Lactose intolerance is a condition where consumption of milk and milk-based products leads to stomach problems. The symptoms can include excessive farting, loose stools, abdominal bloating and cramping, nausea and rumbling in the stomach.
Milk contains a sugar called lactose. This is broken down into glucose and galactose in the digestive tract by an enzyme called lactase.
For a given quantity of lactose consumed, there should be a proportionate quantity of lactase secreted in the digestive tract. In those with lactose intolerance, there is insufficient lactase production.
As a result, lactose is broken down and fermented in the gut, leading to the formation of a lot of gases. This leads to bloating and other digestive symptoms.
Most cases of lactose intolerance develop between the ages of 20 and 40. However, it can start at any age.
Not everybody is lactose intolerant to all milk products. In fact, some are only intolerant to milk, but not cheese and yogurt. Some are intolerant when larger quantities of dairy are consumed, and not when a small amount is consumed (for example milk added to coffee).
Remember that lactose intolerance is not milk allergy. In milk allergy, patients develop a rash over the body. It not due to lactose, but due to the protein in the milk.
So, what can you have if you are lactose intolerant? Well, if it just milk and not milk products, go ahead and have those. Western countries have lactose-free milk available, so you could look for those options.
Almond milk, soya milk and coconut milk are generally safer options, though their range of utilisation may not be of the same spectrum as milk.
Not taking milk could lead to certain vitamin and calcium deficiencies, so make up for it through other foods and supplements if needed.