When a mum says she doesn’t have enough breastmilk she is rarely believed. She is told her body will provide. She’s told it’s about technique, confidence or trying harder. New research published in Science suggests it’s time we started taking women seriously.
How many women struggle to produce breastmilk sufficient in volume and composition to meet their baby's needs? The answer is that we don't really know.
What we do know is that concerns about insufficient milk supply are among the most commonly reported reasons women stop breastfeeding or introduce infant formula. The latest Infant Feeding Survey showed 44% of women who stopped breastfeeding in the first weeks (and provided a reason for doing so) reported they did not have enough milk.
Too often women’s concerns are described as perceived insufficient milk supply (which rather downplays women’s own experience) with an assumption that the problem lies in mothers' confidence or their breastfeeding technique. But we shouldn’t assume that all difficulties can be overcome with better advice or just greater perseverance, nor that all women’s concerns about their milk supply are unfounded.
Indeed, a long-held assumption in breastfeeding research has bee that Mums can always draw on their body’s own stores to protect the quality of their milk, even when their diet is inadequate. This new research directly challenges that assumption. The evidence suggests that biological ‘buffering’ is incomplete, particularly for some specific vitamins and nutrients, meaning that what a Mum eats and how well-nourished she is can have a real impact on her milk.
Jauhal et al. analysed more than 1,500 human milk samples from women in Burkina Faso, Pakistan and Canada, investigating the relationships between maternal nutrition, mammary gland function, milk composition and infant growth.
They identified biological markers associated with different aspects of mammary function, including milk synthesis, metabolic activity and inflammation.
In the two populations experiencing greater nutritional disadvantage, maternal nutritional supplementation improved infant growth trajectories and was associated with changes in milk composition. In short, when women had access to more food, it positively impacted on their babies growth.
Perhaps particularly interesting was the Canadian arm of the research. Even among 400 adequately nourished women, researchers identified patterns in breast milk composition associated with differences in infant growth. This suggests that the relationship between maternal physiology, milk composition and infant growth deserves much greater attention in high-income countries, not just in settings where undernutrition is common.
So, what could be driving these differences, even in women who appear adequately nourished? One answer the research point to is an often overlooked B-vitamin: pantothenic acid, found in a wide variety of everyday foods, like eggs, meat and wholegrains. In lower-income study settings, more than half of mothers had insufficient pantothenic acid levels in their milk, and low levels were linked to signs of disrupted milk production. When Mums received nutritional supplementation, pantothenic acid levels improved and their babies growth imrpoved alongside it. Although deficiency in wealthier countries is rare, if meaningful variation in milk composition can be seen even among well-nourished Canadian women it raises important questions about whether women experiencing food insecurity in the UK might face similar challenges.
Our 2024 Out of Milk report found that women experiencing food insecurity were more likely to stop breastfeeding or introduce formula, and that concerns about their milk supply was frequently the reason. Importantly, these women were no less likely to seek breastfeeding support than women who were food secure. The issue was not that they weren;t trying.
As one mother, Rose, told us:
"Not eating properly makes having a good breast milk supply challenging."
We couldn’t establish whether these women were producing sufficient milk. That uncertainty matters hugely in terms of how we support women and for the research we prioritise. It was precisely why we called for more research into how maternal nutrition affects breast milk production and composition, and for better tools to identify lactation issues.
The new research published in Science is a step in the right direction. But the scale of what we still don’t know is significant. We don’t have a clear picture on how common insufficient milk supply actually is nor the number of babies who may not be receiving adequate nourishment through breastfeeding alone. These questions really matter, they sit right at the heart of how we care for women and their babies. Women deserve to have their experiences taken seriously and ensuring babies receive sufficient nourishment must always be central to good infant feeding care.
Despite the mammary gland’s central role in infant health, it has been significantly understudied. Research has historically focused more on the breat in the context of cancer than in the context of lactation despite the two sharing many similar biological pathways. This new study raises an exciting possibility – that breastmilk could one day become a vital diagnostic tool, a non-invasive window into mammary health helping to identify women who may need support or intervention.
A lack of evidence about how common insufficient milk supply might be is not evidence that it isn’t happening. When women tell us this is why they stopped breastfeeding, let’s listen to them, and do the research which means we can actually answer their questions and work out potential solutions, rather than wave them away with platitudes about “perceptions”.
After all, it may not be all in their heads.
