I was a milk child, my mother says. Unlike other children, in fact unlike my younger sister, I loved milk and thrived on all things dairy. I could and would have milk three-four times a day, even as an adult.

Then one day, when I was 32, this love affair ended abruptly.

One night at a restaurant I had my favourite Hot Chocolate Fudge ice cream. But as soon as I finished it, I had severe cramps in the stomach and we had to rush back home as I needed to go to the loo right away.

Spoilt milk: People allergic to milk and dairy products need to make sure they are getting enough calcium in their diet.

For a while I thought it was a stomach bug so I took it easy and cut back on milk and other heavy foods. But the day I started dairy again, the symptoms were back. Finally, I was diagnosed as lactose intolerant by our GP (general practitioner) and after 32 years of thoroughly enjoying all things dairy, I had to stop having milk totally. It’s been eight years since, but I still miss not being able to have cold coffee after breakfast.

Lactose intolerance, the inability to digest and absorb the lactose (a type of sugar) in milk, starts suddenly in most cases, and usually at an age when you are least expecting it. And it affects many Indians, if we go by the statistics published by the US-based Eunice Kennedy Shriver National Institute of Child Health and Human Development (Lactose Intolerance: Information for Health Care Providers, January 2006).

Rommel Tickoo, consultant, internal medicine, Max Super Speciality Hospital, Delhi, says, “According to the study, about 70% of south Indians and 30% of north Indians are affected by the condition.

“Actually a multi-centre study was carried out in India to determine the incidence of lactose intolerance in healthy volunteers from different parts of the country. The incidence was found to be 66.6% in the subjects from two south Indian centres at Thiruvananthapuram and Puducherry. In contrast, the incidence in the subjects from a north Indian centre in New Delhi was much lower at 27.4%," says Dr Tickoo.

Why it happens

“Lactose is a large sugar and it divides itself into two sugars called glucose and galactose with the help of an enzyme called lactase secreted by the small intestine. The sugar is not absorbed if the split does not happen. Lactose intolerance is caused by reduced or absent activity of lactase (lactase deficiency)," explains Jyothi Prasad, chief dietitian, Manipal Hospital, Bangalore. Dr Tickoo adds that it is of three types—congenital, secondary or developmental.

Congenital is a rare genetic disorder which prevents enzymatic production of lactase; present at birth, it is usually diagnosed in early infancy. Secondary intolerance usually results from certain gastrointestinal diseases, like infection by intestinal parasites such as Giardia lamblia, rotavirus etc., or inflammation that destroys the lining of the small intestine along with the lactase, as in celiac sprue, a type of stomach inflammation. “This is temporary and lactose digestion improves and intolerance goes away once the underlying causative factor is corrected," says Dr Tickoo. This is the only reversible type of intolerance to dairy products.

Spot it

“The most common symptoms are abdominal cramps, diarrhoea and flatulence. In some people, bloating and nausea may also occur," says Prasad.

“Unfortunately, most people who consider themselves lactose intolerant have never been formally tested for intolerance. And it has been observed that at least 20% of people who think they are lactose intolerant are not, and 20% of people who think they are not intolerant, in fact, are. So formal testing is absolutely essential," advises Dr Tickoo.

Elimination diet (where milk and milk products are eliminated), and milk challenge, where the person fasts overnight and then drinks a glass of fat-free milk in the morning, are the most common tests. Sometimes, blood glucose and stool acidity tests are also done to confirm, Dr Tickoo adds.

How to treat it

The most obvious means of treating lactose intolerance is by reducing the amount of lactose in the diet. “Fortunately, most people who are lactose intolerant can tolerate small or even moderate amounts of lactose, so it is not necessary for them to avoid dairy completely. They can do well by just eliminating milk and ice cream," says Prasad. “In fact, most people can continue to have a small amount of milk in their tea and coffee, have food cooked in milk, and most manage to digest the hidden lactose in processed foods. Yogurt is well digested by most too," she adds.

“For individuals who are intolerant to even small amounts of lactose, the dietary restrictions become more severe. Any product containing milk must be avoided," says Dr Tickoo. Although milk and foods made from milk are the only natural sources of lactose, it is often “hidden" in prepared and processed foods such as cookie, cake and dry potato mixes.

“People with very low tolerance for lactose should know about the many food products that may contain lactose, even in small amounts," explains Dr Tickoo.

Food products that may contain lactose include bread and other baked goods, processed breakfast cereals, soups, margarine, salad dressings, candy sweets, other snacks and mixes for pancakes, biscuits, cookies and malt-based drinks, which have milk solids in them to add sweetness, thereby increasing the lactose content. In addition to food sources, lactose can also be hidden in medicines. Lactose is used as the base for more than 20% of prescription drugs and about 6% of over-the-counter drugs, says Dr Tickoo. Many types of birth control pills, for example, contain lactose, as do some tablets used for stomach acid and gas.

“However, these products typically affect only people with severe lactose intolerance because they contain such small amounts of lactose," Dr Tickoo adds.

What about deficiencies?

Ishi Khosla, clinical nutritionist and director, Whole Foods India, lists strategies on how to deal with the problem.

• Adjust the type of dairy food. Yogurt contains large amounts of lactose too but it is well-tolerated by most lactose-intolerant people. This may be because the bacteria used to make yogurt contains lactase. However, the tolerance for yogurt also varies with people. Home-made yogurt is best because its lactose content is lower.

• Also, whole milk is better tolerated than skimmed milk because the higher quantity of fat in whole milk helps digest the sugar in the milk slowly and hence is better tolerated.

• Go for cheese as it has lower amounts of lactose (see Dairy Data). Many aged cheeses (e.g. Parmesan, Cheddar, Swiss, Gouda, Brie, Camembert, Gorgonzola) contain considerably less lactose than milk. Cheese manufacturers discard most of the lactose as whey; the ageing of cheese converts the remaining lactose to lactic acid.

• Consuming milk with meals may also reduce symptoms of lactose intolerance due to prolongation of gastric emptying (the rate at which the stomach empties into the small intestine), which allows more time for the limited amount of lactase to split the lactose.

• Commercial enzyme preparations (for example, lactase capsules, chewable tablets, solutions) can be had. Besides dairy, soy has been found to be a useful source of calcium and bone-building nutrients.

“The important long-term health consequence of lactose intolerance is calcium deficiency that leads to osteoporosis. Less commonly, vitamin D deficiency may occur and compound the bone disease. Both of these health issues can be prevented easily by calcium and vitamin D supplements. The real problem is that many lactose-intolerant people who consciously or unconsciously avoid milk do not realize that they need supplements," warns Dr Tickoo.


What is casein allergy?

An allergy is different from intolerance. An allergy is linked to the immune system where a person produces antibodies to an offending allergen, in this case a protein called casein in milk. An allergy can be life-threatening, and even small doses can cause an immediate reaction which can be fatal. Intolerance, on the other hand, does not involve the immune system, but causes mild to moderate discomfort when the offending substance is consumed. The allergy is fortunately very rare.

A casein allergy occurs when the body’s immune system mistakenly thinks the protein is harmful and produces antibodies for protection, triggering the release of body chemicals such as histamine that cause the symptoms.

This allergy develops in infancy and most people outgrow it. Some, however, do not. The allergy does not surface in adulthood.

If you are diagnosed with casein allergy, you may need to carry a shot of epinephrine with you in case you accidentally eat food containing casein and suffer a reaction. The best treatment for casein allergy is prevention. So, avoid all foods that contain milk or milk products.

—Jyothi Prasad, chief dietitian, Manipal Hospital, Bangalore .

Write to us at businessoflife@livemint.com