Every five years, a panel of nutrition experts comes together to review scientific evidence regarding diet and health. Their work culminates in a comprehensive set of recommendations for Americans (ages 2 and older) known as the Dietary Guidelines for Americans. The most recent (2010) report emphasizes the need for Americans to reach and maintain a healthy weight, and to choose nutrient-dense foods and beverages more often — meaning those that are rich in nutrients and other substances associated with good health, with relatively fewer calories.
Fat-free and low-fat milk, cheese, and yogurt are highlighted as examples of nutrient-dense choices. They provide calcium, potassium, and vitamin D (when fortified) — all of which are commonly lacking in many Americans’ diets. They also contain high quality protein and are important sources of other minerals such as magnesium, phosphorus, and zinc; vitamins such as riboflavin and vitamin B12; and other beneficial components such as conjugated linoleic acid – a compound that may reduce cancer risk.
Bone is living tissue that is always in flux. Throughout the lifespan, bones are constantly being broken down and built up in a process known as remodeling. Bone cells called osteoblasts build bone, while other bone cells called osteoclasts break down bone.
In healthy individuals who get enough calcium and physical activity, bone production exceeds bone destruction up to about age 30. After that, destruction typically exceeds production.
Adequate, lifelong dietary calcium intake is necessary to reduce the risk of osteoporosis. Consuming adequate calcium and vitamin D and performing regular, weight-bearing exercise are also important to build maximum bone density and strength. After age 30, these factors help slow bone loss, although they cannot completely prevent bone loss due to aging.
Milk and other dairy products are probably best known for their role in building and maintaining strong bones. In addition to this benefit, there is evidence that fat-free and low-fat dairy products may reduce the risk of cardiovascular disease, high blood pressure, and type II diabetes among adults. By choosing unsweetened milk and yogurt, people can reap these nutritional benefits without the excess sugar and calories.
Getting young children in the habit of drinking milk is important as this is a good predictor of milk consumption into adulthood. One way to accomplish this is to serve fat-free or low-fat milk with meals for all family members — children and adults. In addition, many children tend to drink less milk as they grow older. Limiting the availability of less-healthy alternatives such as soft drinks, fruit drinks with added sugars, and sports drinks also may be of benefit.
Some people avoid milk and other dairy products because of concerns about lactose intolerance. Lactose intolerance is the result of a limited ability to digest lactase (a natural milk sugar), resulting in unpleasant gastrointestinal symptoms. Fortunately, there are strategies that can be used so that milk and other dairy products still can be consumed. One strategy is to drink small amounts of milk with meals; another is to eat yogurt with live and active cultures. There also are a variety of lactose-free and lactose-reduced dairy products available in grocery stores, and temporary aids such as lactase supplements. For some, fortified soy milk may be an appropriate alternative. It always is advisable to discuss symptoms and options with a health care provider to find out what is best for you or a family member.
For details about the Dietary Guidelines for Americans, visit www.cnpp.usda.gov/dietaryguidelines.htm.
Jamie Benedict is an associate professor of nutrition in the College of Agriculture, Biotechnology and Natural Resources at the University of Nevada, Reno. She teaches several undergraduate nutrition courses and directs the nutrition graduate program. Her research focuses on environmental characteristics that influence nutritional health, including school policies and practices. She earned her doctorate in nutritional science at the University of Arizona, and is a registered dietitian.