MSPI (Milk-Soy Protein Intolerance): What Parents Need To Know

We break down everything parents need to know about MSPI, including symptoms, how MSPI is different from a milk allergy and how it's safe to give Ready. Set. Food! to babies with MSPI.

Many babies who have trouble digesting milk proteins also have trouble digesting soy proteins. When they have trouble digesting both, they usually have MSPI (milk-soy protein intolerance). What is MSPI? What are its symptoms? Is it safe to give Ready. Set. Food! to babies with MSPI? This article covers everything parents need to know about MSPI.

What is MSPI?

MSPI is milk-soy protein intolerance. It is a type of milk protein intolerance, and a type of soy intolerance. It is an adverse reaction to both cow's milk and soy that involves the digestive system.

If your child has MSPI, they can't digest cow's milk or soy properly. Their digestive system can't break down the proteins in cow's milk or soy. So, they suffer from digestive symptoms whenever they consume cow's milk or soy products.

No one knows for sure what causes MSPI. But MSPI is usually temporary---your baby will often outgrow it by 1-3 years of age.

What are the symptoms of MSPI?

Symptoms of MSPI may include:

  • Bloody or mucousy stools
  • Diarrhea or loose stools
  • Gassiness
  • Bloating
  • Stomach aches/pains
  • Constipation
  • Abdominal pain
  • Colic (excessive crying, sometimes around 18 hours/day)
  • Spitting up
  • Reflux
  • Weight loss
  • Repeated vomiting
  • Nausea
  • Irritability after having dairy or soy
  • Trouble sleeping
  • Changes in appetite

Symptoms of MSPI tend to emerge minutes to hours after eating cow's milk or soy products.

Is MSPI a milk allergy?

MSPI is not a milk allergy. Food allergies always involve the immune system.

MSPI is not a milk allergy.

  • When someone has an allergy to a food, like milk or soy, their immune system treats the proteins in that food as foreign invaders.
  • Their immune system produces antibodies to defend against the food's proteins.
  • These antibodies trigger a reaction each time the person consumes the food they are allergic to.

Milk intolerances, like MSPI, never involve the immune system.

  • MSPI is not an allergy to milk (or soy), because it doesn't involve the immune system. Instead, MSPI only involves the digestive system.

Milk allergies and MSPI can cause similar symptoms, though, so it can be hard to tell the difference.

But milk allergies can cause symptoms, like hives and swelling, that MSPI doesn't. Also, milk allergies can be life-threatening, while MSPI is rarely ever life-threatening.

Learn more about how to tell the difference between symptoms of a food allergic reaction and food intolerance.

How is MSPI diagnosed?

There's no specific test that can diagnose MSPI perfectly. But, if your baby has bloody stools or another MSPI symptom, your doctor may recommend an elimination diet. This means you'll stop feeding your baby anything with milk or soy for a few weeks. If your baby has MSPI, their symptoms should improve when they don't have to digest milk or soy.

Is MSPI the same as lactose intolerance?

MSPI is different from lactose intolerance.

  • Both lactose intolerance and MSPI cause someone to have trouble digesting milk, and both involve digestive symptoms.
  • But people with lactose intolerance have problems breaking down the sugars in milk, not the proteins in milk.
  • Children with MSPI can't break down the proteins in milk. So, they still have digestive problems when they have lactose-free milk products (cow's milk products with the sugars removed), like lactose-free formula.
  • Also, children with MSPI have trouble digesting soy, but people with lactose intolerance have no problems digesting soy.
  • Milk protein intolerances, like MSPI, are more common in young children than lactose intolerance.
  • And MSPI is often outgrown after a few years, but lactose intolerance is less likely to be outgrown.

Can I give Ready. Set. Food! to a baby with MSPI?

Yes, you can safely use Ready. Set. Food! if your baby has MSPI. Ready. Set. Food! is designed for all families, even families with babies who have milk sensitivities.

Many children with MSPI can have small amounts of milk without suffering from digestive symptoms. Ready. Set. Food! uses very small amounts of milk in each packet. Our gentle system contains less milk than 1 teaspoon of yogurt or cow’s milk, so it's safe for babies who are sensitive to cow’s milk. So, even if your baby has an intolerance to milk, the system is still safe and likely won't cause discomfort.

Doctors usually recommend reintroducing milk to babies with a milk intolerance (such as MSPI) or a delayed allergy to milk at some point. So, we'd recommend asking your pediatrician or allergist about when they recommend reintroducing dairy, prior to starting Ready. Set. Food!

There is no cure for food allergies once they develop. If you are unsure if your baby has a food intolerance or food allergy, talk to your doctor.

You can also learn more about the difference between a food allergy and a food intolerance here.

To further adapt to every family's needs, Ready. Set. Food! offers a system with just peanut and egg, for if your baby struggles to tolerate milk.

Introduce Allergens Safely and Easily with Ready. Set. Food!

All health-related content on this website is for informational purposes only and does not create a doctor-patient relationship. Always seek the advice of your own pediatrician in connection with any questions regarding your baby’s health.

These statements have not been evaluated by the Food and Drug Administration. Products are not intended to diagnose, treat, cure or prevent any disease.  If your infant has severe eczema, check with your infant’s healthcare provider before feeding foods containing ground peanuts.