A number of my friends are pregnant or have recently given birth. One of the most common questions they ask me is whether there is anything they can do, nutritionally, in order to reduce the likelihood of suffering from postnatal depression or reduced mood after the birth of their baby. Depression that comes on during or up to 12 months after pregnancy is sometimes referred to as ‘peri-natal’ depression.
First of all I would like to include a link to the Royal College of Psychiatrists who have a leaflet that fully explains postnatal depression. In this leaflet is a self-help section dedicated to ideas that can be implemented during pregnancy and after the birth in order to help women to understand their feelings and reduce anxiety surrounding postnatal depression.
A healthy diet rich in vegetables, beans and pulses, fruits, nuts and seeds, unrefined and unprocessed meats and fish and wholegrain carbohydrates will go far in feeding the body during pregnancy. The foetus needs nourishing as it grows and is completely reliant on the mother for essential nutrients: vitamins, minerals, fats and protein. Today I would like to write about the potential and exciting role that omega 3 fatty acids may play in the prevention of postnatal depression. In past blog posts I have mentioned the link between lack of omega 3 fats in the diet and the blood and the risk of suffering depression, there are also studies indicating that omega 3 supplements are useful in the treatment of depression and other mood disorders.
The human brain contains a lot of fat, vital for its structure and efficient functioning. Long chain omega 3 fatty acids make up a large proportion of the fat found in the brain. These long chain fats can be found, preformed, in oily fish such as mackerel, salmon, trout and sardines. Omega 3 fats can also be found in flaxseeds and walnuts in a short-chain (alpha linolenic acid) form, the body can then convert these into the longer chain forms (although this process is not very efficient and a lot of vegetarian omega 3 would be needed to form small amounts of the long chain fats in the body).
During pregnancy the long chain omega 3 fatty acid DHA (docosahexaenoic acid) is selectively transferred from the mother to the foetus i.e. omega 3 fats are taken from the mother in order to be transferred to the developing baby. The reason that this happens is that DHA is absolutely crucial for the brain growth and development in the foetus as well as visual function. If the mother is not getting much omega 3 from her diet then any stores in her own body will be diminished so that the baby does not miss out. Scientists are now suggesting that this drop in DHA in the mothers body could be linked to the risk of postnatal depression. This seems to make a lot of sense, if DHA is transferred from the mother her brain stores of this essential fat may become depleted and hence contribute to the risk of suffering postnatal depression.
A study in 2002(1) investigated the link between omega 3 fatty acids and postnatal depression by assessing the DHA content of mothers’ breast milk and seafood consumption. If there are high concentrations of the essential fatty acid DHA in the mothers milk it is an indication that her levels have not been hugely depleted during pregnancy. Seafood is a good source of omega 3 fats so looking at intakes during and after pregnancy can be used as an indicator to possible body levels. The study assessed data taken from 14532 individuals. The evidence suggested that higher concentrations of DHA in the mothers milk and greater seafood consumption during and after pregnancy both predicted lower rates of postnatal depression. Low DHA content in breastmilk and lower seafood consumption were associated with higher rates of postnatal depression (1). The findings do not prove that low levels of omega 3 fats cause postnatal depression or that higher levels protect against it but they do give an indication that these fats may play an important role.
In 2003 (2) a group of scientists measured the levels of DHA in the blood plasma of 112 women at the time of birth and then again 32 weeks later. They also assessed the mental health of the women using a questionnaire known as the Edinburgh Postnatal Depression Scale (EPDS). A EPDS score of 10 or over was used to define ‘possibly depressed’ and less than 10 as not depressed. The results showed that available DHA levels were significantly lower in the ‘possibly depressed’ women as compared to the not depressed group. The authors of the study conclude that “Although further studies are needed for confirmation, increasing the dietary DHA intake during pregnancy and postpartum, seems prudent”.
Last year a number of papers were published (3,4,5) that investigated the link between omega 3 fatty acid supplements and depression in pregnant women who were already suffering depression before birth. Results were mixed but there was a definite trend in the usefulness of omega 3 supplements in controlling depression. A small, preliminary study (6) in women suffering from postnatal depression found that taking a supplement for 8 weeks significantly reduced the depression scores in these women. The results are very interesting and further, larger trials are called for. A review of the available evidence (7) for the use of omega 3 fatty acids in postnatal depression suggests that more research into omega 3 fats for the prevention and treatment of postnatal depression would be welcome, so far the evidence suggests that these fats could provide positive help and are especially interesting since there is a lack of knowledge about the safety of standard antidepressant therapies during pregnancy and the postnatal period.
As I was completing this post I came across a small study published only last month (8). The study looked at the relationship between omega 3 fatty acids in the blood and risk of postnatal depression. The research involved 16 depressed and 22 non-depressed women in the final trimester of pregnancy. A high level of DHA and a high level of total omega 3 fatty acids in the blood was associated with a significantly reduced risk of postnatal depression. Women who had the lowest omega 3 fatty acid levels were six times more likely to be depressed postnatally compared to women who had higher omega 3 fatty acid levels.
Eating abundant omega 3 or taking a supplement during pregnancy and after pregnancy may well help to keep baby blues away: Although the evidence is quite new, and more larger studies are needed, it certainly seems prudent that pregnant women ensure a good supply of omega 3 fatty acids in their diet. Oily fish such as salmon, trout, mackerel and sardines represent great ways of boosting intakes. For vegetarians and vegans ground flaxseeds and walnuts can provide some omega 3 fats. It is known that these fats are essential for the growth and development of the foetal brain and nervous system and there are also links between development after birth and omega 3 levels. It would certainly seem sensible to up dietary consumption during pregnancy. I would also suggest speaking to your midwife or health professional about supplemental omega 3 fatty acids if you feel you do not regularly eat oily fish or omega 3 rich nuts and seeds. (Be aware that tuna is high in mercury and is not generally recommended during pregnancy).
Please also read the leaflet mentioned at the start of the post for more emotional tips and ways of dealing with pregnancy and birth.
(1) Hibbeln JR. 2002. Seafood consumption, the DHA content of mothers’ milk and prevalence rates of postpartum depression: a cross-national, ecological analysis. J Affect Disord. 69(1-3):15-29.
(2) Otto SJ, de Groot RH, Hornstra G. 2003. Increased risk of postpartum depressive symptoms is associated with slower normalization after pregnancy of the functional docosahexaenoic acid status. Prostaglandins Leukot Essent Fatty Acids. 69(4):237-43.
(3) Su KP et al. 2008. Omega-3 fatty acids for major depressive disorder during pregnancy: results from a randomized, double-blind, placebo-controlled trial. J Clin Psychiatry. 69(4):644-51.
(4)Freeman MP et al. 2008. Omega-3 fatty acids and supportive psychotherapy for perinatal depression: a randomized placebo-controlled study. J Affect Disord. 110(1-2):142-8.
(5) Rees AM et al. 2008. Omega-3 fatty acids as a treatment for perinatal depression: randomized double-blind placebo-controlled trial. Aust N Z J Psychiatry. 42(3):199-205.
(6) Freeman MP et al. 2006. Randomized dose-ranging pilot trial of omega-3 fatty acids for postpartum depression. Acta Psychiatr Scand.113(1):31-5.
(7)Rees AM et al. 2005. Role of omega-3 fatty acids as a treatment for depression in the perinatal period. Aust N Z J Psychiatry. 2005 Apr;39(4):274-80.
(8) Rees AM et al. 2009. Omega 3 deficiency associated with perinatal depression: Case control study. Psychiatry Res. 166:254-259
Written by Ani Kowal
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