Definition

Lactose intolerance is a medical condition characterised by the inability of an individual to break down lactose, the sugar found in milk. Individuals with lactose intolerance may encounter symptoms such as diarrhea, excessive gas, and abdominal distension following the consumption of milk. This condition is also referred to as lactose malabsorption, which is typically a benign condition but can cause unpleasant symptoms.

Lactose intolerance occurs when the body produces insufficient quantities of the enzyme required to metabolize lactose. Despite inducing unpleasant symptoms, individuals with lactose intolerance can effectively manage these symptoms without completely excluding dairy items from their dietary intake.

Causes

Lactose intolerance develops when the small intestine is unable to produce the lactase enzyme, which is responsible for breaking down lactose (the sugar in milk). Lactase normally breaks down lactose into two simpler sugars, glucose and galactose, which the body absorbs through the small intestine walls. If your body does not have enough lactase, the lactose in your food will not be absorbed and will remain in your stomach until it reaches the large intestine or colon. Bacteria will interact with unprocessed lactose in the large intestine, resulting in lactose intolerance symptoms.

Lactose intolerance can be classified into three types:

• Primary lactose intolerance

Primary lactose intolerance is the most common type. During the early stages of life, individuals with primary lactose intolerance can produce adequate quantities of lactase enzyme to break down breast milk. As grow older and transition from consuming breast milk to other types of food, the production of the lactase enzyme diminishes. Upon reaching adulthood, the concentration of the lactase enzyme diminishes to a level insufficient for the digestion of lactose. Consequently, individuals begin to experience symptoms of lactose intolerance upon consuming dairy products.

• Secondary lactose intolerance

Secondary lactose intolerance occurs when the small intestine is unable to produce normal amounts of the enzyme lactase due to certain diseases, surgeries, or trauma involving the small intestine. Some diseases often associated with secondary lactose intolerance are gastrointestinal infections, Celiac disease, bacterial overgrowth, and Crohn's disease. Treating this type of lactose intolerance can restore the function of the gut to produce enzymes and improve symptoms, although in some cases, it may take a long time.

• Congenital lactose intolerance.

Although it is rare, some babies are born with lactose intolerance due to low levels of lactase. This condition can be inherited from both parents in an autosomal recessive manner, which means that both parents have the recessive gene and pass it on to their children. Premature babies may also have congenital lactose intolerance because they cannot produce lactase like full-term babies.

Risk factor

The risk factors associated with lactose intolerance are as follows:

• Aging

Lactose intolerance typically manifests in the adult population. This syndrome is infrequently observed in infants and young individuals.

• Racial or cultural background

Lactose intolerance is more prevalent in individuals of African, Asian, Hispanic, and Indian ancestry.

• Preterm infants

Babies born prematurely have lower lactase levels than full-term babies because the small intestine cells that produce lactase in premature babies are not fully developed until the third trimester.

• Medical condition affecting the small intestine

Medical conditions affecting the small intestine can cause lactose intolerance. The conditions cannot prevent the unregulated proliferation of bacteria (bacterial overgrowth), celiac disease, or Crohn's disease.

• Oncological therapy

Individuals undergoing radiation or chemotherapy for stomach cancer may develop lactose intolerance.

Symptoms

The onset of symptoms occurs within 30 minutes to 2 hours after consuming dairy products. 

Common signs and symptoms include the following:

• Diarrhea
• Nausea and vomiting
• Abdominal spasms
• Abdominal distension and swelling
• Excessive flatulence

Additional symptoms are migraines, muscular discomfort, joint discomfort, oral sores, and impaired focus.

Diagnosis

Lactose intolerance is typically diagnosed based on the symptoms you experience after consuming dairy products and the improvement in symptoms after limiting your dairy consumption. Your doctor will ask you about any prior medical disorders and your family's

medical history to eliminate the possibility of other underlying factors. To confirm the diagnosis, several further tests may be conducted, such as:

• Hydrogen breath test

This examination aims to assess the hydrogen levels in the breath following the ingestion of dairy products. If there is lactose malabsorption, this examination will give positive results.

• Stool acidity test

This examination measures the pH of the feces. Lactose will be fermented by bacteria, producing lactic acid and lowering the pH of the feces. The feces' pH will decrease due to bacteria fermenting the unbroken lactose and producing lactic acid.

• Lactose tolerance test

This test is designed to determine the level of lactose absorption in the body after consuming dairy products. Blood glucose levels are checked every two hours through blood tests after consuming dairy products. If the blood sugar does not increase, it indicates lactose intolerance.

• Biopsy

This examination is rarely done because it is very invasive. This examination is conducted if the doctor suspects a secondary etiology of lactose intolerance.

Management

You can predict your body's reaction to lactose and determine the optimal amount of dairy to consume without experiencing intolerance symptoms. Some individuals with severe lactose intolerance may need to avoid dairy and other lactose-containing foods.

Limiting Dairy Consumption

Certain people with lactose intolerance can tolerate dairy products without experiencing any disruptive effects. Experts advise consuming dairy products in quantities that do not cause symptoms. Skim milk, which is low in fat, is more easily digested than whole milk. Strategies to modify your dietary habits to reduce the symptoms of lactose intolerance are:

• Consume less milk and low-lactose foods.
• Drink milk after consuming other foods.
• Consume alternative dairy products, including hard cheese, ice cream, and others.
• Administering lactase enzyme pills. Consult your doctor regarding this alternative.

Maintain a Healthy Diet

Eliminating or reducing dairy consumption elevates the risk of calcium deficiency. Nevertheless, calcium is also present in the following food sources:

• Organic broccoli and leafy greens
• Cereals and beverages that have been calcium-fortified
• Sardines and salmon
• Milk alternatives, including soy milk
• Oranges
• Almond nut

Consume an adequate intake of vitamin D. Food sources rich in vitamin D include eggs, liver, and yogurt. Sun exposure is the primary source of vitamin D. Seek advice from your doctor about vitamin D supplements.

Complications

Milk and its derived products are rich sources of calcium, protein, and vitamins A, B12, and D. Lactose helps the absorption of additional nutrients, such as magnesium and zinc. These vitamins and minerals are essential for growth and bone strength. Individuals with lactose intolerance may have difficulty fulfilling their essential vitamin and mineral requirements. If this insufficiency persists, it can lead to detrimental weight loss and the following conditions:

• Osteopenia, which refers to a condition characterised by reduced bone density
• Osteoporosis is characterized by the thinning and weakening of bones, significantly increasing the likelihood of fractures.
• Malnutrition

Prevention

You can prevent symptoms of lactose intolerance by carefully reading the labels of the foods you consume daily. It is important to check the labels of the food items: cereal, meat, bread, salad vinaigrette, cake mix, and creamer. Butter, cheese, cream, powdered milk, dried milk, or whey are likely present in the product, suggesting a significant likelihood that it contains lactose.

Consult your doctor or nutritionist regarding your micronutrient needs to prevent complications.

When to see a doctor?

Consult your physician if you frequently encounter indications of lactose intolerance or have concerns regarding your blood calcium levels.

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