Lactose Intolerance and Milk Allergy Information
Milk is a wonderful food, rich in vitamins, minerals, protein, fat and sugar. It's creamy and smooth, silky and soft. It thickens, it creams, it melts and it fills. Just about perfect - unless the darn stuff makes you ill. It's time the truth be told. Most of mankind cannot digest the stuff. As babies, many of us can process milk but our bodies lose this ability as we age. In fact 20 percent of adults in Europe, 80 percent in Africa or the Middle East, 95% of Chinese, 98% of Southeast Asia and almost 100% of native Americans cannot handle milk. If you assume 20% for the United States, 60 million Americans are lactose intolerant. That's quite a large voting and purchasing block.
Considering such percentages, milk intolerance is the norm for planet Earth. Ten thousand years ago, before the domestication of cows, goats and camels, no human adult could digest milk. What good would such a talent have served a hunter-gatherer population? Then, a mutation on chromosome 2 coupled with recent evolution grants some of us the ability to tolerate milk as adults. The mutation is a dominant gene, so one from either parent will allow you to smile and say, "Got Milk?"
There are two basic forms of milk intolerance. The most common stems from an inability to break down the milk sugar, lactose. Less common is a true allergic reaction to the protein in milk, casein. Either form causes any number of stomach and digestive discomforts. If you are lucky enough to tolerate milk and wonder what milk intolerance feels like, I have a friendly suggestion. Swallow 50 grams of sorbitol, xylitol or manitol, so called alcohol sugars that are poorly digested. For safety, you might want to stay close to a bathroom.
Lactose Intolerance
Much of the useable energy in food comes from strings of sugar molecules known as saccharides or simply carbohydrates. Long strings are called starches and, as we chew, the strings are broken, then become shorter and sweeter. The simplest carbohydrates are known as monosaccharides and consist of single molecules like glucose, fructose and galactose. Disaccharides are groups of two simple sugars. Cane and beet sweeteners are dissaccharides built from glucose and fructose. The bond between glucose and fructose must be broken during digestion for our bodies to absorb and utilize these simple sugars.
Milk sugar is called lactose and is a disaccharide composed of glucose and galactose. Proper digestion of milk sugar requires the enzyme lactase to cleave lactose into its two parts, glucose and galactose. Unless broken in two, it cannot be absorbed across the intestinal membrane. If unbroken lactose remains in the intestine, gut bacteria will eventually ferment the lactose, producing copious amounts of hydrogen, carbon dioxide and methane gas. Yes, it's so much more pleasant to let lactase enzyme do the work. Give thanks to at least one of your parents if they provided the mutated gene allowing lactase enzyme to be manufactured in your adult body.
Oddly, human breast milk has one of the highest concentrations of lactose sugar in nature, around 9%. Grazing mammals like cows have only half this amount. But that's way too much for any adult that has lost the ability to make the miracle enzyme, lactase. Lowfat milk varieties offer no relief as they reduce only fat and not sugar. Processed milk products like yogurt and cheese do have reduced lactose levels which allow some marginally intolerant people to cope. Listed below are typical values of lactose in common products.
Regular Milk (8 oz) has 12g of lactose.
Reduced Fat Milk (8oz) has 13g of lactose.
Regular Yogurt (6 oz) has 9g of lactose.
Lowfat Yogurt (6 oz) has 12g of lactose.
Ice Cream (2 oz) usually has 3g of lactose.
Cottage Cheese (1 oz) has only 0.1g of lactose.
Cheddar Cheese (1 oz) has only 0.02g of lactose.
Real Butter (1 teaspoon) has olnly 0.03g of lactose.
Milk Allergy
A milk allergy is more extreme than an intolerance. The offending component is not a sugar but milk protein, called casein. Our body's immune system has the responsibility to protect against invasion by germs. It does this by dectecting marker proteins on the outer layer of bacteria and virus particles. Foreign proteins bind to custom sites on immunoglobulin antibodies. This activates the antibodies allowing them to attach to and rupture MAST cells. In turn, toxic chemicals like histamine are released which kill germs and irritate surrounding tissue. Unfortunately for those with milk allergy, antibodies target friendly milk protein as if it came from a nasty germ instead of a clean bottle. All sorts of allergic symptoms can result, including digestive upsets similar to those caused by lactose intolerance.
Avoidance Strategies
If you are lactose intolerant, you need to avoid amounts of lactose that exceed your natural supply of lactase enzyme. To estimate this level, note that an 8 ounce glass of milk contains about 12 grams of lactose. A few sips might add up to about 1/12 of this or 1 gram of lactose. If you can only tolerate a few sips of milk, don't eat anything with lactose above 1 gram. As an alternative strategy, supplement your meals with lactase enzyme tablets, available at any drugstore. Take a pill with your first bite and another at the end of your meal. This will probably help your problem but not completely fix it. So, it would not be wise to order a milkshake for dessert. Unless you are feeling very lucky.
When possible, read food labels carefully. Anything that contains lactose is suspect, including milk, milk solids, whey, lactose itself, lactoserum, butter, cream, cheese, yogurt and kefir. If your problem is a full blown milk allergy, you must avoid anything that contains lactose or casein. Even foods manufactured in a factory that uses milk products occassionally can be problematic for the allergic. For instance, all chocolate is processed on equipment that handles milk chocolate at times. So all chocolate, even dark chocolate, is suspect for those with a sensitive milk allergy.
Kosher products labeled pareve or fleishig are usually free of milk. However, if a D for dairy is next to a circled K or U on the label, the food may contain milk solids.
Milk substitutes made from plant products like soybeans are safe for those with either lactose intolerance or milk allergy. The number of such products grows daily as companies become aware of the potential size of the market. Safe substitutes include soy milk, yogurt and cheese along with variants made from rice, nuts, grains, coconut and even hemp.
Alton Brown of Good Eats fame has a great video on these topics.
You Tube Video Link to "Lactose Man":
http://www.youtube.com/watch?v=9PqQtdtcJtE