When the digestive enzyme, lactase, is absent, lactose in the diet cannot be absorbed, and it passes through the small intestine into the colon, carrying extra fluid with it. When it reaches the colon, bacteria in the colon break down the lactose into lactic acid and certain gasses. Undigested lactose and lactic acid have laxative effects. This, plus the extra gas generated by the bacterial action on the lactose, can cause cramps, bloating, loose stools, and excessive flatus.

The amount of lactase in the lining of the small intestine tends to diminish slowly with age. Some individuals may begin to notice symptoms of lactase deficiency at age 30, while others may not notice symptoms until much later in life. In others, lactase deficiency may be acquired suddenly through an insult such as a viral infection, or alcohol injury to the bowel.

It is important to remember that the symptoms caused by lactase deficiency can be troublesome, but they do not cause any lasting harm. On the other hand, eliminating all milk products may result in dietary deficiencies, which can cause lasting harm. Milk products are good sources of calcium, vitamin D and B vitamins.

Recommendations:
1. Since tolerance levels vary, those who enjoy milk products should experiment to find the quantity of milk products they can enjoy without excessive symptoms.

2. Lactaid digestive aid products such as Dairy Easeä and Lactaidä can be used when eating cheese or other milk based products. These products can be purchased over the counter at most pharmacies. Lactose reduced milk is available in most supermarkets.

3. Three portions of milk, cheese, or yogurt is usually necessary to get the minimum daily requirement of 1200 mg of calcium each day. Sardines, tofu, calcium fortified orange juice, collard greens, kale, and broccoli also contain calcium, but it would require four or five portions of these foods each day to provide enough. Therefore, a calcium supplement should be considered for those who do restrict their intake of milk products.