Smackdown: Whole grains versus fruits and vegetables effects on inflammation and the gut microbiome

Various governments^[1][2] provide recommendations^[3] for healthier eating for good reason—a suboptimal diet is one of the leading preventable risk factors^[4] for non-communicable diseases, such as heart disease and diabetes, which are are the first and seventh most common causes of death^[5] in the U.S., respectively.

Recently, several studies have demonstrated the beneficial potential of fruit and vegetables^[6] (FV) and whole grains^[7] (WG) for diet-induced diseases and associated inflammation. Unfortunately, almost 80%^[8] of the global population consumes less than the World Health Organization’s intake recommendation of five FV servings per day and more than 90%^[9] consumes less than the WG recommendation of 2.5 servings per day. You can see how some parts of the world fare in Figure 1.

One of the mechanisms through which these anti-inflammatory benefits of FVs and WGs are thought to be mediated, besides their high vitamin, mineral, and phytochemical content^[10], is the metabolism of the various fibers they provide and their interaction with the gut microbiome^[11]. When consumed, dietary fibers that cannot be decomposed by digestive enzymes end up being fermented by microbiota in the gut to form short chain fatty acids (SCFAs). These SCFAs have demonstrated various benefits for gut barrier function^[12], carbohydrate and lipid metabolism^[13], and inflammation^[14].

While several studies have been conducted regarding FV or WG intake and inflammation or gut microbiota changes, this is the first experimental study to examine outcomes from both food groups in the same study. The purpose of the study under review was to determine the impact of increasing WG and FV intake against the background of a typical Western diet (high in processed food) on markers of inflammation and gut microbiota composition in overweight or obese individuals.

A suboptimal diet is the leading preventable risk factor for some of the most common causes of mortality. Recently, several studies have demonstrated a positive influence of FV and WG intake on inflammation and gut microbial composition. This is the first study to examine the influence of both FV and WG intake on markers of inflammation and gut microbiota.