Precious Metals

[Guest guest]

By Sally Squires

People don't usually think of grocery shopping as a mining expedition. But

there's increasing evidence that it's wise to seek essential minerals when

cruising the supermarket aisles.

This month a team of scientists at the U.S. Department of Agriculture's

Western Human Nutrition Research Center reported in the American Journal of

Clinical Nutrition that copper appeared to improve immune function in a

small group of men.

That's not the only mineral getting a closer look. From calcium to zinc,

essential minerals appear to be worth their weight in nutritional gold. In

some cases they may help you achieve a healthy weight, too.

" If I were a betting lady, I would bet on getting some of the minerals to

keep me healthier, " said Judith S. Stern, professor of nutrition and

internal medicine at the University of California, , where the research

center is located.

That's because growing evidence points to the blood-pressure-lowering

benefits of potassium, possible diabetes prevention from magnesium and

potential immune system boosting from zinc.

But, as Stern notes, it can be challenging to find the right balance of

minerals. " Zinc has been a favorite mineral of late, " she said. " But you

don't want to overdo it on zinc, because doing so so affects copper

absorption. "

For that reason, Stern and other nutrition experts say that food is the

leading choice to meet mineral requirements. " Even when we put these things

in a pill, " Stern said, " we still haven't duplicated all the effects of

fruits and vegetables. "

So to help you dig for your daily minerals, here's a guide to the gems and

the foods that deliver them.

Calcium. The most common mineral in the body, calcium is best known for

building strong bones and teeth. It also plays a key role in maintaining

blood vessels, producing hormones and enabling nerves to signal each other.

Growing evidence suggests that it may help with weight control, keep blood

pressure in check and reduce the risk of colon polyp recurrence, a risk

factor for colon cancer. The U.S. Dietary Guidelines Advisory Committee

recently noted that many Americans fall short on calcium.

Kids and teens need the most -- about 1,300 milligrams per day (roughly

the amount found in four glasses of skim milk or fortified orange juice).

Adults 51 and older require 1,200 milligrams per day; those 50 and under

need 1,000 milligrams.

Food sources: Low-fat and nonfat dairy products; fish with bones, such as

canned salmon; fortified food, including juice and soy milk; and some green

vegetables, such as spinach.

Copper. Too little copper appears to depress the immune function and

weaken bones. Too much may help promote heart disease. Aim for 900

micrograms per day for adults, 19 and older. That's equal to about a cup of

lentil soup and an ounce of cashews.

Food sources: Oysters, crab and other shellfish; liver; almonds and other

nuts; lentils, mushrooms, shredded wheat and chocolate.

Iron. Without it, blood could not carry oxygen, protein would not form

and key biochemical reactions throughout the body would not occur. Iron

bolsters the immune system and is required for growth and reproduction,

which is why pregnant women need the most: 27 milligrams per day (about the

equivalent of five cups of raisin bran cereal). Women of childbearing ages

need about 18 milligrams per day; men 19 and older and post-menopausal women

need the least: eight milligrams per day -- about that found in 3/4 cup of

tofu.

Food sources: Beef, dark chicken meat, oysters, raisin bran, black strap

molasses and prunes. Beans, soy and spinach are rich in iron, but also have

phytates, which can cut iron absorption in half; this is why vegetarians are

urged to eat more iron-rich food than meat-eaters. Vitamin C helps boost

iron absorption, so drink some orange juice with your raisin bran for better

absorption.

Magnesium. Key to hundreds of vital functions, magnesium helps maintain

muscle, bone and nerves, and promotes a steady heartbeat. The latest

findings suggest it may help prevent migraine headaches, could help reduce

asthma and may treat impaired glucose tolerance, a precursor of diabetes.

Men 19 and older need the most, about 400 milligrams per day, equal to about

an ounce of almonds, a bowl of high-fiber cereal, a cup of brown rice and a

bowl of black-eyed peas. Women need about 300 milligrams per day.

Food sources: Whole grains, especially bran cereals; nuts and green

vegetables, including spinach.

Potassium. Vital to the internal integrity of all cells in the body,

potassium is also key for controlling blood pressure. Too little potassium

can cause fatigue, muscle cramps, bloating and, in severe cases, fatal

irregular heartbeats. New research suggests potassium may help prevent

stroke, osteoporosis and kidney stones. Those 14 and older need nearly five

grams per day -- about the amount found in 10 servings of fruit and

vegetables.

Food sources: Fruit (especially bananas and oranges), vegetables

(especially potatoes) and nuts.

Zinc. Important to protect against infection, preserve brain function and

for reproduction, zinc is a key element of enzymes, enables protein

production and allows communication between cells. Too little zinc can cause

rashes, delay puberty, impair hearing, reduce appetite, cause night

blindness and produce severe diarrhea. New research suggests zinc may help

treat the common cold and could be helpful in diabetes, macular degeneration

and bolstering the immune systems of those with HIV. Aim for 11 milligrams

per day for men, 19 and older; eight milligrams for women. That's equal to

about six oysters. Just don't regularly exceed the tolerable upper limit of

40 milligrams per day for adults 19 and older, since too much zinc over a

long period can cause toxicity, including copper deficiency, diarrhea and

vomiting.

Food sources: Shellfish, beef, nuts, legumes and whole grains.•