You’ve just pushed a little human out of you*. I think it’s fair to say you’re pretty knackered. There’s a helpless – probably howling – scrunched-up creature who YOU are now responsible for. There’s nothing more daunting, or wonderful (the two are not mutually exclusive), than that. And now…now you’ve got to feed the little thing. More than likely, a midwife (or 10) has thrusted your tiny baby onto your breast, critically analysed the ‘latch’ and, quite possibly, made you feel as worthy as something brown and steaming on the side of a pavement.

*sorry if you’re a bloke reading this. Likely not quite so relevant for you!
If you choose to go down the breastfeeding path (let’s not go into the feelings of ineptitude and frustration if this doesn’t happen, nor the pros and cons of breast versus bottle), mothers are often barraged with advice regarding healthy eating in order to optimise their baby’s health or reduce reflux or colic-like symptoms. Food exclusion or elimination diets are frequently recommended by Dr Google or well-wishing friends and family. But is there any evidence behind it?

it is often said that maternal nutrition has little or no effect on many nutrients in human milk. Indeed, nutrients such as folate and calcium are largely unaffected by the amount consumed by the mothers. However, research suggests that certain components of the maternal diet may have more of an effect on her milk than previously thought. Omega 3 fatty acids, for example, which are essential for brain and eye development in the first year of life, cannot be made by humans and so those present in breast milk must come from the mother’s diet, either from food or supplements. Suboptimal maternal nutrition (in terms of types of fats consumed, at least) may affect breast milk composition to the extent that the neurological development of the infant is compromised. Vitamin D and the B group vitamins in breast milk are also affected by maternal diet and their effects on infant outcomes are hot topics in the world of paediatric nutritional science.

Researchers in Texas and California have recently found that a high-fat versus a high-carbohydrate diet, and a high-glucose versus high-galactose (a different type of sugar) diet in breastfeeding women is associated with changes in the microorganisms present in breastmilk, as well as changes in the types of ‘human milk oligosaccharides’: carbohydrates that help to ensure a healthy balance of bacteria in the gut. These components of breast milk have the potential to alter the balance of bacteria in the gut of breastfed infants, although it remains to be seen what, if any, health benefits this has for them.

On the other side of the coin, breastfeeding mothers often consider cutting out certain food groups in the fear that their child is allergic or intolerant due to symptoms such as a runny nose, eczema, reflux and diarrhoea or constipation. Cow’s milk, hen’s eggs, peanuts, tree nuts, fish, and wheat are among the most common foods excluded. It is true that potential allergens (usually proteins that are interpreted as a threat by the immune system in susceptible individuals, invoking an immune response) eaten by the mother can pass through breast milk. If the infant is allergic, excluding this food from the maternal diet may (or may not, depending on the extent of the allergy) be necessary if he/she is partially or exclusively breastfed.

Symptoms of infantile colic – defined according to Rome III criteria as episodes of irritability, fussing or crying that begin and end for no apparent reason and last ≥3hours per day, ≥3days per week, for ≥1week – often overlap with those of food allergy and mothers may be tempted to exclude certain foods in a desperate attempt to improve matters. A high quality study found a significant reduction in the duration of infant crying or fussing when mothers eliminated dairy foods, eggs, peanuts, tree nuts, wheat, soy and fish for seven days. On the contrary, another study showed that elimination of cow’s milk (and cow’s milk only) from the mother’s diet had no effect on colic symptoms. Due to such conflicting evidence, it has been recommended that breastfeeding mothers of infants with colic undergo a time-limited (e.g. two weeks) trial of excluding cow’s milk or even following a hypoallergenic diet, but if there is no definite benefit after this time, the dietary restrictions should be lifted.

Excluding nutritiously dense foods without first seeking the advice of a specialist dietitian puts the mother at risk of nutritional deficit. Breastfeeding mothers have been shown to have increased ‘bone mobilisation’ (the natural process by which the body dissolves part of the bone in order to maintain or raise the levels of calcium in the blood) compared to non-breastfeeding females, and this is more pronounced in mothers consuming a restricted diet lacking cow’s milk protein for at least two months, despite adequate calcium supplementation. Other reports have shown a decrease in bone mineral density (i.e. the amount of calcium and other minerals in your bone, which affects risk of osteoporosis and bone fracture) in lactating mothers on a cow’s milk-elimination diet.

Ergo, unless an allergy is diagnosed by a health professional, it could potentially be detrimental to maternal health to exclude foods unnecessarily. The only exception may be if the infant has had a severe allergic reaction to a food, such as wheezing, swelling of the tongue and throat or a drop in blood pressure, then it is usually safer for the mother to avoid the suspected food until a health professional is consulted.

Parenthood has enough challenges (yes, I’m using the word ‘challenges’ to avoid any unsavoury language) without having to be preoccupied over what you’re eating. Of course, the wellbeing of your little one is paramount, but not at the expense of Mum’s sanity, or indeed Mum’s health. My take home messages are:

– if you’re following the basic principles of a ‘healthy balanced diet’ (see the EatWell Guide), plus a 10μg vitamin D supplement, as recommended by the government, while breastfeeding then you’ll probably be alright!

– if your baby/child suffers from non-life threatening symptoms such as excessive crying, diarrhoea or eczema or, indeed, any other symptom that you are unsure about, then consult a healthcare professional before making any dietary changes. Any severe reactions such as wheezing or swelling and emergency medical care should be sought.

Natasha Schoeler PhD

Natasha is a postgraduate student at KCL. She completed her PhD on the genetics of response to the ketogenic diet and is keen to follow a career combining clinical paediatric dietetics and ketogenic diet research.


Foodtalk blog posts are written by a variety of health and care professionals in order to showcase different perspectives in the world of nutrition and health.