Could milk allergies or lactose intolerance become a growing trend for consumers like "gluten free"?
By: Howard Bonnemann, SDSU Extension, Lecturer & Dairy Plant Manager
Many individuals are able to consume milk and other dairy products, obtaining all of the associated nutritional benefits without experiencing any type of adverse reaction or digestive challenge. However, some individuals are not able to consume dairy products for a myriad of reasons. These reasons are often lumped together and people refer to being allergic to milk or being lactose intolerant without a clear understanding that milk allergy and lactose intolerance are two very distinct and separate digestive issues.
If an individual is lactose intolerant what is actually occurring is that their digestive system is no longer able to produce sufficient quantities of β – d – galactosidase (lactase) enzyme. This enzyme is responsible for catalyzing the breakage of the β 1→4 bond between the two mono-saccharides, galactose and glucose, that make up the disaccharide lactose. When this bond is broken the two simple sugars are able to be readily digested, absorbed across the intestinal wall and utilized by the metabolic system to obtain energy for continued function. If the bond is not broken, the much larger disaccharide molecule (lactose) is not absorbed across the intestinal wall. This intact lactose molecule then continues to remain within the intestines binding additional water and serving as a fermentable substrate for the microflora within the intestines. This often results in diarrhea, excess production of gas, bloating and cramps. All of these symptoms are undesirable but none are truly life-threatening. It is not unusual for an individual who once was able to consume dairy products to lose the ability to produce sufficient quantities of enzyme and become lactose intolerant. Often the ability, or inability, to produce sufficient quantities of enzyme is a hereditary trait.
In contrast, a milk allergy is the result of a set of reactions to one of the protein fractions found in milk, not the milk carbohydrate. According to Food Allergy Research and Education1, a food allergy is the overreaction of the immune system to a specific food protein. True allergic reactions may induce mild symptoms such as hives or itching, or much more severe symptoms including difficulty breathing, anaphylaxis (presentation of multiple symptoms at once), loss of consciousness, or possibly death. Individuals with a milk allergy are generally very young with an immune system that has not yet been able to achieve some level of balance with all of the types of antibodies present. Milk allergy often occurs in infants who are then provided formula with a different source of protein to alleviate the reaction symptoms. Quite often an individual will "outgrow" a milk allergy.
The dairy industry has developed approaches to alleviate both of these challenges. Addressing lactose intolerance, the industry bottles milk which has already been enzymatically treated to breakdown the lactose into galactose and glucose prior to bottling. Lactase tablets, containing the necessary enzyme, are also available at many grocery outlets and drug stores. Individuals who experience mild symptoms when consuming milk may be able to consume fermented dairy foods such as yogurt or cheese with few challenges. The microorganisms utilized in culturing these products breakdown and digest large portions of the lactose during their growth and subsequent production of lactic acid.
To address milk allergies many infant formulas have been developed utilizing an enzymatic hydrolysis of the milk proteins to "snip" the long protein molecules into much shorter protein building blocks that still provide the nutritional requirements without the challenge to the system of having to have already developed the enzymes to be able to digest the protein fractions without inducing an allergic reaction. These enzymatic processes do result in an increase in initial cost of the products but allow consumption of dairy-based foods by individuals initially challenged because their own system is unable to generate sufficient quantities of these enzymes.