Eating just a handful of nuts lowers risk of depression according to study

Eating a handful of nuts each day has been found to lower the risk of depression, according to a study. The small dietary addition can lower the risk of depression by 17 per cent.

Middle-aged and older adults who consume a daily 30g serving of nuts were less likely to report taking antidepressants or being diagnosed with depression, according to data from the UK Biobank. Walnuts, almonds, Brazil nuts, cashews, hazelnuts and pistachios are all included in the list of nuts that are associated with lower risk of depression.

Researchers speculate that the anti-inflammatory and antioxidant properties of nuts have a protective effect that helps to explain why this happens. Nuts contain essential nutrients – bioactive substances such as phenols or phytosterols, essential micronutrients, fibre, high-quality protein, monounsaturated and polyunsaturated fatty acids, and vitamins – which can all play a beneficial role in mental health.

Bruno Bizzozero-Peroni, a researcher at the Health and Social Research Centre at the University of Castilla-La Mancha in Spain, said: “Our findings highlight yet another benefit of consuming nuts, with a 17% decrease in depression associated with nut consumption. This provides an even stronger rationale for people to become enthusiastic about consuming nuts.”

Researchers looked at data from more than 13,000 people aged 37 to 73 between 2007 and 2020. They did not report having depression at the start of the study, published in the journal Clinical Nutrition.

Nut consumption was assessed by questionnaires and self-reported doctor’s diagnosis of depression or antidepressant use were recorded. A follow-up of more than five years recorded more than 1,100 (8.3 per cent) cases of depression were recorded. 

Results revealed those who had a low to moderate nut consumption, defined by one serving of 30g per day, had a 17% lower risk of depression compared to those who did not eat nuts. Researchers said the finding was regardless of other factors that could impact mental health, such as lifestyle, medical conditions, and body mass index.

The team wrote: “Our results highlight the potential role of nut consumption as a healthy dietary behaviour to prevent depression in those free of other known risk factors for depression, such as obesity, unhealthy lifestyle behaviours (smoking, frequent alcohol consumption, low intake of fruits and vegetables, insufficiently active, and inadequate sleep duration), loneliness, and medical conditions such as cardiovascular, metabolic, or mental comorbidities.”

Commenting on the study, Dr Jenna Macciochi, senior lecturer in immunology at the University of Sussex, who was not involved in the research, said: “This study builds on the growing literature in nutritional psychology showing diet to be a factor in mood disorders. Specifically, they found a positive association between nut intake and a lower risk of depression compared to no nut intake.

“This study shows association and does not prove a mechanistic effect, but the authors do suggest multiple feasible mechanisms through which nut consumption may be working. I think there is still a lot we need to learn regarding the potential mechanisms at play and a deeper understanding of this in the future will be useful when making dietary recommendations.

“In the meantime, the best evidence for supporting good mental health through diet is probably from consuming a Mediterranean-style anti-inflammatory diet pattern of which nuts are considered to be a component of.”