The regular consumption of omega-3 fatty acids is now pretty widely accepted as being a good insurance policy for your long-term heart and brain health. This is largely because of their powerful anti-inflammatory and antioxidant properties. But how does that effect depression?
Omega-3 fatty acids contain valuable antioxidants that support the cardiovascular system and joint mobility. Omega-3 from fish oil is also linked with healthier blood pressure and lower cholesterol levels and plays an important role in brain function, including mood and memory.
Omega-3 supports the whole nervous system, and targets many diseases by getting to the root cause: chronic inflammation.
Normal inflammation is a healthy response in the body, to help it deal with injury and infection. Your body sends white blood cells to the area to repair it and fight infection.
But inflammation can get out of control when your immune system is not working the way it should. This results in chronic inflammation when there is no external threat, and basically means your immune system is attacking your own cells. This can result in autoimmune diseases like cancer, rheumatoid arthritis, and allergies, as well as heart disease and dementia. Often the cause of inflammation is linked to diet. Omega-3 occurs naturally in certain foods, but your best source is either eating a lot of fatty fish, or taking a good quality fish oil supplement.
Good news for treating severe depression
New research also shows omega-3 fatty acids, specifically EPA and DHA (the kinds that come from fish oil), to be a promising new avenue for treating major depressive disorder alongside conventional anti-depressants.
A review of research into omega-3 polyunsaturated fatty acid supplementation for major depressive disorder, conducted at the University of Amsterdam and published in 2016, concluded that a high dose of EPA omega-3, alongside anti-depressant medication, was recommended for the treatment of major depression. In a range of separate studies a pattern emerged: people suffering from severe depression, who took high doses of EPA omega-3, showed a higher rate of recovery and reduction of depressive symptoms than those that were only taking an anti-depressant.
In 2017, a collaborative research effort by scientists from universities in the UK, Italy and Taiwan published their findings. Their research was guided by the knowledge that depression has been associated with neural inflammation and reduced neurogenesis. Laboratory tests revealed that a combination of omega-3 polyunsaturated fatty acids and conventional anti-depressants can reverse this process.
Interleukin-1 β, a pro-inflammatory protein that is observed at high levels in depressed patients, seems to be responsible for slowing neurogenesis in the human hippocampus. High levels of IL-1β are known to affect synaptic function, learning and memory. IL-1β also increases levels of certain neurotoxic enzymes, which have been detected in people suffering from depression, and in the hippocampus of patients with Alzheimer’s disease.
Earlier research has already shown that inhibiting these neurotoxins can restore the process of healthy neurogenesis in Alzheimer’s and Huntington’s disease, with improved cognitive and motor function.
What this latest study revealed was that EPA or DHA, in combination with the anti-depressants sertraline or venlafaxine, reversed the decreased neurogenesis that plays a part in major depression.
These findings support previous research that has shown evidence of a positive effect of omega-3 on brain inflammation in the contexts of both depression and dementia.