The enzyme lactase is necessary to digest lactose, the natural sugar present in many dairy products. When you are lactose intolerant, you have low levels of lactase and also experience uncomfortable and often embarrassing symptoms when you consume foods containing lactose. However, the symptoms usually don't last too long.
Onset
If you don't produce enough lactase enzyme in your small intestine to digest lactose, most of the lactose in the food you consume moves unprocessed into your colon, where it interacts with the normal intestinal bacteria, causing symptoms that can include bloating, stomach ache, foul-smelling gas and diarrhea. It typically takes 30 minutes to 2 hours from when you first started eating to begin experiencing symptoms.
Duration
Usually, once you've evacuated your bowel, your symptoms cease. The undigested lactose exits your system and your body returns to normal. However, you may be more intolerant of some types of dairy than others, causing additional bouts of diarrhea and gas. In addition, if you've consumed a large amount of dairy, it may take longer to resolve. While the duration is not typically longer than a few hours, your dairy tolerance and consumption play a part in how long you suffer with symptoms.
Treatment
Lactase enzyme supplements, available in pill or drop form, may mitigate any symptoms. In addition, you can try lactose-free and lactose-reduced dairy products and determine if either are good alternatives for you. Some forms of dairy, such as yogurt, contain probiotics that may prevent the occurrence of symptoms. Your threshold for intolerance dictates how much or little dairy you can consume.
Considerations
If you are lactose intolerant and have symptoms for more than a day, contact your health care provider. If you forgo dairy, find other sources of calcium and vitamin D as both are critical for bone health. If you begin to lose weight or other symptoms develop, contact your health care provider to better assess your condition.
