Casein is a protein found mainly in mammal milk. In fact, casein makes up nearly 80 percent of the proteins in cow's milk—and cow's milk is the number one allergen for young children The main allergen offender in milk is the alpha s1-casein protein.

Casein can also be found in a host of other foods and products, making it one of the more difficult substances to avoid for those with a casein allergy.

In addition to milk, casein can be found in:

  • butter
  • cheese
  • yogurt
  • ice cream
  • puddings and custards
  • milk (and white) chocolate
  • curds
  • whey
  • creamed soups and vegetables
  • sodium caseinate
  • lactose (including sodium lactylate)
  • lactalbumin and other products that begin with "lact"
  • protein-enriched foods (such as wheat or "high energy" foods)
  • caramel coloring
  • recaldent (found in certain brands of chewing gum)
  • certain "natural ingredients" (when in doubt, contact the manufacturer)
  • as a binding agent in dairy-free cheese (including soy), semi-sweet chocolate,               margarine, tuna fish, hot dogs, sausage and lunch meats as well as non-food products such as paints, some cosmetics and glue


  • abdominal pain
  • diarrhea
  • vomiting
  • swelling of the face, lips and tongue
  • hives
  • atopic dermatitis
  • congestion, tightness in the throat and asthma
  • anaphylaxis (very rarely)

In Children

Three percent of American children have a food allergy, with cow's milk being the most likely culprit. A casein allergy will typically show up when an infant is three months old and resolve by the time the child is three years old. The American Academy of Pediatrics recommends children are not introduced to cow's milk before one year of age. In addition to the above-mentioned soy and rice milks, alternative replacements for formulas may include goat milk, which contains only trace amounts of the alpha s1-casein protein. Goat's milk tastes similar to cow's milk and has similar proportions of fat, iron, and proteins and may be easier to digest as well. Goat's milk also has more calcium than cow's milk.

Additional symptoms for infants and children who are allergic to casein may include;  

  • irritability or acting out
  • redness or itching around the mouth, eyes, or anus
  • unusually picky eating or milk avoidance
  • bowel disruption

New research shows that casein may also be a factor in autism spectrum disorders (ASD) as well as other physical and mental disorders including chronic fatigue syndrome, fibromyalgia and depression. A 2012 Penn State University study found that some children with ASD responded positively from the removal of casein from their diet. Studies are ongoing.

Casein-free Substitutes

Fortunately for allergy sufferers, there are many substitutes on the market for casein-based products, including:

  • soy, rice or potato-based milks
  • sorbets and Italian ices
  • certain brands of soy-based products such as Tofutti
  • Pareve-brand creams and creamers
  • most soy ice creams
  • coconut butter
  • certain brands of soup including Imagine

*In recipes calling for one cup of milk, you can substitute one cup soy rice, soy or coconut milk or one cup water combined with one egg yolk. To replace yogurt use soy yogurt or soy sour cream or one cup pureed ?fruit or one cup of unsweetened applesauce.