A recently published study in JAMA looked into the potential benefits of a plant-based diet on gout risk.
Study: Differences in plant-based diets affect risk of gout. Image credit: Ju Jae-Young/Shutterstock.com
How does diet affect gout?
Gout is an inflammatory joint disease that affects approximately 4% of Americans. The disease is often painful and potentially disabling, and is associated with increased risk of cardiometabolic disease, mortality, and poor mental health.
Certain foods, such as alcohol, red meat, fish, and sugary drinks, have been shown to increase the risk of gout, while nonfat dairy products, coffee, certain vegetables, and ascorbic acid may reduce the risk of gout.
Healthy eating patterns, such as the Dietary Approaches to Stop Hypertension (DASH) and Mediterranean diets, have also been shown to reduce the risk of gout, but less is known about the effect of a plant-based diet on the development of gout.
About the Research
The study used data from Americans who participated in the Health Professionals Follow-up Study, conducted between 1986 and 2012, and the Nurses' Health Study, conducted between 1984 and 2010. All study participants were free of gout at the start of the study.
The aim of this study was to measure the average exposure to the overall plant-based dietary index (PDI), healthy PDI (hPDI), and unhealthy PDI (uPDI). These indices were calculated based on 18 food groups determined using a food frequency questionnaire.
What did the study find?
The study included approximately 123,000 participants with a mean age of 54 years in men and 50.9 years in women. Over a period of approximately 2.8 million person-years, 2,700 new cases of gout were reported.
Overall PDI did not correlate with the incidence of gout in either men or women, but when comparing hPDI to uPDI, hPDI was negatively correlated with gout and uPDI was positively correlated.
In the hPDI cohort, there was a 17% increase in gout risk from the highest to lowest quintile, whereas in the uPDI cohort there was a nearly 20% decrease in gout risk from the highest to lowest quintile.
The decrease with increasing hPDI was more pronounced in women. No significant associations were observed when only men were evaluated.
Risk in the uPDI cohort was particularly elevated in women, with those in the highest uPDI quintile of unhealthy plant food intake having an increased gout risk of approximately 33%; this risk was not significant in men.
Whole grains reduced gout risk by 7% per serving, tea and coffee by 5% per serving, and dairy products by 15% per serving. Conversely, fruit juice and sugar-sweetened beverages increased gout risk by 6%, while vegetable oils increased gout risk by 16% per serving. This is the first time that an inverse association between whole grains and gout risk has been reported.
Healthy foods that do not increase the risk of gout include fruits, vegetables, nuts, legumes, etc. Unhealthy plant foods that do not increase the risk of gout include sweets, desserts, potatoes, refined grains, etc.
Animal fats and fish were associated with an increased risk of gout, but consumption of eggs, meat in general, or other animal products was not associated with an increased risk of gout.
Fish is rich in purines, which increase serum uric acid levels and therefore vulnerability to gout. The reduced risk of gout from sweets and desserts and the lack of association with refined grains requires further investigation to understand the mechanisms responsible for this association.
Conclusion
The findings add support to current dietary guidelines that recommend increasing consumption of healthy plant foods and decreasing consumption of unhealthy plant foods to reduce the risk of gout.
The benefit of incorporating eggs and dairy products into a vegetarian diet is a reduction in serum uric acid levels and therefore a reduced risk of gout. These dietary patterns are more likely to be sustained in the long term compared to more strict or restrictive diets.
“The hPDI shares features with the DASH and Mediterranean diets, such as an emphasis on consumption of fruits, vegetables, whole grains, nuts, and legumes. This adds to the growing literature on candidate dietary patterns for gout prevention.”
