The Effects of Moderate Whole Grain Consumption on Fasting Glucose and Lipids, Gastrointestinal Symptoms, and Microbiota

Abstract

This study was designed to determine if providing wheat, corn, and rice as whole (WG) or refined grains (RG) under free-living conditions will change parameters of health over a six-week intervention in healthy, habitual non-WG consumers. Measurements of body composition, fecal microbiota, fasting blood glucose, total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), and triglycerides were made at baseline and post intervention. Subjects were given adequate servings of either WG or RG products based on their caloric need and asked to keep records of grain consumption, bowel movements, and GI symptoms weekly. After six weeks, subjects repeated baseline testing. Significant decreases in total, LDL, and non-HDL cholesterol were seen after the WG treatments but were not observed in the RG treatment. During Week 6, bowel movement frequency increased with increased WG consumption. No significant differences in microbiota were seen between baseline and post intervention, although, abundance of order Erysipelotrichales increased in RG subjects who ate more than 50% of the RG market basket products. Increasing consumption of WGs can alter parameters of health, but more research is needed to better elucidate the relationship between the amount consumed and the health-related outcome.

Whole-grain consumption and its effects on hepatic steatosis and liver enzymes in patients with non-alcoholic fatty liver disease: a randomised controlled clinical trial

“…At baseline, patients were randomly allocated to two groups to receive dietary advice either to obtain at least half of their cereal servings each day from whole-grain foods (intervention group (n 56)) or from usual cereals (control group (n 56)) for 12 weeks. This time period was designated based on those previous studies showing beneficial effects of whole grains on metabolic markers in 6 and 8 weeks (16,17) . A dietitian met with participants at baseline to explain the 2012 Dietary Guidelines for Americans (9) used in the study and also to provide educational information to facilitate their understanding and adherence.…”

“…Similarly, some previous studies have suggested that whole-grain foods may improve glucose and lipid biomarkers in healthy obese or hyperglycaemic adults (14) . Many randomised controlled trials have also evaluated the effects of whole-grain products on blood glucose concentrations and serum lipids, but they have found inconsistent results (15)(16)(17)(18) .…”

Microbiota modulation by eating patterns and diet composition: impact on food intake

“…They first increase stool mass and decrease transit time, improving digestion and absorption. Fiber and other nondigestible carbohydrates, such as resistant starch, can also be fermented by the commensal microbiota (14). The major end products of this carbohydrate fermentation are short-chain fatty acids (SCFAs), particularly acetate, propionate, and butyrate (52).…”

Insight about Colonic Microbiota Imbalance and Obesity

“…There have been several studies that report changes in the gut microbiota following a whole grain intervention. Most studies report only modest to no changes in gut microbiota composition (Cooper et al, 2017).…”

“…41 million children under the age of 5 were overweight or obese in 2016. Over 340 million children and adolescents aged [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] were overweight or obese in 2016 (WHO, accessed: January 2019).…”