House Call, MD: Health Carefully Explained

by Leah Frankel, MS, RD

Vitamin: An organic compound (contains carbon) that is a natural component in foods, which cannot be synthesized by the body in adequate amounts and is essential for normal physiological function

Fat Soluble Vitamins: Vitamins which must be absorbed by consuming foods that contain fat

Vitamin A:

• Other names: Vitamin A exists in three forms: retinol, retinal and retinoic acid; there are also precursor forms (a compound that our body can convert into vitamin A) known as carotinoids, like β-carotene

• Function: Important for normal vision, gene regulation, immune function, growth and development, reproduction

• Recommended intake*: 900 µg/day (males over 18 years), 700 µg/day (females over 18 years); inadequate intake can cause night blindness, impaired embryonic development, anemia and spontaneous abortion

• Upper limit: 3000 µg/day; exceeding the upper limit can cause liver toxicity

• Sources: Turkey, sweet potato, carrots, liver, dairy products, fish, squash, spinach

Vitamin D:

• Other names: Calciferol; 7-dehydrocholesterol and ergosterol are precursors for vitamin D

• Function: Regulates calcium and phosphorus levels in the blood

• Recommended Intake: 5 µg/day (or 200 IU (International Units) males and females 18-50 years), 10 µg/day (or 400 IU males and females 50-70 years); inadequate intake can cause bone impairment including rickets in children and osteomalacia in adults

• Upper Limit: 50 µg/day; exceeding the upper limit can cause calcification of soft tissues, high levels of calcium and phosphorus in the blood

• Sources: Fatty fish, fortified milk, liver, egg yolk, fortified cereals

Vitamin E:

• Other Names: α-tocopherol

• Function: As an antioxidant it protects cells from breakdown by free radicals

• Recommended Intake: 15 mg/day (males and females 18 years and over); inadequate intake can cause problems with the neuromuscular, vascular and reproductive systems

• Upper Limit: 1000 mg/day; exceeding the upper limit can disrupt the body’s use of other fat soluble vitamins

• Sources: Nuts, vegetable oils, asparagus, cereal

Vitamin K:

• Other Names: Phylloquinones (vitamin K₁, found in green plants), menaquinones (vitamin K₂, created by bacteria), menadione (vitamin K₃, synthetic form)

• Function: Blood clotting and bone formation

• Recommended Intake: 120 µg /day (males 18 years and over), 90 µg/day (females 18 years and over); inadequate intake can cause hemorrhaging since there is a delay in blood clotting time

• Upper Limit: not determinable; no adverse effects have been seen except with excess amounts of menadione which can cause jaundice in infants

• Sources: green leafy vegetables, carrots, potato, plant oils

Water Soluble Vitamins: Vitamins which are only soluble in water, they are distributed through the water parts of cells

Thiamin:

• Other names: vitamin B₁

• Function: vital for carbohydrate metabolism and neural function

• Recommended intake: 1.2 mg/day (males 18 years and over), 1.1 mg/day (females 18 years and over); inadequate intake can cause anorexia, weight loss, and disrupt cardiac and neurologic function, thiamin deficiency is known as beriberi

• Upper limit: not determinable; little is known about thiamin toxicity, however massive doses have depressed the respiratory system leading to death

• Sources: fortified cereals, enriched or whole grains, pork, ham

Riboflavin:

• Other names: vitamin B₂

• Function: important for the metabolism of carbohydrates, protein and fats

• Recommended intake: 1.3 mg /day (males 18 years and over), 1.1 mg/day (females 18 years and over); inadequate intake can cause burning and itching of the eyes, cracks in the lips, purple swollen tongue

• Upper limit: not determinable; no adverse effects have been seen with high oral doses, however this does not mean high doses are beneficial

• Sources: organ meats, fortified cereal, dairy products, bread products

Niacin:

• Other names: nicotinic acid, nicotinamide

• Function: vital for metabolism of carbohydrates, fats and proteins

• Recommended intake: 16 mg /day (males 18 years and over), 14 mg/day (females 18 years and over); inadequate intake can cause anorexia, muscular weakness, indigestion, and skin eruptions, niacin deficiency is known as pellagra which consists of dermatitis, dementia and diarrhea

• Upper limit: 35 mg /day; excessive doses of niacin can cause flushing, gastrointestinal distress and toxicity to the liver

• Sources: meat, fish, poultry, rice, fortified cereal, peanuts

Pantothenic Acid:

• Other names: none

• Function: important for metabolism, especially for fats

• Recommended intake: 5 mg /day (males and females 18 years and over); inadequate intake can cause impairments in fat synthesis and energy production

• Upper limit: not determinable; no toxicity has been noted with pantothenic acid, however massive doses have been shown to cause mild gastrointestinal distress and diarrhea

• Sources: chicken, beef, broccoli, egg yolks, years, sweet potatoes, cereal

Vitamin B­­₆:

• Other names: there are several derivatives including pyridoxine, pyridoxal, pyridoxamine, pyridoxal phosphate

• Function: vital for protein metabolism

• Recommended intake: 1.3 mg /day (males and females 18-50 years), 1.7 mg/day (males 50 years and over), 1.5 mg/day (females 50 years and over); inadequate intake can cause weakness, sleeplessness, peripheral neuropathies, impaired immunity

• Upper limit: 100 mg/day; excessive doses can cause changes in gait and peripheral sensation

• Sources: potatoes, banana, fortified cereals, chicken, rice, beef

Folate:

• Other names: folic acid, folacin, pteroylmonoglutamic acid

• Function: aids in metabolism or proteins, and formation of red and white blood cell formation in bone marrow

• Recommended intake: 400 µg /day (males and females 18 years and over); inadequate intake can cause anemia, skin lesions, poor growth and birth defects including neural tube defect

• Upper limit: 1000 µg/day; excessive doses can mask vitamin B₁₂ deficiency

• Sources: liver, mushrooms, green leafy vegetables, beef, enriched grains, fortified cereals

Vitamin B­₁₂:

• Other names: cobalamin

• Function: important for metabolism of proteins and normal function of cells especially in the gastrointestinal tract and bone marrow

• Recommended intake: 2.4 µg /day (males and females 18 years and over); inadequate intake can cause impaired cell division, anemia, numbness and tingling of the feet, leg weakness, jaundice, neurologic disorders

• Upper limit: not determinable; no toxicity has been found with vitamin B₁₂

• Sources: liver, kidney, milk, eggs, fish, cheese, fortified cereals

Biotin:

• Other names: none

• Function: vital for metabolism, particularly with fats

• Recommended intake: 30 µg /day (males and females 18 years and over); inadequate intake can cause dermatitis, anorexia, nausea, depression, elevated cholesterol

• Upper limit: not determinable; no toxicity has been found with biotin

• Sources: liver, kidney, milk, eggs, fish, cheese, fortified cereals

Vitamin C:

• Other names: ascorbic acid

• Function: important for collagen and carnitine formation, is a protective antioxidant, promotes resistance to infection, aids in iron absorption

• Recommended intake: 90 mg /day (males 18 years and over), 75 mg/day (females 18 years and over); inadequate intake can cause scurvy which has symptoms including poor wound healing, swelling, hemorrhages, weakness, swollen or bleeding gums, fatigue

• Upper limit: 2,000 mg/day; excessive doses can cause gastrointestinal distress and diarrhea, increased risk for developing kidney stones, and excessive iron absorption

• Sources: citrus fruits, tomatoes, potatoes, brussel sprouts, broccoli

Minerals: An inorganic compound (does not contain carbon), or an element, that is essential for normal physiological function

Macrominerals (bulk elements): Minerals that are required in large doses (100 mg/day or more)

Calcium:

• Other Names: None

• Function: Vital for bone and teeth formation, nerve transmission, regulation of the heart muscle function, blood clotting,

• Recommended Intake: 1,000 mg /day (males and females 18-50 years), 1,200 mg/day (males and females 50 years and over); inadequate intake can cause low bone mass, and if paired with low vitamin D intake can cause osteomalacia

• Upper Limit: 2,500 mg/day; excessive doses can cause high calcium levels in the blood, calcification of soft tissues, kidney stones, renal insufficiency, and can interfere with absorption of iron, zinc and manganese

• Sources: Dark green leafy vegetables, dairy products, calcium set tofu, clams, oysters

Phosphorus:

• Other Names: Phosphate

• Function: Important for the storage and transfer of energy, component in DNA, combines with calcium as the major inorganic molecule in bones and teeth

• Recommended Intake: 700 mg /day (males and females 18 years and over); inadequate intake can cause anorexia, muscle weakness, osteomalacia, anxiety, bone pain

• Upper Limit: 4,000 mg/day (males and females 18-70 years), 3,000 mg/day (males and females 70 and over); excessive doses can cause bone loss, interfere with calcium absorption

• Sources: Meat, poultry, fish, eggs, dairy, breads, cereal

Magnesium:

• Other names: None

• Function: plays a role in metabolism of fats and protein, affects muscle contraction and relaxation

• Recommended intake: 420 mg /day (males 30 years and over), 320 mg/day (females 30 years and over); inadequate intake can cause tremors, muscle spasms, anorexia, nausea, vomiting

• Upper Limit: 350 mg/day (based only on supplements, does not reflect intake from food); excessive doses can affect calcium’s role in bones

• Sources: seeds, nuts, legumes, dark green vegetables, milk, starches

Microminerals (trace elements): Minerals that are required in small doses (less than 100 mg/day)

Iron:

• Other Names: ferritin, ferrous (fumarate, sulfate and gluconate)

• Function: component in hemoglobin which is important for oxygen transportation, essential for normal immune system function

• Recommended intake: 8 mg /day (males 18 years and over, females 50 years and over), 18 mg/day (females 18-50 years); inadequate intake can cause anemia

• Upper limit: 45 mg/day; excessive doses can cause gastrointestinal distress and accumulation of iron in the liver

• Sources: liver, seafood, kidney, meat, poultry, beans, egg yolks, whole grains and enriched breads

Zinc:

• Other Names: None

• Function: Important for breakdown and build up of carbohydrates, protein, fats, and in the regulation of gene expression

• Recommended Intake: 11 mg /day (males 18 years and over), 8 mg/day (females 18 years and over); inadequate intake can cause short stature, delayed sexual maturation, delayed wound healing, skin lesions, impaired appetite, immune deficiencies

• Upper Limit: 40 mg/day; excessive doses can interfere with copper absorption, anemia, fever, gastrointestinal irritation

• Sources: Meat, fish, poultry, fortified cereals, milk, oysters, dry beans, nuts

Fluoride:

• Other Names: None

• Function: Protects against dental caries, antibacterial agent in the mouth, stimulates new bone formation

• Recommended intake: 4 mg /day (males 18 years and over), 3 mg/day (females 18 years and over); inadequate intake can cause increased dental caries

• Upper Limit: 10 mg/day; excessive doses can cause fluorosis which results in discoloration of teeth, or tooth flaking

• Sources: drinking water that is fluoridated, seafood, fluoridated dental products

Copper:

• Other Names: None

• Function: Aids in metabolism of iron, an important component of many enzymes

• Recommended Intake: 900 mg /day (males and females 18 years and over); inadequate intake can cause anemia, neutropenia, skeletal abnormalities, hair and skin discoloration

• Upper Limit: 10,000 mg/day; excessive doses can cause liver cirrhosis, abnormalities in red blood cell formation, gastrointestinal distress

• Sources: Liver, nuts, seeds, whole grain products, seafood, cocoa

*Note: Recommended intakes and upper limits vary based on age, gender, pregnancy and lactatation