Plant-based milk drinkers could be at higher risk of depression, study finds

6 January 2025, 12:04 | Updated: 6 January 2025, 13:12

People who drink plant-based milk alternatives such as soy or oat could be at a higher risk of depression, a study has found.

But drinkers of semi-skimmed dairy products are at a lower risk of both anxiety and depression, experts suggested. 

Over 350,000 people signed up to the study by UK Biobank. 

Those who enrolled were monitored for over 10 years, with researchers keeping an eye out for mental health changes. 

It was found that people who drink semi-skimmed milk were12% less likely to have depression and 10% less likely to be anxious when taking in age, physical health and income into account. 

Skimmed milk was found to have no positive impacts, although consuming milks with no dairy were linked to a 14% increased risk in developing depression. 

This may be because dairy-based milk is a rich source of calcium, which has been shown to activate pathways in the body that can boost serotonin production.

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High levels of serotonin in the brain has been found to help stave off depression, while low amounts of the chemical results in low moods.

Commonly used antidepressants, known as selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs), are aimed at ramping up levels of the chemical in the brain.

The study authors, from the Southern Medical University, wrote: “Milk is a rich source of nutrients such as lactose, lipids, protein, and minerals, which are essential for maintaining human health.”

Meanwhile, semi-skimmed milk has a particular fatty-acid profile that “might provide greater cerebral protection compared to full cream milk and skimmed milk”, the authors added.

This potentially reduces the risk of both depression and anxiety, they said. 

The authors added: “The analysis indicates the possibility of an inverse association between the consumption of semi-skimmed milk and the risks of depression and anxiety.“

These findings suggest that semi-skimmed milk may have a protective effect against these mental health conditions, presenting new prospects for dietary interventions.”

The research was published in the journal Frontiers in Nutrition.

However, plant-based milks are sometimes fortified with vitamins and minerals, such as ​​ calcium, vitamin B12 and iodine, which can benefit those who avoid dairy or animal products or are at risk of deficiency.

 Retail sales of dairy and dairy alternatives to milk and cream reached £5.71 billion in the UK in 2024, according to Mintel.

The average price of a liter of semi-skimmed milk was 79 pence per liter in the Britain in the 52 in the 52 weeks ending on November 30, 2024, research published by Statista showed. Meanwhile, plant-based alternatives cost over £1.4.