Short Term Consumption of Whole Grain Foods Independent of Weight Loss Does Not Affect Surrogate Markers of CVD
Authors: Meydani Mohsen , Thomas Michael , Barnett Junaidah B. , Vanegas Sally , Chen Oliver , Dolnikowski Gregory , Jonnalagadda Satya , Saltzman Edward , Roberts Susan , Meydani Simin Nikbin 
Published: November 2023

Several epidemiological studies reported an association between a diet rich in whole grains (WG) and reduced risk of cardiovascular disease (CVD). Diets rich in WG may decrease the risk of CVD through the effects of b‐glucan, which slows carbohydrate absorption and lowers LDL cholesterol and total cholesterol by reducing reabsorption of bile acids. In addition, some randomized controlled trials and numerous cohort studies show that consuming whole grain foods lowers hypertension and reduces hsCRP levels, which are strong predictors of vascular inflammatory disease. Finally, many antioxidant and bioactive compounds in WG reduce oxidative stresses associated with several chronic diseases, including CVD. The current study investigated the effects of a diet rich in WG compared to refined grain (RG) independent of weight loss on several surrogate markers of CVD and the status of antioxidants and oxidative stress markers. Forty nine men and 32 post‐menopausal women (40–65 yr, BMI < 35.0 kg/m2), following a 2‐wk run‐in period with food provided, were randomly assigned to consume one of two weight‐maintenance diets with food provided for 6 wk. The diets differed in WG and fiber contents (WG [n=41]: 207 ± 39 g whole grains/d, 40 ± 5 g fiber/d or RG [n=40]: 0 g whole grains/d, 21 ± 3 g fiber/d), but were otherwise similar in energy, macro‐ and micro‐nutrient composition, the types of foods, and meal structure. Plasma alkylresorcinols (ARs), biomarkers of WG intake, were measured by GC/MS at the end of the run‐in (PRE) and intervention (POST) periods to assess diet adherence. PRE plasma ARs did not differ between the two groups but were higher at POST in WG vs. RG (p < 0.001). Body weight was maintained throughout the intervention in both groups, and urinary creatinine levels remained unchanged. There was no significant difference in changes from PRE to POST between RG and WG groups in the CVD markers including LDL, HDL, VLDL, hsCRP, HbA1c, systolic and diastolic blood pressure. However, there were significant differences in changes from PRE to POST between RG and WG groups in total cholesterol (change for RG >WG, p<0.05). The urinary excretion of 8‐isoprostane‐F2a, a marker of whole body oxidative stress increased in RG group (p=0.01) and decreased in WG group resulting in a significant difference between the change from PRE to POST between the two groups (p=0.04). No differences in measures of total antioxidant status (measured as ORAC and ATBS Trolox equivalents) between the WG and RG at PRE or Post were observed. In summary, while WG were effective in reducing oxidative stress, increased consumption of WG compared to RG independent of weight loss had no effect on blood pressure, CRP levels and most other risk factors for CVD, and there was a greater decrease in total cholesterol in RG group compared to WG group.

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