Sources, RDAs, and Functions

Recently top researchers, scientists and nutritionists throughout North America revised the Recommended Dietary Allowances (RDAs) to include Estimated Average Requirements (EARs), and Tolerable Upper Intake Levels (ULs) to define the maximum amount of any given nutrient one should consume.  It is not intended to be a recommended level of intake, but merely the amount that your body can biologically tolerate without having adverse side effects.  Where an EAR is not available, Adequate Intakes (AIs) are given.  Together, these make up the new  Dietary Reference Intakes  (DRIs) which are given to assist healthy individuals in planning and analyzing their diets.

Listed below is each individual vitamin, the recommended intake, food sources for each nutrient, including estimated amounts for single serving sizes, and finally, nutrient functions.

VITAMIN A: Male RDA=1000 RE.  Female RDA=800 RE.  Rich sources for vitamin A include carrots (2000 RE), sweet potatoes (2500 RE), cantaloupe (515 RE), apricots (90 RE), liver (6000 RE), cheese (170 RE), and egg yolks (95 RE). Vitamin A helps in vision, especially night; promotes growth; prevents drying of skin and eyes; is an antioxidant; and promotes efficient immune function.

VITAMIN D: Age 9-50 AI=5 mcg; Age 51-70 = 10 mcg; Age 71+ = 15 mcg.  Food sources include fortified milk (2.5 mcg), and fatty fish (Salmon 35 mcg, Halibut 20 mcg).  Your body when exposed to sunlight makes Vitamin D.  Therefore deficiencies are rarely seen--only in cases where individuals are not exposed to the sun.  Vitamin D helps your body absorb calcium and phosphorus, and is necessary for optimal bone maintenance.

VITAMIN E: RDA=22 IU .  found in vegetable oils (3 IU), nuts (6 IU), seeds (50 IU), and wheat germ (2 IU). Vitamin E is primarily an antioxidant.  Also, it may decrease risk for coronary heart disease, cancer, cataract formation, and neurological disorders.

VITAMIN K: RDA=60-80 micrograms.  Vitamin K is found in green vegetables (120 mcg), cauliflower (300 mcg),  milk (10 mcg),and eggs (25 mcg).  It is important for normal blood clotting function.

VITAMIN C:. Male RDA=90 mg, Female RDA =75mg, UL=2000 mg.  Smokers add 35 mg.  Rich sources of vitamin C include citrus fruits (70 mg), kiwi (60 mg), cabbage (45 mg), red bell peppers (140 mg), potatoes (20 mg) and broccoli (80 mg).  Vitamin C is necessary for collagen synthesis (healthy joints).  It also is an antioxidant, improves iron absorption and aids in the synthesis of other important compounds in the body.

FOLIC ACID: RDA=400 micrograms.  Women capable of becoming pregnant should consume 400 micrograms from supplements in addition to their folate from food to prevent neural tube defects in the fetus. Important sources of folate are green leafy vegetables (60 mcg), wheat germ (25 mcg), beans (290 mcg), whole grains (30 mcg), citrus fruit (60 mcg), and brussels sprouts (20 mcg). Coenzyme involved in DNA synthesis.  May reduce risk of certain birth defects and cervical cancer.

VITAMIN B6: Male RDA=1.3 mg (age 51+=1.7 mg); Female RDA=1.3 mg (age 51+ 1.5 mg).  Vitamin B6 is found in beef (0.3), chicken (1.1)and other animal foods; also in bananas (0.7), beans (0.3), whole grains (0.2), spinach (0.1) and broccoli (0.1). B6 is a coenzyme involved in energy metabolism, and in the synthesis of neurotransmitters.

VITAMIN B12: RDA=2.4 micrograms.  Food sources of B12 are dairy products (0.9 mcg), meat (2.3 mcg), chicken (0.6 mcg) egg (0.5 mcg) and other animal foods. Vitamin B12 is involved in folate metabolism, DNA synthesis and proper nerve function.

THIAMIN (B1): Male RDA=1.2 mg; Female RDA = 1.1 mg.   Thiamin can be found in whole grains (0.3 mg), enriched grains (0.5 mg), seeds (1.7 mg), beans (0.3 mg), peas (0.2 mg), pork (0.7 mg), and brewer’s yeast (1.25 mg). It is a coenzyme involved in carbohydrate metabolism and nerve function.

RIBOFLAVIN (B2): Male RDA=1.3 mg Female RDA = 1.1 mg.  Food sources of Riboflavin include enriched grains (0.3 mg), whole grains (0.2 mg), milk (0.4 mg), mushrooms (0.1 mg), spinach (0.1 mg), beans (0.2 mg), nuts (0.1 mg), eggs (0.3 mg) and liver (4.7 mg). Riboflavin acts as a coenzyme involved in energy metabolism.

NIACIN (B3): Male RDA=16 mg; Female RDA=14 mg.  Niacin can be found in enriched grains (5.2 mg), whole grains (3.8 mg), mushrooms (1.0 mg), fish (17 mg), liver (12 mg) and peanuts (7 mg). It serves as a coenzyme involved in energy metabolism, fat synthesis and fat breakdown.

PANTOTHENIC ACID:  AI = 5 mg.  Food sources of pantothenic acid are mushrooms (1 mg), liver (5 mg), broccoli (1 mg), eggs (1 mg), and most other foods.  It is a coenzyme involved in energy metabolism, fat synthesis and fat breakdown.

BIOTIN:  AI = 30 micrograms.  Biotin can be found in cheese (2 mcg), egg yolks (8 mcg), cauliflower (2 mcg), peanut butter (30 mcg), mushrooms (6 mcg), bananas (3 mcg), and grains (3 mcg).  Biotin is a coenzyme involved in glucose production and fat synthesis.

CALCIUM:  Male AI = 1000 mg; Female AI = 1000 mg (adolescents and elderly should consume 1,300 mg and 1,200 mg respectively) Rich food sources are milk (300 mg), yogurt (450 mg) and other dairy products;  Non-animal sources include leafy vegetables (30 mg) and tofu (70 mg). Calcium is essential for bone and tooth formation and maintenance.  It is also involved in blood clotting, nerve impulse transmission, muscle contractions and cell regulations.

POTASSIUM: Male RDA=2000 mg; Female RDA=1600 mg.  Food sources of potassium include spinach (170 mg), squash (220 mg), bananas (470 mg), orange juice (500 mg), milk (375 mg) and most other fruits and vegetables. Potassium is an electrolyte involved in nerve impulse transmission and cell fluid regulation.

PHOSPHORUS: Adult RDA=700 mg. Age 9-18 RDA=1250 mg. Food sources of phosphorus are dairy products (230 mg), processed foods (50 mg), fish (450 mg) and soft drinks (55 mg). It is important for growth and maintenance of bones and teeth, and forms a part of various high-energy metabolic compounds.

MAGNESIUM: Male RDA=420 milligrams, Female RDA=320 milligrams.  Magnesium can be found in beef (25 mg), wheat bran (25 mg), green vegetables (25 mg) and nuts (90 mg). It is involved in virtually every nutrient metabolic pathway.  There are over 300 enzymes that depend on Magnesium for proper function.

IRON: Male RDA=10 milligrams, Female RDA=15 milligrams.  Iron is found in meats (4 mg), spinach (1 mg), seafood (2 mg), broccoli (1 mg), peas (1 mg), and enriched breads (1 mg). It is an essential part of hemoglobin, which binds oxygen in the blood and carries it to the individual cells.

ZINC: Male RDA=15 milligrams, Female RDA=12 milligrams.  Food sources of zinc are meats (5 mg), seafood (1.5 mg), milk (1 mg) and whole grains (2.5 mg). There are over 200 enzymes that depend on Zinc for proper function, including those involved with growth, immunity, sexual development and reproduction.

SELENIUM: Male RDA=70 micrograms Female RDA=55 mcg.  Selenium concentrations vary from food to food due to varied levels in soil from region to region.  Average food levels are chicken (45 mcg), beef (15 mcg), eggs (15 mcg), whole grains (70 mcg), fish (80 mcg) and other seafood.  Selenium serves primarily as an antioxidant, and may lower risk for lung, prostate and colon cancers.

COPPER: No RDA. 1.5-3.0 milligrams recommended.  Copper is found in most all foods, but is most concentrated in liver (5 mg), raisins (0.5 mg), beans (0.5 mg), nuts (0.4 mg), whole grains (0.4 mg), potatoes (0.4 mg). Copper is involved with many enzymes performing many different metabolic functions, including hormone synthesis, energy metabolism, and iron absorption.

CHROMIUM: No RDA.  50-200 micrograms recommended. Food sources of chromium are mushrooms (15 mcg), apples (8 mcg), oysters (10 mcg), meats, organ meats, whole grains (3 mcg), nuts, seeds, and brewer’s yeast (3 mcg). Enhances insulin action by stimulating glucose uptake.  May improve growth in Cr deficient, malnourished children.

MANGANESE: No RDA.  2-5 milligrams recommended.  Manganese is found in nuts (1 mg), rice (1 mg), oats (1 mg) and beans (1 mg).Manganese is involved with enzymes involved in carbohydrate metabolism.