A scientific analysis of metabolites from plant-based-diets – especially those rich in whole grains, fruits, and vegetables – may in the future yield clues as to how such eating patterns lower the risk of type 2 diabetes, finds a new study of more than 8,000 people.
The research looked at healthy, unhealthy, and overall plant-based diets, but only metabolic profiles for the healthy and overall plant-based diets showed an inverse relationship with type 2 diabetes.
A primarily “unhealthy” plant-based diet was one including mainly refined grains (e.g., white bread and pasta), fruit juices, potatoes, sugar-sweetened beverages, and sweets/desserts.
“Individual metabolites from consumption of polyphenol-rich plant foods like fruits, vegetables, coffee, and legumes are all closely linked to healthy plant-based diet and lower risk of diabetes,” lead author Frank Hu, MD, said in a press release.
Dr. Hu, of the department of nutrition at Harvard T.H. Chan School of Public Health, Boston, and colleagues reported their findings in Diabetologia.
High-throughput profiling of the metabolome
Given that an individual’s metabolic profile reflects their diet, there is a growing trend in nutritional research to use a technique called high-throughput metabolomics to profile biological samples.
The team conducted an analysis of blood plasma samples and dietary intake using food frequency questionnaires of 10,684 participants from three prospective cohorts (Nurses’ Health Study, Nurses’ Health Study II, and Health Professionals Follow-Up Study). Participants were predominantly White and middle-aged (mean age 54 years), with a mean body mass index of 25.6 kg/m2.
Metabolite profile scores were generated from the blood samples, taken in the 1980s and 1990s, and matched to any cases of incident type 2 diabetes reported during follow-up, which ended in 2016-2017.
The team looked at three different plant-based diets – by definition, higher in plant foods and lower in animal foods – and further categorized them according to the actual foods consumed, to generate an overall plant diet index (PDI), a healthy PDI, or an unhealthy PDI.
In all, 8,827 participants completed the study, and 270 cases of diabetes were reported.
Multi-metabolite profiles were composed of 55 metabolites for the overall PDI, 93 metabolites for healthy PDI, and 75 metabolites for unhealthy PDI.
The findings are that metabolomics can be harnessed and “the identified metabolic profiles could be used to assess adherence to ... plant-based diets as part of type 2 diabetes prevention ... and provide new insights for future investigation,” the researchers concluded.
One coauthor received research support from the California Walnut Commission and Swiss ReManagement; another reported being a scientific consultant to LayerIV. The other authors have reported no relevant financial relationships.
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