Telomeres are structures located at the ends of our chromosomes. Although they contain no genetic information themselves, they preserve the integrity of chromosomes by keeping their ends from fraying, much as shoelace tips protect the laces.
Telomeres become shorter and less effective over time as chromosomes replicate. Scientists view them as markers of an individual’s biological age at a cellular level.
New research indicates that eating ultra-processed foods is linked to the accelerated shortening of telomeres and cell aging.
The researchers, from the University of Navarra in Pamplona, Spain, presented their findings at this year’s European and International Congress on Obesity (ECOICO 2020) in September.
The findings also feature in a study paper in The Americal Journal of Clinical Nutrition.
Lucia Alonso-Pedrero, who is a doctoral researcher at this university, led the study.
The consumption of ultra-processed foods, or UPFs, is on the rise worldwide. UPFs are manufactured food products comprising the building blocks of naturally occurring foods: protein isolates, sugars, fats, and oils.
However, while their components are often extracted from natural sources, UPFs ultimately contain no, or very little, in the way of whole foods.
The companies that produce UPFs often add flavorings and emulsifiers for taste, as well as colorings and other cosmetic additives to achieve the desired appearance. UPFs are nutritionally poor and often unbalanced.
UPFs are highly profitable for their producers due to their inexpensive ingredients, cost effective manufacturing processes, and long shelf life in stores. What makes them so attractive to consumers is their convenience and their relative imperishability.
Previous research has not conclusively established a link between UPFs in general and telomere length (TL). However, researchers have noted associations between TL and alcohol, sugar-sweetened beverages, processed meats, and foods high in saturated fat and sugar.
Other research indicates a UPF connection to several serious conditions, such as obesity, hypertension, depression, metabolic syndrome, some types of cancer, and type 2 diabetes. However, these conditions also tend to be age-related and thus difficult to associate definitively with the consumption of UPFs.
The NOVA system classifies foods according to the degree of processing that their production involves, as opposed to their nutritional content. The goal of Alonso-Pedrero and her colleagues was to investigate the effect of UPF consumption in older adults using NOVA as a means of categorizing the foods that they consumed.
The researchers began their analysis with data from the SUN project, which the University of Navarra is conducting with other Spanish universities. The ongoing study began recruiting in 2000 and includes volunteers over the age of 20 years. Participants are required to fill out and return questionnaires every 2 years.
In 2008, all SUN participants over the age of 55 years took part in a genetic study that forms the foundation of the new research. A total of 886 individuals — 645 men and 241 women — provided saliva samples for DNA analysis and self-reported their daily food consumption. Their average age was 67.7 years.
The team sorted the participants into four groups of equal size, or quartiles, according to the number of UPF servings that they consumed daily:
- low: under 2 servings
- medium-low: 2–2.5 servings
- medium-high: 2.5–3 servings
- high: more than 3 servings
In terms of telomeres, Alonso-Pedrero and her colleagues detected a clear correspondence between TL and the consumption of UPFs.
The likelihood of shortened telomeres increased dramatically with the number of UPF servings, starting with the medium-low group. That group was 29% more likely to exhibit reduced TL, while the medium-high group was 40% more likely to do so. Those in the high group were 82% more likely to have shortened telomeres.
The study’s authors write:
“In this cross-sectional study of elderly Spanish subjects, we showed a robust strong association between UPF consumption and TL. Further research in larger longitudinal studies with baseline and repeated measures of TL is needed to confirm these observations.”
The researchers also made a number of general observations regarding those who consumed more than 3 servings of UPFs per day. People in this quartile:
- were more likely to have diabetes, a family history of cardiovascular disease, and abnormal blood fats under their skin
- were the participants most likely to snack between meals
- consumed less protein, carbohydrate, fiber, fruit, vegetables, olive oil, and other micronutrients
Individuals who ate more UPFs were less likely to adhere to a healthful Mediterranean diet. In exchange, they consumed more fats, saturated fats, polyunsaturated fats, sodium, sugar-sweetened beverages, cholesterol, fast food, and processed meats.
The study authors also found that those who consumed higher amounts of UPFs were more likely to experience depression — especially when they were less active physically.
Finally, the findings linked the consumption of UPFs to excessive body weight, hypertension, and all-cause mortality.
