Galactosemia is a rare genetic disorder passed from parent to child. Galactosemia occurs in approximately 1 in 48,000 births in the United States. Children with galactosemia are unable to breakdown (metabolize) galactose, a simple sugar. Galactose combines with glucose (a source of energy for the body) to make lactose, a complex sugar commonly found in human milk, animal milks (cow, goat), and milk products.

Galactosemia should not be confused with cow's milk allergy or lactose intolerance. 

  • Cow’s milk allergy is among the more common food allergies. Symptoms include fussiness, gassiness, and diarrhea. Treatment calls for avoiding foods containing cow’s milk. Children usually outgrow cow’s milk allergy by 3–5 years of age. 
  • Lactose intolerance occurs when a person is unable to metabolize lactose, but can usually breakdown galactose. Lactose intolerance is rare in infants and more common in older children and adults. Symptoms of lactose intolerance include bloating, cramping, and diarrhea. Like cow's milk allergy, it is treated by avoiding foods containing lactose, particularly milk and milk products. 
Unlike lactose intolerance or cow’s milk allergy, undiagnosed galactosemia can be a life-threatening condition.

Signs of galactosemia

Symptoms of galactosemia (vomiting, poor weight gain, irritability, refusal to breast or bottle-feed) appear within days of drinking human milk or cow’s milk formula. If galactosemia is identified early, babies can be put on a galactose-free diet and there is little risk for permanent damage. If diagnosis is delayed for weeks or months, irreversible damage can occur. 

Types of galactosemia 

Galactose is converted into glucose by three enzymes. When one of the enzymes is missing, galactose builds up in the blood. High levels of galactose can damage a baby’s brain, liver, and kidneys. There are three types of galactosemia depending upon which enzyme is missing:

Type 1—Galactose-1 phosphate uridyl transferase deficiency (classic galactosemia) 

Type 2—Deficiency of galactose kinase 

Type 3—Deficiency of galactose-6-phosphate epimerase

The classic form of galactosemia (type 1) is the most common and the most severe. Babies with classic galactosemia are unable to metabolize even small amounts of galactose; whereas babies with type 2 or 3, also called the Duarte form of galactosemia, are usually able to metabolize some galactose. As a result, babies with type 2 or 3 may have fewer, albeit some, dietary restrictions depending upon how much galactose they are able to metabolize. Because it is difficult to know how much galactose a child can eat without adverse effects, parents of children with types 2 and 3 galactosemia often choose to avoid galactose altogether. However, others choose to partially breastfeed and monitor galactose levels. 

State laws require that all U.S. babies be tested for galactosemia soon after birth. A small sample of blood is taken from the baby’s heel and sent to a state lab for testing. In order for the test to be accurate, babies must be drinking breast milk or formula for at least 24 hours. If one parent has galactosemia, both parents can have genetic testing done to determine the risk of having a child with the disorder. 

Managing galactosemia: diet 

Galactosemia is a lifelong condition that children will not outgrow. However, galactosemia can be easily managed by following a galactose-free diet. Galactose is derived from the complex sugar, lactose, so any food containing lactose (milk and milk products) should be avoided as well. The majority of fruits, vegetables, grains, breads, fats, and sugars are safe to eat as long as they contain little or no galactose. 

Product labels on packaged foods list the ingredients found in each product. Check labels carefully each time you shop, since ingredients can change without notice.

Ingredients you want to avoid include: 

  • Butter 
  • Milk 
  • Casein, Caseinates (proteins derived from dry milk and commonly used as food additives) 
  • Dry Milk Solids 
  • Lactose 
  • Curds 
  • Whey, Whey Solids

Foods to avoid:

  • Milk and Milk Products (Cheeses, Cottage Cheese, Cream, Cream Soups and Sauces, Ice Cream, Milk Chocolate, Pudding, Sherbet, Sour Cream, Yogurt)
  • Organ Meats (Liver, Heart, etc.)
  • Garbanzo Beans 

Common ingredients that do not contain lactose and are ok for children with galactosemia include: 

  • Acacia 
  • Agar 
  • Calcium Compounds 
  • Carob 
  • Gums & Fibers 
  • Lactate 
  • Lactic Acid 
  • Lactalbumin 
  • Tragacanth 
  • Xanthum Gum

Individuals with types 2 or 3 galactosemia may be able to eat small amounts of galactose. These foods contain 5–10mg of galactose in each 100 gm serving: 

  • Apple, Apricot, Asparagus, Avocado 
  • Banana, Bean Sprouts, Beets, Broccoli, Brussels Sprouts 
  • Cabbage, Cantaloupe, Carrot, Cauliflower, Celery, Sweet Corn, Cucumber 
  • Eggplant 
  • Green Grapes, Grapefruit 
  • Kale, Kiwi 
  • Lettuce 
  • Onion (green and yellow), Onion, Oranges 
  • Pears, Peas, Potato (white), Pumpkin 
  • Radish 
  • Spinach, Sweet Potato 
  • Turnip 
  • Zucchini 

For more information on the amount of lactose in foods visit the Galactosemia Foundation website.

Managing galactosemia: lifestyle 

Researchers have begun to examine the long-term consequences of galactosemia. Research suggests that despite early diagnosis, there may still be developmental delays. IQ values may be normal, but children with galactosemia have been found to exhibit a range of learning problems including speech and language deficits and problems with visual perception and social adjustment. This is not true of all children with galactosemia, but the fact that it occurs in some children highlights the importance of early diagnosis and strict dietary control. 

What can parents do? 

  • Treat a child with galactosemia as you would any other child. 
  • Watch for signs of learning needs, remembering that not all children with galactosemia have developmental delays. 
  • Provide galactose-free foods for special occasions such as birthdays or holidays. 
  • Keep a supply of galactose-free treats on hand for unexpected occasions. 
  • Maintain a strict diet. Even small bites of foods containing galactose add up, and can cause elevations in blood galactose. 
  • Don’t hide the fact that your child has galactosemia. But don’t give your child too much information too soon. 
  • Explain to your child that cars, like bodies, require different types of fuel to run well. 
  • Explain to your child that some children are allergic to certain foods and must avoid those foods their entire life. Help your child compile a list of favorite galactose-free foods. 
  • Explain to your child that everyone has similarities and differences. Making a list of each will help your child take pride in himself and be respectful of others.

Last updated December 28, 2021

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