Lactose Intolerance in Babies and Children by

Lactose intolerance is the body’s inability to digest lactose, a sugar found in milk and other dairy products. When a person is lactose intolerant, their body is unable to produce enough of the enzyme lactase in the digestive tract. Because of this, lactose cannot be absorbed and the metabolism of this sugar produces uncomfortable gas and bloating, among other symptoms.

Lactose Intolerance in Babies and Children

Lactose intolerance affects different ethnic populations at different rates, with African-Americans, Native Americans and Asian Americans experiencing the condition at much higher rates than Americans of northern European descent.

Age makes a difference, too. Lactose intolerance is typically not seen in babies, but instead appears after the age of weaning. It is much more likely for an infant to be allergic to cow’s milk protein than to be deficient in the lactase enzyme. Properly defining lactase deficiency can help when trying to achieve an accurate diagnosis.

Types of Lactase Deficiency

  • Congenital Lactase Deficiency: This extremely rare condition is a life-threatening medical emergency that is usually detected soon after birth. These babies cannot digest lactose, and may exhibit severe diarrhea, bloating, lack of weight gain or weight loss, and dehydration. These babies cannot breastfeed or drink cow’s milk based formula, but need a formula free of lactose.
  • Developmental Lactase Deficiency: This is a temporary low level of lactase in some preterm babies that they outgrow as their systems mature.
  • Primary Lactase Deficiency: This genetic condition is attributed to the absence or low levels of the lactase enzyme which develops over time. Lactase production generally decreases between ages 3 and 5, but sometimes not until adolescence or adulthood. This is the most common type of lactose intolerance, affecting nearly 70 percent of the world’s population.
  • Secondary or Transient Lactase Deficiency: This condition is caused by an injury to the gut in infancy from gastroenteritis, diarrhea, chemotherapy, intestinal parasites, celiac disease, medications, foods, or other environmental causes. It occurs due to a slowing of lactase production, and generally resolves without treatment.

For babies and small children, then, lactose intolerance is typically a temporary condition, and not a sign that their intolerance will last a lifetime. The most common symptoms of lactose intolerance include abdominal bloating, gas pain, flatulence, loose stools or diarrhea, and vomiting. These can occur anywhere from 30 minutes to two hours after lactose-containing foods are consumed. In babies, the symptoms may mistakenly be described as “colicky”, prolonged crying periods during or after a feeding, excessive gas, spit-up, watery or foul-smelling stools, difficulty with feedings, or persistent unexplained fussiness.

The medical tests typically used for diagnosing lactose intolerance in adults are not accurate in young babies, so the diagnosis is typically made based on the symptoms above. In the case of nursing babies, many pediatricians recommend a mom avoid consuming dairy products for a week or longer, to see if that improves her infant’s symptoms. Breastfeeding is still best – especially if baby is experiencing diarrhea as a symptom. If the baby drinks cow’s milk or milk-based formula, he or she can be switched to soy formula, hydrolyzed protein formula, or amino acid-based formulas. For older children, rice milk, soy milk, oat milk, coconut milk, and almond milk are sometimes used as substitutes for cow’s milk. Eliminating cow’s milk based products will give baby’s gut a chance to heal.

If a breastfed newborn experiences colicky symptoms, mom must initially try to determine whether her infant is lactose-intolerant, or whether the baby is simply having trouble with breastfeeding. Working with a healthcare professional knowledgeable about breastfeeding is important. A lactation consultant can work with mom and baby to be sure breastfeeding is going well, and can help narrow down the causes for baby’s colicky symptoms.

Sometimes lactose intolerance is mistakenly diagnosed when a breastfed baby is actually suffering from lactose overload. Lactose overload happens when a breastfed baby gets too much milk, too fast. These babies are typically gaining weight well, but are unhappy, especially when feeding or shortly thereafter. Symptoms are much the same as for lactose intolerance, including large, explosive, frothy, green bowel movements. This typically happens in babies younger than 3 months old, though older babies can suffer, as well. Lactose overload can be treated with proper breastfeeding management to regulate mom’s milk supply.

Another consideration is whether the baby’s or child’s symptoms indicate lactose intolerance or allergy to cow’s milk protein instead. Lactose intolerance is a digestive condition, while an allergy is an immune response. Many of the symptoms are the same, but an allergy is typically accompanied by a dry, itchy rash; itching and swelling of the face, lips, or mouth; or, hives, watery eyes, or a runny nose after consumption of dairy products.

Sorting out whether a fussy baby is lactose intolerant or is suffering from another condition can be challenging for parents.

* Neither Colic Calm or Tummy Calm are intended to treat TLD or lactose intolerance.


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