Omega-3 and Depression

 
 

Omega-3 and Depression

Depression is a multifactorial illness whose etiology is influenced by a pattern of familial inheritance, environmental, and nutritional factors or from a combination of all.

Symptoms of depression include: Constant sadness, lack of motivation, constant irritation, lack of concentration and interest, feelings of isolation, hopelessness, feeling worthless or guilty for no reason, thoughts of ending yourself, fatigue, low energy, sleeplessness, weight change.

A variety of alternative medicine therapies, including dietary supplements, is used for the treatment of depression, although the evidence supporting them is quite patchy. Among the more commonly used supplements are omega-3 and omega-6 polyunsaturated fatty acids present in mainly fatty fish and flaxseed (linseed) oil. Cells use the three main types of fatty acids (FA): saturated FAs, that do not contain any double bonds; monounsaturated FAs, that contain a single double bond; and polyunsaturated FAs (PUFA), which contain multiple double bonds. PUFAs are essential for the function of the brain, nervous, endocrine and immune systems.

Once consumed in the diet, PUFAs are converted by enzymes in the body to produce omega-6 and omega-3 metabolites. Some Omega-6 fatty acids, such as arachidonic acid (AA), can be manufactured in the body using linoleic acid as a starting point. Omega-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are manufactured in the body using alpha linolenic acid as a starting point. Oily fish such as tuna, salmon, mackerel, and sardines are rich in preformed EPA and DHA. Omega-3 fatty acids are considered as an important anti-inflammatory factor able to reduce pro-inflammatory cytokines (chemicals produced by these cells in order to communicate to each other). High blood levels of Omega-3 fatty acids and low levels of Omega-6 fatty acids have been associated with inhibitory effects on tumour/cancer formation and various inflammatory diseases and with lesser passing away from cardiovascular diseases in a range of populations.

Similarly, research has shown that there are strong correlations between low consumption of fish (rich in omega-3 PUFAs) and high prevalence of depressive disorders or bad mood and many neurodegenerative conditions. However, in societies and nations consuming larger quantities of fish, high in essential fatty acids (EFAs), experience lower rates of major depression. Furthermore, higher concentrations of DHA (major brain PUFA) in red blood cell membranes and higher EPA to AA (higher omega-3 than omega-6) ratios in plasma have been associated with less severe levels of depression. It has been seen in scientific studies that there are lower concentrations of total PUFAs and a higher ratio of high levels of omega-6 polyunsaturated fatty acids to omega-3 PUFAs in participants with depression. However, in Western countries the intake of PUFAs has decreased and a steady rise in fried and fast-foods, vegetable and seed oils and a variety of commercially prepared baked goods. An Omega-3 deficiency in rat brain has been associated with decreased learning ability and cognitive performance but improves with Omega-3 addition along with the improvement of the mood state. This is due to the fact that the activity of some neurotransmitters involved in psychiatric disorders affects the metabolism of PUFAs. Studies have shown a decrease in the omega-3 PUFAs content of red blood cell membrane in depressed patients and the addition of PUFAs in clinical trials has shown to have beneficial effects. Some studies have also shown that in patients with schizophrenia, decreased omega-3 PUFAs levels were observed.

It has been concluded that 5% and 20% of women giving birth will be affected by postnatal depression which can adversely affect the mother-child relationship, infant development and well-being. Studies have shown that insufficient dietary intake, mothers may become depleted of omega-3 PUFAs during pregnancy leading to increase in risk of suffering depressive symptoms.

More scientific work would be required to establish the function of PUFAs in the nervous system to appreciate the possible health implications of reduced dietary intake of PUFAs.

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