Lactose, the sugar found in milk and other dairy products, requires a specific enzyme -- lactase -- for it's digestion. Most infants are born with the ability to make this enzyme but sometimes lose that ability as they age. Lactose intolerance is most common in people of Asian, African, Native American or Mediterranean descent. Although not dangerous, approximately 30 million American adults may have some amount of lactose intolerance by age 20, reports MedLine Plus.
Abdominal Bloating and Cramps
Stomach cramps and bloating may be a symptom of lactose intolerance. People who suffer from other digestive problems, such as celiac or Crohn's disease and irritable bowel syndrome, may be more likely to have lactose intolerance because an inflammation of the upper small intestine reduces levels of the lactase enzyme.
Diarrhea and Flatulence
Gas and diarrhea, as well as noises or rumbling in the stomach, are common signs of lactose intolerance. According to Jackson Seigelbaum Gastroenterology, these symptoms occur when undigested lactose reaches the large intestine to be broken apart by bacteria, resulting in lactic acid and other acidic chemicals.
Slow Infant Growth
Although most infants are born with the ability to digest lactose, those born prematurely may not produce the lactase enzyme. Lactase is needed to digest all milk, even breast milk. Infants who cannot digest milk are at risk for slow growth and weight loss and should be monitored by their pediatrician.
