In a recent study published in the Journal of Nutrition, researchers examined the effects of a plant-based diet on mortality.
More young individuals are moving towards plant-based diets, which demands further study on how these diets affect health. There are many reasons why people choose to have a plant-based diet. Some motivations usually include health, environment, ethics, religion, or a combination of these.
Plant foods are known as staple healthy foods, whereas red meat has been strongly correlated with higher risks for cardiovascular diseases. A recent study showed that substituting meat for plants while keeping the same caloric intake was associated with lower mortality. However, entirely replacing all meats with vegetables may have different effects and there are mixed global reports on the benefits of plant-based diets on mortality.
A group at the Johns Hopkins Bloomberg School of Public Health examined how a fully vegetarian diet impacts mortality using long-term survey data and published their findings in the Journal of Nutrition.
The Health Plant-Based Diet Index
This study used the results from the Third National Health and Nutrition Examination Survey in the United States, which surveyed over 11,000 individuals on their dietary habits and health factors. To determine the extent of the participants’ vegetarianism, the scientists created a healthy plant-based diet index. The index scores each respondent based on their diet. This provides a useful and less biased way to quantify the degree of plant-based foods in an individual’s diet, as many vegetarian studies are biased towards participants who are more health-conscious. For this index, only healthy plant foods received a positive score, whereas less healthy vegetables and meats received a negative score.
Characteristics of individuals with more plant foods in their diet
Based on the healthy plant-based index, participants with a higher score, meaning they had more healthy plant foods in their diet, were more likely to be female, white, older, and married. Moreover, they were likely to have achieved higher levels of education, be more physically active, and less likely to smoke. The top 10% of participants based on their score consumed more healthy nutrients, such as fibre and vitamin C, but less unhealthy components like sodium, fats, and cholesterol.
More plant foods associated with a lower risk of mortality
The team recorded 2228 deaths after following up with patients over a period of about 19 years. They analyzed the data from the index and determined that for individuals with a score above the median, a 10-point increase was associated with a statistically significant lower risk in mortality.
This study sheds light on the relationship between a plant-based diet and lower risk of mortality in individuals who have a healthy plant-based index score that is above the median. Their findings also demonstrate that the index can indicate health benefits and that a shift towards more healthy plants in the diet can possibly reduce the risk of mortality.
Although the results support the idea that plant-based diets are healthy, further large-scale studies are needed to solidify our understanding of the benefits of plant-based diets.
Written by Branson Chen, BHSc
Reference: Kim H, Caulfield LE, Rebholz CM. Healthy Plant-Based Diets Are Associated with Lower Risk of All-Cause Mortality in US Adults. The Journal of Nutrition. 2018 Apr 1;148(4):624-31.