The surprising science of breast milk

However, breast milk is a constantly changing fluid so in a way it’s a moving target, with some components still not fully understood, says Fewtrell, the professor of paediatric nutrition at University College London.   

“We can quite successfully produce formulas to provide adequate and safe nutrition so the baby grows and develops as expected,” she says. “Indeed, there have been improvements to the composition of formulas in recent years so that they can more closely reproduce the growth patterns and some outcomes seen in breast-fed infants. However I think it would be impossible to ever mimic the ‘non-nutrient’ components in this complex fluid.”

As for my investigation into my own body’s toxic load, and the harmful chemicals that were perhaps present in my breastmilk, Bloxam, the dietician, reassures me:  “I’d encourage breastfeeding wherever possible as the benefits for mother and baby would far outweigh any risks [from contamination].” 

Still it appears I’m not the only one wondering about the ingredients in my own milk. Stephanie Canale, previously a family medical doctor, is the founder of Lactation Lab in California, a private company that analyses breast milk for nutritional content as well as environmental toxics. Mothers send in frozen samples of their breast milk to check the levels of various ingredients including minerals and vitamins. The idea is that they can then adapt their diet accordingly.

Canale says that when we look at a baby’s nutrition, we need to include everything from prenatal vitamins to the food a breastfeeding mother consumes and the meals a weaning baby eats. Formula may be one part of that mosaic, in families where it is used. 

“It’s this holistic approach,” says Canale who would like to see stricter regulations in the US about the contents of formula. “I’m from Canada and it still surprises how much high-fructose corn syrup is present in US products, including formula. Moms are going to drive this change by saying we need to be better aware of what is going into these products, especially formula because that child is eating the same thing every single day – there’s no variation [like there is naturally with breast milk].”

In the case of the toxic chemicals – whether they find their way into breast milk or into formula – the question is clearly not just about how we can provide our children with safe nutrition. It is also about how we can provide them and future generations with a safe, liveable environment, and reduce pollution along the entire food chain. One answer, surely, is to start by using fewer harmful chemicals in the first place.

* Listen to My Toxic Cocktail, Anna Turns’s investigation for BBC Radio 4’s Costing the Earth series on BBC Sounds. Go Toxic Free: Easy and Sustainable Ways to Reduce Chemical Pollution by Anna Turns is out now

This article was updated on 27 June to include a quote from the FDA.

Join one million Future fans by liking us on Facebook, or follow us on Twitter or Instagram.

If you liked this story, sign up for the weekly features newsletter, called “The Essential List” – a handpicked selection of stories from BBC Future, Culture, Worklife, Travel and Reel delivered to your inbox every Friday.