Amino acids are chemical compounds found in plant and animal proteins. There are 20 different types of amino acids. About half of these the body synthesizes (or creates); they are called nonessential amino acids. The rest—called essential amino acids—must be acquired from diet. The body uses both nonessential and essential amino acids to make proteins that are an integral element in repair and growth of body tissue, immune protection, and the transmission of nerve impulses.
ANTHOCYANINS
Anthocyanins are a large group of flavonoid pigments in the red-blue-purple range. Individual anthocyanins show promise as anti-cancer and anti-inflammatory agents.
Antioxidants help protect the body against free radicals—unstable molecules that can damage cells and cause cancer. A number of antioxidants are found in food while others are synthesized in the body. Many antioxidants come in the form of vitamins, such as vitamins A, C, and E, while others are phytonutrients, such as lycopene, beta-carotene, lutein, and selenium. Whole foods, such as fruits, vegetables, nuts, and grains, are among the best sources of antioxidants.
ARGININE
Also known as L-arginine, this amino acid is synthesized by most healthy adults. Arginine plays a crucial role in the body’s ability to rid itself of ammonia. It also relaxes blood vessels (as nitric oxide) and may be useful in treating heart failure, erectile dysfunction, and vascular headaches.
ASTAXANTHIN
Astaxanthin is a carotenoid that produces a red pigment most commonly found in seafood (it gives salmon its dark pink color). It is a strong antioxidant, which may promote heart health by protecting arterial fat from oxidation.
BETA-CAROTENE
A member of the large carotenoid family, beta-carotene is a strong red-orange pigment, first discovered in carrots. It’s used by the body mainly as a source of vitamin A, and it also functions as an antioxidant.
BETA-CRYPTOXANTHIN
Similar to beta-carotene, beta-cryptoxanthin is a carotenoid that can be converted in the body to vitamin A (although only about half as effectively as beta-carotene). In its pure form, it is a red pigment and an antioxidant.
BETA-GLUCANS
A group of sugars found in the cell walls of certain plants and fungi, beta-glucans help boost immunity and are used to fight cancer, diabetes, and cholesterol. Dietary beta-glucans are found in some mushrooms, bran, seaweed, and yeast cells.
Though little is known about its role in the body, boron may promote bone and joint health and increase estrogen levels in women. This trace element is found in all plant foods.
CAFFEOYLQUINIC ACID
An antioxidant and possible cancer inhibitor found in coffee, artichokes, and propolis, a resin created by bees from tree sap. Caffeoylquinic acid may inhibit cancer growth and reduce the risk of inflammatory and cardiovascular diseases.
Along with protein and fats, carbohydrates are one of the main dietary components the body needs in order to function. Carbohydrates come primarily in the form of sugars, starches, and fiber (the latter can’t be digested). Once carbohydrates are consumed, the digestive system converts the sugars and starches into sugar molecules, which enter the bloodstream and provide energy for cells and tissue. Whole, minimally processed foods, such as vegetables, fruits, whole grains, legumes, and low-fat dairy, are the best kinds of carbohydrates; the fiber in these foods is important for digestive health. It also helps slow sugar absorption, resulting in an even, sustained level of energy. Overly processed foods—including sugary cereals, white flour, and potato chips—have little fiber, and their starches and sugars rapidly turn into glucose in the body, spiking blood sugar, which can cause energy levels to quickly plummet. Excess glucose that the body doesn’t need for immediate energy, or for future reserves in the form of glycogen (stored in the liver and muscles), turns to fat.
These fat-soluble plant pigments, ranging in color from yellow through orange to red, typically function as antioxidants; the body can even convert a few into vitamin A. The best-known carotenoid is carotene, from which the group gets its name.
A waxy fat compound, cholesterol is important for making some hormones and forming cell membranes. Cholesterol is found in animal foods and in the body, where the liver manufactures it from fatty foods. Cholesterol is transported through the body by molecules called lipoprotein: low-density lipoprotein (LDL) is known as “bad” cholesterol because it builds up on arterial walls and can lead to atherosclerosis; high-density lipoprotein (HDL) is considered “good” cholesterol because it helps move excess cholesterol from the arteries to the liver for disposal, and may protect against heart attack.
CYNARIN
Cynarin is a form of dicaffeoylquinic acid, which contributes to a sensation of sweetened taste after eating artichokes. Found in artichokes and echinacea, cynarin has been studied for its antioxidant, immuno-suppresant, and anti-microbial effects.
This antioxidant has proved successful in prohibiting the growth of cancerous tumors in animal studies (although the research is still pending for humans). Ellagic acid is found mainly in strawberries, cranberries, raspberries, pomegranates, and walnuts.
ELLAGITANNINS
Found in fruits and vegetables, ellagitannins are phytochemicals that convert into ellagic acid when eaten.
ERGOTHIONEINE
An amino acid and an antioxidant, ergothioneine’s purpose in the human body is still being studied. Ergothioneine is produced only by bacteria and fungi (it gets its name from the grain-loving ergot fungus) and obtained exclusively through diet.
Along with carbohydrates and protein, fats are one of the body’s most basic nutrients. Just as amino acids make up protein molecules, so do fatty acids comprise fat molecules. Fats are considered to be saturated or unsaturated:
Saturated fats are primarily found in animal products. In the diet, saturated fats tend to increase the body’s production of LDL (“bad”) cholesterol and reduce the production of HDL (“good”) cholesterol. They have a higher melting point than similar unsaturated fats, and foods containing saturated fats (like butter) are often solid at room temperature.
UNSATURATED FATS
Unsaturated fats are mostly found in plant products, and they tend to lower the body’s production of LDL (“bad”) cholesterol. There are two main types of unsaturated fats:
Monounsaturated fats Found in olive oil and nuts, monounsaturated fats tend to increase the body’s production of HDL (“good”) cholesterol and reduce the production of LDL (“bad”) cholesterol.
Polyunsaturated fats Polyunsaturated fats tend to reduce the body’s production of cholesterol—both HDL (“good”) cholesterol and LDL (“bad”) cholesterol. Both omega-3 and omega-6 are polyunsaturated fats that have many health benefits. Omega-3 fatty acids are found in many types of cold-water fish, walnuts, and flaxseed; they are crucial to brain and heart health, and may reduce inflammation and lower risk of some chronic diseases (see OMEGA-3 FATTY ACIDS for more information). Omega-6 fatty acids, which are also important to brain development, are plentiful in many types of vegetable oil, such as corn, soybean, and safflower. Unfortunately, many Americans get too many omega-6 fatty acids in their diets, and this imbalance may promote inflammation.
The indigestible portion of plant foods, fiber passes through the body without being absorbed. There are two main types: insoluble fiber, which does not dissolve in water and helps prevent constipation; and soluble fiber, which forms a gel in water, lowers cholesterol, slows the body’s absorption of sugar, and has probiotic properties, thereby helping the immune system. Fruits, vegetables, whole grains, and legumes contain both types. Adequate consumption of fiber is associated with a lower risk of heart disease and type 2 diabetes.
A large group of plant-produced compounds (primarily pigments in the yellow and blue-to-red range), flavonoids may promote antioxidant and other beneficial responses in the body.
GAMMA-TOCOPHEROL
Gamma-tocopherol is a potent antioxidant that disables nitrogen free radicals, and is one of the eight compounds that make up the vitamin E group.
GLUTATHIONE
The most important cellular antioxidant found in the body, glutathione prevents damage by carcinogens, neutralizes free radicals, and inhibits other kinds of toxic damage. It is essential to proper functioning of the immune, nervous, gastrointestinal, and pulmonary systems. Many foods contain glutathione, but a diet rich in fresh vegetables and fruits will help the body produce more of this powerful antioxidant.
Indoles are a group of alkaloid (bitter-tasting, nitrogen-based) compounds found in broccoli, cabbage, and other cruciferous vegetables. These phytonutrients are thought to be powerful cancer fighters. One variety, indole-3-carbinol, is believed to be particularly effective at fighting breast cancer.
ISOTHIOCYANATES
Also found in the cruciferous family of vegetables, isothiocyanates have been shown in animal studies to have anti-cancer properties.
LENTINAN
Lentinan stimulates the body’s immune response, and recent studies suggest it can improve longevity and the quality of life for cancer patients. Found in shiitake mushrooms, lentinan is also being investigated for amplifying the immune response to pathogens.
LIGNANS
A group of chemicals found primarily in flaxseed, lignans are known as phytoestrogens—or plant-derived estrogen-like compounds. They may have antioxidant properties, although their role in human health is still being studied.
LIGNINS
Commonly found in trees and woody plants, lignins are a form of insoluble dietary fiber. Animal studies suggest lignins may have antiviral effects.
LUTEIN
One of the carotenoid pigments, lutein means “yellow.” Lutein is an antioxidant important to eye health and is thought to protect the retina from the negative oxidative effects of light. It may also help prevent age-related macular degeneration.
LYCOPENE
A bright red pigment, lycopene is a member of the large group of carotenoids. This powerful antioxidant is primarily found in tomatoes, watermelon, and red grapefruit. Foods rich in lycopene appear to reduce the risk of prostate cancer.
LYSINE
This essential amino acid helps build protein in the body. It must be consumed through lysine-rich foods, such as beans, meat, and eggs.
MELATONIN
Melatonin is important to the body’s daily biological rhythms and sleep patterns. A hormone synthesized by the body from the amino acid tryptophan, melatonin is also found in foods such as cherries, bananas, oats, and onions. Melatonin is produced by the pineal gland, the retina, and the skin; production of this hormone increases at night, particularly in a dark environment.
Whereas vitamins are organic (i.e., they contain carbon) and are produced by plants and animals, minerals are derived from inorganic substances, from the earth and water. Plants absorb these minerals, which are in turn eaten by animals. The body needs some minerals, such as calcium, in large quantities. Trace minerals, on the other hand, such as chromium, iron, selenium, and zinc, are needed only in small quantities each day.
CALCIUM
A nutritional mineral essential to bone health and growth, calcium is also required for muscle and heart function; when the body lacks calcium, it will draw calcium from the bones to support these vital functions. Deficiency may, therefore, result in fractures and diseases such as osteoporosis.
COPPER
A nutritional trace mineral that helps the body absorb iron, copper plays a role in brain development, immune function, and bone strength.
IRON
This trace mineral is required for transfer of oxygen to the body through the bloodstream, and is an important component of muscle cells and red blood cells. Sufficient iron is important to brain development and a healthy immune system. There are two main dietary forms of iron: heme (found in animal foods) and nonheme (found in plant foods). Heme iron is more readily absorbed by the body. An overdose of this mineral can be toxic, while deficiency may result in anemia and fatigue.
MAGNESIUM
A trace mineral, magnesium is essential for helping the body absorb and regulate calcium, making it crucial for bone health. Magnesium also helps regulate heart rhythms and reduce blood pressure. Deficiency has been associated with asthma, osteoporosis, cardiovascular disease, muscle spasms, and migraines.
MANGANESE
A nutritional trace mineral, manganese is required by enzymes involved in healing wounds, forming bone, and metabolizing food. Manganese also helps protect mitochondria (components of the body’s cells that produce energy) from oxidative damage.
PHOSPHORUS
A nutritional mineral, phosphorus is essential to every cell in the body for energy production and regulation of the body’s pH level. Phosphorus helps bone mineralization; 85 percent of the body’s phosphorus is found in bone. Many foods contain phosphorus, and deficiency is rare.
POTASSIUM
A nutritional mineral that helps maintain the liquid balance between cells and their surroundings, potassium modulates nerve response and is necessary for muscle contraction. It is also essential for healthy brain and nerve function, the production of DNA and RNA, and the maintenance of normal blood pressure. Adequate potassium intake can reduce the risk of high blood pressure and stroke. Deficiency may result in muscle weakness, intestinal blockage, and heart rhythm irregularities.
SELENIUM
Selenium is a nutritional trace mineral that acts as a catalyst to recharge antioxidants and has a role in enzyme production. Some studies have shown a correlation between sufficient dietary selenium and a reduced risk of cancer and cardiovascular diseases. Adequate selenium is important to a healthy immune system, although large amounts can be harmful.
ZINC
A nutritional trace mineral, found in more than 200 enzymes, zinc has roles in the metabolism of RNA, DNA, and proteins. It is essential to the function of the immune system.
A type of polyunsaturated fat (along with omega-6 fatty acids), omega-3s are important to cardiovascular and neurological health. There are three types: ALA (alpha-linolenic acid), EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid). Of the three, ALA is considered an essential fatty acid; the body can’t make it on its own, so it must be obtained through diet. Although the body can synthesize EPA and DHA, experts believe it’s also best to consume these fatty acids through diet.
ALA
Found in flaxseed and other vegetable sources such as canola oil, alpha-linolenic acid in the diet reduces the incidence of coronary heart disease, according to studies.
DHA
Found in oily cold-water fish, docosahexaenoic acid is considered particularly important for fetal brain, neurological, and ocular development. There is also evidence that sufficient DHA in the diet lowers the risk of Alzheimer’s disease.
EPA
Plentiful in oily cold-water fish, eicosapentaenoic acid is also believed to be particularly helpful in preventing heart disease.
PAPAIN
An enzyme found in papayas, papain helps break down proteins and aids digestion. It is an ingredient in some meat tenderizers.
Phytonutrients, also called phytochemicals, include a wide range of plant compounds (phyto means “plant”) that promote health. Some groups of phytonutrients currently being researched include carotenoids, phytosterols, and limonoids.
PHYTOSTEROLS
These compounds, found in plants, are similar to cholesterol. Phytosterols reduce cholesterol absorption from food, but since they may also reduce absorption of other compounds, and because some cholesterol absorption is important, they are best consumed as a natural ingredient in food.
POLYSACCHARIDES
These carbohydrate compounds are made up of groups of saccharides, or “sugars.” Common polysaccharides with nutritional importance are glycogen (a storage form of carbohydrates), starches, and dietary fiber.
PREBIOTICS
Prebiotics are nondigestible foods that help feed beneficial bacteria (including PROBIOTICS, see below) in the intestinal tract. The most beneficial prebiotics are carbohydrate fibers called oligosaccharides, which are found in fruits, vegetables, whole grains, and legumes.
PROBIOTICS
Probiotic means “life-supporting,” and these beneficial bacteria help improve overall health. Sufficient amounts of beneficial bacteria in the intestines are necessary to maintain a healthy immune system and aid digestion. Probiotics can be useful in treating intestinal disorders, protecting against candida infection, and reducing lactose in dairy products for those who have lactose intolerance. Bacteria, such as Lactobacillus bulgaricus, L. acidophilus, and Streptococcus thermophilus, are used to make yogurt and other fermented foods.
Along with fats and carbohydrates, protein is a main component for fueling the body. Protein compounds are made up of chains of amino acids. “Complete” dietary proteins, such as quinoa, fish, eggs, meat, and cheese, contain all the essential amino acids, while “incomplete” proteins, such as grains, legumes, vegetables, and fruits, contain only some of them. The body breaks down the protein in foods into its amino acids and uses them as the building materials for all its cells, as well as for energy.
QUERCETIN
This flavonoid compound is found in plants, particularly onions, apples, and tea. Quercetin has antioxidant and anti-inflammatory properties, and may protect against some forms of cancer and provide relief for allergy sufferers.
RETINOL
Retinol is one of several retinoids, which are forms of vitamin A found in animal foods such as meats, eggs, and dairy products. Retinol is easier for the body to use than other retinoids.
TERPENOIDS
Terpenoids are a very large, diverse group of chemical compounds with widely varied effects in nutrition and herbal medicine. Terpenoids give cinnamon, ginger, eucalyptus, and cloves their aromatic qualities. Some terpenoids are used as building blocks for steroids and sterols in the body.
THIOPROLINE
This amino acid is created in some legumes and mushrooms when they are boiled. Thioproline is considered an effective nitrite-trapping agent, and may therefore play a role in preventing cancer.
Organic compounds made by plants or animals, vitamins are essential for normal growth and promoting a healthy metabolism. Vitamins come in two varieties: fat-soluble and water-soluble. Fat-soluble vitamins, including A, D, E, and K, dissolve in fat and can be stored in the body’s fatty tissue, so your body doesn’t need a daily supply. Water-soluble vitamins, such as C and B complex, can’t be stored; any excess is carried out of the body, so you need a fresh supply every day.
CHOLINE
A member of the B family of vitamins, choline is essential for keeping cell membranes healthy. Choline is required for proper brain and nerve function and plays a crucial role in the ability of cells to communicate with one another. Choline is also used to transport fat from the liver.
FOLATE
Folate plays an important role in cell division, growth, and red blood cell health. Also known as vitamin B9, this water-soluble vitamin is important to fertility in both men and women, and critical during pregnancy and infancy. A deficiency can cause anemia and birth defects and is a risk factor for heart disease, stroke, and cancer. The synthetic form of folate, used in supplements and fortified foods, is called folic acid.
NIACIN
A water-soluble vitamin, also known as vitamin B3 or nicotinic acid, niacin is found in foods and can be produced in the body from the amino acid tryptophan. Niacin is essential to cell metabolism and the production of energy, and important to DNA repair and cancer prevention. It also has an important role in the body’s ability to manufacture fatty acids, steroids, and cholesterol.
PANTOTHENIC ACID
A water-soluble vitamin, also known as vitamin B5, pantothenic acid is important to cell metabolism. It helps the body utilize fats, carbohydrates, and proteins. Pantothenic acid demonstrates antioxidant activity and has been studied as a means of reducing the pain of rheumatoid arthritis. Pantothenic acid is found in most foods.
RIBOFLAVIN
A water-soluble vitamin, also known as vitamin B2, riboflavin is a bright yellow flavonoid. The antioxidant is important to cell metabolism and production of energy. Sufficient riboflavin may also combat migraine headaches.
THIAMIN
Also known as vitamin B1, thiamin was the first water-soluble vitamin to be discovered. This antioxidant helps maintain proper nerve and brain function.
VITAMIN A
Vitamin A is fat soluble and part of a group of chemicals called retinoids. It is important to healthy cell growth, bone and skin health, reproduction, and the proper function of the immune system. The vitamin is also an essential part of the chemical mechanism of sight; a deficiency can cause night blindness.
VITAMIN B6
Vitamin B6 is a basic building block for many of the body’s essential enzymes, as well as hemoglobin, niacin, insulin, and neurotransmitters. Also known as pyridoxine, this water-soluble vitamin is essential to cell metabolism of amino acids and glycogen, and important for maintaining healthy nerve, blood, and genetic function, as well as a strong immune system.
VITAMIN B12
Vitamin B12 is produced by bacteria and found in animal foods. The water-soluble vitamin is essential for the production of DNA and RNA and is important for maintaining healthy red blood cells and the nervous system.
VITAMIN C
A water-soluble compound, also known as ascorbic (meaning “anti-scurvy”) acid, vitamin C is a powerful antioxidant that protects the body’s cells from free radicals. It helps to create enzymes that metabolize fats; produce collagen and connective tissues for muscles, bones, and blood vessels; and regulate iron absorption.
The name for a group of fat-soluble prohormones (chemical precursors to hormones), vitamin D helps the body to absorb and maintain calcium and phosphorus levels in the blood and is tied with increased serotonin production, which boosts mood. It is also important for healthy bones and teeth. Few foods naturally contain vitamin D, but our bodies can manufacture it if our skin is exposed to sufficient sunlight.
Fat-soluble vitamin E has strong antioxidant properties; in particular, it protects fat and cholesterol in the body against damage by free radicals. Consumed in its natural form, it may have a role in preventing cancer and nerve damage and reducing stroke damage. (The synthetic form of vitamin E is not as effective.) It may also serve to reduce cholesterol and enhance immunity.
VITAMIN K
Vitamin K is essential to normal blood coagulation. It helps maintain bone mass and may be a factor in slowing Alzheimer’s disease. It is a fat-soluble vitamin that occurs in two main forms: phylloquinone, which is found in food, and menaquinones, which are found in food and produced by bacteria in the intestines.
ZEAXANTHIN
Similar to lutein, zeaxanthin is a common carotenoid pigment that is extremely beneficial for eye health. There is evidence connecting low levels of zeaxanthin in the blood with age-related macular degeneration. The best source of zeaxanthin is dark, leafy greens, such as collard greens, spinach, and kale.