José M. Ordovás

GLP-1 medicines for the treatment of obesity show considerable variability between individuals. Using data from 23andMe, scientists at this genetic testing company conducted genome-wide association studies in nearly 28,000 people treated with these drugs, analysing self-reported weight loss and adverse effects. Their findings, published in Nature, identified variations in two genes involved in gut hormone pathways that regulate appetite and digestion, although the authors caution that the effects of genetics appear to be modest.

An international team has analyzed data from nearly 60 studies involving more than 48,000 children with different types of diets and compared the nutritional profile and various health parameters between those following vegan, lacto-ovo-vegetarian, and omnivorous diets. The results indicate that plant-based diets, if well-planned, can promote healthy growth with benefits such as a better cardiovascular profile and lower cholesterol levels. However, they may have difficulty achieving adequate levels of vitamins D and B12, calcium, iron, and zinc. According to the authors, the findings underscore the need for careful planning and supplementation in children following these types of diets. The study is published in Critical Reviews in Food Science and Nutrition. 

The Planetary Health Diet promotes environmentally sustainable consumption, based, among other things, on increasing vegetable intake and reducing dairy and red meat consumption. Previous studies had found an association with better human health, although there were some conflicting results. Now, a study combining two cohorts of more than 150,000 people and a meta-analysis of 37 studies involving more than three million volunteers reinforces this association, finding that greater adherence to the diet is associated with lower all-cause mortality. The results are published in the journal Science Advances.

Adipose tissue retains a ‘memory’ of obesity through cellular transcriptional and epigenetic changes that persist after weight loss, which may increase the likelihood of regaining weight, experiments in human and mouse cells show. The findings, published in Nature, could help explain the problematic ‘yo-yo effect’, the rapid weight rebound often seen with dieting. 

A US research team has identified several genes that may be associated with a strict vegetarian diet. Some of these genes have "important roles in lipid metabolism and brain function", according to the paper, which suggests that these differences could explain the ability to subsist on a vegetarian diet in those who carry these genes. The study, published in the journal PLoS ONE, used data from the UK Biobank to compare a group of more than 5,000 vegetarians with a group of more than 320,000 non-vegetarians.