Lactose intolerance and cows' milk allergy: Infants may be on unnecessary lactose-free diets
Many children may be put on lactose-free diets unnecessarily, due to common misconceptions in the community about cows' milk allergies and lactose intolerance. Over the past 10 years, there has been a sharp decline in the consumption of fresh cows' milk and an increased consumption of lactose-free milk among children due to unfounded concerns about allergies. Avoidance of dairy products can lead to nutritional rickets in young children, as well as low bone mineral density and increased risk of fracture later in life. Low calcium intake closely correlates with the intake of other micronutrients.
Primary lactose intolerance does not actually manifest clinically before five years of age; if symptoms such as abdominal pain, flatulence and diarrhea occur, it is usually caused by underlying gut conditions such as viral gastroenteritis, giardiasis, cows' milk enteropathy, celiac disease or Crohn’s disease, and therefore likely to be transient, with symptoms easing with the resolution of the underlying pathology. There is ongoing confusion between lactose intolerance and cows' milk allergy which leads to misdiagnosis and inappropriate dietary management – these confusions are seen not only among the general public, but among health care providers too.
The treatment of lactose intolerance involves the reduction but not complete elimination, of lactose-containing foods. By contrast, breastfed infants with suspected cows' milk allergy should undergo a strict diet with no cows' milk protein at all. There are a complex set of classifiers of lactose intolerance, including developmental lactase deficiency, congenital lactase deficiency, lactase non-persistence and secondary lactose intolerance. Clinical presentation of lactose intolerance differs significantly between infants and older children, with symptoms occurring within 30-60 minutes of ingesting lactose-containing foods. Therefore, diagnosis relies on the observation of gastrointestinal symptoms soon after ingesting lactose-containing foods, including breastmilk, cows' milk or another mammalian milk. There are complex laboratory tests to aid diagnosis which should be undertaken before nutrition adjustments are made.
Confusion between cows' milk allergy and lactose intolerance may lead to a delayed diagnosis of cows' milk allergy, as well an inappropriate dietary intervention. Contrary to common belief, most infants with cows' milk allergy can tolerate dietary lactose. Lactose-containing extensively hydrolyzed formulas offer potential benefits in the treatment of formula-fed infants with cows' milk allergies due to the prebiotic effects on the fecal microbiome and metabolome.
Further evidence-based educational health campaigns are needed to address the knowledge gaps and misconceptions, both in the medical profession and the community at large.
Heine RG, AlRefaee F, Bachina P, De Leon JC, Geng L, Gong S, Madrazo JA, Ngamphaiboon J, Ong C, Rogacion JM.
World Allergy Organ J. 2017 Dec 12;10(1):41. doi: 10.1186/s40413-017-0173-0. eCollection 2017. Review
