Symptoms:

The signs and symptoms of lactose intolerance usually begin 30 minutes to two hours after eating or drinking foods that contain lactose. Common signs and symptoms include:

• Diarrhea, which is the most common symptom
• Nausea
• Abdominal cramps
• Bloating
• Gas

Risk factors:

A few risk factors can make you or your child more prone to lactose intolerance:

• Age. Lactose intolerance usually starts after age 5 — the condition is uncommon in babies and young children. A child with chronic diarrhea before age 1 usually has another underlying problem.
• Ethnicity. Lactose intolerance is more common in certain ethnic and racial populations. Lactose intolerance is more common in black, Asian, Hispanic and American Indian populations.
• Premature birth. Infants born prematurely (28 to 32 weeks of gestation) may have reduced levels of lactase, because this enzyme increases in the fetus late in the third trimester.

Tests and diagnosis:

• Lactose tolerance test
• Hydrogen breath test
• Stool acidity test.

Causes of lactose intolerance:

Primary lactase deficiency is a condition that develops over time. After about age 2 the body begins to produce less lactase, though most people will not notice symptoms until they are much older.

Secondary lactase deficiency occurs when injury to the small intestine or certain digestive diseases reduce the amount of lactase a person produces. These diseases include celiac disease, inflammatory bowel disease, and Crohn’s disease.
How is lactose intolerance treated?

Lactose intolerance is easy to treat. No treatment can improve the body’s ability to produce lactase, but symptoms can be controlled through diet.

Drink less milk and more often.

Drink milk with other foods, rather than drinking milk alone. This slows the digestive process, so you reduce your chance of experiencing lactose intolerance.

Use lactose-reduced or lactose-free product.

Watch out for hidden lactose.

Although milk and foods made from milk are the only natural sources of lactose, it is often added to prepared foods. People with very low tolerance for lactose should know about the many food products that may contain even small amounts of lactose, such as

• Bread and other baked goods
• Processed breakfast cereals
• Instant potatoes, soups, and breakfast drinks
• Margarine
• Lunch meats (other than kosher)
• Salad dressings
• Candies and other snacks
• Mixes for pancakes, biscuits, and cookies
• Powdered meal-replacement supplements

Some products labeled non-dairy, such as powdered coffee creamer and whipped toppings, may actually include ingredients that are derived from milk and therefore contain lactose.

Eat other sources of calcium like greens, broccoli, canned salmon, almonds, oranges.

Supplements:

Supplements also may help you manage lactose intolerance:

• Use lactase enzyme tablets. These tablets contain the enzyme that breaks down lactose, reducing the amount your body must digest on its own. You can take tablets just before a meal or snack. Improvement of symptoms may vary from one person to another, but tablets do help many people.
• Take a calcium supplement. Calcium supplements are helpful for many people, but especially if you have lactose intolerance and are unable to eat dairy products.
• Try probiotics. Probiotics are living organisms present in your intestines that help maintain a healthy digestive system. Probiotics are also available as active or "live" cultures in some yogurts and as supplements in capsule form. These are sometimes used for gastrointestinal conditions such as diarrhea and irritable bowel syndrome. They may also help your body digest lactose. Probiotics are generally considered safe if used properly and may be worth a try if other methods don't help.