Do you ever experience gas, bloating and stomach cramps shortly after drinking milk or eating dairy products? It has been estimated that as many as three-quarters of the world population may have some degree of intolerance to dairy, most of which remains undiagnosed. Humans are the only mammals which continue to consume milk after weaning, and in the West in particular, milk and milk products form a significant proportion of the average diet.
There are two types of dairy intolerance, lactose intolerance, and casein intolerance. Neither should be confused with milk allergy which is potentially much more serious than a mere intolerance. If you suffer from a dairy intolerance it means that your body is sensitive to milk and has difficulty digesting either the lactose or casein in milk. No allergic response is involved. A true milk allergy, on the other hand, is most commonly found in babies, during the first few months of life, and might include the symptoms more commonly associated with an allergic reaction, including the risk (luckily quite rare) of life-threatening anaphylaxis.
Lactose Intolerance vs Casein Intolerance
Lactose intolerance (sometimes known as lactose deficiency) is found in persons who have difficulty digesting lactose, the sugar found in milk. It is likely that someone who has difficulty tolerating cow’s milk will not benefit from switching to goat, sheep or buffalo milk, as these contain similar levels of lactose to cow’s milk.
Casein intolerance is found in persons who have difficulty digesting casein, a protein found in milk and milk products. Symptoms are very similar to the symptoms of lactose intolerance (see below), but may also occasionally include general lethargy and joint pain.
Those suffering from casein intolerance need to avoid milk products with high protein content. So, for example, they may find that they have difficulty tolerating protein powders (of the type sometimes taken by athletes and body builders), milk, cheese and ice cream. Milk products with lower levels of protein, such as butter and cream may be easier to tolerate.
Lactose intolerance is more common than casein intolerance.
Symptoms of lactose intolerance
Symptoms usually occur anything between 30 minutes and 2 hours after consuming milk or a milk product. Any of the following symptoms may be present:
- Excessive stomach rumbling
- Flatulence
- Stomach bloating
- Stomach cramps, diarrhea
- Nausea (occasionally vomiting, seen particularly in teenagers)
Why am I lactose intolerant?
During infancy, the small intestine produces an enzyme called lactase, which helps break down lactose. Levels of lactase fall as we get older. This is why lactose intolerance usually affects adults rather than young children, although the condition is sometimes found in babies who were born prematurely.
Sometimes the condition occurs in persons after an injury to the small intestine or after a bout of gastroenteritis.
Lactose intolerance is higher in persons of African or Asian descent, and lowest in those of North European descent. It is interesting to note that traditional Chinese cooking is virtually dairy-free.
Diagnosis of lactose intolerance
If you frequently suffer from a combination of any of the above symptoms, you should make an appointment to see your doctor. The doctor will want to know the full history of your symptoms and diet and may ask about whether anyone else in your family has similar symptoms. They may conduct a physical examination, checking your abdomen for tenderness or bloating, possibly listening to your stomach with a stethoscope.
There are tests available to see whether you are lactose intolerant, although an exclusion diet may be all that is needed to decide whether you should avoid milk and milk products. Your doctor may ask you to try to fully exclude milk and dairy products from your diet for a period of weeks or months and to keep a diary of everything you have eaten and any symptoms.
The following tests are occasionally conducted to check for lactose intolerance:
Hydrogen breath test
During this test you are required to blow into a container after drinking a milk drink. Undigested lactose produces higher than average levels of hydrogen in the breath.
Blood tests might be used to measure levels of glucose in your blood after consuming a milk drink. If glucose levels do not show the usual elevation expected after consuming a milk drink this might suggest that your body cannot properly digest milk.
Stool tests might look for fatty acids such as lactic acid which are produced by undigested lactose.
Management of dairy intolerance
Once a diagnosis of dairy intolerance is made, your doctor will be able to advise you on changes you need to make to reduce the severity of your symptoms. The most obvious lifestyle change is to eliminate milk and dairy products from your diet as much as possible. It may be useful to visit a registered dietician to discuss how you can make these changes without limiting your consumption of essential nutrients.
You may find that you are able to tolerate small quantities of milk or dairy products. Some people find that they are more able to tolerate dairy eaten with other foods. Some will find it best to avoid dairy altogether. You might want to start with a total elimination diet and gradually reintroduce small amounts of some dairy products to see whether symptoms come back.
As well as the obvious things such as milk, cheese, cream and butter, look out for whey, curds, dry milk solids, milk powder, all of which contain lactose.
Many foods contain hidden milk, including some bread, cakes, biscuits, pastries, processed breakfast cereals, soups, protein bars, pizzas and even some crisps. Read labels carefully and keep a food diary to help you link what you have eaten with the appearance of symptoms.
Some people with dairy intolerance find that it helps to take lactase enzyme tablets or drops before eating. If you decide to start taking these you should first speak to your doctor as these are not suitable for everybody.
You might also consider taking probiotics to help restore the balance of healthy bacteria in your gut. Probiotic yoghurts are unlikely to help, as the bacteria in these will almost certainly be destroyed by stomach acids before reaching the intestines. Some people who are sensitive to lactose report finding that probiotic capsules lactobacillus acidophilus (with coating which prevents them from dissolving in the stomach) helpful. These capsules are usually expensive to buy and more research needs to be done to be sure of the benefit.
Calcium deficiency
It is important that you do not become calcium deficient when you eliminate or reduce dairy products from your diet. Calcium is needed for healthy bones and teeth, whatever your age. Children and young adults need high levels of calcium for growth. Older persons whose diet does not contain sufficient calcium may be at risk of osteoporosis, which increases the likelihood of fractures and broken bones.
Speak to your doctor or registered dietician about ways in which you can maintain adequate calcium levels whilst excluding milk and dairy products. Bony fish, such as sardines, dark green vegetables such as spinach, spring greens and watercress, rhubarb, black treacle (molasses) and sesame seeds all contain naturally occurring calcium. You may find it necessary to switch to calcium enriched soya or nut milk, calcium enriched breakfast cereals or a calcium food supplement.
Also make sure you also have adequate levels of vitamin D, as this helps the body to absorb calcium.