Does Soy Formula Help With Acid Reflux? The Benefits and Risks Of Soy-Based Milk

Soy formula may help deal with acid reflux in babies and prevent its recurrence. Soy milk is alkaline and will help neutralize the acid found in the esophagus and stomach. It is also a digestible protein for babies who cannot metabolize cow’s milk protein. Pediatricians often recommend soy formula when they rule out protein allergy in infants. It can meet the baby’s nutritional needs like other types of infant milk but it does come with some exceptions. 

Soy formula is a safe and appropriate feeding option but only for full-term babies over six months of age.

It is particularly recommended for babies with galactosemia and those with recurrent vomiting or gastroesophageal reflux (GER). However, soy formula use also raises some potential health concerns.

To be sure it is the right formula to give your baby, always check with your pediatrician before using it.

What is acid reflux?

Acid reflux is a condition when stomach contents regurgitate back to the esophagus from the stomach, causing spit-ups.

Baby spit-up is common which can either be mild or a serious affliction.

The most common causes of infant acid reflux are:

  • Premature birth
  • Underdeveloped digestive system
  • Improper latching and milk oversupply
  • Lying flat most of the time

More serious acid reflux is often due to:

  • GERD
  • Narrowed small intestine or pyloric stenosis
  • Injury of esophageal lining due to the build-up of white blood cells (Eosinophilic esophagitis)
  • Food intolerance

Acid reflux due to food intolerance in infants is often associated with sensitivity to cow’s milk. Babies with allergies may experience bouts of vomiting, irritability, and feeding problems.

Cow’s milk is rich in fat. It is known that fatty foods contribute to acid reflux. That is because fat slows down digestion causing undigested food to back up into the esophagus.

With a baby’s immature digestive system, acid reflux and spit-ups are inevitable until the stomach muscles gain control.

How can soy formula help with reflux?

Mom is bottle feeding her infant daughter soy formula to help with her acid reflux

Soy formula does not contain cow’s milk protein making it easily digestible. It also contains half the fat content of other types of infant formula.

It is alkaline with a pH level of 7.94, which can help tame stomach acid and help in preventing regurgitation.

Infants with galactosemia often feed on soy formula upon the doctor’s prescription.

Galactosemia, or lactose intolerance, is the body’s inability to break down simple sugar (galactose) in milk.

Babies with severe acid reflux may also be recommended to switch to soy-based infant formula to manage their symptoms.

Soy formula contains the same number of calories and other nutrients as other types of formula milk. It is the most viable milk alternative for parents with ethical and environmental concerns.

According to a study, soy formulas do not affect the growth and development of healthy full-term babies.

Babies who use soy formula are recommended to offer soy-follow-up formula by 12 months of age.

Soy formula has high aluminum content that interferes with calcium absorption. Follow-up soy formula will help babies meet their calcium requirement until two years of age.

Limitations of soy formula use

Soy formula is not the best option for all babies as it comes with some limitations.

Among them is its inefficiency in providing calcium which puts babies at risk of osteopenia.

Osteopenia is a condition where the bones become weak due to the loss of bone mineral density (BMD).

Thus, calcium is detrimental to pre-term babies since it may weaken their bones. That is why premature babies with low birth weights are not recommended to use soy formula.

Babies with the following conditions should take other milk alternatives other than soy:

  • Premature babies
  • Low birth weight
  • Congenital hypothyroidism
  • Infants with renal failure
  • Babies under six months of age
  • Babies with soy-protein sensitivity

Milk Soy Protein Intolerance (MSPI)

So, your doctor transitioned your baby to soy formula because of acid reflux. But what if your baby’s symptoms like excessive spit-ups, vomiting, gas, and indigestion did not clear up?

Indeed, some babies do not respond to standard acid reflux treatments. When their discomfort and fussiness continue, it is likely that they are also unable to digest soy protein.

Milk soy protein intolerance (MSPI) is the temporary inability of the body to digest proteins in both cow and soy products. It happens in both breastfed and formula-fed babies and is hard to diagnose and treat.

An elimination diet or removing cow and soy protein in the baby’s food can point out whether the baby has MSPI or not.

Breastfeeding mothers may be advised to remove such products from their diet for a while to assess the development of the symptoms.

What happens if the baby is allergic to cow’s milk and soy protein?

Mom is breastfeeding her infant daughter

MSPI mimics the symptoms of lactose intolerance, but they are different cases.

Infants with lactose intolerance cannot digest sugar (lactose) in their food.

Feeding them with lactose-free formula generally alleviates their symptoms. However, the lacto-free formula still contains milk protein which babies with protein sensitivity cannot tolerate.

If your healthcare provider deduces that your baby has milk protein intolerance, an elimination diet will help.

When the symptoms improve after two weeks of a diet without milk or soy, the baby probably has MSPI.

When that is the case, breastfeeding moms should have a diet free of cow’s milk and soy. Formula-fed infants will take the hypoallergenic formula as recommended by the doctor.

The most common prescribed formulas are Alimentum, Nutramigen, and Neocate (see all 3 below).

Similac Alimentum with 2'-FL HMO Hypoallergenic Infant Formula, for Food Allergies and Colic, Suitable for Lactose Sensitivity, Ready-to-Feed Baby Formula, 32-oz Bottle (Case of 6)

Enfamil Nutramigen Infant Formula, Hypoallergenic and Lactose Free Formula, Fast Relief from Severe Crying and Colic, DHA for Brain Support, Ready to Use Bottle, 32 Fl Oz, Pack of 6

Neocate Infant - Hypoallergenic, Amino Acid-Based Baby Formula with DHA/ARA - 14.1 Oz Can


Are there any other types of milk to give for acid reflux aside from soy formula?

Anti-Regurgitation (AR) formulas, partially-hydrolyzed, extensively hydrolyzed, and amino acid-based formulas may be given to babies with acid reflux.

When should I worry about acid reflux?

If your baby’s spit-up comes with the following symptoms, call your doctor: wheezing sound during feeding, irritability and fussiness, inconsolable and colicky crying, signs of pain like aching of the back and wriggling, feeding difficulties, low birth gain, and spit-ups with odd colors like green and red.


Soy protein may benefit most infants with acid reflux, but it is not the appropriate milk for all.

If you have trouble feeding your baby and are concerned about weight gain, do not hesitate to talk to your doctor.

There are other options for treating acid reflux even if your baby exhibits sensitivity to milk proteins.

Your doctor can provide a treatment plan to manage the symptoms without impeding the baby’s growth and development.

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Ann Marie is a licensed nurse in the Philippines. She experienced handling and assisting deliveries of newborns into the world. She also trained in labor rooms and pediatric wards while in nursing school - helping soon-to-be mothers and little kids in the process. Though not a mother by nature but a mother by heart, Ann Marie loves to take care of her younger cousins as well as nephews and nieces during her free time.

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