Producing energy is an essential role of carbohydrates in your diet.

Four Critical Roles That Nutrients Play in Vital Body Functions

by Sue Roberts, M.P.H., R.D.

Nutrients perform a multitude of functions, including energy production, growth and development, regulation and hydration, which keep your body running smoothly. Food provides the majority of required nutrients, although your body also produces some. Six types of nutrients exist, namely carbohydrates, fats, proteins, water, vitamins and minerals. Getting the right balance of these promotes good health, both for children and adults.

Energy Production

Energy fuels all of your body’s internal functions and daily living activities, in much the same way that gas fuels your car. The “gas” your body depends on comes mainly from carbohydrates. Even though fats and proteins can be burned for energy, they have other primary functions. Your brain and nervous system rely solely on carbohydrates for fuel. Carbohydrates and protein provide four calories per gram; fat provides nine calories per gram. Alcohol provides seven calories per gram, but is not technically considered a nutrient since it makes no contribution to health.

Growth and Development

Muscles, bones and organs are constantly being broken down and rebuilt. Proteins are largely responsible for this. Adults routinely generate and degrade 250 grams of protein daily, report Gordon Wardlaw and Anne Smith in “Contemporary Nutrition.” The Council for Responsible Nutrition notes that red blood cells live only 120 days; new ones continually replace the old. According to the Dietary Reference Intakes, teen and adult women typically need 46 grams of protein per day, male teens require between 52 and 56. Depending upon their age, children need 13 to 34 grams daily. Over time, an insufficient protein intake affects proper muscle and organ growth. Normal fluid levels become unbalanced, too.


Proper body functioning depends upon a wide variety of complex and interrelated chemical processes, requiring regulation to be effective. Vitamins and minerals are largely responsible for this regulation. Hormones, neurotransmitters and collagen, a type of connective tissue found in tendons, bones and teeth, depend upon vitamin C for their synthesis. As an antioxidant, vitamin C helps prevent cancer cell growth. Rich food sources of vitamin C include green peppers, citrus fruits, Brussels sprouts and broccoli. The mineral copper, found mainly in legumes, liver, nuts, seeds and seafood, assists in regulating hormone synthesis, protein metabolism and hemoglobin formation.


You may not think of water as a nutrient, but it plays a critical role in many body processes. Water comprises approximately 50 to 70 percent of your body’s weight, report Ellie Whitney and Sharon Rolfes in “Understanding Nutrition.” Water forms the foundation of body fluids, and it aids in temperature regulation and urine production. Cellular processes are so dependent upon water that death can occur after only several days without it. According to the Dietary Reference Intakes, adult women require approximately 11 cups of water daily; children need between 5.5 and 10 cups, depending on age. Dietary sources of water include fruits, vegetables, juices, milk and other beverages.

About the Author

Sue Roberts began writing in 1989. Her work has appeared in such publications as “Today’s Dietitian” and "Journal of Food Science." Roberts holds a Bachelor of Science in nutrition from Pennsylvania State University, a Master of Public Health in nutrition from the University of Minnesota and a Master of Science in food science from Michigan State University. She is a registered dietitian and certified nutritionist.

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