Lactose intolerance is a condition in which you have digestive symptoms—such as bloating, diarrhea, and gas—after you consume foods or drinks that contain lactose. Lactose is a sugar that is naturally found in milk and milk products, like cheese or ice cream. manage lactose intolerance

In lactose intolerance,

digestive symptoms are caused by lactose malabsorption. Lactose malabsorption is a condition in which your small intestine cannot digest, or break down, all the lactose you eat or drink.

Not everyone with lactose malabsorption has digestive symptoms after they consume lactose. Only people who have symptoms are lactose intolerant.

Most people with lactose intolerance can consume some amount of lactose without having symptoms. Different people can tolerate different amounts of lactose before having symptoms. Lactose intolerance is different from a milk allergy. A milk allergy is an immune system disorder.

How common is lactose malabsorption?

While most infants can digest lactose, many people begin to develop lactose malabsorption—a reduced ability to digest lactose—after infancy. Experts estimate that about 68 percent of the world’s population has lactose malabsorption. Lactose malabsorption is more common in some parts of the world than in others.

In Africa and Asia,

most people have lactose malabsorption. In some regions, such as northern Europe, many people carry a gene that allows them to digest lactose after infancy, and lactose malabsorption is less common. In the United States, about 36 percent of people have lactose malabsorption.

While lactose malabsorption causes lactose intolerance, not all people with lactose malabsorption have lactose intolerance.

Who is more likely to have lactose intolerance?

You are more likely to have lactose intolerance if you are from, or your family is from, a part of the world where lactose malabsorption is more common. In the United States, the following ethnic and racial groups are more likely to have lactose malabsorption:

• African Americans.
• American Indians.
• Asian Americans.
• Hispanics – Latinos.

 

Because these ethnic and racial groups are more likely to have lactose malabsorption, they are also more likely to have the symptoms of lactose intolerance. Lactose intolerance is least common among people who are from, or whose families are from, Europe.

Signs And Symptoms:

Causes of Lactose Intolerance:

Lactose intolerance is caused by lactose malabsorption. If you have lactose malabsorption, your small intestine makes low levels of lactase—the enzyme that breaks down lactose—and can’t digest all the lactose you eat or drink.

The undigested lactose passes into your colon. Bacteria in your colon break down the lactose and create fluid and gas. In some people, this extra fluid and gas cause lactose intolerance symptoms.

In some cases,

Your genes are the reason for lactose intolerance. Genes play a role in the following conditions, and these conditions can lead to low levels of lactase in your small intestine and lactose malabsorption:

• Lactase non-persistence:
  • In people with lactase non-persistence, the small intestine makes less lactase after infancy.
  • Lactase levels get lower with age. Symptoms of lactose intolerance may not begin until later childhood, the teen years, or early adulthood.
  • Lactase non-persistence, also called primary lactase deficiency, is the most common cause of low lactase levels.
• Congenital lactase deficiency:
  • In this rare condition, the small intestine makes little or no lactase, starting at birth.

 

Not all causes of lactose intolerance are genetic. The following can also lead to lactose intolerance:

• Injury to the small intestine.
  • Infections, diseases, or other conditions that injure your small intestines, like Crohn’s disease or celiac disease, may cause it to make less lactase.
  • Treatments—such as medicines, surgery, or radiation therapy – for other conditions may also injure your small intestine.
  • Lactose intolerance caused by injury to the small intestine is called secondary lactose intolerance.
  • If the cause of the injury is treated, you may be able to tolerate lactose again.
• Premature birth:
  •  In premature babies, or babies born too soon, the small intestine may not make enough lactase for a short time after birth.
  • The small intestine usually makes more lactase as the baby gets older.

Types of lactase deficiency:

I. Primary lactase deficiency:

Primary lactase deficiency is the most common cause of lactose intolerance worldwide. This type of lactase deficiency is caused by an inherited genetic fault that runs in families.

Primary lactase deficiency develops when your lactase production decreases as your diet becomes less reliant on milk and dairy products. This is usually after the age of 2 when breastfeeding or bottle-feeding has stopped, although the symptoms may not be noticeable until adulthood.

II. Secondary lactase deficiency:

Secondary lactase deficiency is a shortage of lactase caused by a problem in your small intestine. It can occur at any age, and maybe the result of another condition, surgery to your small intestine, or taking certain medication.

Secondary lactase deficiency is the most common cause of lactose intolerance in the UK, particularly in babies and young children.

Possible causes of secondary lactase deficiency include:

• Gastroenteritis – an infection of the stomach and intestines.
• Coeliac disease – a bowel condition caused by an adverse reaction to a protein called gluten.
• Crohn’s disease – a long-term condition that causes inflammation of the lining of the digestive system.
• Ulcerative colitis – a long-term condition that affects the large intestine.
• Chemotherapy – a cancer treatment.
• Long courses of antibiotics.

 

The decrease in the production of lactase in secondary lactase deficiency is sometimes only temporary, but it may be permanent if it’s caused by a long-term condition. It’s also possible to develop secondary lactase deficiency later in life, even without another condition to trigger it. This is because your body’s production of lactase naturally reduces as you get older.

Complications:

Lactose intolerance may affect your health if it keeps you from getting enough nutrients, such as calcium and vitamin D. Milk and milk products, which contain lactose, are some of the main sources of calcium, vitamin D, and other nutrients.

You need calcium throughout your life to grow and have healthy bones. If you don’t get enough calcium, your bones may become weak and more likely to break. This condition is called osteoporosis. If you have lactose intolerance, you can change your diet to make sure you get enough calcium while also managing your symptoms.

What is the difference between lactose intolerance and milk allergies?