Human beings are believed to have begun to consume cows' milk about 10,000 years ago, following the domestication of cattle. Evidence of cow herding for food production purposes dates to at least 4,000 B.C. Cow’s milk is valued as a food resource because it contains many of the nutrients that are essential to the growth, maintenance and health of the human body. Its versatility allows it to be consumed in many ways that are pleasing to human tastes. Milk is composed of protein, carbohydrate, fat, water-soluble vitamins, minerals and water. In fact, it is 87% water. The U.S. Department of Agriculture (USDA)’s MyPlate food guidance system and the U.S. Department of Health and Human Services (HHS)'s Dietary Guidelines for Americans recognize milk and milk products as one of the five major food groups from which people of all ages should make their food selections. These authorities recommend two-to-three daily servings of milk, cheese or yogurt, depending on a person’s stage of life. These recommendations reflect the fact that an 8–ounce serving of milk is a good-to-excellent source of nine essential nutrients, making it one of the most “nutrient-dense” foods available (a nutrient-dense food is one that provides a high level of essential nutrients compared to its calorie content). These nine essential nutrients, their value to good health and their availability from milk are outlined in the descriptions below.
A Nutrient-by-Nutrient Look at Milk
Calcium: 30% Daily Value. An 8–ounce serving of milk provides 30% of the Daily Value of calcium. Calcium helps build and maintain strong bones and teeth. This mineral also plays an important role in nerve function, muscle contraction and blood clotting. Vitamin D: 25% Daily Value. When fortified, a glass of milk provides about 25% of the Daily Value for Vitamin D. Vitamin D helps promote the absorption of calcium and enhances bone mineralization. Milk is one of the few dietary sources of this important nutrient. Protein: 16% Daily Value. The protein in milk is high quality, which means it contains all of the essential amino acids in the proportions that the body requires for good health. Protein builds and repairs muscle tissue and serves as a source of energy during high-powered endurance exercise. An 8–ounce glass of milk provides about 16% of the Daily Value for protein. Potassium: 11% Daily Value. Potassium regulates the body’s fluid balance and helps maintain normal blood pressure. It’s also needed for muscle activity and contraction. Vitamin A: 6%-10% Daily Value. A glass of 2%, 1% or fat-free milk provides 10% of the Daily Value of Vitamin A; a glass of whole milk provides 6%. This nutrient helps maintain normal vision and skin. It also helps regulate cell growth and maintains the integrity of the immune system. Vitamin B12: 13% Daily Value. Vitamin B12 helps build red blood cells that carry oxygen from the lungs to working muscles. Just one 8–ounce glass of milk provides about 13% of the Daily Value for this vitamin. Riboflavin: 24% Daily Value. Milk is an excellent source of riboflavin, providing 24% of the Daily Value. Riboflavin, also known as Vitamin B2, helps convert food into energy — a process crucial for exercising muscles. Niacin: 10% Dietary Reference Intake (or Niacin equivalent). Niacin is important for the normal function of many enzymes in the body and is involved in the metabolism of sugars and fatty acids. A glass of milk provides 10% of the Dietary Reference Intake for niacin. Phosphorus: 20% Daily Value. Phosphorus helps strengthen bones and generates energy in the body’s cells. Milk is an excellent source of phosphorus, providing 20% of the Daily Value.
Milk’s role in supplying these essential nutrients is so important that recognized health and human nutrition authorities recommend that people consume it according to the following schedule at various stages of life:
|Children||2 to 3||2 servings/day|
|Children||4 to 8||2 1/2 servings/day|
|Children||9 to 18||3 servings/day|
|Adults||19 to 50||3 servings/day|
Milk is probably best known for its calcium content. In fact, about 76% of all the calcium that is available to us in our total food supply is found in milk and other dairy products. Regardless of its fat content, milk provides about 300 milligrams of calcium per 8-ounce serving. A diet that includes three servings of milk, cheese or yogurt each day provides calcium and other nutrients that may be sufficient to help reduce the risk of osteoporosis, high blood pressure (hypertension) and colon cancer. The following chart shows the amount of calcium available in various types of milk and compares that availability with the caloric and fat values of those same milks (per 8–ounce serving).
Milk By the Numbers
|1 Cup Milk||Calories||Fat||Calcium|
|Chocolate, 2% Reduced-fat||178||4.7||284|
|Chocolate, 1% Low-fat||157||2.3||286|
Source: USDA Nutrient Database for Standard Reference.
The variety of nutrients it provides as well as the nutrient-density of milk lends credence to its often-heard description as “nature’s most nearly perfect food.” Virtually all of the fluid milk that is consumed in Washington is produced within our state. For more information, please click on th following resources: