"A little poison embitters much sweetness." --UNKNOWN, Old English Homilies. Ser. i, p. 23. (c. 1175)

Lactose is the sugar unique to mammalian milk. Human milk contains about 75 grams of lactose per litre while cow's milk contains about 45 grams per litre. Its concentration ranges from less than one percent in seagoing mammals such as seals, sea lions, and walruses to over seven percent in primates such as monkeys, baboons and humans. The concentration of lactose in human milk is low at birth to reduce discomfort since the immature lactose-handling system is not fully developed. Galactose and glucose, the two simple carbohydrates, combine in the breast to make lactose. Galactose is essential for the brain development while glucose provides the needed energy.

Lactose is truly the wonder sugar of nature--a gift for the newborn. Here is a summary of what lactose does for the baby:
• expedites brain development;
• provides source of quick energy'
• aids in absorption of proteins, calcium and mother minerals;
• promotes growth of "good" intestinal bacteria which synthesize vitamins and help absorption of nutrients;
• reduces incidence of rickets and softening of bones;
• reduces insulin secretion;
• helps control obesity.

In the intestines, lactose breaks down under the influence of an enzyme, lactase. If sufficient lactase enzyme is not present, some lactose escapes into the colon where it proves a good food for the bacteria to thrive on. Bacterial growth, however, brings many undesirable effects. The fermentation of lactose produces carbon dioxide gas and water in the intestine. The results are flatulence, diarrhea and cramps--the most common symptoms of lactose intolerance. Infants always have enough lactase enzyme in their intestines. With weaning time approaching lactase levels decrease and nearly disappears when the child is able to take other diets (1 - 1 1/2 years). It is perhaps nature's admonition to assure weaning at the appropriate time, and also a warning to stop using milk. Therefore, those who retain lactase enzyme activity can be aptly called, "milk-freaks." Abnormal are not those who react to lactose but those who do not according to the paradigm of nature.

Billions of people around the globe suffer from lactose intolerance because of insufficiency of lactase enzyme. These people can not take milk without severe side effects. However, it is only since 1965 that we have begun to appreciate it. The incidence of lactose intolerance appears genetically controlled. Almost all African Blacks and South Indian Dravidians are intolerant; southeast asians and people from the Mediterranean Sea show intolerance range over 80%; Pakistanis and north Indians show only 10% intolerance whereas many northern European people are around 5% intolerance. Danes are people with lowest, around 2%, lactose intolerance. (No wonder cows are popular in the Danish land.)

Unfortunately, the symptoms of milk intolerance are frequently ascribed to psychological or socio-cultural causes. Even when traced, they are often erroneously classified as milk allergies and not as milk intolerance. This confusion arises because the symptoms of intolerance range from disturbances of gastrointestinal tract to mental and emotional maladies. Intolerant subjects not only have diarrhea, but possibly, nasal congestion, asthma, chest infections, skin rashes, cramps, flatulence, lack of mental concentration, failure to thrive and retention of body fluids. Common belief does not associate these symptoms with lactose intolerance. As a result most lactose-intolerant people remain unaware of their handicap.

Of the 13 million lactose-intolerant people in Pakistan, only one in 10 have figured out their problem, rest are still wondering. Countless cases of infantile diarrhea are treated without questioning lactose intolerance. Contrary to popular belief, symptoms of lactose intolerance do not always appear immediately after exposure to milk. This is another reason why we fail to associate milk consumption with the symptoms.

Worsening lactose intolerance is fat in our diet, consumption of alcohol and prolonged intestinal diseases which reduce production of lactase enzyme.

Expecting reduced consumption of milk, the Nature, in a highly astute gesture, makes absorption of calcium more efficient in those who are intolerant to lactose, to conserve calcium. Lactose intolerant subjects absorb about 35 percent of calcium in the food, 10 percent more than lactose-tolerant subjects. Still, calcium supplements are recommended, especially for women, to reduce risk of developing osteoporosis when milk is not consumed regularly.

Phototherapy of jaundiced infants does not develops lactose intolerance nor is giardiasis caused by lactose intolerance.

However, lactose intolerance is not always bad. Lactose malabsorbers contract fewer infections of the intestine because the fermentation of lactose produces a volatile fatty acid that inhibits growth of pathogenic bacteria. Lactose-intolerant adults also have reduced chances of developing senile cataracts.

Learning to live with milk intolerance begins with identifying it conclusively. The simplest test to determine intolerance is to test if milk-containing foods produce the symptoms. More objectively, a blood sugar test confirms milk intolerance. Lactose, when digested, produces glucose that gives rise to blood sugar. If a 50 gram dose of lactose (equivalent to lactose in three-quarter litre milk) does not produce a noticeable rise in blood sugar, it is a sign of lactose indigestion or milk intolerance. The stool of lactose-intolerant subjects is acidic and breath full of hydrogen gas.

Managing lactose intolerance is becoming increasingly difficult as we begin using processed foods. A common fallacy is to consider milk-free products as lactose-free while a majority of prepared and pre-processed foods and even some drugs contain lactose. Lactose is a popular additive because it is less sweet, cheap and dissolves easily. It, therefore, appears in the most unsuspected products such as margarine or cookies.

Serendipitously, the technology to curb the problem of lactose intolerance existed before the problem came to recognition. The common process, cheese making, removes lactose. Fermented products such as yogurt, buttermilk, cottage cheese, etc. are low in lactose and also contain bacteria that produce lactase enzyme. In populations where milk intolerance is common, yogurt has long been popular as a substitute.

Fermented foods were first made famous as an elixir of longevity by the Russian writer Metchinkoff in 1908. Every culture and nation has its own brand of cultured milk product: kumiss in Mongolia, kry in Iceland, kefu in Balkan countries, mazum in Armenia, lassi in India and leken in Egypt.

Cheeses also serve as a good source of lactose-free nutrition. Yogurt and cheese have also earned a reputation for "binding" stools, or reversing diarrhea due to their reduced lactose content.

Lactose, the sweetness of milk, proves quite bitter for many. It may just be the reason why would want to give up milk. And if you must patronize cow, why not use yogurt, cheese or other cultured products.

[11 August 1993 The Daily Dawn]