Healthful plant-based eating is associated with lower adiposity and inflammation

Researchers from Harvard University School of Public Health analyzed data from 831 women who participated in the Nurses’ Health Study II. Health-related data and blood samples were collected at baseline (1996-99) and during a follow up period 12-14 years later (2010-11). Plasma biomarkers predictive of cardiometabolic diseases were measured including adiponectin, leptin, insulin, and high-sensitivity C-reactive protein (hsCRP).

Dietary data was collected every 4 years using a semi-quantitative Food Frequency Questionnaire (FFQ). Three plant-based diet indices were calculated from the FFQ data:

1. Overall plant-based diet index (PDI): all plant-based foods

2. Healthful plant-based diet index (hPDI): foods rich in whole grains, fruits, vegetables, and nuts

3. Unhealthful plant-based diet index (uPDI): fruit juices, sugar-sweetened beverages, refined grains, and sweets

In the follow-up period, participants’ mean BMI increased from 24.6 to 26.3. Mean plasma concentrations of all biomarkers also increased, as well as the prevalence of hypertension and hypercholesterolemia.

A higher hPDI score (higher adherence to a healthful plant-based diet) was significantly associated with lower plasma concentrations of leptin, insulin, and hsCRP, and a higher plasma concentration of adiponectin, even after adjustment for BMI and other covariates.

Conversely, a higher uPDI (representing a lower quality plant-based diet) was associated with higher concentrations of leptin and insulin. These results were seen in both cross-sectional and longitudinal analysis.

Conclusion

Not all plant-based diets are equal. It is diets rich in healthful plant foods which are favourably associated with lower concentrations of biomarkers for adiposity and inflammation. Whilst diets rich in refined plant foods do not seem to offer any benefit.