65. The MTHFR 677C>T polymorphism is associated with unmetabolized folic acid in breast milk in a cohort of Canadian women (lay summary)

Page R, Wong A, Arbuckle TE, MacFarlane AJ. American Journal of Clinical Nutrition 2019 Aug 1;110(2):401-409. doi: 10.1093/ajcn/nqz056

Infants who are only breastfed are unique in that in addition to their own genetics, physiology and metabolism, their nutrient intake is dependent on their mother.  While it is expected that both mother’s nutrition and genetics influence what is in her breast milk, just a few studies have examined this.

The purpose of this study was to determine where specific components of the mother’s genetics are associated with folate content of her breast milk.  Adequate intake of folate (also known as vitamin B9) is very important during periods of rapid growth such as pregnancy and infancy.   Folate is required to make red and white blood cells and change carbohydrates into energy. Folic acid is the synthetic (man-made) form of folate and is broken down (metabolized) by the liver into folates.

Both total folate and unmetabolized folic acid were measured in 551 samples of breast milk from MIREC Study participants.  Maternal blood samples were analysed for some genetic markers associated with folate.

The results of this study showed that none of the genetic markers measured were associated with total breast milk folate.  One of the markers was associated with unmetabolized folic acid.

In conclusion, this study found that total breast milk folate was not associated with any of the genetic markers examined.  The association between one of the markers and unmetabolized folic acid underscores the need to better understand what factors determine folate content of breast milk.

This study was led by researchers at Health Canada.