Depression: Eating More Fish Helps Mood and Positively Affects the Brain

Consuming fish, especially those rich in Omega-3, at least twice a week may help women reduce the risk of depression. In men, however, this link is not observed. The hypothesis is that long-chain polyunsaturated fatty acids, combined with female hormones, may act on the brain, positively influencing mood.

This discovery was made by researchers at the Menzies Research Institute in Tasmania (Australia), and was recently published in the American Journal of Epidemiology.

Omega-3 Are Essential for Neuron Functioning

Omega-3 fatty acids are fundamental components of neuronal cell membranes. In particular, DHA (docosahexaenoic acid) is the most abundant fatty acid in the nervous system. The role of Omega-3s is to maintain membrane fluidity and ensure growth and communication between brain cells. Numerous studies have suggested that Omega-3 fatty acids may have protective effects against neurological diseases such as Alzheimer’s and may positively affect mood and behavior.

Fish Consumption: Effects in Men and Women

The study monitored 1,400 men and women aged 26 to 36, who kept a diary of their eating habits, indicating the frequency and types of fish and seafood consumed. Mental health information was also collected for each participant. After five years of observation, accounting for lifestyle, education, and profession, researchers identified a relationship between fish consumption and depression incidence. In particular, among women, each additional portion of fish consumed per week was associated with a 6% lower risk of depression.

Women who ate fish at least twice a week had a 25% lower likelihood of depressive episodes from the start of the study compared to those who ate less. This relationship was not evident in men. The difference in effects is thought to be due to the combination of Omega-3s with female hormones (estrogen and progesterone), which help maintain proper brain function. Another hypothesis involves the generally lower fish consumption by men, who tend to get Omega-3s from other sources, especially meat. The beneficial Omega-3 fatty acids for the brain are the long-chain ones, mainly found in fish oil.

Fish Oil as Part of a Balanced Diet

The results of this study suggest that fish has positive effects on women's mental well-being, although the exact mechanism remains unclear. This finding is significant considering that about 5 million people in the UK suffer from depression and females between 16 and 42 years old are more than twice as likely to be affected. It is clear that the human body, including the brain, requires proper nutrition to function correctly, and deficiencies can manifest as depression in some cases.

It is recommended to eat at least two portions of fish per week, including one portion of species high in Omega-3, such as mackerel, fresh tuna, salmon, or sardines. Shellfish and white fish can also help reduce mineral deficiencies such as zinc and iodine. According to researchers, consuming fish oil containing Omega-3 can promote health and be part of a balanced diet.

Source: Smith KJ, Sanderson K, McNaughton SA, Gall SL, Dwyer T, Venn AJ. “Longitudinal associations between fish consumption and depression in young adults.” Am J Epidemiol. 2014 May 15;179(10):1228-35.