Depression and other mental disturbances
Depression has become a national disease in Finland. More than 300 000 Finns are taking medication for depression, and the costs of mental disturbances accrued to the society, income transfers included, amount to approximately 2.9 billion euros per year.
Omega-3 fatty acids have a critical role in the development and functioning of the central nervous system. There is a continuous increase in the amount of research evidence in the relationship between the Omega-3 fatty acids (EPA, DHA) and serious depression. In the light of epidemiologic, experimental and clinical evidence, it seems that the fats obtained from the diet, together with other nutrition related factors, affect the sensitivity to depression as well as the severity of depression. There is active research going on the subject matter, and results are gained at a rapid tempo (Logan 2004).
The epidemiologic and clinical cross sectional studies conducted in the 1990s repeatedly suggested that it was exactly the low content of Omega-3 fatty acids in the serum cholesterol esters or the too low ratio of Omega-3 and Omega-6 fatty acids in the phospholipids of the red blood cells that were connected with depression. The too scarce intake of Omega-3 fatty acids in the nutrition has been found to be related with depression (Tanskanen et al. 2000), and a recent international comparison showed a strong negative correlation between sea-fish consumption and the occurrence of bipolar disorders (Noaghiul and Hibbeln 2003).
In literature there are numerous case descriptions related with the topic, the oldest being traced back to more than 20 years. The first ones of these report linseed oil – that is known to contain plenty of ALA – having alleviated the symptoms related with e.g. bipolar depression and the fear of public places at several different dosage levels (Rudin 1981).
It is known that depression patients’ [cell membranes have stiffened] cell membranes differ from normal ones (Mendels and Frazer 1974), and the Omega-3 treatment has been found to improve the situation (Edwards et al. 1998). The share of nutritional factors in connection with depression has been underestimated in the present society (Horrobin 2002a). It has been found in several studies that the Omega-3 content in depression patients’ blood is lower than normal (Adams et al. 1996, Peet et al. 1998, Maes et al. 1999, Tiemeier et al. 2003). The amount of ALA measured from the fat tissue had also negative correlation with the occurrence of depression among aged Cretan men (Mamalakis et al. 2004). The correlation between scarce ALA intake and depression was discovered also in Japanese patients (n=771), with a newly diagnosed lung cancer (Suzuki et al. 2004).
Certain degree of overlapping has been discovered in the occurrence of cardiovascular diseases and depression, and the weakened Omega-3 status is considered the connecting risk factor. Omega-3 fatty acids amounts significantly lower than normal have thus been measured in the plasma of depression patients suffering from acute coronary, particularly DHA (Frasure-Smith et al. 2004). The increased homocystein content, known as a risk factor to cardiovascular diseases, has for its part been discovered to be connected with the rich intake of Omega-6 fatty acids in the Western diet (Assies et al. 2004). The medical treatments generally applied to several depression patients don’t bring about the desired outcome (Kornstein & Schneider 2001). The research community has in this connection been particularly interested in the role of Omega-3 fatty acids, and the effects of EPA in the treatment of depression seems promising (Horrobin 2002b).
In one study, ethyl EPA was given as daily doses of 1, 2 and 4 grams to patients suffering from long-term depression and whose symptoms were not alleviated with medical treatment verified sufficient as such. It was an interesting discovery that ‘less proved more’. The best treatment response was achieved in the treatment group taking daily 1 g of E-EPA. This dose reduced the patients’ depression, anxiety, sleep disorders, fatigue, sexual unwillingness and self-destructive thoughts most effectively (Peet & Horrobin 2002).
In most studies, the difference between EPA and placebo medicine has been significant despite of very small test groups (< 20), which means that the effect on depression symptoms has been a very powerful one. The persons participated in the studies have been mostly females, which means that it is impossible to make any generalizations regarding men. According to the research reports, however, men have also been discovered to benefit from the additional Omega-3 treatment (Peet and Horrobin 2002). According to the preliminary discoveries, it seems that at least pure EPA and possibly the combination of EPA and DHA could provide additional benefits to depression patients receiving medical treatment.
Is there enough EPA in human systems?
The transformation of alpha linolenic acid to EPA may be obstructed by several factors such as aging, diseases, stress as well as excessive intake of Omega-6 fatty acids (Bourre 2004). Considering the high content of Omega-6 fatty acids in the most commonly used vegetable oils in relation to the Omega-3 acids, it is entirely possible that the insufficient intake of Omega-3 fatty acids causes neuropsychiatric consequences among some individuals.
”Should doctors treating depression patients recommend Omega-3 fatty acids to their patients?”, asks Antti Tanskanen in his article and answers: ”According to research data, they wouldn’t cause any harm, either, and they would help to improve the moods of some female patients in medical treatment. This means that E-EPA could be used as an additional depression medication”. There is preliminary evidence on the similar impact on the treatment of bipolar depression, too.
What about DHA then?
It may be connected with the development of postpartum depression. During pregnancy, essential fatty acids are transferred from the mother to the foetus even 2.2 g/day (Bourre et al. 2004). If the DHA-level of the human body becomes normal very slowly after giving birth, the woman may have an increased risk of becoming depressed (Otto et al. 2003).
References
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