Over the years I have had many questions from mothers about the lactose content of their medication and how this might affect their CMPA babies by passage through breastmilk.
If a breastfeeding mother is taking a tablet which contains lactose it is unlikely to affect the levels of lactose in her milk and therefore produce symptoms in her baby.
Lactose intolerance is very different to CMPA. Lactose is the sugar in breastmilk which varies little with maternal consumption. Lactose intolerance is usually identified soon after birth with failure to thrive (Savilahti).
Lactose intolerance occurs when a person does not produce the enzyme lactase, or does not produce enough of it, and is therefore unable to digest lactose. If it is not digested and broken down, lactose cannot be absorbed. The undigested lactose passes rapidly through the gut until it is broken down by bacteria, producing gastric pain, bloating and diarrhoea.
See https://www.breastfeedingnetwork.org.uk/factsheet/lactose-intolerance-and-breastfeeding/
The production of lactase decreases in most humans from the age of two years although symptoms of intolerance are rare before the age of six. Lactose intolerance in adults is very common. This is probably a throwback to early dietary consumption in pre-historic humans. Production of lactase also varies between cultures. It is most common in people of African, Asian, Hispanic and American Indian descent. One article I found suggests that 100% of the residents of Ghana, Malawi, South Korea, and Yemen are believed to be lactose intolerant.
CMPA is due to an allergy to the protein in dairy products (not the same as the sugar). Cows’ Milk Protein Allergy (CMPA) and Breastfeeding – The Breastfeeding Network
Savilahti et al identified only 16 cases of congenital lactase deficiency over 17 years despite the fact that the gene for lactose intolerance is very common in Finland. In each case the mother reported watery diarrhoea usually after the first breastfeed but up to 10 days after birth. Poor absorption of lactose was confirmed between 3 and 90 days after delivery at which time all infants were dehydrated and 15 of the 16 weighed less than at birth. On a lactose feed diet the children all caught up with their growth.
Temporary lactose intolerance
Some premature babies are temporarily lactose intolerant due to their immaturity. Babies may also show temporary secondary lactose intolerance following exposure to maternal antibiotics passing through breastmilk. There is no need to alter feeding or add probiotics as all factors to restore the gut are in breastmilk. It is self-limiting.
Lactose in maternal medication
So, if a breastfeeding mother is taking a tablet which contains lactose it is unlikely to affect the levels of lactose in her milk and therefore produce symptoms in her baby.
SPS also provided information on the absorption of lactose from medication in January 2024. https://www.sps.nhs.uk/articles/assessing-the-clinical-impact-of-lactose-in-medicines/
“Lactose in medicines
Lactose is widely used as an excipient in pharmaceutical manufacturing. Although anecdotal reports of drug-induced lactose intolerance exist, when used as an excipient the lactose content in most medicines is too small to cause problems. Daily lactose exposure from medicines is unlikely to exceed 2g per day. Whereas the threshold for lactose intolerance symptoms is approximately 12g (equivalent to 250ml of milk). Therefore, it is unlikely that severe gastrointestinal (GI) symptoms will be due to lactose in medicines, especially in adults without a diagnosis of severe intolerance. “
References
- Anderson J Lactose intolerance and the breastfed baby. www.breastfeeding.asn.au/bf-info/lactose
- BfN Lactose intolerance and Breastfeeding https://www.breastfeedingnetwork.org.uk/factsheet/lactose-intolerance-and-breastfeeding/
- Jones W Breastfeeding and Medication Routledge 2018
- Savilahti E, Launiala K, Kuitunen P. Congenital lactase deficiency. A clinical study on 16 patients. Arch Dis Child 1983;58:246-252
- Shulman R, Feste A, Ou C (1995). Absorption of lactose, glucose polymers or combination in premature infants. Journal of Pediatrics, 127, 626-631.
- SPS Assessing the clinical impact of lactose in medicines https://www.sps.nhs.uk/articles/assessing-the-clinical-impact-of-lactose-in-medicines/
