Does Baby Formula Actually Decrease the Risk of Allergies and Autoimmune Disease?

Research Highlights

The effects of diet during infancy are formative and instrumental to health later on in life. It has been well established that babies should be given formula rather than cow’s milk in the first 4-6 months. This comes from evidence that cow’s protein can induce allergic or autoimmune diseases at a young age.  Now, numerous countries are reporting that the rate of allergies and autoimmune diseases have been increasing in recent years.  In order to see if formula can help prevent allergies and autoimmune diseases, a systematic review done in the UK has been performed to potentially inform future guidelines on feeding infants.

The review encompassed 52 studies with over 19,000 total participants. The studies varied in their use of hydrolysed formula. 37 of the studies were intervention trials. However, 30 of the 37 trials were observing infants with high risk of the relevant diseases due to family history. The review does admit that risk of bias and conflict was harder to minimize for allergies than autoimmune disease, because of the increased difficulty in identifying bias

Overall, the study observed the multiple risks of diseases when using formula versus cow’s milk. The study calculated risk of eczema, wheeze (the respiratory sound), allergic rhinitis, and food allergies. 27 of the total studies yielded information on eczema. When compiled, the results showed that there was no significant difference in risk of eczema from the ages between hydrolysed formula and cow’s milk formula. This was found for both ages 0-4 and 5-14. The analysis of the wheeze data was deemed “inconclusive” in the results. Allergic rhinitis (the most common type is known as seasonal allergies) was shown to have a significantly reduced risk when only partially hydrolysed formula was used. This effect was only observed in ages 0-4, and not ages 5-14. However, no risk reduction was found when it came to food allergies. Allergies to cow’s milk, eggs, and peanuts were recorded, but none of them showed any statistical differences whether formula or cow’s milk was used.

The comprehensive study was not able to show many cases, if any, in which formula needs to be recommended in place of cow’s milk. Current international guidelines deem hydrolysed formula as the safest option, particularly for infants with family history of allergies. This study could not find evidence to support this recommendation. Additionally, the study willingly points to its limitations to show why past experiments and trials may say otherwise. They found inadequate method when it came to randomization and selection bias in studies that were supported by hydrolysed formula manufacturers. There was also possible research fraud in an 2003 investigation. Though this particular investigation was removed from subsequent studies, it may have caused publication bias in reviews that overestimate the benefits of hydrolysed formula. Ultimately, this overall analysis recommends that future studies be overseen in a better and more unbiased manner in order to determine if today’s guidelines are actually beneficial to infant, and overall, health. 

BMJ 2016;352:i974

Lena Chatterjee is the 2015-2016 Research Highlights Editor.