nutrient source

Food sources of nutrients and how the nutrient functions in the body

CALORIES are needed to provide energy so the body functions properly. The number of calories in a food depends on the amount of energy the food provides. The number of calories a person needs depends on age, height, weight, gender, and activity level. People who consume more calories than they burn off in normal daily activity or during exercise are more likely to be overweight.

Fat: 1 gram = 9 calories
Protein: 1 gram = 4 calories
Carbohydrates: 1 gram = 4 calories
Alcohol: 1 gram = 7 calories

FAT should account for 30% or less of the calories consumed daily, with saturated fats accounting for no more than 10% of the total fat intake. Fats are a concentrated form of energy which help maintain body temperature, and protect body tissues and organs. Fat also plays an essential role in carrying the four fat-soluble vitamins: A, D, E, and K.

Excess calories from protein and carbohydrates are converted to and stored as fat. Even if you are eating mostly “fat free” foods, excess consumption will result in additional body fat. Fat calories in food are readily stored, while it takes energy to transform protein and carbohydrates to body fat. The only proven way to reduce body fat is to burn more calories than one consumes.

Saturated Fat:

• tends to increase blood cholesterol levels. Most saturated fats tend to be solid at room temperature, with the exception of tropical oils.
• found mostly in meat and dairy products, as well as some vegetable oils, such as coconut and palm oils (tropical oils). Butter is high in saturated fat, while margarine tends to have more unsaturated fat.

Polyunsaturated Fat:

• tends to lower blood cholesterol levels
• found mostly in plant sources. (safflower, sunflower, soybean, corn, cottonseed)

Monounsaturated Fat:

• tends to lower LDL cholesterol (the “bad” cholesterol)
• found in both plant and animal products, such as olive oil, canola oil, peanut oil, and in some plant foods such as avocado

CHOLESTEROL intake should not exceed 300 milligrams a day. Individuals differ on their absorption of dietary cholesterol, what is important is one’s level of blood cholesterol. High blood cholesterol has been linked to the occurrence of atherosclerosis. Atherosclerosis is a buildup of fatty deposits in the coronary arteries and other blood vessels, and is a leading cause of heart attacks.

Dietary cholesterol is only found in foods from animal sources, including meat, fish, milk, eggs, cheese, and butter. You may have heard the terms HDL and LDL discussed in relation to blood cholesterol and heart disease. HDL and LDL are lipoproteins, substances found in the bloodstream that transports cholesterol and triglycerides in the body.

HDLs help remove cholesterol from the blood, protecting you from heart disease (atherosclerosis).

LDLs are thought to deposit cholesterol in artery walls, increasing your risk of heart disease (atherosclerosis). Most abundant type, LDL carries approximately 65% of the total circulating cholesterol. High levels of LDL are associated with atherosclerosis.

CARBOHYDRATES are a major source of energy and should account for 50% to 60% of calories consumed each day.


• monosaccharides and disaccharides
• found in fruits (sucrose, glucose, fructose, pentose), milk (lactose), and soft drinks and sweets.

Complex Carbohydrates:

• found in whole grain cereals, flour, bread, rice, corn, oats, potatoes, and legumes.

DIETARY FIBER Sources of fiber from highest to lowest are high fiber grain products, nuts, legumes (kidney, navy, black and pinto beans), vegetables, fruits, and refined grain products.

Soluble Fiber:

• may help lower blood cholesterol by inhibiting digestion of fat and cholesterol; helps control blood sugar in people with diabetes.
• found in peas, beans, oats, barley, some fruits and vegetables (apples, oranges, carrots), and psyllium.

Insoluble Fiber:

• helps prevent constipation, hemorrhoids, and diverticulosis
• found in bran (wheat, oat, and rice), wheat germ, cauliflower, green beans, potatoes, celery

PROTEIN should account for 10% to 20% of the calories consumed each day. Protein is essential to the structure of red blood cells, for the proper functioning of antibodies resisting infection, for the regulation of enzymes and hormones, for growth, and for the repair of body tissue.

Amino acids are the building blocks of protein and are found in a variety of foods. Meat, milk, cheese, and egg are complete proteins that have all the essential amino acids. Other sources of protein include whole grains, rice, corn, beans, legumes, oatmeal, peas, and peanut butter. For those who do not eat meat, eggs, or dairy products, it is important to eat a variety of these other foods in order to get enough protein.

SODIUM intake is recommended to be less than 3,000 milligrams daily. One teaspoon of table salt contains about 2,000 milligrams of sodium. The difference between “sodium” and “salt” can be confusing. Sodium is a mineral found in various foods including table salt (sodium chloride). Table salt is 40% sodium.

People with high blood pressure (hypertension) may be instructed by their doctor or dietitian to reduce sodium intake. High blood pressure can increase the risk of heart attack, stroke, or kidney disease. The body needs a small amount of sodium to help maintain normal blood pressure and normal function of muscles and nerves. High sodium intake can contribute to water retention.

Sodium is found in table salt, baking soda, monosodium glutamate (MSG), various seasonings, additives, condiments, meat, fish, poultry, dairy foods, eggs, smoked meats, olives, and pickled foods.

POTASSIUM is essential for maintaining proper fluid balance, nerve impulse function, muscle function, cardiac (heart muscle) function

Sources: bananas, raisins, apricots, oranges, avacadoes, dates, cantaloupe, watermelon, prunes, broccoli, spinach, carrots, potato, sweet potato, winter squash, mushrooms, peas, lentils, dried beans, peanuts, milk, yogurt, lean meats

VITAMINS AND MINERALS are required for the regulation of the body’s metabolic functions, and are found naturally in the foods we eat. Many foods are fortified in order to provide additional nutrients, or to replace nutrients that may have been lost during the processing of the food. Most people are able to obtain satisfactory nutrition from the wide selection of foods available in the United States.

If a person is not able to eat a variety of foods from the basic food groups, then a vitamin and mineral supplement may be necessary. However, except for certain unusual health conditions, very few persons should need more than 100% of the Recommended Daily Allowance for any single nutrient. Large doses of vitamin and mineral supplements can be harmful.

Vitamins come in two varieties: fat soluble and water-soluble. Fat-soluble vitamins can be stored in the body for long periods of time, while excess amounts of water-soluble vitamins are excreted in the urine.

Vitamin A

• needed for new cell growth, healthy skin, hair, and tissues, and vision in dim light
• sources: dark green and yellow vegetables and yellow fruits, such as broccoli spinach, turnip greens, carrots, squash, sweet potatoes, pumpkin, cantaloupe, and apricots, and in animal sources such as liver, milk, butter, cheese, and whole eggs.

Vitamin D

• promotes absorption and use of calcium and phosphate for healthy bones and teeth
• sources: milk (fortified), cheese, whole eggs, liver, salmon, and fortified margarine. The skin can synthesize vitamin D if exposed to enough sunlight on a regular basis.

Vitamin E

• protects red blood cells and helps prevent destruction of vitamin A and C
• sources: margarine and vegetable oil (soybean, corn, safflower, and cottonseed), wheat germ, green leafy vegetables.

Vitamin K

• necessary for normal blood clotting and synthesis of proteins found in plasma, bone, and kidneys.
• sources: spinach, lettuce, kale, cabbage, cauliflower, wheat bran, organ meats, cereals, some fruits, meats, dairy products, eggs.

Vitamin C (Ascorbic acid)

• an antioxidant vitamin needed for the formation of collagen to hold the cells together and for healthy teeth, gums and blood vessels; improves iron absorption and resistance to infection.
• sources: many fresh vegetables and fruits, such as broccoli, green and red peppers, collard greens, brussel sprouts, cauliflower, lemon, cabbage, pineapples, strawberries, citrus fruits

Thiamin (B1)

• needed for energy metabolism and the proper function of the nervous system
• sources: whole grains, soybeans, peas, liver, kidney, lean cuts of pork, legumes, seeds, and nuts.

Riboflavin (B2)

• needed for energy metabolism, building tissue, and helps maintain good vision.
• sources: dairy products, lean meats, poultry, fish, grains, broccoli, turnip greens, asparagus, spinach, and enriched food products.


• needed for energy metabolism, proper digestion, and healthy nervous system
• sources: lean meats, liver, poultry, milk, canned salmon, leafy green vegetables

Vitamin B6 (Pyridoxine)

• needed for cell growth
• sources: chicken, fish, pork, liver, kidney, whole grains, nuts, and legumes

Folate (Folic Acid)

• promotes normal digestion; essential for development of red blood cells
• sources: liver, yeast, dark green leafy vegetables, legumes, and some fruits

Vitamin B12

• needed for building proteins in the body, red blood cells, and normal function of nervous tissue
• sources: liver, kidney, yogurt, dairy products, fish, clams, oysters, nonfat dry milk, salmon, sardines


• needed for healthy bones and teeth, normal blood clotting, and nervous system functioning
• sources: dairy products, broccoli, cabbage, kale, tofu, sardines and salmon


• needed for the formation of hemoglobin, which carries oxygen from the lungs to the body cells
• sources: meats, eggs, dark green leafy vegetables, legumes, whole grains and enriched food products


• needed for healthy bones and teeth, energy metabolism, and acidbase balance in the body
• sources: milk, grains, lean meats, food additives


• needed for healthy bones and teeth, proper nervous system functioning, and energy metabolism
• sources: dairy products, meat, fish, poultry, green vegetables, legumes


• needed for cell reproduction, tissue growth and repair
• sources: meat, seafood, and liver, eggs, milk, whole-grain products

Pantothenic Acid

• needed for energy metabolism
• sources: egg yolk, liver, kidney, yeast, broccoli, lean beef, skim milk, sweet potatoes, molasses


• needed for synthesis of hemoglobin, proper iron metabolism, and maintenance of blood vessels
• sources: seafood, nuts, legumes, green leafy vegetables


• needed for enzyme structure
• sources: whole grain products, fruits and vegetables, tea