health brief

Ultra-Processed Food Linked with Cancer and Mortality Risks

A new study supports the public health importance of staying away from ultra-processed foods, finding a significant association with colorectal cancer in men. The study, led by Tufts University and published in August in The BMJ, looked at the diets of 46,341 men and 159,907 women every four years for 24 to 28 years using food frequency questionnaires.

These ready-to-eat or ready-to-heat commercial formulations comprised of little or no whole foods currently contribute 57 percent of the total daily calories consumed by American adults—a rate which has been continuously rising over the last two decades.

Commonly containing high levels of added sugar, unhealthy fats and refined starch, ultra-processed foods negatively impact gut microbiota and contribute to increased risks of weight gain and obesity. Most of these convenience foods are low in nutrients and bioactive compounds; contain food additives, colors and emulsifiers; and can be potentially carcinogenic when meats are processed with sodium nitrates and heat treatments or when the packaging leaches its harmful components (like bisphenol A) into the food.

A second recent study in Italy involving 22,895 adults over the age of 35 compared the role of nutrient-poor foods with ultraprocessed foods in the development of chronic disease and early death. Researchers found that both types of foods increased the risk of an early death, especially from cardiovascular diseases. When researchers compared the two types of food to see which contributed the most to the risk of an early death, ultra-processed foods were associated with poor health outcomes independently of their low nutritional composition, but not the other way around.

Serotonin Theory of Depression Debunked

The idea that depression is caused by a chemical imbalance— specifically, a serotonin deficiency—has been popular and influential since the 1960s, leading to the wide use of antidepressants. A recent multi-institution study led by the University of Reading, in the UK, and published in Molecular Psychiatry has debunked this theory. The researchers did a systematic review of studies on the topic and found no convincing evidence of an association between serotonin and depression, and no support for the hypothesis that depression is caused by lowered serotonin activity or concentrations. The serotonin theory of depression has historically provided convincing justification for the use of antidepressants and may discourage people from discontinuing treatment, potentially leading to lifelong dependence on such drugs.