Could a Plant-based Diet Reduce Diabetes Risk?

Several recent studies have evaluated how diet may affect a person’s risk of developing diabetes—particularly, how a diet more focused on plants and less on animal products may be beneficial. The research was presented during Nutrition 2019, the annual meeting of the American Society for Nutrition, at the Baltimore Convention Center.

T2D Prevention: Go Green?

One study, presented on June 11, found that shifting to a more plant-based diet could be beneficial in minimizing the risk of type 2 diabetes (T2D). For the study, researchers evaluated patients from the Coronary Artery Risk Development in Young Adults (CARDIA) cohort. CARDIA is a multi-center, community-based, prospective cohort study with 30 years of follow-up. A total of 2,717 patients were recruited from the study, all of whom did not have T2D through year 20. They were followed through year 30 for T2D diagnosis. Dietary intake information for the first 20 years of the study was collected through an interview pertaining to diet history. Quality of diet was evaluated using the A Priori Diet Quality Score (APDQS); scores ranged from 0—132, with scores increasing with the addition of nutritionally rich plant foods, such as fruits, vegetables, and plant-derived fats (such as seeds, nuts, and vegetable oils) and proteins (such as avocado, legumes, and soy). Researchers calculated patients’ change in diet quality over the study period.

The mean age at baseline was 25 years; 43% of participants were black, and 58% were women. There were 206 incident T2D cases. The mean year 0 APDQS was 64 points; mean 20-year change was 7 points.

“In multivariable-adjusted analysis, we found that the greatest increase in dietary quality over 20 years (median APDQS increased by 22 points) was associated with a 60% decrease in risk of T2DM as compared to a small decrease in diet quality (median APDQS decreased by 8 points); HR _{Q5 vs. Q1}: 0.40; 95% CI:0.24–0.67),” the researchers observed. With each 10-point increase over the 20-year period, T2D risk decreased by 23% (95% CI: 0.67–0.88, P-trend = 0.0009).

Nutrients: Straight From the Source

Another study, presented on June 9, suggested that an intake in animal products may increase T2D risk. Particularly, the study looked at the affect of DNA methylation, which can be affected by vitamins B₂, B₆, and B₁₂, as well as folate and methionine, the researchers noted.

The study included data on patients from the Nurses’ Health Study (1984-2012; n = 69,949 [all women]), Nurses’ Health Study II (1991-2011; n = 90,239 [all women]), and Health Professionals Follow-Up Study (1986-2010; n = 40,539 [all men]). Every two to four years, the researchers collected dietary data, which included dietary intakes of vitamins B₂, B₆, and B₁₂; folate; and methionine. They adjusted for cereal fiber, animal protein, polyunsaturated and saturated fatty acids ratio.

The final analysis included a total of 1,763,428 years of follow-up, during which time 8,141 T2D cases were recorded. Patients in the highest quintile of vitamins B₂ and B₆, compared to those in the lowest quintile, had a 10% (95% CI 3%-16%) and 11% (95% CI 3%-16%) lower risk of T2D, respectively. Folate and methionine intakes were not associated with T2D risk. Vitamin B₁₂ intake was not associated with T2D risk either, until analyzed specifically by source: “vitamin B12 from food sources was associated with a higher T2D risk (HR [95% CI] =1.11 [1.02-1.19]). On the other hand, supplemental vitamin B12 was associated with lower T2D risk (HR [95% CI] for Q5 vs Q1=0.92 [0.85-0.98]).”

In their abstract the authors speculated, “A higher vitamin B12 intake from food seems to be associated with a higher T2D risk, which may be due to consumption of animal products.”