Whole Grain Compared with Refined Wheat Decreases the Percentage of Body Fat Following a 12-Week, Energy-Restricted Dietary Intervention in Postmenopausal Women

Abstract

Observational studies show inverse associations between intake of whole grain and adiposity and cardiovascular risk; however, only a few dietary intervention trials have investigated the effect of whole-grain consumption on health outcomes. We studied the effect of replacing refined wheat (RW) with whole-grain wheat (WW) for 12 wk on body weight and composition after a 2-wk run-in period of consumption of RW-containing food intake. In this open-label randomized trial, 79 overweight or obese postmenopausal women were randomized to an energy-restricted diet (deficit of ~1250 kJ/d) with RW or WW foods providing 2 MJ/d. Body weight and composition, blood pressure, and concentration of circulating risk markers were measured at wk 0, 6, and 12. Fecal output and energy excretion were assessed during run-in and wk 12. Plasma alkylresorcinol analysis indicated good compliance with the intervention diets. Body weight decreased significantly from baseline in both the RW (-2.7 ± 1.9 kg) and WW (-3.6 ± 3.2 kg) groups, but the decreases did not differ between the groups (P = 0.11). The reduction in body fat percentage was greater in the WW group (-3.0%) than in the RW group (-2.1%) (P = 0.04). Serum total and LDL cholesterol increased by ~5% (P < 0.01) in the RW group but did not change in the WW group; hence, the changes differed between the groups (P = 0.02). In conclusion, consumption of whole-grain products resulted in a greater reduction in the percentage fat mass, whereas body weight changes did not differ between the RW and WW groups. Serum total and LDL cholesterol, two important risk factors of cardiovascular disease, increased with RW but not WW consumption, which may suggest a cardioprotective role for whole grain.

Selected individual determinants of cereal, fruit and vegetable consumption among menopausal women in view of potential health risks

“…In this context, a decrease in BMI associated with more frequent consumption of wholegrain cereals (wholegrain rice and noodles, whole grains, and oat meal), fruits and vegetables, which was documented in our study, confirmed beneficial effect of these products with regards to the maintenance of due body weight. These findings are consistent with the results of a Danish study which revealed that wholegrain products play a role in the reduction of adipose tissue in postmenopausal women [18]. This is also important for gynecological practice as excess body weight represents one of main modifiable risk factors of breast and endometrial cancer [8].…”

“…The cardioprotective role of wholegrain cereals, associated with normalization of the lipid profile of blood, was also confirmed in a study of Danish postmenopausal women [18]. Furthermore, the preference of cereals, fruits and vegetables among menopausal women reflects the influence of these products on body weight.…”

“…The wholegrain products have higher biological value due to greater contents of dietary fiber and vitamin B complex, and lower values of glycemic index than in the non-wholegrain foods. This is reflected by their role in the prevention of chronic conditions, including obesity, type 2 diabetes mellitus, cardiovascular disorders, and some neoplasms [1,17,18]. Also fruits and vegetables play an important role in the prevention of these conditions due to their high contents of dietary fiber, antioxidative vitamins, bioflavonoids, and some minerals, including potassium and magnesium [1,2].…”

Two Randomized Cross-Over Trials Assessing the Impact of Dietary Gluten or Wholegrain on the Gut Microbiome and Host Metabolic Health

“…The sample size for the wholegrain protocol was estimated based on an expected difference in HOMA-IR between the wholegrain and the control periods of 0.25 with a weighted standard deviation of 0.6. The expected difference was based on an average difference of 0.26 among three difference studies [22,25,39]. The weighted standard deviation of 0.6 was based on unpublished data on within-group variation of 0.52 and 0.72 in refined grain and WG groups, respectively, from the study Kristensen et al 2012.…”

“…A recent study of ten healthy individuals consuming a gluten-free diet for one month observed alterations in GM composition and lowered immune response [19]. Wholegrain consumption has been associated with a decreased risk of T2D and CVD in prospective studies [20,21] and has been suggested to beneficially influence glucose metabolism [22], adiposity [23,24], and blood lipids [25,26]. Wholegrains have prebiotic effects, due to the high content of dietary fibers [27], which by microbial fermentation lead to production of short-chain fatty acids (SCFA) [28].…”