Tuesday, January 31, 2012

Fishy breast milk - the scientific summary

I have wanted to write on the topic of fishy breast milk for some time but I have not had chance to do so since my boys takes quite a huge chunk of my time at night. Luckily today somehow I have half an hour to do so!
The topic of fishy breast milk is something that I only encounter recently. My first son was literally fed with fishy breast milk that my wife produced for more than 1 year without an issue. She went back to work after 2 months of maternity leave and after that, the boy drank thawed frozen breast milk that is at least 2-4 months old. I noticed the fishy smell but did not really think about it as he still drank them and did not show any health problem at all. Well, recently he developed asthma syndrome but then there is no indication so far that this is the result of the fishy breast milk.
I started to search on fishy breast milk topic as it was more apparent for my second boy. My wife had nearly four months maternity leave so by the time she went back to work, the frozen breast milk had already been 4 months in storage. I became aware of the issue of fishy smell and upon some searches in google realized that many mothers are facing the same issue. However, I have not managed to come across any article that talks about the issue using scientific references. So in this article, I would like to share what I can gather.
Apparently there has been quite a number of studies that indicates that mother's food intake can modify the content of breast milk and thus affect the odor. Harris, W. S. et. al. in their study (http://www.ajcn.org/content/40/4/780.short) reported that mothers taking fish oil supplement reported fishy odor in their breast milk 1 to 3 hours after taking fish oil supplements. However, a recent study by Sandgruber, S. et. al. (http://www.sciencedirect.com/science/article/pii/S0308814611004390) seemed to dispute this idea as they reported no statistically significant modification of the odor of breast milk upon fish oil intervention. It would seem that the jury is still out there on whether the smell comes from fish oil intake or not. I reckon it will be really difficult to conduct a double blinded study on this issue as mother's metabolism may potentially be a major variable including other genetic factors. In addition, it will not be easy to control diet of a big group of mothers concerned about their child's well being.
However, Spitzer, J. and Buettner, A. (http://www.sciencedirect.com/science/article/pii/S0308814609011935) in their study showed that odor active compounds are more active in stored breast milk. In addition, Sangruber, S. et. al. (http://www.sciencedirect.com/science/article/pii/S0308814611009605) continued their study and reported that fishy smell was not apparent in breast milk stored at -80 C. They mentioned that apparent flavor change was apparent when the milk was stored at -19 C.
Therefore, would seem that to prevent fishy breast milk issue, a -80 C freezer may be required. I have not come across a small unit of -80 C freezer though so it may prove to be a potential untapped market or simply further study on how to prevent appearance of fishy odor in storage of -19 C may be required.
At this moment, I and my wife are trying to see whether the pasteurization mentioned in some sites actually works in preventing the milk to turn fishy. Will update this post when I have more information.

Update: I realised that at times my wife's breast milk will smell quite fishy before even I pasteurised it. Unfortunately the pasteurisation did not get rid of the smell. One possible factor that I would not be able to probe is the effect of direct freezing as my wife pumped milk at work so she has to keep it in a domestic fridge for about 8 hours. Amazingly my son seems to just gobble up whatever milk, pasteurised or not, that is presented to him. I guess it means good..

2 comments:

Becky and Jared said...

Thanks for your comments, if only my husband now staying at home had so much interest in my breastmilk! I do take fishoil supplements and have noticed more fish smelling BM with the fish oil vs the flaxseed omega 3 vitamins!

Becky and Jared said...

Thanks for your comments, if only my husband now staying at home had so much interest in my breastmilk! I do take fishoil supplements and have noticed more fish smelling BM with the fish oil vs the flaxseed omega 3 vitamins!