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Lactose Intolerance


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Lactose intolerance
Gastrointestinal system
Lactose intolerance is the term used to describe a failure to break down a sugar called lactose that is found in milk and dairy products. As milk and dairy products are used extensively in the food industry, many people are also intolerant to a wide range of foods. Lactose intolerance is a very common digestive disorder, estimated to affect about three quarters of the world's population. People of Asian, African, African-American and Hispanic origin are most likely to be affected, and at an earlier age than those of European origin.
Lactose intolerance occurs because of a deficiency of an enzyme called lactase. This enzyme is produced in the small intestine and is responsible for breaking lactose down into two smaller sugars, glucose and galactose, to allow these sugars to be absorbed into the bloodstream.

There are three major causes of lactose intolerance:

Primary lactase deficiency, also know as late onset lactase deficiency, is the most common form of lactose intolerance affecting more than half of the world's population. It is a condition that runs in families and tends to develop between 5 and 20 years of age.

Secondary lactase deficiency occurs as a result of damage to the lactase producing cells of the small intestine, either through diseases such as Crohn's disease or coeliac disease (gluten sensitivity) or infections such as gastroenteritis that cause severe diarrhoea. Some antibiotics may cause lactose intolerance by interfering with the intestine's ability to produce lactase.

Congenital lactase deficiency is a rare genetic condition that results in a deficiency of lactase, or a defective lactase that does not work properly, from birth. Whatever the reason for the lactase deficiency, the failure to break down lactose prevents this sugar from being absorbed into the bloodstream, and this produces a laxative action. Bacteria in the large intestine feed on the unabsorbed lactose, releasing large amounts of gas such as hydrogen and methane. The laxative effect and the gases are responsible for the symptoms of lactose intolerance.
The main symptoms of lactose intolerance are diarrhoea, wind, a bloated feeling, stomach pains and rumbling tummy. The time that someone begins to develop symptoms, and the severity of the symptoms depends on the amount of lactase they produce and the amount of lactose they eat. Generally, as a person gets older and the amount of lactase they produce declines, they become more lactose intolerant. Similarly, if the person eats more lactose in the form of milk and other dairy products than the enzyme is capable of breaking down, the severity of the symptoms increases. In babies, these symptoms may appear as infant colic. If a baby has a congenital lactase deficiency it will not be able to digest the milk it receives and so will not grow properly.
Treatment depends on the age of the person and the severity of the symptoms.
In babies with mild lactose intolerance who are experiencing colic after feeds, adding a few drops of lactase to expressed breast milk will help ease symptoms. If the baby is bottle fed, the baby's formula milk can be changed to a lactose-free or lactose-low formula milk. In babies with congenital lactase deficiency, special formula milk products will be needed to make sure that the baby has the correct balance of nutrients.
In older children and adults, lactose intolerance can largely be managed by avoiding products that contain milk and other dairy products. However, as dairy products supply important nutrients such as calcium, vitamin D and other vitamins that help build strong bones and maintain health, people should try not to eliminate dairy foods entirely from the diet, but should try and identify and avoid those products that cause the worst symptoms.
When to see your pharmacist
Your pharmacist will be able to give you general advice about lactose intolerance and which foods you should try to avoid. Your pharmacist will also be able to give more specific advice about the use of lactase drops, soya-based formula baby milks and nutritional supplements.
When to see your doctor
If you suspect that you or a member of your family, particularly a baby, is intolerant to lactose you should visit you doctor. Your doctor will ask you to describe the symptoms and when they occur, and may then perform a simple test to confirm the diagnosis.
Living with lactose intolerance
Although intolerance to lactose can be troublesome, symptoms can largely be avoided provided you are careful about what you eat. Learn to recognise the dairy products and other food products that you know have caused problems in the past and try to avoid them in future. Get into the habit of reading food labels and recognising the names of ingredients that may contain hidden amounts of lactose such as dried milk, powdered milk or whey. Switch brands of your favourite foods to ones that are lactose-free or contain lower amounts of lactose.

If you want to eat dairy products, eat them in small quantities or together with other products such as meat that are lactose-free or lactose-low that help slow down digestion. Cheddar and other hard cheeses, and live yoghurt contain lower amounts of lactose than soft cheeses and milk and may, in small quantities, be used instead.

Eat a variety of fresh vegetables such as broccoli and beans or tofu to make up for the calcium that is essential for healthy bone development that is normally provided by dairy products. Alternatively, dairy-free or non-dairy products based on soya milk are a good alternative to dairy products. Soya milk, obtained from plants, contains about 20% more calcium than ordinary milk together with vitamins A, B1, B2, B12, D and E, folic acid and zinc but does not contain lactose. Soya is also a good source of high quality protein and has been shown to lower cholesterol levels. Isoflavones present in soya may also help to reduce menopausal symptoms and osteoporosis. There is a wide range of meals, desserts and snacks available based on soya milk, providing almost as much choice as products based on ordinary milk and therefore providing plenty of variety for those who are lactose intolerant.

Take regular walks in the fresh air as the sun helps the body produce vitamin D, an essential vitamin also necessary for healthy bone development, normally obtained from dairy products.

A source of calcium and vitamin D is particularly important for growing teenagers. If your teenager's lactose intolerance is severe, seek advice from a qualified dietician. The dietician will be able to suggest a range of suitable lactose-free alternatives that provide a well-balanced diet with all the necessary vitamins and minerals to support healthy development.