Nutrition Glossary

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Nutrition Glossary

Index

A-C


D-F
G-I
K-L
M-N
P-S
T-Z

Amino acid: One of the building blocks of protein. The term "amino acids" dates to the middle of the 19th century. The idea that amino acids are "Bausteine" (building stones) came from the Nobel Prize winning German biochemist Albrecht Kossel (1853-1927).

Vitamin C, an essential nutrient found mainly in fruits and vegetables. The body requires it to form and maintain bones, blood vessels, and skin. Like other vitamins, ascorbic acid is an organic compound. An organic compound is a substance that (1) occurs in living things, or organisms (hence, the word "organic") and (2) contains the elements carbon and oxygen (hence, the word "compound," meaning combination of elements).

Ascorbic acid is a water-soluble vitamin, one that cannot be stored by the body except in insignificant amounts. It must be replenished daily.

Purpose and Benefits
Ascorbic acid helps produce collagen, a protein needed to develop and maintain healthy teeth, bones, gums, cartilage, vertebrae discs, joint linings, skin and blood vessels. Ascorbic acid also does the following: Promotes the healing of cuts, abrasions and wounds; Helps fight infections; Inhibits conversion of irritants in smog, tobacco smoke, and certain foods into cancer-causing substances; Appears to dilate (widen, enlarge) blood vessels and thereby lessen the risk of developing high blood pressure and heart disease; Helps regulate cholesterol levels; Prevents the development of scurvy, a disease characterized by weakness, fatigue, anemia, swollen joints, bleeding gums and loose teeth. Scurvy was common aboard ships in earlier times because crews traveled for long periods without eating fresh vegetables or fruit. Many sailors died of the disease. Scurvy is rare today; Appears to lower the risk of developing cataracts, clouding of the lens of the eye that impairs vision; May help protect diabetics against deterioration of nerves, eyes and kidneys;  May (or may not) inhibit the development of colds and decrease the intensity of cold symptoms. (This is highly controversial.); Aids iron absorption; and May reduce levels of lead in the blood.

Food Sources
Fruits: oranges, lemons, limes, grapefruits, tangerines, pears, bananas, melons, papayas, strawberries, mangos, blackberries, blueberries, kiwis, pineapples, watermelons, raspberries, cranberries, cantaloupes, rose hips, acerola cherries. Vegetables: asparagus, broccoli, green peppers, red peppers, cabbage, kale, cauliflower, potatoes, sweet potatoes, yams, squash, peas, turnips, turnip greens, onions, corn, pumpkins, carrots, parsley, sauerkraut. Herbs: garlic, watercress. Other sources: fish and milk (occurs in small amounts).

Quick GuidePortion Control Tips: Lose Weight and Stick to Your Diet

Portion Control Tips: Lose Weight and Stick to Your Diet

Recommended Daily Intake in Milligrams
Infants from birth to 1 year: 30 to 35 mg; Babies 1 to 3 years: 40 mg; Children 4 to 10: 45 mg; Pregnant women: 75-90; Lactating women: 75-90; Smokers: 100 mg; Diabetics, elderly persons, patients suffering from stress or allergies: up to 200 mg as determined by a physician; All others: 60 mg (unless a physician indicates otherwise); A milligram equals 1/1000 of a gram. A gram equals .0353 of an ounce.

Side Effects From Overdose
Some people taking large amounts of ascorbic acid may experience diarrhea, nausea, skin irritation, burning upon urination, and depletion of the mineral copper. There is evidence that large doses of ascorbic acid contribute to the development of kidney stones. In addition, patients suffering from iron overload or a disease called glucose-6-phosphate dehydrogenase (G6PD) deficiency (an inherited condition affecting the red blood cells) may need to monitor their intake of ascorbic acid according to a physician's instructions.

Toxicity
In the laboratory, vitamin C can induce the formation of genotoxins (agents that damage DNA). If generated in significant amounts, these genotoxins could generate mutations and so conceivably contribute to the development of cancer.

Interactions
Ascorbic acid can cause adverse reactions when taken with some drugs. Therefore, patients taking drugs should always read warning labels and advisories on containers and printed pharmacy instructions. If in doubt about a possible reaction, patients should consult a pharmacist or physician.

Blood sugar, high: Elevated levels of blood glucose (hyperglycemia) can be found in a number of conditions. The hyperglycemia leads to spillage of glucose into the urine, hence the term sweet urine. (Diabetes mellitus means "sweet urine.")

Blood sugar, low: The sugar here is glucose. Low blood glucose constitutes hypoglycemia . Hypoglycemia is only significant when it is associated with symptoms. It has many causes including drugs, liver disease, surgical absence of the stomach, pre-diabetes, and rare tumors that release excess insulin.

Breastfeeding: Feeding a child human breast milk. According to the American Academy of Pediatrics, human breast milk is preferred for all infants. This includes even premature and sick babies, with rare exceptions. It is the food least likely to cause allergic reactions; it is inexpensive; it is readily available at any hour of the day or night; babies accept the taste readily; and the antibodies in breast milk can help a baby resist infections.

In breast milk, the amino acids (the building blocks of proteins) are well balanced for the human baby, as are the sugars (primarily lactose) and fats. The baby's intestinal tract is best aided in its digestion by the vitamins, enzymes, and minerals found in breast milk. Breastfed babies do eat more often than formula fed babies since breast milk is more quickly digested and leaves the stomach empty more frequently.

Exclusive breastfeeding is ideal nutrition and it is sufficient to support optimal growth and development for the first 6 months after birth, according to the American Academy of Pediatrics. Furthermore, it is recommended that breastfeeding continue for at least 12 months, and thereafter for as long as mutually desired. Infants weaned before 12 months of age should not receive cow's milk feedings, but should receive iron-fortified infant formula. See also: Breastfeeding practices; and Breast milk.

Calcium: A mineral found mainly in the hard part of bones. Bone is a storage area for calcium. Calcium is added to bone by cells called osteoblasts. It is removed from bone by cells called osteoclasts. Calcium is not just essential for healthy bones. It is also important for muscle contraction, heart action and normal blood clotting. A low blood calcium (hypocalcemia) makes the nervous system highly irritable with tetany (spasms of the hands and feet, muscle cramps, abdominal cramps, overly active reflexes, etc.). Food sources of calcium include dairy foods, some leafy green vegetables such as broccoli and collards, canned salmon, clams, oysters, calcium-fortified foods, and tofu. According to the National Academy of Sciences, adequate intake of calcium is 1 gram daily for both men and women. The upper limit for calcium intake is 2.5 grams daily.

Overly high intake of calcium (hypercalcemia) may cause muscle weakness and constipation, affect the conduction of electrical impulses in the heart (heart block) lead to calcium stones (nephrocalcinosis) in the urinary tract, impair kidney function, and interfere with the absorption of iron predisposing to iron deficiency.

Calcium deficiency: A low blood calcium (hypocalcemia). Hypocalcemia makes the nervous system highly irritable with tetany (spasms of the hands and feet, muscle cramps, abdominal cramps, overly active reflexes, etc.). Chronic calcium deficiency contributes to poor mineralization of bones, soft bones (osteomalacia) and osteoporosis; and, in children, rickets and impaired growth. Food sources of calcium include dairy foods, some leafy green vegetables such as broccoli and collards, canned salmon, clams, oysters, calcium-fortified foods, and tofu. According to the National Academy of Sciences, adequate intake of calcium is 1 gram daily for both men and women. The upper limit for calcium intake is 2.5 grams daily.

Calorie: A unit of food energy. In nutrition terms, the word calorie is used instead of the more precise scientific term kilocalorie. A kilocalorie represents the amount of energy required to raise the temperature of a liter of water one degree centigrade at sea level. Technically, however, this common usage of the word calorie of food energy is understood to refer to a kilocalorie (and actually represents, therefore, 1000 true calories of energy).

Carbohydrate: One of the three nutrients that are used as energy sources (calories) by the body. (The other energy sources are in the form of fats and proteins. Carbohydrates come in the form of simple sugars and complex forms, such as starches and fiber. Complex carbohydrates come naturally from plants. Intake of complex carbohydrates can lower blood cholesterol when they are substituted for saturated fat. The energy produced by carbohydrates is 4 calories per gram. Proteins also provide 4 calories per gram, while fats provide 9 calories per gram.

Carbohydrate loading: Carbohydrate loading is a technique used to increase the amount of glycogen in muscles. For five to seven days before an event, the athlete eats 10-12 grams of carbohydrate per kilogram of body weight, while gradually reducing the intensity of workouts. (To find out how much you weigh in kilograms, simply divide your weight in pounds by 2.2.)The day before the event, the athlete rests and eats the same high- carbohydrate diet. Most athletes should not worry about carbohydrate loading. If they eat a diet that derives more than half of its calories from carbohydrates, their body will have adequate levels to fuel their athletic activity. Carbohydrate loading may be beneficial for athletes engaged in endurance sports which require 90 minutes or more of non-stop effort.

Celiac Disease:A disorder resulting from an immune reaction to gluten, a protein found in wheat and related grains, and present in many foods. Celiac disease causes impaired absorption and digestion of nutrients through the small intestine. Symptoms include frequent diarrhea and weight loss. A skin condition dermatitis herpetiformis can be associated with celiac disease. The most accurate test for celiac disease is a biopsy of the involved small bowel. Treatment is to avoid gluten in the diet. Medications are used for refractory (stubborn) celiac disease.

Cholesterol: The most common type of steroid in the body, cholesterol has gotten something of a bad name. However, cholesterol is a critically important molecule. It is essential to the formation of:

  • Bile acids (which aid in the digestion of fats)
  • Vitamin D
  • Progesterone
  • Estrogens (estradiol, estrone, estriol)
  • Androgens (androsterone, testosterone)
  • Mineralocorticoid hormones (aldosterone, corticosterone) and
  • Glucocorticoid hormones (cortisol).

Cholesterol is also necessary to the normal permeability and function of cell membranes, the membranes that surround cells.

Cholesterol is carried in the bloodstream as lipoproteins. Low-density lipoprotein (LDL) cholesterol is the "bad" cholesterol because elevated LDL levels are associated with an increased risk of coronary artery (heart) disease. Conversely, high-density lipoprotein (HDL) cholesterol is the "good" cholesterol since high HDL levels are associated with less coronary disease.

After the age of 20, cholesterol testing is recommended every 5 years.

A diet high in saturated fats tends to increase the blood cholesterol levels while diets high in unsaturated fats tend to do the opposite, to lower blood cholesterol levels.

Although some cholesterol is obtained from the diet, most cholesterol is made in the liver and other tissues. The treatment of elevated cholesterol therefore involves not only diet but also weight loss and regular exercise (and, occasionally, medications).

Chondroitin Sulfate: A glycosaminoglycan (formerly called a mucopolysaccharide) found in cartilage, bone, blood vessels and connective tissues. There are two forms: chondroitin sulfate A and chondroitin sulfate C. One or both types accumulate abnormally in several of the mucopolysaccharidosis disorders. Chondroitin sulfate B is now called dermatan sulfate.

DASH Diet: An eating plan designed to lower the blood pressure. DASH is an acronym for Dietary Approaches to Stop Hypertension. The DASH "combination diet" has been shown to decrease the blood pressure and so helps prevent and control high blood pressure. The DASH "combination diet" is rich in fruits, vegetables, and low fat dairy foods, and low in saturated and total fat. It also is low in cholesterol, high in dietary fiber, potassium, calcium, and magnesium, and moderately high in protein.

The DASH eating plan is recommended by the NIH's National Heart, Lung, and Blood Institute (NHLBI) which states: "Use the Dietary Approaches to Stop Hypertension (DASH) eating plan as a guide. DASH encourages you to eat more fresh fruits, vegetables and low fat dairy products, and to limit saturated fat and salt. The DASH eating plan can help you lose weight and maintain a healthier body. In fact, according to the report, sticking to the DASH eating plan can be as effective as some medications in lowering your blood pressure."

Dextrose: Better known today as glucose, this sugar is the chief source of energy in the body. Glucose is chemically considered a simple sugar. It is the main sugar that the body manufactures. The body makes glucose from all three elements of food, protein, fat and carbohydrates, but in largest part from carbohydrates. Glucose serves as the major source of energy for living cells. It is carried to each cell through the bloodstream. The cells cannot, however, use the glucose without the help of insulin. When sampled in blood, glucose is tested in transit.

DVs (Daily Values): a new dietary reference term that will appear on food labels. It is made up of two sets of references, DRVs and RDIs.

The term DV is a new term appearing on food labels. It stands for Daily Value, a new dietary reference value designed to help consumers use food label information to plan a healthy diet. Daily Values (DVs) comprise two sets of reference values for nutrients: Daily Reference Values (DRVs) and Reference Daily Intakes (RDIs). Only the Daily Value term will appear on the food label.

The Daily Value serves as a basis for declaring on the label the percent of the DV for each nutrient that a serving of the food provides. For example, the Daily Value for fat, based on a 2,000-calorie diet, is 65 grams (g). A food that has 13 g of fat per serving would state on the label that the "percent Daily Value" for fat is 20 percent.

The DV provides a basis for thresholds that define descriptive words for nutrient content, called descriptors, such as "high fiber" and "low fat." For example, the descriptor "high fiber" can be used if a serving of food provides 20 percent or more of the Daily Value for fiber-- that is, 5 g or more.

DRVs and RDIs have an important regulatory role. They serve as the basis for calculating percent Daily Values. DRVs are for nutrients for which no set of standards previously existed, such as fat and cholesterol. RDIs, on the other hand, replace the term "U.S. RDAs" (Recommended Daily Allowances), which were introduced in 1973 as a reference value for vitamins, minerals and protein in voluntary nutrition labeling. Despite the name change, the actual values (except the value for protein) will remain the same--at least for the time being.

U.S. RDAs should not be confused with RDAs. The latter are short for Recommended Dietary Allowances, which are set by the National Academy of Sciences. FDA used the RDAs as the basis for setting U.S. RDAs (now called RDIs). The confusion caused by the similarity of those terms was one of the reasons for the switch to RDI.

DRVs (Daily Reference Values): a set of dietary references that applies to fat, saturated fat, cholesterol, carbohydrate, protein, fiber, sodium, and potassium

DRVs for the energy-producing nutrients (fat, carbohydrate, protein, and fiber) are based on the number of calories consumed per day. For labeling purposes 2,000 calories has been established as the reference for calculating percent Daily Values. This level was chosen, in part, since many health experts say it approximates the maintenance calorie requirements of the group most often targeted for weight reduction: postmenopausal women. The label will include--at least on larger packages--a footnote on the nutrition panel in which daily values for selected nutrients for both a 2,000- and a 2,500-calorie diet are listed. Manufacturers have the option of listing daily values for other calorie levels, if label space allows and as long as the Daily Values for the other two levels are listed too.

Whatever the calorie level, DRVs for the energy- producing nutrients are always calculated as follows:

  • fat based on 30 percent of calories
  • saturated fat based on 10 percent of calories
  • carbohydrate based on 60 percent of calories
  • protein based on 10 percent of calories. (The DRV for protein applies only to adults and children over 4. RDIs for protein for special groups have been established.)
  • fiber based on 11.5 g of fiber per 1,000 calories. Thus, someone who consumes 3,000 calories a day--a teenage boy, for example--would have a recommended intake for fat of 100 g or less per day. [0.30 times 3,000 = 900; 900 (calories) divided by 9 (calories per g of fat) = 100 g].

Quick GuidePortion Control Tips: Lose Weight and Stick to Your Diet

Portion Control Tips: Lose Weight and Stick to Your Diet

The DRVs for cholesterol, sodium and potassium, which do not contribute calories, remain the same whatever the calorie level. Due to the association between certain nutrients and diseases, the DRVs for some nutrients represent the uppermost limit that is considered desirable. Eating too much fat or cholesterol, for example, has been linked to an increased risk of heart disease. Too much sodium can heighten the risk of high blood pressure in some people.

The label will show DVs for fats and sodium as follows:

  • total fat: less than 65 g
  • saturated fat: less than 20 g
  • cholesterol: less than 300 mg (milligrams)
  • sodium: less than 2,400 mg

Dehydration: Excessive loss of body water. Diseases of the gastrointestinal tract may lead to dehydration. One clue to dehydration is a rapid drop in weight. A loss of over 10% (15 pounds in a person weighing 150 pounds) is considered severe. Symptoms include increasing thirst, dry mouth, weakness or lightheadedness (particularly if worsening on standing), or a darkening/decrease in urination are suggestive. Severe dehydration can lead to changes in the body's chemistry, kidney failure, and become life-threatening. The best way to treat dehydration is to prevent it from occurring. If one suspects fluid loss is excessive, notify a physician. Intravenous or oral fluid replacement may be needed.

Electrolytes: These are nutrients that affect fluid balance in the body and are necessary for our nerves and muscles to function. Sodium and potassium are the two electrolytes most often added to sports drinks. Generally, electrolyte replacement is not needed during short bursts of exercise since sweat is approximately 99% water and less than 1% electrolytes. Water, in combination with a well-balanced diet, will restore normal fluid and electrolyte levels in the body. Replacing electrolytes may be beneficial during continuous activity of longer than 2 hours, especially in a hot environment.

Enzyme: A protein that acts as a catalyst to mediate and speed a specific chemical reaction.

Fat: 1) With proteins and carbohydrates, one of the three nutrients used as energy sources by the body. The energy produced by fats is nine calories per gram. Proteins and carbohydrates each provide four calories per gram. 2) Total fat is the sum of saturated, monounsaturated, and polyunsaturated fats. Intake of monounsaturated and polyunsaturated fats can help to reduce blood cholesterol when substituted for saturated fats in the diet.

Fatty Acids: There are three main types of fatty acids: saturated, monounsaturated and polyunsaturated. All fatty acids are molecules composed mostly of carbon and hydrogen atoms. A saturated fatty acid has the maximum possible number of hydrogen atoms attached to every carbon atom. It is therefore said to be "saturated" with hydrogen atoms.

Some fatty acids are missing one pair of hydrogen atoms in the middle of the molecule. This gap is called an "unsaturation" and the fatty acid is said to be "monounsaturated" because it has one gap. Fatty acids that are missing more than one pair of hydrogen atoms are called "polyunsaturated."

Saturated fatty acids are mostly found in foods of animal origin. Monounsaturated and polyunsaturated fatty acids are mostly found in foods of plant origin and some sea foods. Polyunsaturated fatty acids are of two kinds, omega-3 or omega-6. Scientists tell them apart by where in the molecule the "unsaturations," or missing hydrogen atoms, occur.

Fiber: The parts of fruits and vegetables that cannot be digested. This fiber is of vital importance to digestion, helping the body move food through the digestive tract, reducing serum cholesterol, and contributing to disease prevention. Also called bulk or roughage.

Fiber and cholesterol: Soluble fiber substances are effective in helping reduce the blood cholesterol. This is especially true with oat bran, fruits, psyllium and legumes. High soluble-fiber diets may lower cholesterol and low-density lipoproteins ( the 'bad' lipoproteins ) by 8% to 15%.

Folate (folic acid): Folic acid is an important factor in nucleic acid synthesis (the genetic material of all cells). Deficiency leads to megaloblastic anemia. Important as a supplement for women of childbearing age to prevent nervous system birth defects.

Food, "Super":Foods with alleged healing or health-promoting capabilities. The healing power of foods is a popular concept. Medicinal or nutritionally high- powered foods have been part and parcel of the natural products industry for a long time and, through emerging scientific research and particularly through growing public interest, they have reached the mainstream. Not all items advertised as "super" foods or healing foods have been proven to promote health, however, and some may be contraindicated for people with certain health conditions. Before making drastic changes to your diet, always consult with your physician or a professional nutritionist.

Functional foods: As defined by the Institute of Medicine in Washington, are "those foods that encompass potentially healthful products including any modified food or ingredient that may provide a health benefit beyond the traditional nutrients it contains." Functional foods can include foods like cereals, breads and beverages which are fortified with vitamins, herbs or neutraceuticals.

Glucosamine: A molecule derived from the sugar glucose by the addition of an amino (NH2) group, glucosamine is a component of a number of structures including the blood group substances and cartilage.

Glucosamine is an unproven nutritional supplement. It has received acclaim as a "cure" for arthritis -- for which there is no evidence.

Glucosamine has also been hailed as a remedy for the relief of osteoarthritis symptoms. It may improve symptoms in selected patients with osteoarthritis, according to preliminary European studies, but definitive longterm proof is lacking. Glucosamine has not been evaluated for other forms of arthritis.

Glucosamine has been marketed as a "cartilage rebuilder" partly on the assumption that, because glucosamine is a component of cartilage, consuming it will help rebuild damaged cartilage. (The notion that glucosamine would help rebuild cartilage is analogous to the idea that eating hair will put hair back on a bald head). There is no evidence that glucosamine alone, or in combination with chondroitin, is of any value in rebuilding cartilage.

Glucose: The sugar that is the chief source of energy. Glucose is considered a simple sugar. Found in the blood, it is the main sugar that the body manufactures. The body makes glucose from all three elements of food-protein, fat and carbohydrates-but in largest part from carbohydrates. Glucose serves as the major source of energy for living cells. It is carried to each cell through the bloodstream. Cells, however, cannot use glucose without the help of insulin. Glucose is also known as dextrose.

Gluten: A protein found in wheat or related grains and many foods that we eat. Gluten can be found in a large variety of foods including soups, salad dressings, processed foods and natural flavorings. Unidentified starch, binders and fillers in medications or vitamins can be unsuspected sources of gluten.

HDL cholesterol: Lipoproteins, which are combinations of lipids (fats) and proteins, are the form in which lipids are transported in the blood. The high-density lipoproteins transport cholesterol from the tissues of the body to the liver so it can be gotten rid of (in the bile). HDL cholesterol is therefore considered the "good" cholesterol. The higher the HDL cholesterol level, the lower the risk of coronary artery disease.

Herbal - 1. An adjective, referring to herbs, as in an herbal tea.
2. A noun, usually reflecting the botanical or medicinal aspects of herbs; also a book which catalogs and illustrates herbs.
The word "herbal" was pronounced with a silent "h" on both sides of the Atlantic until the 19th century but this usage persists only on the American side.

Infant Vitamin Requirements - Vitamins are organic substances that are essential in minute quantities for the proper growth, maintenance, and functioning of the baby. Vitamins must be obtained from food because the body cannot produce them. The exception is vitamin D, which can be produced by the skin when it is exposed to the sun.

There are four fat-soluble vitamins (A, D, E, and K) and several water-soluble vitamins (the "B" vitamins - niacin, folate, pantothenic acid, and biotin). These vitamins have been added to infant formulas to ensure proper nutrition. Unless otherwise directed by their pediatricians, routine vitamin supplementation is not necessary for healthy full-term infants taking formulas.

High doses of certain vitamins can have adverse effects. For example, high doses of vitamin A can cause headaches, vomiting, liver damage, brain swelling, and bone abnormalities. High doses of vitamin D can lead to high levels of calcium in blood and kidney and heart damage. Therefore, high doses of vitamins should NOT be given to infants and young children without supervision by their pediatricians.

Infants who are low birth weight (LBW) or premature need supplemental vitamins (and iron) and special formulas. These specialized formulas contain more calories per ounce than routine formula, but are manufactured in a special way so as to be easily absorbed by the immature digestive system. There are several brands of this type of formula (for example, Similac Special Care and Similac LBW (Ross Pharmaceuticals)). Part of preparing an infant for discharge from the neonatal ICU involves establishing proper nutrition, which must be continued by the parents at home. Individual recommendations will be made by the infant's neonatologist.

Iodine: Essential element in the diet. The thyroid gland uses iodine to make thyroid hormones. The two most important thyroid hormones are thyroxine (T4) and triiodothyronine (T3). Thyroxine (T4) has four iodine molecules attached to its structure, while triiodothyronine (T3) has three iodine molecules attached. Iodine is found in seafood, bread, salt, and seaweed.

Iodine deficiency: Iodine is a natural requirement of our diets. Iodine deficiency can lead to inadequate production of thyroid hormone from the thyroid gland (hypothyroidism). For example, in some parts of Zaire, Ecuador, India, and Chile, remote, mountainous areas, such as in the Alps (in the past), Andes and the Himalayas have a particular predisposition to severe iodine deficiency, goiter, and hypothyroidism. Since the addition of iodine to table salt, iodine deficiency is rarely seen in the United States.

Iodine excess: Too much iodine may lead to the development of a goiter (swelling of the thyroid gland) and hypothyroidism (abnormally low thyroid activity). Certain foods and medications contain large amounts of iodine. Examples include seaweed; iodine-rich expectorants (such as SSKI and Lugol's solution) used in the treatment of cough, asthma, chronic pulmonary disease; and amiodarone (Cordarone), an iodine-rich medication used in the control of abnormal heart rhythms (cardiac arrhythmias).

Iron deficiency: Deficiency of iron results in anemia because iron is necessary to make hemoglobin, the key molecule in red blood cells responsible for the transport of oxygen. In iron deficiency anemia, the red cells are unusually small (microcytic) and pale (hypochromic). Characteristic features of iron deficiency anemia in children include failure to thrive (grow) and increased infections. The treatment of iron deficiency anemia , whether it be in children or adults, is with iron and iron-containing foods. Food sources of iron include meat, poultry, eggs, vegetables and cereals (especially those fortified with iron). According to the National Academy of Sciences, the Recommended Dietary Allowances of iron are 15 milligrams per day for women and 10 milligrams per day for men.

Iron excess: Iron overload can damage the heart, liver, gonads and other organs. Iron overload is a particular risk for:

  • People with certain genetic conditions such as hemochromatosis; and
  • People receiving repeated blood transfusions.

According to the National Academy of Sciences, the Recommended Dietary Allowances of iron are 15 milligrams per day for women and 10 milligrams per day for men.

Iron poisoning: Iron supplements meant for adults (such as pregnant women) are a major cause of poisoning in children. Care should be taken to keep iron supplements safely away from children.

K (potassium): K is the symbol for potassium, the major positive ion (cation) found inside of cells. The chemical notation for potassium is K+.

The proper level of potassium is essential for normal cell function. An abnormal increase of potassium (hyperkalemia) or decrease of potassium (hypokalemia) can profoundly affect the nervous system and heart, and when extreme, can be fatal.

The normal blood potassium level is 3.5 - 5.0 milliEquivalents/liter (mEq/L), or in international units, 3.5 - 5.0 millimoles/liter (mmol/L).

Lactase: Enzyme that breaks down the milk sugar lactose.

Lactase deficiency: Lack of an enzyme called lactase in the small intestine that is needed to digest lactose, a component of milk and most other dairy products. Lactose is sometimes also used as an ingredient in other foods, so those with a lactase deficiency should check labels carefully.

Most people are born with the ability to make adequate amounts of lactase, but lactase production normally decreases with age, more so in some persons than others. There are significant differences relative to lactase production among ethnic groups.

Inadequate lactase production can cause difficulty digesting lactose-containing products, which include dairy products themselves and foods containing dairy products as ingredients.

The most common symptoms of lactase deficiency are diarrhea, bloating, and gas. The diagnosis may be made by a trial of a lactose-free diet or by special testing. In some cases, other diseases of the intestine may need to be excluded by further medical evaluation.

Lactobacillus acidophilus: The bacteria found in milk and fermented milk products, particularly yogurt with "live cultures" of L. acidophilus. L. acidophilus assists with the digestive process within the intestinal tract. It can be decimated by the use of antibiotics, and many health professionals urge people to use probiotics to counter this unfortunate side effect of antibiotic use.

Lactose intolerance: The inability to digest lactose, a sugar component of milk and most other dairy products. Lactose is sometimes also used as an ingredient in other foods, so those with a lactase deficiency should check labels carefully. The basis for this condition is lack of an enzyme in the small intestine called lactase. Lactase is essential to digest lactose. Without enough lactase, there is lactose intolerance.

Underproduction of lactase can cause difficulty digesting lactose- containing products, which include dairy products themselves and foods containing dairy products as ingredients.

The most common symptoms of lactose intolerance are diarrhea, bloating, and gas. The diagnosis may be made by a trial of a lactose- free diet or by special testing. In some cases, other diseases of the intestine may need to be excluded by further medical evaluation.

Most people are born with the ability to make adequate amounts of lactase but lactase production normally declines with age, more so in some persons than others, and there are also significant differences relative to lactase production among ethnic groups.

Lipid - A chemical compound characterized by the fact that it is insoluble in water. Both fat and cholesterol are members of the lipid family.

Lipoprotein: A complex of lipid and protein, the way lipids travel in the blood.

LDL cholesterol: Lipoproteins which are combinations of lipids (fats) and proteins are the form in which lipids are transported in the blood. The low-density lipoproteins transport cholesterol from the liver to the tissues of the body. LDL cholesterol is therefore considered the "bad" cholesterol.

Magnesium deficiency: Can occur due to inadequate intake or impaired intestinal absorption of magnesium. Low magnesium (hypomagnesemia) is often associated with low calcium (hypocalcemia) and potassium (hypokalemia) levels. Deficiency of magnesium causes increased irritability of the nervous system with tetany (spasms of the hands and feet, muscular twitching and cramps, spasm of the larynx, etc.). According to the National Academy of Sciences, the Recommended Dietary Allowances of magnesium are 420milligrams per day for men and 320 milligrams per day for women. The upper limit of magnesium as supplements is 350 milligrams daily, in addition to the magnesium from food and water.

Metabolism: The whole range of biochemical processes that occur within us (or any living organism). Metabolism consists both of anabolism and catabolism (the buildup and breakdown of substances, respectively).

Metabolic rate: The metabolic rate is the amount of energy liberated per unit of time. Our metabolic rate is represented by the work we do, heat from body metabolism, and stored energy, such as in the form of fat.

The "basal metabolic rate" (BMR) is the metabolic rate determined at rest 12 to 14 hours after the last meal. In healthy humans the BMR is approximately 2000 kcal/day. (The metabolic rate is actually lowest during sleep.)

The metabolic rate is affected by recent food ingestion, muscle exertion, environmental temperature, height, weight, body surface area, age, sex, emotional state, body temperature, pregnancy, menstruation, level of thyroid hormones, and "stress" hormones (epinephrine and norepinephrine).

Mitochondria: The mitochondria are normal energy- producing structures within cells. They are located in the cell's cytoplasm outside the nucleus.

The mitochondria are responsible for energy production. They consist of two sets of membranes, a smooth continuous outer coat and an inner membrane arranged in tubules or in folds that form plate- like double membranes (cristae). The mitochondria are in fact the principal energy source of the cell (thanks to the cytochrome enzymes of terminal electron transport and the enzymes of the citric acid cycle, fatty acid oxidation, and oxidative phosphorylation). The mitochondria convert nutrients into energy as well as doing many other specialized tasks.

Each mitochondrion has a chromosome that is made of DNA but is otherwise quite different from the better known chromosomes in the nucleus. The mitochondrial chromosome is much smaller. It is round (whereas the chromosomes in the nucleus are shaped like rods). There are many copies of the mitochondrial chromosome in every cell (whereas there is normally only one set of chromosomes in the nucleus).

No matter whether we are male or female, we inherit our mitochondrial chromosome from our mother. In other words, the mitochondrial chromosome is transmitted in a matrilinear manner. We have Eve to thank for our mitochondrial chromosome.

Niacin for high cholesterol: Niacin or nicotinic acid, one of the water-soluble B vitamins, improves all lipoproteins when given in doses well above the vitamin requirement. Nicotinic acid lowers the total cholesterol, "bad" LDL-cholesterol, and triglyceride levels, while raising the "good" HDL-cholesterol level.

There are two types of nicotinic acid: immediate release and timed release. Most experts recommend starting with the immediate-release form; discuss with your doctor which type is best for you.

Nicotinic acid is inexpensive and widely accessible to patients without a prescription but must not be used for cholesterol lowering without the monitoring of a physician because of the potential side effects. (Nicotinamide, another form of the vitamin niacin, does not lower cholesterol levels and should not be used in the place of nicotinic acid.)

All patients taking nicotinic acid to lower serum cholesterol should be closely monitored by their doctor to avoid complications from this medication. Self-medication with nicotinic acid should definitely be avoided because of the possibility of missing a serious side effect if not under a doctor's care.

Patients on nicotinic acid are usually started on low daily doses and gradually increased to an average daily dose of 1.5 to 3 grams per day.

Nicotinic acid reduces LDL-cholesterol levels by 10 to 20 percent, reduces triglycerides by 20 to 50 percent, and raises HDL-cholesterol by 15 to 35 percent.

A common and troublesome side effect of nicotinic acid is flushing or hot flashes, which are the result of the widening of blood vessels. Most patients develop a tolerance to flushing, and in some patients, it can be decreased by taking the drug during or after meals or by the use of aspirin or other similar medications prescribed by your doctor. The effect of high blood pressure medicines may also be increased while you are on niacin. If you are taking high blood pressure medication, it is important to set up a blood pressure monitoring system while you are getting used to your new niacin regimen. A variety of gastrointestinal symptoms including nausea, indigestion, gas, vomiting, diarrhea, and the activation of peptic ulcers have been seen with the use of nicotinic acid.

Three other major adverse effects include liver problems, gout, and high blood sugar. Risk of these three complications increases as the dose of nicotinic acid is increased. Your doctor will probably not prescribe this medicine for you if you have diabetes, because of the effect on your blood sugar.

Niacin deficiency: Deficiency of niacin, one of the B-complex vitamins, causes pellagra.

Pellagra was known as the "disease of the four D's" -- dermatitis, diarrhea, dementia and death. The disease is specifically characterized by:

  • Dermatitis: A rash on areas of the skin exposed to light or trauma and ulcerations within the mouth
  • Diarrhea
  • Dementia: Mental disorientation, confusion, delusions and depression
  • Death, if untreated.

Pellagra, once a puzzle, was solved by Joseph Goldberger (1874-1929). Serving in the Public Health Service, Dr. Goldberger proposed that pellagra was due to a nutritional deficiency and in 1915 began experiments with Mississippi prison inmates (who "volunteered" in return for full pardons). Dr. Goldberger fed them a poor diet he believed caused pellagra and within months, many developed the disease. Their symptoms of pellagra were reversed when meat, fresh vegetables and milk were added to their diet.

Niacin, Dr. Goldberger subsequently showed, was the principle that had this remarkable effect. A readily-available B vitamin, niacin cures pellagra and prevents it.

The name "pellagra" comes from the Italian "pelle", skin + "agra", rough = rough skin, referring to the skin problems in pellagra.

Nicotinic acid: Deficiency of nicotinic acid (also known as niacin), one of the B-complex vitamins, causes pellagra.

Pellagra was known as the "disease of the four D's" -- dermatitis, diarrhea, dementia and death. The disease is specifically characterized by:

  • Dermatitis: A rash on areas of the skin exposed to light or trauma and ulcerations within the mouth
  • Diarrhea
  • Dementia: Mental disorientation, confusion, delusions and depression
  • Death, if untreated.

Pellagra, once a puzzle, was solved by Joseph Goldberger (1874-1929). Serving in the Public Health Service, Dr. Goldberger proposed that pellagra was due to a nutritional deficiency and in 1915 began experiments with Mississippi prison inmates (who "volunteered" in return for full pardons). Dr. Goldberger fed them a poor diet he believed caused pellagra and within months, many developed the disease. Their symptoms of pellagra were reversed when meat, fresh vegetables and milk were added to their diet.

Niacin, Dr. Goldberger subsequently showed, was the principle that had this remarkable effect. A readily-available B vitamin, niacin cures pellagra and prevents it.

The name "pellagra" comes from the Italian "pelle", skin + "agra", rough = rough skin, referring to the skin problems in pellagra.

Nutraceuticals: A food or part of a food that allegedly provides medicinal or health benefits, including the prevention and treatment of disease A nutraceutical may be a naturally nutrient-rich or medicinally active food, such as garlic or soybeans, or it may be a specific component of a food, such as the omega-3 fish oil that can be derived from salmon and other cold-water fish.

Nutrition: 1) The science or practice of taking in and utilizing foods. 2) A nourishing substance, such as nutritional solutions delivered to hospitalized patients via an IV or IG tube.

Nutritionist: 1) In a hospital or nursing home, a person who plans and/or formulates special meals for patients. It can also simply be a euphemism for a cook who works in a medical facility but who does not have extensive training in special nutritional needs. 2) In clinical practice, a specialist in nutrition. Nutritionists can help patients with special needs, allergies, health problems, or a desire for increased energy or weight change devise healthy diets. Some nutritionists in private practice are well-trained, degreed, and licensed. Depending on state law, however, a person using the title may not be trained or licensed at all.

Phytochemical/Phytonutrient: The active health-protecting compounds that are found as components of plants.

Currently, the terms "phytochemical" and "phytonutrient" are being used interchangeably to describe those plant compounds which are thought to have health-protecting qualities.

The antioxidant, immune boosting and other health promoting properties of active compounds in plants are being investigated. Phytonutrients or phytochemicals that are being studied presently include (and are not limited to) terpenes, carotenoids, limonoids, and phytosterols.

Protein: One of the three nutrients that are used as energy sources (calories) by the body. (The other energy sources are in the form of fats and carbohydrates. Proteins are essential components of the muscle, skin, and bones of animals. Proteins and carbohydrates each provide 4 calories of energy per gram, while fats provide 9 calories per gram.

RDAs (Recommended Dietary Allowances): a set of estimated nutrient allowances established by the National Academy of Sciences. It is updated periodically to reflect current scientific knowledge.

RDIs (Reference Daily Intakes): a set of dietary references based on the Recommended Dietary Allowances for essential vitamins and minerals and, in selected groups, protein. The name "RDI" replaces the term "U.S. RDA."

Unlike DRVs, which are a new concept, many consumers may already have a good idea of what the RDIs are. Since the RDIs (the former U.S. RDAs used by FDA) have been around for almost 20 years as the established estimated values for vitamins, minerals and protein.

Selenium: An essential mineral that is a component of a key antioxidant enzyme, glutathione reductase, in tissue respiration. Deficiency of selenium causes Keshan disease, a fatal form of cardiomyopathy (disease of the heart muscle) first observed in Keshan province in China and since found elsewhere. According to the National Academy of Sciences, the Recommended Dietary Allowances of selenium are 70 milligrams per day for men and 55 milligrams per day for women. Food sources of selenium include seafood, some meats such as kidney and liver, and some grains and seeds. Too much selenium may cause reversible changes in the hair (balding) and nails, garlic odor to the breath, intestinal distress, weakness and slower mentation (slowed mental functioning).

Selenium Deficiency: Deficiency of the essential mineral selenium causes Keshan disease, a fatal form of cardiomyopathy (disease of the heart muscle) first observed in Keshan province in China and since found elsewhere. According to the National Academy of Sciences, the Recommended Dietary Allowances of selenium are 70 milligrams per day for men and 55 milligrams per day for women. Food sources of selenium include sea foods, some meats such as kidney and liver, and some grains and seeds.

Serving Size: 1. The portion of food used as a reference on the nutrition label of that food.
2. The recommended portion of food to be eaten. The National Cancer Institute defines a serving as:

  • One medium-sized fruit (such as apples, oranges, bananas, pears)
  • 1/2 cup of raw, cooked, canned or frozen fruits or vegetables
  • 3/4 cup (6 oz.) of 100% fruit or vegetable juice
  • 1/2 cup cut-up fruit
  • 1/2 cup cooked or canned legumes (such as beans and peas)
  • 1 cup of raw, leafy vegetables (such as lettuce and spinach)
  • 1/4 cup dried fruit (such as raisins, apricots, mango)

Sodium: The major positive ion (cation) in fluid outside of cells. The chemical notation for sodium is Na+. When combined with chloride, the resulting substance is table salt.

Excess sodium (such as from fast food hamburger and fries) is excreted in the urine. Too much or too little sodium can cause cells to malfunction, and extremes can be fatal.

Normal blood sodium level is 135 - 145 milliEquivalents/liter (mEq/L), or in international units, 135 - 145 millimoles/liter (mmol/L).

Trans fatty acids: These are byproducts of partial hydrogenation, a process in which some of the missing hydrogen atoms are put back into polyunsaturated. Some of the hydrogenated fatty acids take on a "straighter" structure: these are the trans fatty acids. "Hydrogenated vegetable oils," such as vegetable shortening and margarine, are solid at room temperature because straightening fatty acids allows them to pack more tightly.

Triglyceride: A fatty substance that is composed of three fatty acids each of which is attached to a glycerol molecule. Like cholesterol, triglyceride in the blood either comes from the diet or the liver. Also, like cholesterol, triglyceride cannot dissolve and circulate in the blood without combining with a lipoprotein are a form of fat that is transported through the blood to the body tissues.

Whether elevated triglyceride levels in the blood lead to atherosclerosis and heart attacks is controversial. While most doctors now believe that an abnormally high triglyceride level is a risk factor for arteriosclerosis, it is difficult to conclusively prove that raised triglyceride by itself can cause atherosclerosis. However, it is increasingly recognized that elevated triglyceride is often associated with other conditions that increase the risk of atherosclerosis including obesity, low levels of HDL- cholesterol, insulin resistance and poorly controlled diabetes mellitus, and small, dense LDL cholesterol particles.

Vitamins: The word "vitamin" was coined in 1911 by the Warsaw-born biochemist Casimir Funk (1884-1967). At the Lister Institute in London, Funk isolated a substance that prevented nerve inflammation (neuritis) in chickens raised on a diet deficient in that substance. He named the substance "vitamine" because he believed it was necessary to life and it was a chemical amine. The "e" at the end was later removed when it was recognized that vitamins need not be amines.

The letters (A, B, C and so on) were assigned to the vitamins in the order of their discovery. The one exception was vitamin K which was assigned its "K" from "Koagulation" by the Danish researcher Henrik Dam.

  • Vitamin A: Retinol. Carotene compounds responsible for transmitting light sensation in the retina of the eye. Deficiency leads to night blindness.
  • Beta carotene: An antioxidant which protects cells against oxidation damage that can lead to cancer. Beta carotene is converted, as needed, to vitamin A. Food sources of beta carotene include vegetables such as carrots, sweet potatoes, spinach and other leafy green vegetables; and fruit such as cantaloupes and apricots. Excessive carotene in the diet can temporarily yellow the skin, a condition called carotenemia, commonly seen in infants fed largely mashed carrots.
  • Vitamin B1: Thiamin, acts as a coenzyme in body metabolism. Deficiency leads to beriberi, a disease of the heart and nervous system.
  • Vitamin B2: Riboflavin, essential for the reactions of coenzymes. Deficiency causes inflammation of the lining of the mouth and skin.
  • Vitamin B3: Niacin, an essential part of coenzymes of body metabolism. Deficiency causes inflammation of the skin, vagina, rectum and mouth, as well as mental slowing.
  • Vitamin B6: Pyridoxine, a cofactor for enzymes. Deficiency leads to inflammation of the skin and mouth, nausea, vomiting, dizziness, weakness and anemia.
  • Folate (folic acid): Folic acid is an important factor in nucleic acid synthesis (the genetic material). Folate deficiency leads to megaloblastic anemia.
  • Vitamin B12: An essential factor in nucleic acid synthesis (the genetic material of all cells). Deficiency leads to megaloblastic anemia, as can be seen in pernicious anemia.
  • Vitamin C: Ascorbic acid, important in the synthesis of collagen, the framework protein for tissues of the body. Deficiency leads to scurvy, characterized by fragile capillaries, poor wound healing, and bone deformity in children.
  • Vitamin D: A steroid vitamin which promotes absorption and metabolism of calcium and phosphorus. Under normal conditions of sunlight exposure, no dietary supplementation is necessary because sunlight promotes adequate vitamin D synthesis in the skin. Deficiency can lead to osteomalacia in adults and bone deformity (rickets) in children.
  • Vitamin E: Deficiency can lead to anemia.
  • Vitamin K: An essential factor in the formation of blood clotting factors. Deficiency can lead to abnormal bleeding.

Zinc deficiency: According to the National Academy of Sciences, the Recommended Dietary Allowances of zinc are 12 milligrams per day for women and 10 milligrams per day for men. Food sources of zinc include meat including liver, eggs, seafood, nuts and cereal.

Deficiency of zinc is associated with short stature, anemia, increased pigmentation of skin (hyperpigmentation), enlarged liver and spleen (hepatosplenomegaly), impaired gonadal function (hypogonadism), impaired wound healing, and immune deficiency.

In a genetic disease called acrodermatitis enteropathica, there is impaired zinc uptake from the intestine. The condition is characterized by the simultaneous presence of dermatitis (skin inflammation) and diarrhea. The skin on the cheeks, elbows and knees and the tissues about the mouth and anus are inflamed. There is balding of the scalp, eyebrows and eyelashes. Wound healing is delayed. In addition, there are recurrent bacterial and fungal infections due to immune deficiency. The key laboratory finding is an abnormally low blood zinc level reflecting the impaired zinc uptake. Treatment with zinc is curative.


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Reviewed on 9/9/2004

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