Prioritize Nutrients, Limit Ultraprocessed Food in Diabetes

Marlene Busko

August 08, 2023

In a large cohort of older adults with type 2 diabetes in Italy, those with the highest intake of ultraprocessed food and beverages (UPF) were more likely to die of all causes or cardiovascular disease (CVD) within a decade than those with the lowest intake — independent of adherence to a healthy Mediterranean diet.

Adults in the top quartile of UPF intake had a 64% increased risk of all-cause death and a 2.5-fold increased risk of CVD death during follow-up compared with those in the lowest quartile, after adjusting for variables including Mediterranean diet score.

These findings from the Moli-sani study by Marialaura Bonaccio, PhD, from the Institute for Research, Hospitalization and Healthcare (IRCCS) Neuromed, in Pozzilli, Italy, and colleagues, were recently published online in the American Journal of Clinical Nutrition.

"Dietary recommendations for prevention and management of type 2 diabetes almost exclusively prioritize consumption of nutritionally balanced foods that are the source of fiber [and] healthy fats and [are] poor in free sugars, and promote dietary patterns — such as the Mediterranean diet and the DASH diet — that place a large emphasis on food groups (eg, whole grains, legumes, nuts, fruits, and vegetables) regardless of food processing," the researchers note.

The research suggests that "besides prioritizing the adoption of a diet based on nutritional requirements, dietary guidelines for the management of type 2 diabetes should also recommend limiting UPF," they conclude.

"In addition to the adoption of a diet based on well-known nutritional requirements, dietary recommendations should also suggest limiting the consumption of ultraprocessed foods as much as possible," Giovanni de Gaetano, MD, PhD, president, IRCCS Neuromed, echoed, in a press release from the institute.

"In this context, and not only for people with diabetes, the front-of-pack nutrition labels should also include information on the degree of food processing," he observed.

Caroline M. Apovian, MD, who was not involved with the study, agrees that it is wise to limit consumption of UPF.

However, we need more research to better understand which components of UPF are harmful and the biologic mechanisms, Apovian, who is co-director, Center for Weight Management and Wellness, Brigham and Women's Hospital, and a professor of medicine at Harvard Medical School, Boston, Massachusetts, told Medscape Medical News in an interview.

She noted that in a randomized crossover trial in 20 patients who were instructed to eat as much or as little as they wanted, people ate more and gained weight during 2 weeks of a diet high in UPF, compared with 2 weeks of an unprocessed diet matched for presented calories, carbohydrate, sugar, fat, sodium, and fiber.

Ultraprocessed Foods Classed According to Nova System

UPF is "made mostly or entirely from substances derived from foods and additives, using a series of processes and containing minimal whole foods," and they "are usually nutrient-poor, high in calories, added sugar, sodium, and unhealthy fats," the Italian researchers write.

High intake of UPF, they add, may exacerbate health risks in people with type 2 diabetes, who are already at higher risk of premature mortality, mainly due to diabetes-related complications.

The researchers analyzed data from a subset of patients in the Moli-sani study of environmental and genetic factors underlying disease, which enrolled 24,325 individuals aged 35 and older who lived in Molise, in central-southern Italy, in 2005-2010.

The current analysis included 1065 participants in Moli-sani who had type 2 diabetes at baseline and completed a food frequency questionnaire by which participants reported their consumption of 188 foods and beverages in the previous 12 months.

Participants were a mean age of 65 years and 60% were men.

Most UPF intake was from processed meat (22.4%), crispbread/rusks (16.6%), nonhomemade pizza (11.2%), and cakes, pies, pastries, and puddings (8.8%).

Researchers categorized foods and beverages into four groups with increasing degrees of processing, based on the Nova Food Classification System:

  • Group 1: Fresh or minimally processed foods and beverages (eg, fruit, meat, milk)

  • Group 2: Processed culinary ingredients (eg, oils, butter)

  • Group 3: Processed foods and beverages (eg, canned fish, bread)

  • Group 4: UPF (22 foods and beverages including carbonated drinks, processed meats, sweet or savory packaged snacks, margarine, and foods and beverages with artificial sweeteners)

Participants were divided into four quartiles based on UPF consumption.

The mean percentage of UPF consumption out of total food and beverage intake was 2.8%, 5.2%, 7.7%, and 14.4% for quartiles 1, 2, 3, and 4, respectively. By sex, these rates for quartile 1 were < 4.7% for women and < 3.7% for men, and for quartile 4 were ≥ 10.5% for women and ≥ 9% for men.

Participants with the highest UPF intake were younger (mean age, 63 vs 67 years) but otherwise had similar characteristics as other participants.

During a median follow-up of 11.6 years, 308 participants died from all causes, including 129 who died from CVD.

Compared to participants with the lowest intake of UPF (quartile 1), those with the highest intake (quartile 4) had a higher risk of all-cause mortality (hazard ratio [HR], 1.70) and CVD mortality (HR, 2.64) during follow-up, after multivariable adjustment. The analysis adjusted for sex, age, energy intake, residence, education, housing, smoking, body mass index, leisure-time physical activity, history of cancer or cardiovascular disease, hypertension, hyperlipidemia, aspirin use, years since type 2 diabetes diagnosis, and special diet for blood glucose control.

After further adjusting for Mediterranean diet score, the risk of all-cause and CVD mortality during follow-up for patients with the highest versus lowest intake of UPF remained similar (HR, 1.64 and 2.55, respectively).

There was a linear dose–response relationship between UPF and all-cause and CVD mortality.     

Increasing intake of fruit drinks, carbonated drinks, and salty biscuits was associated with higher all-cause and CVD mortality rates, and consumption of stock cubes and margarine was further related to higher CVD death.

The researchers acknowledge that the study was observational, and therefore cannot determine cause and effect, and was not designed to specifically collect dietary data according to the Nova classification. The findings may not be generalizable to other populations.  

The analysis was partly funded by grants from the AIRC and Italian Ministry of Health. The authors have reported no relevant financial relationships.

Am J Clin Nutr. Published online July 26, 2023. Abstract

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