Research Highlight: Ultra-processed Food Intake Linked with Leptin Resistance in Women

Hey ladies, we've got one if you need a good reason to skip the chips. A recent study indicates that women who consume more ultra-processed foods are more susceptible to leptin resistance and could have changes in their gut bacteria. Leptin resistance is linked with pro-inflammatory conditions, neuroinflammation, and metabolic disorders, including obesity.

Ariana E. Fernandes, MS, a nutritionist in the department of endocrinology and metabolism and faculty of medicine member at Hospital das Clinicas at the University of São Paolo, notes her work is some of the first to identify obesity-associated biometrics through diet quality markers and gut microbiota. Along with changes in gut microbiota, ultra-processed food intake was linked with leptin levels, which could impact leptin resistance.

This cross-sectional study examined 59 women (aged 18 to 40) from January 2018 to January 2022. Anthropometric and metabolic data were collected, and subjects completed three 24-hour food recalls on two weekdays and one weekend day. Classifications were used to categorize foods as unprocessed or minimally-processed, processed ingredients, processed food, or ultra-processed food. Stool samples were collected at home and analyzed in a lab.

Within the subjects, 20 women had obesity, 20 were of average weight, and 19 were listed as lean with a BMI below 18. The mean calorie consumption was roughly 1625 kcal per day. Unprocessed foods accounted for around 52% of total calorie intake and processed foods accounted for over 10% of total calories.

Ultra-processed foods made up almost 32% of total calories. In those consuming more unprocessed or minimally processed foods, leptin-adjusted fat mass levels were lower, while those eating more ultra-processed foods had higher levels. Low levels of leptin improve leptin sensitivity and decrease leptin resistance.

Leptin resistance may lead to obesity because the brain does not respond to leptin, and a person does not experience satiety. When this occurs, the body is unable to sense hormonal messages that tell the body to stop eating.

Researchers identified three species of gut microbiota positively linked with unprocessed or minimally-processed foods and twelve that were negatively correlated. In addition, five species were positively linked with ultra-processed food intake, and four were negatively correlated. Microbiota diversity was not correlated with food intake evaluated by processing level.

It's unclear if the higher levels of some bacteria are linked with healthier parameters. More studies are necessary to understand how species-specific increases impact different populations. The environment, as well as genetics, are also important components that modify the microbiota.

A more detailed classification of bacterial strains is needed to explain the impact of ultra-processed or minimally processed foods on species that are beneficial or detrimental to health.

By Lisa Andrews, MEd, RD, LD

Reference:

Fernandes AE, et al.   Differences in the gut microbiota of women according to ultra-processed food consumption. Nutr Metab Cardiovasc Dis. 2022;doi:10.1016/j.numecd.2022.09.025.