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Diff: Lactose intolerance

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'''Lactose intolerance''' is a digestive disorder characterized by the body's inability to fully digest lactose, a sugar found in milk and dairy products. Individuals with lactose intolerance experience symptoms such as bloating, diarrhoea, and abdominal pain after consuming lactose-containing foods. This condition is prevalent worldwide, with varying degrees of severity among affected individuals.
==Overview==
Definition:

Malabsorption of Lactose: Lactose intolerance results from a deficiency of lactase, the enzyme responsible for breaking down lactose into simpler sugars that can be absorbed by the small intestine.

Prevalence:

Global Impact: Lactose intolerance is common, affecting a significant portion of the global population. Rates of lactose intolerance vary by ethnicity and geographical region.

Degrees of Severity:

Lactase Non-persistence: Many individuals with lactose intolerance have a genetic predisposition known as lactase non-persistence, where the production of lactase decreases after childhood.
==Causes and Risk Factors==
Genetic Factors:
	'''Lactose intolerance''' is a digestive condition in which lactose, the natural sugar in milk and many dairy products, is not fully digested. It usually happens because the small intestine has low levels of lactase, the enzyme that breaks lactose down.

Lactase Gene Expression: Genetic factors play a crucial role, with some populations having a higher prevalence of lactase non-persistence.
	Undigested lactose passes into the colon, where bacteria ferment it. This can produce gas and draw fluid into the bowel, causing symptoms such as bloating, wind, abdominal pain, and diarrhoea.

Age-related:
	== Symptoms ==
	Symptoms often begin within a few hours of eating or drinking lactose. They can include:

Primary Lactose Intolerance: The most common form occurs as individuals age, and the production of lactase decreases naturally.
	* Bloating.
	* Wind.
	* Stomach cramps or abdominal pain.
	* Diarrhoea.
	* Nausea.
	* Rumbling or discomfort after dairy.

Secondary Causes:
	The amount of lactose needed to cause symptoms varies. Some people tolerate small amounts, especially with meals, while others need stricter limits.

Gastrointestinal Disorders: Conditions such as celiac disease, Crohn's disease, and infections can lead to secondary lactose intolerance.
==Symptoms==
Gastrointestinal Distress: Symptoms typically occur within 30 minutes to two hours after consuming lactose-containing foods and may include bloating, diarrhoea, abdominal pain, and flatulence.
==Diagnosis==
Hydrogen Breath Test:
	== Causes ==
	Common causes include:

Lactose Tolerance Test: A hydrogen breath test measures the amount of hydrogen in the breath after consuming a lactose-containing solution.
	* '''Lactase non-persistence''', where lactase production falls after childhood.
	* '''Secondary lactose intolerance''', caused by small bowel injury or illness such as gastroenteritis, coeliac disease, Crohn's disease, or some treatments.
	* '''Premature birth''', where lactase production may be temporarily low.
	* '''Congenital lactase deficiency''', a very rare inherited condition present from birth.

Stool Acidity Test:
	Lactose intolerance is different from milk allergy. Milk allergy is an immune reaction to milk proteins and can be dangerous. Lactose intolerance is about digesting milk sugar and is mainly a gut problem.

Stool Acidity Test: This test is commonly used in infants and young children. Undigested lactose in the stool causes increased acidity.
	== Diagnosis ==
	Diagnosis can be based on symptoms and response to reducing lactose, but testing may be used when the cause is unclear. Tests include hydrogen breath testing, lactose tolerance testing, and stool acidity testing in some children.

Elimination Diet:
	Other conditions can look similar, including irritable bowel syndrome, coeliac disease, inflammatory bowel disease, infection, and milk allergy. That is why persistent or severe symptoms should not automatically be blamed on lactose.

Elimination Diet: Temporarily removing lactose-containing foods from the diet and then reintroducing them can help identify the cause of symptoms.
==Management and Treatment==
Dietary Modification:
	== Management ==
	Management is usually dietary. Many people reduce lactose rather than remove all dairy. Options include:

Lactose-free Diet: Individuals with lactose intolerance often manage symptoms by avoiding or limiting dairy products. Lactose-free alternatives are available.
	* Smaller portions of milk or dairy.
	* Lactose-free milk and dairy products.
	* Hard cheeses or yoghurt if tolerated.
	* Lactase enzyme products.
	* Fortified plant drinks where dairy intake is low.
	* Attention to calcium, iodine, protein, and vitamin D intake.

Lactase Supplements:
	NHS and NIDDK guidance both note that many people with lactose intolerance can still tolerate some lactose. The right amount depends on the person.

Lactase Enzyme Supplements: These supplements can be taken with meals to help digest lactose.
	== See Also ==
	* [[Common_Medical_Terms]]
	* [[Vitamin_D]]
	* [[Osteoporosis]]

Gradual Introduction:
	== References ==
	* [https://www.nhsinform.scot/illnesses-and-conditions/nutritional/lactose-intolerance/ NHS inform: Lactose intolerance]
	* [https://www.niddk.nih.gov/health-information/digestive-diseases/lactose-intolerance/definition-facts NIDDK: Lactose intolerance definition and facts]
	* [https://www.niddk.nih.gov/health-information/digestive-diseases/lactose-intolerance/symptoms-causes NIDDK: Lactose intolerance symptoms and causes]
	* [https://www.niddk.nih.gov/health-information/digestive-diseases/lactose-intolerance/treatment NIDDK: Lactose intolerance treatment]
	* [https://medlineplus.gov/lactoseintolerance.html MedlinePlus: Lactose intolerance]
	* [https://medlineplus.gov/genetics/condition/lactose-intolerance/ MedlinePlus Genetics: Lactose intolerance]

Gradual Introduction of Dairy: Some individuals can tolerate small amounts of lactose, and gradual reintroduction may be possible.
==Complications==
Nutritional Deficiencies: Long-term avoidance of dairy products may lead to deficiencies in calcium and vitamin D, impacting bone health.
==Cultural and Dietary Considerations==
Cultural Variation: Lactose intolerance is more prevalent in some ethnic groups, and cultural dietary practices often adapt to accommodate this condition.
	[[Category:Medicine]]
	[[Category:Nutrition]]