Teens and Dietary Fat
To some degree, fat is an essential ingredient in our diet. It's needed to carry and store fat-soluble vitamins (vitamins A, D, E, and K), protect cell walls and internal organs, insulate the body, and maintain healthy skin and hair. Yet, too much fat can be unhealthy. High levels of dietary fat, especially saturated fats (those mostly from animal sources) increase the risk of developing chronic medical problems, such as obesity, heart disease, stroke, and certain types of cancer.
Nutrition experts recommend we limit fat consumption to no more than 30 percent of our total calories. Dietary fat intake is particularly worrisome among teens. More and more teens are eating their meals and snacks away from home at fast food restaurants and other eating establishments. These foods are typically higher in total fat and saturated fat and contain less fiber, calcium, and iron than foods prepared at home. A high fat diet and sedentary lifestyle have contributed to an epidemic of obesity among teens. According to a National Health Survey (HANES III), more than 15 percent of 12 to 19-year-olds are overweight. Overweight children typically don't lose the excess weight and grow into overweight adults.
Teens, Sex Hormones, and Breast Cancer Risk
Diet influences the risk for many types of disease. High levels of fat increase the risk of obesity, an important known risk factor for the development of many types of cancer. Breast cancer rates are high in countries like the U.S., where fat makes up about 34 percent of total calories. In China, where breast cancer rates are relatively low, fat makes up only 15 to 20 percent of calories. However, researchers caution, these are merely observations and the findings do not necessarily demonstrate a link between dietary fat and breast cancer risk. Many other factors, such as age at the first menstrual period and family history of breast cancer also influence personal risk for the disease.
A high-fat diet also increases the levels of estrogen and progesterone, two female sex hormones that may be associated with an increased risk for breast cancer later in life. Researchers wanted to see if dietary intervention could reduce the levels of these hormones. Nearly 300 prepubertal girls were entered into a study and randomly assigned to receive usual care or dietary intervention. Those in the intervention group received behavioral therapy and nutrition counseling to reduce their fat intake. This group of girls lowered their fat intake from 34 percent calories from fat to 28 percent calories from fat. That can be done with some simple substitutions, such as eating a piece of fruit instead of a candy bar or a bag of potato chips, or a salad instead of fries. Although it was only a modest reduction of six percent, the girls in the intervention group had significantly lower concentrations of sex hormones.
The study doesn't demonstrate a definite link between dietary fat and risk for breast cancer. However, for some women higher levels of sex hormones are associated with an increased risk for breast cancer. During adolescence, decreasing the intake of dietary fat may lower the levels of sex hormones and may reduce the risk of breast cancer later in life.
Teens and Dietary Fat