These individuals cannot digest dairy milk or milk products because their sysems lack the digestive enzyme lactase, needed to break down milk sugar into usable energy and nutrients. The usual symptoms of this condition are bloating and swelling of the intestines, diarrhea, and, in severe cases, nausea. Although some infants are afflicted with lactose intolerance, the condition is more common among adults and seems to increase with age. As we grow older, we tend to drink less milk and thus our bodies produce less lactase, which in turn leads to lactose intolerance. People of African, Asian, and Middle Eastern origins are most likely to suffer from this condition.
Many people have allergic reactions to certain foods, one of the most common of which is dairy milk.
Soy milk products, on the other hand, have a very low rate of associated allergic reactions. Allergies occur when the body perceives a food molecule as a foreign, and possibly harmful, substance and develops antibodies to fight it. Once the antibodies form, the body will always reject that type of food. Symptoms of milk allergy are similar to those of lactose intolerance, although milk allergy may also give rise to rashes and other forms of skin irritation. Infants, in particular, are highly susceptible to milk allergies.