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11 Featured Nutrients: Why You Need Them
Beta Carotene
 What it does:
In the body, beta carotene is converted to
vitamin A, a nutrient essential for healthy vision, immune function and cell
growth. It also acts as an antioxidant that neutralizes free radicals.
More carrots, less cancer?
After early research linked diets rich in beta carotene with reduced risk for
cancer, scientists supposed that beta-carotene supplements might also help
prevent cancer. Unfortunately, two large clinical trials in the 1990s revealed
that taking mega-dose beta-carotene supplements increased rates of lung cancer
in smokers. Test-tube research shows that, in high doses, beta carotene can act
as a pro-oxidant (boosting free-radical production and risk of disease) and this
might happen in the body, too, says Robert Russell, M.D., director of the Jean
Mayer USDA Human Nutrition Research Center on Aging at Tufts University. Skip
supplements; eat your veggies, says Russell; "there doesn't appear to be any
health risk to getting plenty of beta carotene from foods." (Yellow skin is
temporary and harmless, say experts.)
Can beta carotene keep you sharp?
A study in the December 2006 Journal of Gerontology linked high blood levels of
beta carotene with a lower risk of cognitive decline in people predisposed to
Alzheimer's. "Beta carotene may counter free radical damage involved in the
development of Alzheimer's in some people" says Peifeng Hu, M.D., the study's
author and an assistant professor at UCLA School of Medicine.
How much you need:
There's no RDA for beta carotene.
Food Sources of Beta Carotene:
Eat plenty of dark green vegetables and
orange vegetables and fruits (papaya, mango) weekly to meet your vitamin A needs
and reap beta carotene's potential antioxidant benefits.
Vitamin B 12
 What it does:
Vitamin B12 is used in making DNA, the building block of genes, and in maintaining healthy
nerve and red blood cells.
How much you need:
2.4 micrograms a day for people 14 and older provides all the body needs—although
some researchers have argued that a daily intake of 6 micrograms would ensure
absorption.
Food sources of B12
B12 is bound to protein, so foods like meat, fish, eggs and dairy products like yogurt and
milk are the principal sources.
Beef liver, braised (3 oz.) = 60 mcg
Clams, baked or broiled (3 oz.) = 47 mcg
Complete Wheat Bran Flakes (1 cup) = 8 mcg
Nutritional yeast flakes (1 Tbsp.) = 4 mcg
Lobster, steamed (3 oz.) = 3 mcg
Tuna fish, light (3 oz.) = 3 mcg
Salmon, cooked (3 oz.) = 2 mcg
Beef, ground, 90%-lean (3 oz.) = 2 mcg
Milk, 2% (1 cup) = 1 mcg
Cottage cheese, low-fat (1/2 cup) = 1 mcg
Source: ESHA database 2005
Chromium
 What it does:
Chromium is required by the body for the process that turns food into usable
energy, helping insulin prime cells to take up glucose.
How much you need:
Despite disappointing findings on chromium supplements and weight loss, the body still
needs it. The daily recommended intake for adults is 50 to 200 mcg.
Food sources of chromium:
Best sources of chromium are whole-grain breads and cereals, meat, nuts, prunes,
raisins, beer and wine.
Since there's no large database yet for the chromium content of foods, use these
values as a general guide rather than gospel.
Brewer's yeast (1 oz.) = 31.4 mcg
Whole-grain bread (1 oz. slice) = 11.8 mcg
Broccoli (1/2 cup) = 11.0 mcg
Beer (12 oz.) = 9-100 mcg
Grape juice (8 oz.) = 7.5 mcg
Turkey ham (1 oz. slice) = 3.5 mcg
Beef (3 oz.) = 2.0 mcg
Adapted from the Linus Pauling Institute, Oregon State University
Vitamin K
 What it does:
Vitamin K is used by the body to produce an array of different proteins. Some of
them are used to create factors that allow blood to coagulate—critical in
stemming bleeding and allowing cuts and wounds to heal.
How much you need:
The current recommended daily intake of vitamin K is 90 micrograms for women and
120 for men. Luckily, vitamin K deficiency is extremely uncommon.
Food Sources of Vitamin K:
Kale, spinach, broccoli, asparagus, arugula, green leaf lettuce, soybean oil,
canola oil, olive oil and tomatoes.
Kale, cooked (1/2 cup) = 531 mcg
Spinach, raw (1 cup) = 145 mcg
Broccoli, cooked (two 5" spears) = 104 mcg
Asparagus, cooked (1/2 cup) = 68 mcg
Arugula, raw (1 cup) = 62 mcg
Green leaf lettuce (1 cup) = 57 mcg
Soybean oil (1 Tbsp.) = 27 mcg
Canola oil (1 Tbsp.) = 17 mcg
Olive oil (1 Tbsp.) = 8 mcg
Tomato, fresh (1 med.) = 7 mcg
A word of caution:
If you are taking an anticoagulant medication such as warfarin, your doctor may
advise you to avoid overdoing foods rich in vitamin K, since the vitamin can
interfere with the drug's action. If you have any questions, talk to your doctor
before making changes to your diet.
Potassium
 What it does:
Potassium is involved in almost every vital body process: maintaining blood
pressure, heart and kidney function, muscle contraction, even digestion.
How much you need:
Surveys show that most Americans get less than half the recommended amounts of
potassium, which is 4,700 milligrams (mg) daily for adults and teens.
Food sources of potassium:
Foods that are closest to their original states are best, so be sure to choose
whole, unprocessed foods as often as possible, especially fruits and vegetables,
low-fat dairy products, whole grains, fish and lean meats.
Sweet potato, baked, 1 medium = 694 mg
Beet greens, 1/2 cup cooked = 655 mg
Potato, baked, 1 medium = 610 mg
Yogurt, plain, nonfat, 1 cup = 579 mg
Halibut, cooked, 3 oz. = 490 mg
Lima beans, 1/2 cup cooked = 484 mg
Banana, 1 medium = 422 mg
Milk, nonfat, 1 cup = 382 mg
Cantaloupe, 1/4 medium = 368 mg
Orange juice, 3/4 cup = 355 mg
Source: U.S. Dietary Guidelines 2005
Magnesium
 What it does:
Necessary for some of the body's most basic processes, magnesium triggers more
than 300 biochemical reactions—most importantly the production of energy from
the food we eat.
How much you need:
Around 300 mg/day (women) and 350 mg/day (men), with the upper limit for
supplemental magnesium at 350 mg.
Food sources of magnesium:
The mineral is abundant in avocados, nuts and leafy greens including acorn
squash, kiwi and almonds.
1 cup baked acorn squash = 105 mg
1 oz. toasted wheat germ = 90 mg
1 oz. dry-roasted almonds (24 nuts) = 86 mg
2 rectangular biscuits shredded wheat = 80 mg
1/2 cup cooked spinach = 65 mg
1 stalk broccoli = 59 mg
1 medium kiwi fruit = 23 mg
1/2 medium Hass avocado = 103 mg
Vitamin C
 What it does:
Researchers have long known that vitamin C is an essential building block of
collagen, the structural material for bone, skin, blood vessels and other
tissue.
How much you need:
The current recommended daily intake for men is 90 mg and for women it is 75 mg.
The body can only absorb a maximum of about 400 milligrams a day.
Food Sources of Vitamin C:
Virtually everything in the produce section including oranges, green bell
peppers, strawberries, broccoli, cantaloupe and tomatoes, turnip greens, sweet
potatoes and okra.
green bell pepper = 60 mg
orange = 48 mg
strawberries = 45 mg
broccoli = 39 mg
cantaloupe = 29 mg
tomato = 23 mg
turnip greens, cooked = 20 mg
sweet potato, baked with skin = 20 mg
okra, cooked = 13 mg
Vitamin D
 By
all rights, vitamin D should be the one essential nutrient we don't need to fret
about. During the summer months, most of us need only about 10 to 20 minutes of
direct sun on the hands and face for our skin to manufacture enough D for the
whole day. To make up for any shortfall, especially in young children, milk has
been fortified with D since the 1930s.
So it came as a shock a few years back when surveys found that a large number of
Americans aren't getting nearly enough. In one study, for example, 32 percent of
healthy young adults in Boston were found to be vitamin D-deficient.
What it does:
Early on, most of the concern focused on bones, since vitamin D, working along
with calcium, helps build and maintain them.
How much you need:
Official recommendations now call for 200 IU for children and 600 IU for people
over 71, with other groups falling somewhere between.
Food sources of vitamin D:
We rely on fortified milk and breakfast cereals to get most of our dietary
vitamin D. Apart from a few kinds of fish, including herring and sardines, there
aren't many natural food sources, which leaves supplements and direct sunlight.
Folate/Folic Acid
 What it does:
Folate is necessary for the production of new cells, including red blood cells.
Folate deficiency remains a major cause of spinal-cord defects in newborns.
How much you need:
Many dietitians recommend taking a multivitamin with 400 mcg of folic acid;
1,000 mcg per day is the safe upper limit for folic acid.
Food sources of folate:
Rich sources of folate include liver, dried beans and peas, spinach and leafy
greens, asparagus and fortified cereals.
Kidney beans (1 cup cooked) = 230 mcg
Lentils (1 cup cooked) = 358 mcg
Asparagus spears 6 each = 134 mcg
Oatmeal (fortified) = 130 mcg
Spinach (1/2 cup cooked) = 121 mcg
Romaine lettuce (1 cup chopped) = 76 mcg
Peas (1/2 cup cooked) = 47 mcg
Zinc
 What it does:
Zinc is integral to almost every cell of the human body, from keeping the immune
system healthy to regulating testosterone.
How much you need:
The recommended dietary intake for men is 11 mg/day, for women 8 mg/day.
Food Sources of zinc:
Oysters, cooked beef tenderloin, turkey, chickpeas, roast chicken leg, pumpkin
seeds, cooked pork tenderloin, plain low-fat yogurt, wheat germ, tofu, dry
roasted cashews and Swiss cheese.
Oysters, steamed (3 oz.) = 30.0 mg
Cooked beef tenderloin (3 oz.) = 4.8 mg
Turkey, dark meat, roasted (3 oz.) = 3.9 mg
Chickpeas (7 oz.) = 2.8 mg
Roast chicken leg = 2.7 mg
Pumpkin seeds (1/4 cup) = 2.6 mg
Cooked pork tenderloin (3 oz.) = 2.5 mg
Plain low-fat yogurt (1 cup) = 2.2 mg
Wheat germ (2 Tbsp.) = 1.8 mg
Tofu (4 oz.) = 1.7 mg
Dry roasted cashews (1 oz.) = 1.6 mg
Swiss cheese (1 oz.) = 1.0 mg
Vitamin E
 What it does:
Scientists have not yet elucidated all of vitamin E's roles, but they
hypothesize that it has a role in immune function, DNA repair, the formation of
red blood cells and vitamin K absorption.
How much you need:
The RDA in men and women is 23 IU, or 15 milligrams, and because many E-rich
foods come from nuts and oils, some low-fat diets may be inadequate in vitamin
E.
Food Sources of Vitamin E:
Wheat germ oil. Sunflower seeds, cooked spinach, almonds, safflower oil and
hazelnuts.
1 Tbsp. wheat germ oil = 20 mg
1/4 cup sunflower seeds = 12 mg
1 cup cooked spinach = 7 mg
1 ounce almonds (23 nuts) = 7 mg
1 Tbsp. safflower oil = 5 mg
1 ounce hazelnuts (21 nuts) = 4 mg
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