intervention trial - the case for greater use of dietary biomarkers in nutrition intervention studies

AU - Kristensen, Mette Bredal

AU - Pelletier, Xavier

AU - Ross, Alastair B.

AU - Thielecke, Frank

N1 - CURIS 2017 NEXS 035

PY - 2017/1/11

Y1 - 2017/1/11

N2 - Observational studies consistently find an inverse relationship between whole-grain intake and weight gain. We aimed to confirm this in an open-label researcher-blinded parallel design randomised trial. A total of 179 overweight/obese women with a habitually low whole-grain intake (<16 g/day) were randomised to a weight maintenance diet with refined-grain (RG) or whole-grain (WG) foods (80 g/day) for 12 weeks after an initial weight loss program over 8 weeks. Body weight and composition was assessed at baseline, after the initial weight loss, and after the 12-week dietary intervention. During the 12-week dietary intervention phase, there were no group differences in changes in body weight and total fat mass %, whereas abdominal fat mass tended to increase more during the dietary intervention phase in the WG compared to the RG group (0.7 (SD 3.6) vs. -0.3 (SD 3.8) %; p = 0.052). Plasma alkylresorcinol concentrations, biomarkers of wholegrain wheat and rye intake, indicated poor compliance, particularly in the WG group, where >60% of participants had alkylresorcinol concentrations below 70 nmol/L, a concentration indicating low or no intake of whole-grain wheat. Further, weight regain was lower than expected in both intervention groups, further supporting a lack of compliance to the post-weight-loss diet. The rate of compliance was too low to conclude any effect of whole grain on weight maintenance, and reinforces the need to use objective measures of compliance in nutrition intervention studies.

AB - Observational studies consistently find an inverse relationship between whole-grain intake and weight gain. We aimed to confirm this in an open-label researcher-blinded parallel design randomised trial. A total of 179 overweight/obese women with a habitually low whole-grain intake (<16 g/day) were randomised to a weight maintenance diet with refined-grain (RG) or whole-grain (WG) foods (80 g/day) for 12 weeks after an initial weight loss program over 8 weeks. Body weight and composition was assessed at baseline, after the initial weight loss, and after the 12-week dietary intervention. During the 12-week dietary intervention phase, there were no group differences in changes in body weight and total fat mass %, whereas abdominal fat mass tended to increase more during the dietary intervention phase in the WG compared to the RG group (0.7 (SD 3.6) vs. -0.3 (SD 3.8) %; p = 0.052). Plasma alkylresorcinol concentrations, biomarkers of wholegrain wheat and rye intake, indicated poor compliance, particularly in the WG group, where >60% of participants had alkylresorcinol concentrations below 70 nmol/L, a concentration indicating low or no intake of whole-grain wheat. Further, weight regain was lower than expected in both intervention groups, further supporting a lack of compliance to the post-weight-loss diet. The rate of compliance was too low to conclude any effect of whole grain on weight maintenance, and reinforces the need to use objective measures of compliance in nutrition intervention studies.

KW - Faculty of Science

KW - Whole grain

KW - Weight maintenance

KW - Compliance

KW - Biomarkers

KW - Alkylresorcinols

U2 - 10.3390/nu9010055

DO - 10.3390/nu9010055

M3 - Journal article

C2 - 28085022

SN - 2072-6643

VL - 9

JO - Nutrients

JF - Nutrients

IS - 1

M1 - 55

ER -