Suboptimal diets implicated in 70% of new Type 2 diabetes cases, flag experts

18 Apr 2023 --- Poor diet is estimated to have resulted in 14.1 million new diagnoses of the noncommunicable disease in 2018, according to research analyzing the dietary intake of 184 countries. This represents around seven out of ten cases globally. 

The researchers used a risk assessment model they developed based on eleven dietary factors that contribute to Type 2 diabetes either directly or through body weight-mediated effects. 

The most significant number of new diabetes cases were the result of insufficient intake of whole grains (26.1%), excess intake of refined rice and wheat (24.6%), overconsumption of processed meat (20.3%) and excess unprocessed red meat intake (20.1%). 

“Our study suggests poor carbohydrate quality is a leading driver of diet-attributable Type 2 diabetes globally and with important variation by nation and over time,” says senior author Dariush Mozaffarian, professor at the Friedman School of Nutrition Science, Boston, US. 

“These new findings reveal critical areas for national and global focus to improve nutrition and reduce devastating burdens of diabetes.”

An important factor for new Type 2 diabetes cases was insufficient whole grains consumption. Growing rates of diabetes 
Globally, the researchers estimate that Type 2 diabetes cases attributed to the diet increased by 8.6 million from 1990 to 2018. The researchers found that cases increased in all 184 countries, representing a growing burden on individuals, families and healthcare systems. 

“Left unchecked and with incidence only projected to rise, Type 2 diabetes will continue to impact population health, economic productivity, health care system capacity and drive health inequities worldwide,” warns lead author Meghan O’Hearn, impact director for Food Systems for the Future. 

“These findings can help inform nutritional priorities for clinicians, policymakers and private sector actors as they encourage healthier dietary choices that address this global epidemic.”

Excess intake of harmful dietary factors contributed to over 60% of new diabetes cases in 2018. 

Factors that only affected body weight and Body Mass Index had a lower impact on new cases, namely drinking too much fruit juice and insufficient intake of non-starchy vegetables, nuts and seeds. 

Recent research suggests that the order of eating vegetables, protein or fat can improve postprandial blood glucose trajectory and decrease insulin secretion in people with or without Type 2 diabetes. 

Optimal intake 
The researchers used dietary data from the Global Dietary Database, population demographics, estimates on global Type 2 diabetes incidence and data on how food choices impact people living with obesity and type 2 diabetes from literature. 

The authors determined the optimal intake for eleven factors based on observed levels with the lowest morbidity and mortality in literature, feasibility based on observed national consumption levels and consistency with major food-based dietary guidelines. 

Global intakes of the eleven dietary factors included in the study were suboptimal, according to estimates from the Global Dietary Database. The researchers observed insufficient consumption of fruits, non-starchy vegetables, nuts and seeds, whole grains and yogurt. 

At the same time, the consumption of potatoes, refined rice and wheat, processed meats, unprocessed red meats, sugar-sweetened drinks and fruit juices were found to be too high. 

Excess intake of refined rice and wheat, processed meat and unprocessed red meats significantly impacted new diabetes cases.A different study flagged that young adults that experienced high food insecurity had a higher risk of obtaining diabetes ten years later. 

The article, published in Nature Medicine, indicates that globally, poor diet causes a more significant proportion of Type 2 diabetes incidence in men than in women, in younger versus older adults, people with high versus low education and urban versus rural residents. 

In high-income countries, Central and Eastern Europe and Central Asia, populations with lower education had higher diet-attributable diabetes cases than those with high education. The highest burden of diabetes cases through suboptimal diets was for people aged 45-60.

Regional differences 
In Central and Eastern Europe and Central Asia, the researchers linked the highest Type 2 diabetes cases to diets at 85.5%. The team attributed this to diets rich in potatoes, red and processed meats in countries like Poland and Russia. 

Latin America and the Caribbean also had high incidences of diet-attributed diabetes (81.8%), which the researchers credit to increased consumption of sugary drinks and processed meat, combined with low intake of whole grains. 

In South Asia and Sub-Saharan Africa, diets had a lower impact at 68.1% of total Type 2 diabetes cases. India, Nigeria and Ethiopia were among the most populated countries with the lowest incidence of diabetes related to unhealthy eating. 

Specific dietary factors affected Type 2 diabetes cases differently among the regions analyzed. For example, insufficient whole grain intake had a more considerable impact on new diabetes cases in Southeast and East Asia and Latin America (around 35%) than in South Asia (10%). 

Excess processed meats were associated with over half of the new cases in central and eastern Europe and central Asia but only with 4% of cases in South Asia. 

The researchers highlight that public health, clinical and policy interventions should prioritize diet quality to address the disease rather than total calories or weight. However, the authors stress that more research is needed to better understand better how diet quality, energy balance, metabolism and obesity influence Type 2 diabetes.

By Jolanda van Hal