Milk, the foundation for all other dairy products, an exceptional food in itself. Like meat, milk provides all the essential amino acids, which makes it a complete protein. Yet unlike the protein in meat, the protein in fat-free, low-fat, and reduced-fat milk does not come ladened with saturated fat. Because milk is particularly high in the amino acid lysine, it’s an ideal complement to cereals, breads, and other grain products, all of which lack that essential amino acid.
You often see the words “pasteurized” and “homogenized” on milk cartons:
- Pasteurization is the process for heating milk to destroy disease-causing bacteria, as well as yeasts and molds. It’s required for most Grade A milk sold in interstate commerce. However, within each state or locality, compliance is voluntary. Still, 99 percent of all milk sent to market is pasteurized. Not only does pasteurization ensure the safety of the milk supply, it also increases its shelf life. At the same time, it doesn’t significantly affect the nutritional value of milk.
- Homogenization is the process that distributes the milk fat evenly through the milk. It was developed around 1900, but until the 1950s it was common for milk to arrive at stores and households unhomogenized, with a layer of cream at the top of each bottle. You could skim off the cream and use it separately, or shake the bottle to remix the cream with the milk. Today, almost all fluid milk is homogenized by forcing it through a small opening under high pressure. This breaks down the fat into particles so tiny they remain emulsified in the milk rather than floating to the top. For more on homogenized milk, see Homogenized Milk Myths Busted.
Milk’s high-fat cousin, cream, is the product separated from unhomogenized milk. Available both sweet and sour, all cream products are pasteurized or ultrapasteurized and may also contain milk, concentrated milk, dry whole milk, nonfat milk, concentrated nonfat milk, or nonfat dry milk. Cream may also include emulsifiers, stabilizers, nutritive sweeteners, flavorings, and other optional ingredients.
Milk and cream: nutrition
Milk is a nutrient-dense food, which means that in relation to its calories it provides an abundance of important nutrients. Milk is rich in high-quality protein, calcium, vitamin A, vitamin D, riboflavin, and vitamin B12. Milk also has good amounts of potassium and the amino acid lysine.
Almost all milk sold commercially in the United States has vitamins A and D added. Vitamin A is a fat-soluble vitamin that is largely lost when milk fat is removed, and vitamin D is added to milk because a deficiency of vitamin D can interfere with the body’s ability to absorb calcium.
While Americans have cut down on drinking whole milk, they have increased their consumption of fat-free and reduced-fat milk, which contain the nutrients of whole milk without the extra fat. The nutrient content of flavored milks, such as chocolate milk, is similar to that of the corresponding unflavored milk, though flavored milks do have far more calories due to the addition of sugar (sucrose) and other sweeteners.
For a full list of nutrients, check the National Nutrient Database:
- Low-fat milk (1%)
- Reduced-fat milk (2%)
- Skim (nonfat) milk
- Sour cream
- Whipping cream
- Whole milk
Buying milk is no longer a question of telling the milkman to leave one bottle or two. Not only is the milkman primarily a thing of the past, your local supermarket may carry 10 or more different types of fresh milk, as well as canned and dried forms. Although most milk
Milk and lactose intolerance
There are some children and many adults who can’t drink milk or eat dairy products without symptoms of gas, bloating, diarrhea, and cramps. Their bodies can’t digest the lactose, or milk sugar, that is in milk. Lactose intolerance is a problem that affects 65 percent of people worldwide to some degree. Lactose intolerance is very common in people of East Asian, West African, Arab, Jewish, Greek, and Italian descent.
Lactose consists of two chemically combined sugars: glucose and galactose. The problem of digesting dairy products occurs in people who have a deficiency of lactase, an intestinal enzyme that breaks lactose into these two sugars to render them absorbable. Humans produce peak amounts of lactase in infancy, when milk is necessary for survival; thereafter, the supply begins to diminish.
Despite this problem, millions of people like milk and other dairy products, and want to continue enjoying them throughout their lives. It has been found that most lactose-intolerant people can eat at least some dairy products as part of a meal but not alone. Others are less sensitive. Cultured dairy products, such as yogurt and buttermilk, are easier for lactose-intolerant people to digest. And because most of the lactose is removed during cheese making, cheese is rarely a problem. Lactose is in evaporated, condensed, and powdered milk, as well as fluid milk.
Today, lactose-free and lactose-reduced milk treated with lactase are sold in many supermarkets. Lactase is also available in a liquid form that must be added to dairy products at least 24 hours before eating them. If you think you can’t digest lactose, talk to your doctor to see if you really are lactose intolerant.
Antibiotics and hormones in milk
Antibiotic drugs given to cows can and do pass into milk, and millions of samples are tested each year to detect residues. Some surveys have turned up signs of drugs that are illegal in dairy cows, though often the levels are so low as to be barely detectable. The FDA has taken steps to correct this problem, though some people question whether the FDA rules are tough enough and worry that drug residues may still end up in milk. A report released by the FDA in 2015 should help put those concerns to rest; it found that of 1,900 milk samples tested for antibiotics and other veterinary drugs, fewer than 1 percent contained drug residues.
rBST (recombinant bovine somatotropin) is a genetically produced hormone protein approved by the FDA to increase cows’ milk production. Cows injected with rBST every two weeks produce about 10 to 15 percent moremilkthan untreated cows. Scientists assert that the composition of milk from rBST-injected cows is not altered and has no biological effect on humans. There is no mandatory labeling for milk from rBST-supplemented cows. In a major report issued in 1999, the FDA confirmed that milk that comes from cows treated with rBST is safe. Tests of the milk from treated and untreated cows could not determine which was which. Still, many people have concerns about rBST, so some products are voluntarily labeled as “farmer certified to not come from rBST-supplemented cows."
Published July 29, 2016