What is the problem? The adult small bowel does not digest a sugar component of milk called lactose.
Why? Lactose needs an enzyme called lactase. This enzyme gradually decreases with age, until adults develop a deficiency.
What is the frequency of lactose intolerance? It depends on ethnicity: 20% in the Caucasian population, 50% to 100% in other populations. Apart from the human, no other adult mammal tolerates lactose.
At what age does lactose intolerance appear? It can at any age, but usually starting with teenagers. The frequency of lactose intolerance increases with age.
Why is this a problem? Because undigested lactose moves down in the bowel and modifies the intestinal flora. Bacterial fermentation of lactose produces gases (hydrogen, methane and CO2), causing an inflammatory reaction with these common symptoms:
- Cramps and abdominal pain
- Flatulence and rumbling
- Change of stool habits (variables stools and / or diarrhea)
- Sometimes nausea and vomiting
- Symptoms usually appear between 30 minutes and two hours after lactose ingestion. Symptom severity increases with age and depends on the amount of ingested lactose. In most cases, a small amount of lactose is tolerated.
How to make a diagnosis? By a clinical trial: remove lactose from the diet for four weeks and take probiotics to restore normal intestinal flora; symptoms will gradually decrease. There are also laboratory tests, such as the hydrogen test.
Where is lactose found?
- Milk, yogurt, ice cream and most cheeses
- As an additive in many foods and nutritional supplements
- Most breads (except water-based bread).
What is the treatment?
- Buy lactose-free products (lactose-free milk and yogurt) available in all grocery stores
- Choose cheeses with little lactose and lactose free bread
- Replace dairy products by other sources of calcium (broccoli, spinach juice with added calcium, salmon and canned sardines, soy milk) and vitamin D (eggs, liver, vitamin supplement)
- Take probiotics (for a couple of weeks weeks)
- Search the Internet for "lactose-free diet"
What about lactase supplements (Lactaid®)?
The effectiveness varies widely in humans. Use only if you do not have a choice. If you absolutely want to buy milk with lactose, put Lactaid into the milk container and leave it there for 24 hours.