Some, Not All, Ultraprocessed Foods Linked to Type 2 Diabetes Some, Not All, Ultraprocessed Foods Linked to Type 2 Diabetes

High total intake of ultraprocessed food (UPF) is associated with an increased risk of developing type 2 diabetes, suggests a large-scale analysis that nevertheless revealed that the risk applies only to certain such foods.

The research was recently published in Diabetes Care by Zhangling Chen, PhD, Erasmus MC Rotterdam, the Netherlands, and colleagues.

Examining almost 200,000 participants in three US studies, yielding more than 5 million person-years of follow-up, the scientists found that high intake of UPF was associated with a 28% increased risk of type 2 diabetes, after statistical adjustments.

However, the increased risk was restricted to certain UPFs, including ready meals, refined breads, sweetened beverages, and sauces and condiments, with other foods considered UPFs, such as cereals, dark- and whole grain breads, and packaged sweet and savory snacks, among others, associated with a reduced risk of diabetes.

Senior author Jean-Philippe Drouin-Chartier, PhD, Nutrition Center, Laval University, Quebec, Canada, told Medscape Medical News: “While whole grain breads can be considered as ultraprocessed foods, their consumption should not be discouraged. In our study, we observed that whole grain breads consumption is inversely associated with type 2 diabetes risk. This is supported by many studies linking dietary fiber consumption to better cardiometabolic health.”

Ultraproccessed Food Intake Higher in the US Than in Europe

The researchers note that a handful of European studies have also reported an association between UPF consumption and increased type 2 diabetes risk, with the effect ranging from 15% to 53%, depending on the level of intake and the cohort of patients studied.

They note, however, that total UPF intake in the US is “much higher than in Europe,” particularly in the case of ultraprocessed breads and cereals, and artificially or sugar-sweetened beverages.

In the current study, they examined data on 71,781 women from the Nurses’ Health Study (NHS), 87,918 women from the NHS II, and 38,847 men from the Health Professional Follow-up Study (HPFS), none of whom had cardiovascular disease, cancer, or diabetes at baseline.

In all three studies, questionnaires were administered every 2 years to collect demographic, lifestyle, and medical information, and a validated food frequency questionnaire was used every 2-4 years to assess participants’ diets over 30 years of follow-up.

Using the NOVA Food Classification system, the items on the food frequency questionnaire were categorized into one of four groups:

  • Unprocessed or minimally processed foods

  • Processed culinary ingredients

  • Processed foods

  • UPFs, which were subdivided into nine mutually exclusive subgroups

Servings per day were then used to determine individual UPF intake.

Higher total UPF intake was associated with a greater total energy intake, body mass index (BMI), and prevalence of hypercholesterolemia and/or hypertension, as well as lower healthy eating scores and physical activity.

The researchers calculated that, over 5,187,678 person-years of follow-up, there were 19,503 cases of type 2 diabetes across the three study cohorts.

Multivariate analysis taking into consideration a range of potential risk factors, including BMI, revealed that, across the three study cohorts, the highest quintile of UPF intake was associated with a significantly increased risk of type 2 diabetes.

Compared with the lowest quintile of UPF intake, the hazard ratio for incident type 2 diabetes was 1.28 (P < .0001), with an increase in risk per additional serving per day of 3%.

The UPFs associated with a higher type 2 diabetes risk were as previously described, and also included animal-based products and ready-to-eat mixed dishes.

In contrast, intake of UPFs including cereals, dark and whole grain breads, packaged sweet and savory snacks, fruit-based products, and yogurt and dairy-based desserts were linked to a reduced risk of type 2 diabetes.

Then to further validate their findings, the researchers conducted a meta-analysis of their own and four additional studies, comprising 415,554 participants and 21,932 events, with a follow-up of 3.4-32.0 years.

They determined that the pooled relative risk of type 2 diabetes with the highest versus lowest levels of UPF consumption was 1.40, with each 10% increase in total UPF intake associated with a 12% increase in diabetes risk.

Ideal Is to Have Access to Minimally Processed Foods

The NOVA food classification system states that UPFs are industrial formulations “made mostly or entirely with substances extracted from foods, often chemically modified, with additives and with little, if any, whole foods added.”

A recent study questioned the value of the NOVA classification after finding that it had “low consistency” when assigning foods.

Previous studies have nevertheless revealed that UPFs and their constituents negatively affect the gut microbiota and can cause systemic inflammation, insulin resistance, and increased body weight.

Drouin-Chartier concluded: “There is a need to facilitate…access to minimally processed foods. This encompasses [appropriate] pricing and physical access [to such foods], that is, addressing the issue of food deserts.”

The NHS I and II and HPFS studies are supported by National Institutes of Health. Drouin-Chartier has reported a relationship with the Dairy Farmers of Canada. No other financial relationships were declared.

Diabetes Care. Published online February 28, 2023. Abstract

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