A whole-grain cereal-rich diet increases plasma betaine, and tends to decrease total and LDL-cholesterol compared with a refined-grain diet in healthy subjects

Abstract

Epidemiological studies have repeatedly found that whole-grain (WG) cereal foods reduce the risk of several lifestyle-related diseases, though consistent clinical outcomes and mechanisms are elusive. To compare the effects of a WG-rich diet with a matched refinedgrain (RG) diet on plasma biomarkers and bowel health parameters, seventeen healthy subjects (eleven females and six males) completed an exploratory cross-over study with a 2-week intervention diet based on either WG-or RG-based foods, separated by a washout of at least 5 weeks. Both diets were the same except for the use of WG (150 g/d) or RG foods. Subjects undertook a 4 h postprandial challenge on day 8 of each intervention diet. After 2 weeks, the WG diet tended to decrease plasma total and LDL-cholesterol (both P¼0·09), but did not change plasma HDL-cholesterol, fasting glucose, C-reactive protein or homocysteine compared with the RG diet. Plasma betaine and alkylresorcinol concentrations were elevated after 1 week of the WG diet (P¼0·01 and P, 0·0001, respectively). Clostridium leptum populations in faeces were increased after the WG diet, along with a trend for decreased faecal water pH (P¼0·096) and increased stool frequency (P,0·0001) compared with the RG diet. A short controlled intervention trial with a variety of commercially available WG-based products tended to improve biomarkers of CVD compared with a RG diet. Changes in faecal microbiota related to increased fibre fermentation and increased plasma betaine concentrations point to both fibre and phytochemical components of WG being important in mediating any potential health effects.

Plasma Alkylresorcinols, Biomarkers of Whole-Grain Intake, Are Related to Lower BMI in Older Adults

“…The median plasma AR concentration was 20 nmol/L, which is similar to that in participants consuming a controlled diet containing only refined grain in an intervention study (36). The median intake of whole grains without added bran estimated by the present FFQ was 14 g/d; however, this amount was similar to the mean whole-grain intake of ;12 g/d (or 0.77 serving/d) observed among older adults (aged $51 y) as reported in the NHANES 1999-2004 (33).…”

Substituting whole grains for refined grains in a 6-wk randomized trial favorably affects energy-balance metrics in healthy men and postmenopausal women

“…However, a critical limitation of this evidence base has been the relative absence of studies that have provided fully controlled diets to participants. In addition, the few controlled-feeding studies that have been conducted have been highly heterogeneous in study populations, intervention durations, and designs and the types of whole grains studied (13,16,27,28). These factors may explain why favorable effects of whole grains on insulin sensitivity (27), fasting glucose (13), and appetite (16,27) have been reported in some but not all (13,16,27,28) trials.…”

Quinoa (Chenopodium quinoa Willd), from Nutritional Value to Potential Health Benefits: An Integrative Review

“…Higher concentrations of plasma betaine were associated also with lower non-HDL cholesterol, TG, homocysteine and markers of inflammation [70].…”