Population based studies suggest that consumption of higher quantities of fruits and vegetables protects against obesity-related diseases, including hepatic steatosis. There are few clinical studies in the literature that have tested the relationship, much less that have established the mechanisms that could be involved in protection against hepatic steatosis. In order to address this void in our understanding Guo and colleagues conducted a preclinical study with mice to determine the causal relationship between consumption of fruits and vegetables and metabolic disorders. They report their results in the November 2020 issue of The Journal of Nutrition.
For 20 weeks, male mice received diets containing 10% fat as the control in experiment one, or a high fat diet (45% kcal as fat) that included 0, 5, 10, or 15% of a freeze-dried powder containing 24 commonly consumed fruits and vegetables. In the second experiment, mice received an AIN-93 diet (16% kcal as fat) containing either 0, 5, 10, or 15% of the freeze-dried powder. The levels of powder inclusion are the human equivalent of 0-9 servings of fruits and vegetables per day.
Including 15% of the freeze-dried powder in the high fat diet of mice in experiment one led to less weight gain, hepatic steatosis, adipose tissue inflammation, ceramide concentrations in the blood and liver, and sphingomyelinase activity, relative to the levels found in mice receiving the high fat diet without the fruit and vegetable powder. The 15% powder inclusion in diets of mice in the second experiment also led to less hepatic steatosis, inflammation and blood ceramide levels, as compared to those not receiving the powder. Beneficial changes in gut microbiota were observed in mice with reduced steatosis. These observations led the authors to conclude that elevated consumption of fruits and vegetables can mitigate hepatic steatosis development in mice, and that the benefits may result from changes in ceramide alone or in combination with altered gut microbiota. They further suggest the results indicate a need for much higher servings of fruits and vegetables each day in order to derive the maximum health benefits.
References
Guo W, Wu D, Dao MC, Li L, Lewis ED, Ortega EF, Eom H, Thomas M, Nikolova-Karakashian M, Meydani M, Meydani SN. A novel combination of fruits and vegetables prevents diet-induced hepatic steatosis and metabolic dysfunction in mice. The Journal of Nutrition, Volume 150, Issue 11, November 2020, Pages 2950–2960, https://doi.org/10.1093/jn/nxaa259.
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