Lactose intolerance is a relatively common issue, and although the actual number of affected people isn't known, it's thought that perhaps 1 in 5 people experience symptoms (including severe discomfort and bloating, nausea and diarrhoea) after consuming milk products. That number is even higher in certain ethnic groups, especially those who come from cultures without a milk-based cuisine.
Lactose intolerance isn't an allergy; it's an inability to properly digest the sugar that is found in milk and dairy foods (lactose). When we digest milk products, we use an enzyme called lactase to break down these sugars, but lactose-intolerant people don't produce enough of it to do the job.
Lactose intolerance can sometimes be temporary - after a nasty tummy bug or a bout of diarrhoea, for example. This is known as transient lactose intolerance, and happens essentially because the body's store of lactase is wiped out by the illness. In most cases, this type of lactose intolerance will resolve itself, although it may take a few weeks or months for the person to recover completely.
For other people, lactose intolerance is a lifelong condition, and the only real solution is to remove all dairy foods from the diet. Lactose is found in all mammal milks (such as cows', goats', sheeps' and buffalo milk) in equal quantities. Some people appear to be able to tolerate small amounts of milk – for instance, a dash added to a cup of tea - but wouldn't be able to cope with a glass of milk or a latté.
A recent survey of people avoiding lactose in their diets, conducted by [Allergy UK], found that nearly half of those asked had self-diagnosed their lactose intolerance, relying on online searches, unconventional allergy tests and alternative practitioners for their diagnosis. The majority (72%) had completely removed dairy from their diets.
Unsurprisingly, most of these people had stopped eating dairy because of digestive discomfort - 69% citing stomach/ abdominal discomfort, 57% bloating and 54% diarrhoea - with symptoms improving after cutting dairy from the diet.
If you have symptoms like these, the easiest way to find out whether it is dairy/lactose that is causing them is to remove it from your diet and see whether the symptoms clear up. Although this might seem like quite a simple thing to do, you'll need to be aware of hidden milk or lactose in foods by reading labels and checking ingredients lists. If avoiding lactose for a couple of weeks gets rid of your symptoms, then it's important to get some professional advice from your GP before embarking on a completely lactose-free diet. Replacing dairy with an alternative source of calcium is vitally important to make sure you're still getting a good balance of nutrients in your diet.