Carbohydrates, proteins, fats, water, vitamins and minerals are the six classes of nutrients that your body needs for survival, growth and to maintain health. A balanced diet comprising whole grains, fruits, vegetables, meat and dairy foods is the best way of ensuring that you are getting all these nutrients. Since each nutrient is essential for specific functions in the body, prolonged absence of any nutrient from the diet has a negative impact on health.
Simple and complex carbohydrates are the main source of energy in most diets. Although used by all cells, carbohydrates are especially important for the normal functioning of the central nervous system, brain and red blood cells. Fiber, an indigestible form of carbohydrate found in whole grain foods, fruits and vegetables, helps to maintain normal bowel movement that reduces risk of constipation, hemorrhoids, diverticulosis and colon cancer. By increasing excretion of cholesterol, fiber may decrease risk of heart disease, and by providing a feeling of fullness, which may help reduce risk of obesity.
The proteins in your body carry out many functions, ranging from forming organ tissues to making antibodies that fight infection. They are present in every cell of your body, including muscles, bones, skin, nails and hair, and are critical for synthesis of hormones, enzymes, DNA and RNA. Proteins enable normal growth and development of children and teens, and of the fetus during pregnancy, and they provide a secondary source of energy. Eggs, meat, poultry, fish, soybeans, legumes, milk and dairy products are some of the best sources of protein.
Fats and Lipids
Although fat intake is often associated with weight gain, obesity and risk of heart disease, fat is an essential nutrient required in small amounts to maintain health. Fats are crucial for absorption and transport of fat-soluble vitamins A, D, E and K. They help form and maintain cell membranes, insulate and cushion vital organs and are a concentrated source of energy. Opt for heart-healthy unsaturated fats such as olive, canola and sunflower oils in your diet, instead of saturated fats such as butter and lard that can increase risk of cardiovascular disease.
Often ignored as a nutrient, water is vital for numerous functions in the body. It forms about 60 percent of the body weight and helps to maintain blood volume, blood pressure and body temperature. It lubricates joints, moisturizes tissues of the eyes, nose and mouth, enables nerve and muscle function and prevents constipation. Another important function of water is the transport of nutrients to the different cells and excretion of waste from the body. While the need for water varies with age, adults need about eight cups of water every day.
Of the 13 vitamins essential for health, nine are water-soluble and four are fat-soluble. Water-soluble B vitamins thiamin, riboflavin, niacin, folate, vitamin B-6, biotin, pantothenic acid and vitamin B-12 help release energy from food, prevent neural tube birth defects, are needed for DNA and RNA synthesis and play a role in development of the nervous system. Vitamin C acts as an antioxidant and helps build strong gums, teeth and bones. Fat-soluble vitamin A is necessary for vision, vitamin D helps build strong bones, vitamin E functions as an antioxidant and vitamin K aids clotting of blood.
Minerals required in amounts over 100 milligrams daily, such as calcium, phosphorus, magnesium, sulfur, sodium, chloride and potassium are called major minerals, while iron, zinc, copper, manganese, iodine, selenium, molybdenum, chromium and cobalt are trace minerals because their daily requirement is less than 15 milligrams. However, all these minerals are vital for normal functioning of the body such as building and maintaining healthy bones and teeth, formation of blood cells, oxygen transportation, healing wounds, clotting of blood, transmission of nerve signals, contraction of muscles and regulation of water balance.
- Vanderbilt University: Nutrition 101
- Iowa State University: Key Nutrients
- University of Illinois: Macronutrients: The Importance of Carbohydrates, Protein and Fat
- Encyclopedia Britannica: Human Nutrition: Essential Nutrients
- Elmhurst College: Overview of Metabolism
- Washington State University: Nutrition Basics
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