Scientists discover link between types of milk and risk of depression and anxiety

A new study suggests consuming semi-skimmed milk may be linked to a lower risk of depression and anxiety, conditions increasingly affecting young people. It followed 357,568 UK Biobank participants over 13.5 years.

The paper in Frontiers in Nutrition linked full-cream milk with a lower risk of anxiety, while there was no significant relationship seen between skimmed milk and depression or anxiety. It also reveals the role of diet in promoting mental health.

The researchers suggest the nutrient profile of semi-skimmed milk, including its balance of saturated and unsaturated fats, may play a role in maintaining brain health, reducing inflammation and supporting serotonin and dopamine synthesis — key factors in mood regulation.

In contrast, full cream milk, with its higher saturated fat content, shows inconsistent effects, potentially contributing to neuroinflammation and depressive symptoms, suggest the authors. Skimmed milk, lacking sufficient unsaturated fatty acids, offers fewer mental health benefits. Although semi-skimmed milk seems to have promise in lowering the risk of anxiety and depression, they suggest more biological research and ingredient analysis are required to validate these results.

Meanwhile, other recent research by the University of Oxford suggests almond, oat and soy milk offer the largest reductions in nutritional imbalances among milk alternatives. 

According to the study, depression affects 3.8% of people worldwide, and anxiety affects 4%, making them significant contributors to the burden of disease. The disorders are tied to chronic physical conditions — cardiovascular disease, diabetes mellitus, chronic lung disease and chronic pain — and may result in increased risk of suicide.

The nutrients in semi-skimmed milk, including a balance of saturated and unsaturated fats, may maintain brain health.Characteristics of milk drinkers 

The UK Biobank is a long-term prospective cohort study that contains medical and biological data gathered from 2006 to 2010 on 502,402 adults (ages 37 to 73) in the UK with several follow-ups. Researchers excluded 1,527 people with no milk consumption types in the questionnaire taken by 171,246 (47.9%) males and 186,322 (52.1%) females.

The authors detail: “11,640 (3.3%) reported being non-milk consumers, and 345,928 (96.7%) were milk consumers. Semi-skimmed milk (232,878, 65.1%) was the most commonly consumed type, followed by skimmed milk (72,342, 20.2%), full cream milk (23,125, 6.5%), and other types of milk (17,583, 4.9%).”

“Non-consumers of milk were more likely to be drinking coffee. Full-cream milk consumers were more likely to be male, had less income, and be current smokers. Semi-skimmed milk consumers were less likely to be eating vegetables and fruit and more likely to be drinking alcohol 3 to 4 times per week. Skimmed milk consumers were more likely to be older, white, previous smokers, obese and had hypertension, diabetes and cardiovascular disease.”

The researchers used a Mendelian Randomization analysis to suggest a potential causal relationship between milk and mental health disorders.

Role of diet

The researchers note current anxiety and depression treatments largely involve psychological therapy and medications, but this only prevents half of the disease burden.

This is why the researchers turn to diet, claiming it has a significant role in mental health. Dairy is widely consumed and previous nutritional psychiatry studies have shown those with the highest milk consumption have an increased prevalence of mental health symptoms.

Despite the previous research findings, the researchers found a gap in the links between types of milk and depression and anxiety.