According to a new study, consuming healthful plant-based foods such as fruits, vegetables, nuts, coffee, and legumes is associated with a lower risk of type 2 diabetes in otherwise healthy people, implying that they can help prevent diabetes.
The research was published in the ‘Diabetologia’ publication. The goal of the study was to discover the metabolite profiles associated with various plant-based diets and look into any links between those profiles and the risk of type 2 diabetes.
The large number of substances contained in various diets, as well as the complex diversity of molecules made when those compounds are broken down and converted for use by the body, are all metabolites.
Because foods have different chemical compositions, an individual’s metabolite profile should mirror their diet. Recent improvements in high-throughput metabolomics profiling have ushered in a new age of nutritional study. The full examination and identification of all the various metabolites contained inside a biological sample is referred to as metabolomics.
Type 2 diabetes accounts for over 90% of all diabetes occurrences, and it is a serious health problem across the world. In less than two decades, the global frequency of the illness in adults has more than quadrupled, with instances rising from roughly 150 million in 2000 to over 450 million in 2019 and expected to reach 700 million in 2045.
T2D’s worldwide health impact is exacerbated by the illness’s various consequences, both macrovascular, such as cardiovascular disease, and microvascular, which affect the kidneys, eyes, and neurological system.
Unhealthy diets, overweight or obesity, genetic susceptibility, and other lifestyle factors such as a lack of exercise are the primary causes of diabetes. Plant-based diets, especially those that are abundant in high-quality foods such whole grains, fruits, and vegetables, have been linked to a decreased incidence of T2D, although the underlying processes are yet unknown.
Blood plasma samples and food consumption of 10,684 people from three prospective cohorts (Nurses’ Health Study, Nurses’ Health Study II, and Health Professionals Follow-up Study) were analysed by the researchers. The majority of the participants were Caucasian, middle-aged (mean age 54 years), and had a BMI of 25.6kg/m2.
Participants in the study completed food frequency questionnaires (FFQs) that were assessed based on their adherence to one of three plant-based diets: an overall Plant-based Diet Index (PDI), a healthy Plant-based Diet Index (hPDI), or an Unhealthy Plant-Based Diet Index (UPDI) (uPDI).
Diet indices were based on that individual’s intake of 18 food groups: healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, vegetable oils, and tea/coffee); unhealthy plant foods (refined grains, fruit juices, potatoes, sugar-sweetened beverages, and sweets/desserts); and animal foods (animal fats, dairy, eggs, fish/seafood, meat, and miscellaneous animal-based foods).
The researchers divided plant foods into healthy and harmful categories based on their links to T2D, cardiovascular disease, some malignancies, and other disorders including obesity and high blood pressure.
The researchers used blood samples collected in the early stages of the three trials listed above to establish metabolite profile scores for the participants, and any incidences of incident T2D were documented during the study’s follow-up period. The team was able to uncover any associations between metabolite profile, diet index, and T2D risk by analysing these data together with the diet index scores.
Participants who were diagnosed with T2D during follow-up had a lower intake of nutritious plant-based foods, as well as lower PDI and hPDI scores, compared to those who did not acquire the condition. They were also more likely to have high blood pressure and cholesterol, take blood pressure and cholesterol medications, have a family history of diabetes, and be less physically active.
Plant-based diets were linked to distinct multi-metabolite profiles, which differed considerably between good and unhealthy plant-based diets, according to the metabolomics data.
Furthermore, metabolite profile scores for both the overall plant-based diet and the healthy plant-based diet were inversely associated with incident T2D in a generally healthy population, independent of BMI and other diabetes risk factors, while the unhealthy plant-based diet had no such association. As a consequence, higher metabolite profile scores for PDI and hPDI suggested both better diet adherence and a reduced risk of T2D.
After controlling for levels of trigonelline, hippurate, isoleucine, a limited set of triacylglycerols (TAGs), and numerous other intermediate metabolites, the relationship between plant-based diets and T2D essentially vanished, indicating that they may play a crucial role in linking such diets to incident diabetes.
Trigonelline, for example, is present in coffee and has been shown in animal studies to reduce insulin resistance, while greater levels of hippurate are linked to improved glycaemic management, increased insulin secretion, and a decreased incidence of T2D. The researchers believe that these metabolites should be explored further because they might give mechanistic reasons for how plant-based diets can reduce T2D risk.
Professor Hu explained, “While it is difficult to tease out the contributions of individual foods because they were analysed together as a pattern, individual metabolites from consumption of polyphenol-rich plant foods like fruits, vegetables, coffee, and legumes are all closely linked to a healthy plant-based diet and lower risk of diabetes.”
The authors concluded, “Our findings support the beneficial role of healthy plant-based diets in diabetes prevention and provide new insights for future investigation…our findings regarding the intermediate metabolites are at the moment intriguing but further studies are needed to confirm their causal role in the associations of plant-based diets and the risk of developing type 2 diabetes.”
Because they only gathered blood samples at one moment in time, the scientists believe that long-term repeated metabolomics data is required to understand how dietary changes lead to changes in the metabolome, thereby raising T2D risk.