Skip to content

Nutrients in a Nutshell

Macronutrients

The energy (or calorie)-containing components of food

Carbohydrates: Complex molecules composed of carbon, hydrogen and oxygen atoms. Plants trap energy from the sun and use it to convert carbon dioxide and water into carbohydrates. The basic units of all carbohydrates are sugar molecules either singly, as in glucose and fructose, or in pairs, as in sucrose and lactose, or in long chains of glucose molecules, as in starch.  All starches are ultimately broken down into glucose to supply energy (4 calories per gram) to the brain and body.  We use carbohydrates in the form of glucose as the fuel for all of our cells.  Our bodies store small amounts of carbohydrate in the form of glycogen in our liver and muscles.

Proteins: Complex molecules composed of carbon, hydrogen, oxygen and nitrogen atoms. Twenty-two different amino acids in a countless number of combinations make up proteins.  Eight of these, called essential amino acids, must be obtained from food; the rest we can make.  Proteins are part of every cell in the body, and make up the enzymes and hormones that control the body’s functions.  Protein is not stored in the body and must be replenished daily.  Excess protein is used for energy (4 calories per gram) but is an expensive source; the body must first detach and excrete the nitrogen. Protein does not have to come from animal foods, although animal proteins have the correct balance of essential amino acids and are therefore of high quality. Plant proteins are always low in some of the essential amino acids and thus must be combined with proteins from different plants or from animal foods to provide the full array of amino acids needed to build cells.

Lipids (fats and oils): Long chains of carbon, hydrogen and oxygen atoms. The basic units of lipids are fatty acids.  Two fatty acids, linoleic acid and alpha linolenic acid, are essential to life and must be consumed; the rest we can make.  Three fatty acids and a glycerol molecule make up a triglyceride.  Triglycerides are the major form of fat in foods and the major form for energy storage in the body.  Fats are solid at room temperature because they contain a higher proportion of saturated fatty acids and oils are liquid because they contain a higher proportion of unsaturated fatty acids. Both provide 9 calories per gram. Trans fatty acids are produced by the partial hydrogenation of liquid vegetable oils to make them solid at room temperature.

Fatty acid: A long chain of carbon atoms (4 to 26 or more) linked to each other and surrounded by hydrogen atoms.  One end of the chain contains an acid group (COOH) and the other end a methyl (CH3) group.

Triglyceride: Formed from 3 fatty acids bound to a glycerol molecule.  Glycerol is a form of alcohol.  Lipids are stored in this form in our bodies.

Saturated fatty acid: A fatty acid in which all of the carbon atoms are surrounded by hydrogen atoms.

Unsaturated fatty acid:  A fatty acid in which there are missing hydrogen atoms, meaning that the carbon atoms must form double bonds with each other.  Monounsaturated fatty acids have only one double bond and polyunsaturated fatty acids have 2 or more.  Linoleic acid is an essential omega-6 fatty acid found abundantly in vegetable and seed oils.  Alpha linolenic acid is an essential omega-3 fatty acid, which is difficult to obtain in the modern food supply.  Our bodies process it very inefficiently into EPA and DHA, which are preferentially obtained from cold water fish and cod liver oil.

Trans fatty acid:  Artificial trans fats are linked to many diseases and should be avoided at all costs. This means avoiding any product that lists hydrogenated oils in its ingredient list. Artificial trans fats are fatty acids that are a by-product of the hydrogenation process. They differ from the natural trans fat CLA (Conjugated Linoleic Acid) and have been associated with many diseases, including heart disease and diabetes. CLA, on the other hand has been associated with many health benefits, including having anti-cancer properties and promoting the growth of lean muscle mass. CLA, however, is highly deficient in the American diet, as it is many found in grass fed beef and milk from grass fed cows.

Micronutrients

Needed in tiny amounts; do not provide energy

Vitamins:

Complex molecules that occur in food and work in the body to regulate cell functions and enable chemical reactions to take place.

Fat-soluble vitamins (A, D, E, and K) can be stored in the body and are not easily destroyed in cooking.  Many are being found to regulate the functions of genes.  Must be ingested with fat in order to be well absorbed.

Water-soluble vitamins (C and the B vitamins).  These are more sensitive to degradation by heat, light or storage and are not stored in the body.  We need to eat them every day.

Minerals:

Small inorganic molecules that are involved in nervous system functioning, cellular processes, water balance, and structural systems.

Water:

Water has a number of vital functions in the body; it acts as a solvent, a lubricant, a transportation medium for nutrients and waste, and takes part in temperature regulation and chemical processes.  We require about 8 cups of water per day

Vitamins

Fat soluble

Vitamin A:  Functions in reproduction, growth of both the body and individual cells, and is crucial for night and color vision.  Preformed vitamin A is found in liver, egg yolk, butter, and whole and fortified milk.  The plant form, beta carotene, is found in dark green leafy vegetables, yellow fruits and vegetables and tomatoes and must be converted to vitamin A by the body.  The conversion is inefficient.

Vitamin D:  Functions in the intestinal absorption of calcium and phosphorus, maintains calcium levels in the bones and blood, and in gene regulation.  Most is obtained from sunlight shining on skin, so it is important to get some sun exposure without sunscreen.  Milk is fortified.  Cod liver oil, sardines and salmon are also sources.

Vitamin E:  Functions as an antioxidant and is important for iron metabolism and health of nervous and immune systems.  Vegetable oil, nuts and seeds are the highest sources, some green vegetables and fruit have small amounts.

Vitamin K:  Functions in blood clotting and bone health.  Green vegetables, especially kale, liver, butter, whole milk, cream, eggs and plant oils are the highest sources.  A small amount is synthesized in the intestines.

Water soluble

Vitamin C (ascorbic acid):  Functions as an antioxidant (works with vitamin E), and in the health of the skin and mucus membranes, absorption of iron and immune system.  Best sources are citrus fruits, tomatoes, potatoes with skins, green vegetables, and strawberries.

Vitamin B1 (thiamin):  Functions in the breakdown and use of carbohydrates by the body and in nerve health.  Good sources are pork, whole grains, peanuts, sunflower seeds, legumes, orange juice, “enriched” cereals.

Vitamin B2 (riboflavin):  Functions in turning food into energy.  Milk is a good source, as are mushrooms, broccoli, asparagus, spinach, liver, oysters, “enriched” grain products.

Niacin: Functions in turning food into energy.  Good sources are meats, fish, bran, mushrooms, peanuts, peanut butter, asparagus, “enriched” grains.

Pantothenic acid: Functions in many biochemical pathways.  Most foods contain it, so there is no danger of deficiency.

Biotin: Functions in several biochemical pathways.  Good sources are peanuts, peanut butter, egg yolk, cheese, cauliflower.  A little is synthesized in the intestine; no danger of deficiency.

Vitamin B6:  Functions in the metabolism of amino acids, and the synthesis of neurotransmitters and hemoglobin.  Animal protein foods are good sources but so are spinach, broccoli, bananas, sunflower seeds, and whole grains.

Folate (Folic acid):  Functions in the syntheses of proteins and DNA; prevent neural tube defects.  Found in green leafy vegetables, asparagus, broccoli, orange juice, legumes, “enriched” grain products.

Vitamin B12:  Functions in biochemical pathways that release energy from food, synthesize DNA, and maintain the health of nerves.  Prevents pernicious anemia.  The richest source is meat, followed by poultry, seafood, eggs and milk.  Only found in animal foods.

Choline:  Functions in keeping cell membranes intact.  Some is produced by the body.  Other sources include lettuce, peanuts, liver, coffee, cauliflower and many others.

Minerals—major (needed in larger amounts)

Sodium:  Functions in fluid balance, nerve impulse transmission, and transporting nutrients in and out of cells.  Major sources are salt, soy and other sauces, processed and restaurant foods, soups, salty snacks.

Potassium:  Functions in fluid balance, nerve impulse transmission, and transporting nutrients in and out of cells.  Needs to be in balance with sodium.  Best sources are spinach, squash, bananas, oranges and juice, most vegetables and fruits, milk, meat, whole grains, and legumes.

Chloride: Functions in acid production in the stomach and aids nerve transmission.  The major source is table salt, but some is found in fruits and vegetables, and processed food (because of the added salt).

Phosphorus:  Functions in the structure of bones and cellular molecules, and in converting energy and maintaining acid-base balance.  Found in all foods; no danger of deficiency.

Magnesium:  Functions in maintaining bone strength; works in over 300 enzymatic reactions, especially those generating energy for the body.  The best sources are wheat bran, whole grains, green vegetables, nuts, legumes, and chocolate.

Minerals—trace (needed in very small amounts)

Iron: Functions as part of the hemoglobin molecule to transport oxygen in the blood and in many bodily reactions involving oxygen.  Meats are the best source, followed by seafood, but there are also many vegetable sources, such as spinach, broccoli, peas, bran, “enriched” cereals.  A deficiency leads to anemia.

Zinc: Functions in over 300 reactions involving synthesis of DNA, protein metabolism, wound healing, growth, immunity, alcohol metabolism, sexual development and reproduction.  The best sources are seafood, meat, whole grains, green leafy vegetables, poultry, eggs, nuts and legumes.

Selenium: Functions in many biochemical reactions.  The best sources are meats, eggs, fish, seafood, and whole grains.

Iodine:  Functions as an essential component of thyroid hormones.  The best sources are saltwater fish, dairy products, vegetables grown in iodine-rich soil, and iodized salt.

Copper:  Functions in many biochemical reactions.  The best sources are liver, cocoa, legumes, nuts, whole grains, dried fruits and seafood.

Fluoride:  Increases resistance of tooth enamel to dental caries.  Sources are water containing natural fluoride, toothpaste, dental treatments, tea, and seaweed.

Chromium:  Enhances the function of insulin and thus blood glucose control.  The best sources are egg yolks, whole grains, pork, nuts, mushrooms and beer.

Manganese:  Functions in the formation of bone, and in amino acid, cholesterol and carbohydrate metabolism.  Best sources are nuts, oats, legumes and tea.

Molybdenum: Functions in a small number of biochemical reactions.  The best sources are legumes, grains, nuts, meat and milk.