Lactose intolerance or dairy allergy?
When symptoms like bloating, gas, diarrhea, abdominal cramping, nausea, vomiting, or breathing issues occur after consuming dairy products, you may suspect that you have a problem consuming dairy.
Two reasons that symptoms arise from dairy consumption are lactose intolerance and a dairy allergy.
Lactose intolerance occurs when the body’s digestive system has a problem digesting certain carbohydrates, whereas, a dairy allergy occurs when the body’s immune system reacts to the proteins in dairy (1).
Lactose intolerance
Lactose intolerance is very common, with about 65% of individuals experiencing this syndrome worldwide (2).
Common symptoms include gas, bloating, diarrhea, and abdominal cramping which can occur within a few hours or take a couple of days to occur after you have consumed dairy containing lactose (4).
Lactose intolerance develops as the body produces less lactase, the enzyme that breaks down the larger lactose molecule into its smaller simple sugars, glucose and galactose (5).
Causes of lactose intolerance
Four causes of lactose intolerance include a congenital cause when lactase is deficient at birth; a developmental cause when the small intestine is underdeveloped with premature birth; a secondary cause when injury or disease damages the small intestine; and a primary cause when lactase production is reduced in the small intestine (4) (5).
The small intestine produces the brush border enzyme lactase to digest lactose, and when intestinal lactase is low, bacteria in the large intestine break down lactose, but this fermentation produces gas which raises the osmotic pressure that can lead to symptoms like diarrhea (6) (7).
Intestinal lactase tends to be higher at birth and decreases as we age (6).
Solutions to lactose intolerance
Typical recommendations for those who are lactose intolerant include dietary changes to avoid or reduce the amount of lactose-containing dairy products in the diet (8).
Some research shows that in susceptible individuals, consuming some lactose-containing dairy products may improve intolerance symptoms due to an adaptation that occurs when lactose feeds the bacteria that break this carbohydrate down (6).
Further, another strategy for some who wish to consume lactose-containing dairy products when lactase is low would be to take the lactase enzyme in pill form when consuming dairy products to aid in the digestion of lactose (8) (9).
Dairy allergy
Dairy allergy is a common diagnosis among infants and children, with about 3% of infants diagnosed in the developed world (3).
With various immune-mediated reactions, the IgE-mediated dairy allergy tends to be most common, with about 60% of individuals struggling with this form (10).
This type I hypersensitivity reaction typically produces symptoms like hives, breathing difficulty, coughing, wheezing, and GI symptoms like abdominal pain, diarrhea, and vomiting, which occurs within minutes or can take up to 2 hours after dairy consumption (10).
Causes of dairy allergy
Studies show that various factors play a role in the development of a dairy allergy, genetics, epigenetics, and environmental factors can all play a role (10).
Male children with various other conditions like food allergies, asthma, and atopic dermatitis are twice as likely to have a dairy allergy, and ethnicity also plays a role (10).
Solutions to dairy allergy
A dairy allergy tends to develop in early life and regress and resolve by about age six for most (11).
When the child experiences symptoms from dairy consumption, currently, the solution is to avoid consuming cow’s milk dairy products (3) (11). To avoid nutritional deficiencies, like a calcium deficiency, it would be advisable to consult a pediatric nutritionist if the child’s milk intake falls below 500 ml, according to research (3) (11).