8. Mandatory trans-fat labeling regulations and nationwide product reformulations to reduce trans fatty acid content in foods contributed to lowered concentrations of trans fat in Canadian women’s breast milk samples collected in 2009–2011 (lay summary)

Ratnayake WN, Swist E, Zoka R, Gagnon C, Lillycrop W, Pantazapoulos P. The American Journal of Clinical Nutrition. 2014;100:1036–40. doi: 10.3945/ajcn.113.078352

Canadians are becoming increasingly aware that trans-fats in certain foods are a health risk, especially with regard to cardiovascular health, or “heart health”. In Canada, efforts to reduce trans-fatty acids (TFAs) in foods include requiring that TFA content be shown on food labels and encouraging the food industry to voluntarily limit trans-fatty acid content in all vegetable oils and soft margarines to 2% of total fat, and in all other pre-packaged foods to 5% of total fat.

To assess the impact of these efforts, researchers at Health Canada measured the levels of trans-fatty acids in 639 breast milk samples collected as part of the MIREC Study. They found that the average trans-fatty acid (TFA) contents in total milk fat steadily decreased between 2009 and 2011, as shown in the following table:

Year Samples Collected Number of Samples Avg. % of TFAs in Breast Milk Fat
2009 153 2.7%
2010 309 2.2%
2010 177 1.9%

Moreover, the drop in the trans-fatty acid content in breast milk was even larger when compared to data from 1992, when the average value in Canadian human milk was 7.2%.

There is further good news in relation to diet: the researchers found a large decrease in the consumption of trans-fatty acids among Canadian breastfeeding mothers between 2009 and 2011:

Year Estimated Consumption of TFAs
2009 0.9%
2010 0.5%
2011 0.3%

These estimated values are lower than the World Health Organization’s maximum recommended consumption value of 1% of total energy for a healthy diet.

These results suggest that the trans-fat labeling regulations in 2003 and recommendations by Health Canada in 2007 instructing food manufacturers and restaurants to limit trans-fatty acids in foods have resulted in substantial reductions in trans-fatty acids in the diets of Canadian breast-feeding mothers, and in their breast milk.