Aluminum and Human Health

A metallic ion that is widely distributed in water and soil. Drinking water often contains aluminum beyond levels leached from soil and clay because aluminum hydroxide is often added to municipal water supplies to clarify drinking water.
Aluminum is often added to food. Aluminum compounds make PROCESSED FOOD more creamy and pourable. They are quite versatile and are found in INFANT FORMULA, pickles, relishes, BEER, CREAM OF TARTAR, grated CHEESE, canned foods, BAKING POWDER, and self-rising FLOUR. Aluminum is also found in the medicine chest: A major source of aluminum is ANTACIDS (such as Maalox), which have a high aluminum hydroxide content. Antiperspirants, over-the-counter analgesics (pain relievers, such as buffered ASPIRIN for arthritis), and other pain medications contain aluminum. The average daily intake from all sources ranges from 10 to 100 mg. Most of this is not absorbed; of the fraction of aluminum that is absorbed by the body, most is subsequently excreted.
Although aluminum is not a heavy metal, accumulated evidence suggests that this substance may be harmful. Aluminum may cause dialysis dementia, SENILITY, and brain damage in young patients undergoing hemodialysis for kidney failure. Their increased aluminum intake is due to the use of antacids containing aluminum and to the elevated aluminum content of water used for dialysis. More generally, high levels of aluminum may inhibit phosphate uptake by the intestine and may increase CALCIUM losses by excretion by the kidneys. The imbalance may cause brittle bones and may disturb bone formation. Other evidence suggests that excessive aluminum impairs the body’s immunity.
Aluminum seems to accumulate in the brain with age, and high levels of aluminum are found in the brains of victims of ALZHEIMER’S DISEASE. Whether this is a cause or an effect of the disease is not known.
Patients with kidney disease and anyone regularly consuming antacids that contain aluminum compounds should be aware of the risks. Patients should avoid taking medications containing aluminum with orange juice (CITRIC ACID); this combination can dramatically increase aluminum uptake in the body. Acidic foods like TOMATO sauce, applesauce, and SAUERKRAUT should not be placed in aluminum foil or in uncoated aluminum cookware because these foods dissolve aluminum, which can then be absorbed.

Wow — You think that was a hot flash?

Then you need extra calcium. Both men and women produce the sex hormones testosterone and estrogen, although men make proportionately more testosterone and women, more estrogen. Testosterone builds bone; estrogen preserves it.
At menopause, a woman’s production of estrogen drops precipitously, and her bones rapidly become less dense. As men age and their testosterone levels drop, they’re also at risk of losing bone tissue, but the loss is less rapid and dramatic than a woman’s.
For both men and woman, severe loss of bone density can lead to osteoporosis and an increased risk of bone fractures, a condition more common among women of Caucasian and Asian ancestry. Estrogen supplements can help a woman maintain bone tissue, but taking the hormone may have serious side effects, including an increased risk of breast cancer. Twenty years ago, nutritionists thought it impossible to stop age-related loss of bone density — that your body ceased to absorb calcium when you passed your mid-20s. Today, medications such as alendronate (Fosamax) protect an aging woman’s bones without estrogen’s potentially harmful effects. Increasing your consumption of calcium plus vitamin D may also be helpful, regardless of your gender. But the most recent studies says the value of extra calcium may not be as high as once believed. What can I say? Stay tuned for more on this one.

Calcium supplements: What kind of calcium is in that pill?

Calcium-rich foods give you calcium paired with natural organic acids, a combination that your body easily digests and absorbs.
The form of calcium most commonly found in supplements, however, is calcium carbonate, the kind of calcium that occurs naturally in limestone and oyster shells.
Calcium carbonate is a versatile compound. Not only does it build strong bones and teeth, but it also neutralizes stomach acid and relieves heartburn. Calcium carbonate antacids can be used as calcium supplements. They’re nutritionally sound and generally cost less than products designed solely as nutritional supplements. Some calcium supplements contain compounds that mix calcium with an organic acid. Calcium lactate is calcium plus lactic acid, the combination that occurs naturally in milk. Calcium citrate is calcium plus citric acid, an acid found in fruits. These compounds are easier to digest, but they’re sometimes more expensive than calcium carbonate products. Calcium carbonate is nearly half calcium, a very high percentage. But unless your stomach is very acidic, it’s hard for your digestive system to break the compound open and get at the elemental calcium (the kind of calcium your body can use). You can increase your absorption of calcium from calcium carbonate by taking the tablets with meals.
Because different calcium compounds yield different amounts of elemental calcium, the label lists both the calcium compound and the amount of elemental calcium provided, like this:
Calcium carbonate, 500 milligrams, providing 200 milligrams elemental calcium. Whenever you see the word calcium alone, it stands for elemental calcium.
The human body absorbs calcium most efficiently in amounts of 500 milligrams or less. You get more calcium from one 500-milligram calcium tablet twice a day than one 1,000-milligram tablet. If the 1,000-milligram tablets are a better buy, break them in half.
Warning: Not all antacids double as dietary supplements. Antacids containing magnesium or aluminum compounds are safe for neutralizing stomach acid, but they won’t work as supplements.
In fact, just the opposite is true. Taking magnesium antacids reduces your absorption of calcium, and taking aluminum antacids reduces your absorption of phosphorus. Because manufacturers sometimes change the ingredients in their products without notice, you always need to read the product label before assuming that an antacid can double as a calcium supplement

I’m looking for an iron supplement. What’s this “ferrous” stuff?

The iron in iron supplements comes in several different forms, each one composed of elemental iron (the kind of iron your body actually uses) coupled with an organic acid that makes the iron easy to absorb.
The iron compounds commonly found in iron supplements are:

• Ferrous citrate (iron plus citric acid)
• Ferrous fumarate (iron plus fumaric acid)
• Ferrous gluconate (iron plus a sugar derivative)
• Ferrous lactate (iron plus lactic acid, an acid formed in the fermentation of milk)
• Ferrous succinate (iron plus succinic acid)
• Ferrous sulfate (iron plus a sulfuric acid derivative)

In your stomach, these compounds dissolve at different rates, yielding different amounts of elemental iron. So supplement labels list the compound and the amount of elemental iron it provides, like this:

Ferrous gluconate 300 milligrams
Elemental iron 34 milligrams

This tells you that the supplement has 300 milligrams of the iron compound ferrous gluconate, which gives you 34 milligrams of usable elemental iron. If the label just says “iron,” that’s shorthand for elemental iron. The elemental iron number is what you look for in judging the iron content of a vitamin/mineral supplement.

People who need extra minerals

If your diet provides enough minerals to meet the RDAs, you’re in pretty good shape most of the time. But a restrictive diet, the circumstances of your reproductive life, and just plain getting older can increase your need for minerals. Here are some scenarios.

You’re a strict vegetarian
Vegetarians who pass up fish, meat, and poultry must get their iron either from fortified grain products such as breakfast cereals or commercial breads or naturally from foods such as seeds, nuts, blackstrap molasses, raisins, prune juice, potato skins, green leafy vegetables, tofu, miso, or brewer’s yeast. Because iron in plant foods is bound into compounds that are difficult for the human body to absorb, iron supplements are pretty much standard fare. Vegans — vegetarians who avoid all foods from animals, including dairy products — have a similar problem getting the calcium they need. Calcium is in vegetables, but it, like iron, is bound into hard-to-absorb compounds. So vegans need calcium-rich substitutes. Good food choices are soybean milk fortified with calcium, orange juice with added calcium, and tofu processed with calcium sulfate.

You live inland, away from the ocean
Now here’s a story of 20th century nutritional success. Seafood and plants grown near the ocean are exposed to iodine-rich seawater. Freshwater fish, plants grown far from the sea, and the animals that feed on these fish and plants are not exposed to iodine. So people who live inland and get all their food from local gardens and farms cannot get the iodine they need from food. American savvy and technology rode to the rescue in 1924 with the introduction of iodized salt. Then came refrigerated railroad cars and trucks to carry food from both coasts to every inland city and state. Together, modern salt and efficient shipment virtually eliminated goiter, the iodine deficiency disease, in this country. Nonetheless, millions of people worldwide still suffer from chronic iodine deficiency.

You’re a man
Just as women lose iron during menstrual bleeding, men lose zinc at ejaculation. Men who are extremely active sexually may need extra zinc. The trouble is, no one has ever written down standards for what constitutes “extremely active.” Check this one out with your doctor.
Men who take a daily supplement of 200 micrograms selenium seem to cut their risk of prostate cancer by two-thirds. The selenium supplement also produces an overall drop in cancer mortality, plus a significantly lower risk of prostate cancer, colon cancer, and lung cancer in both men and women.

You’re a woman
The average woman loses about 2 to 3 teaspoons of blood during each menstrual period, a loss of 1.4 milligrams of iron. Women whose periods are very heavy lose more blood and more iron. Because getting the iron you need from a diet providing fewer than 2,000 calories a day may be virtually impossible, you may develop a mild iron deficiency. To remedy this, some doctors prescribe a daily iron supplement.
Women who use an intrauterine device (IUD) may also be given a prescription for iron supplements because IUDs irritate the lining of the uterus and cause a small but significant loss of blood and iron.

You’re pregnant
The news about pregnancy is that women may not need extra calcium. This finding, released late in 1998, is so surprising that it probably pays to stay tuned for more — and definitely check with your own doctor. Meanwhile, pregnant women still need supplements to build not only fetal tissues but also new tissues and blood vessels in their own bodies. Animal studies suggest (but don’t prove) that you may also need extra copper to protect nerve cells in the fetal brain. Nutritional supplements for pregnant women are specifically formulated to provide the extra nutrients they need.

You’re breast-feeding
Nursing mothers need extra calcium, phosphorus, magnesium, iron, zinc, and selenium to protect their own bodies while producing nutritious breast milk. The same supplements that provide extra nutrients for pregnant women will meet a nursing mother’s needs.

Wow — You think that was a hot flash?
Then you need extra calcium. Both men and women produce the sex hormones testosterone and estrogen, although men make proportionately more testosterone and women, more estrogen. Testosterone builds bone; estrogen preserves it.
At menopause, a woman’s production of estrogen drops precipitously, and her bones rapidly become less dense. As men age and their testosterone levels drop, they’re also at risk of losing bone tissue, but the loss is less rapid and dramatic than a woman’s.

For both men and woman, severe loss of bone density can lead to osteoporosis and an increased risk of bone fractures, a condition more common among women of Caucasian and Asian ancestry. Estrogen supplements can help a woman maintain bone tissue, but taking the hormone may have serious side effects, including an increased risk of breast cancer. Twenty years ago, nutritionists thought it impossible to stop age-related loss of bone density — that your body ceased to absorb calcium when you passed your mid-20s. Today, medications such as alendronate (Fosamax) protect an aging woman’s bones without estrogen’s potentially harmful effects. Increasing your consumption of calcium plus vitamin D may also be helpful, regardless of your gender. But the most recent studies — by which I mean the study released in February 2006 as I am typing these words — says the value of extra calcium may not be as high as once believed. What can I say? Stay tuned for more on this one.

Knowing how much mineral is too much

Like some vitamins, some minerals are potentially toxic in large doses:

• Calcium: Though clearly beneficial in amounts higher than the current RDAs, calcium is not problem-free:

• Constipation, bloating, nausea, and intestinal gas are common side effects among healthy people taking supplements equal to 1,500 to 4,000 milligrams of calcium a day.
• Doses higher than 4,000 milligrams a day may be linked to kidney damage.
• Megadoses of calcium can bind with iron and zinc, making it harder for your body to absorb these two essential trace elements.

• Phosphorus: Too much phosphorus can lower your body stores of calcium.
• Magnesium: Megadoses of magnesium appear safe for healthy people, but if you have kidney disease, the magnesium overload can cause weak muscles, breathing difficulty, irregular heartbeat and/or cardiac arrest (your heart stops beating).
• Iron: Overdosing on iron supplements can be deadly, especially for young children. The lethal dose for a young child may be as low as 3 grams (3,000 milligrams) elemental iron at one time. This is the amount in 60 tablets with 50 milligrams elemental iron each. For adults, the lethal dose is estimated to be 200 to 250 milligrams elemental iron per kilogram (2.2 pounds) of body weight. That’s about 13,600 milligrams for a 150-pound person — the amount you’d get in 292 tablets with 50 milligrams elemental iron each. New FDA rules require individual blister packaging for supplements containing more than 30 milligrams iron to foil tiny fingers and prevent accidental overdoses.
  
• Zinc: Moderately high doses of zinc (up to 25 milligrams a day) may slow your body’s absorption of copper. Doses 27 to 37 times the RDA (11 mg/males; 8 mg/females) may interfere with your immune function and make you more susceptible to infection, the very thing that normal doses of zinc protect against. Gram doses (2,000 milligrams/2 grams) of zinc cause symptoms of zinc poisoning: vomiting, gastric upset, and irritation of the stomach lining.
• Iodine: Overdoses of iodine cause exactly the same problems as iodine deficiency: goiter. How can that be? When you consume very large amounts of iodine, the mineral stimulates your thyroid gland, which swells in a furious attempt to step up its production of thyroid hormones. This reaction may occur among people who eat lots of dried seaweed for long periods of time.
• Selenium: In China, nutrition researchers have linked doses as high as 5 milligrams of selenium a day (90 times the RDA) to thickened but fragile nails, hair loss, and perspiration with a garlicky odor. In the United States, a small group of people who had accidentally gotten a supplement that mistakenly contained 27.3 milligrams selenium (436 times the RDA) fell victim to selenium intoxication — fatigue, abdominal pain, nausea and diarrhea, and nerve damage. The longer they used the supplements, the worse their symptoms were.
• Fluoride: Despite decades of argument, no scientific proof exists that the fluorides in drinking water increase the risk of cancer in human beings. But there’s no question that large doses of fluoride — which you’re unlikely to consume unless you drink well or groundwater in the western United States — causes fluorosis (brown patches on your teeth), brittle bones, fatigue, and muscle weakness. Over long periods of time, high doses of fluoride may also cause outcroppings (little bumps) of bone on the spine. Fluoride levels higher than 6 milligrams a day are considered hazardous.
  
• Molybdenum: Doses of molybdenum two to seven times the Adequate Intake (AI) (45 micrograms) may increase the amount of copper you excrete in urine.

Avoiding mineral deficiency

What happens if you don’t get enough minerals and trace elements? Some minerals, such as phosphorus and magnesium, are so widely available in food that deficiencies are rare to nonexistent. No nutrition scientist has yet been able to identify a naturally occurring deficiency of sulfur, manganese, chromium, or molybdenum in human beings who follow a sensible diet. Most drinking water contains adequate fluoride, and Americans get so much copper (can it be from chocolate bars?) that deficiency is practically unheard of in the United States.
But other minerals are more problematic:

• Calcium: Without enough calcium, a child’s bones and teeth don’t grow strong and straight, and an adult’s bones lose minerals and weaken. Calcium is a team player. To protect against deficiency, you also need adequate amounts of vitamin D, the nutrient that allows you to absorb the calcium you get from food or supplements. Milk fortified with vitamin D has done much to eliminate rickets.
• Iron: Iron deficiency anemia is not just an old advertising slogan. Lacking sufficient iron, your body can’t make the hemoglobin it requires to carry energy-sustaining oxygen to every tissue. As a result, you’re often tired and feel weak. Mild iron deficiency may also inhibit intellectual performance. In one Johns Hopkins study, high school girls scored higher verbal, memory, and learning test scores when they took supplements providing Recommended Dietary Amounts of iron. Check with your doctor before downing iron supplements or cereals fortified with 100 percent of your daily iron requirement, the Environmental Nutrition newsletter warns. Hemochromatosis, a common but often-undiagnosed genetic defect affecting one in every 250 Americans, can lead to iron overload, an increased absorption of the mineral linked to arthritis, heart disease, and diabetes, as well as an increased risk of infectious diseases and cancer (viruses and cancer cells thrive in iron-rich blood).
• Zinc: An adequate supply of zinc is vital for making testosterone and healthy sperm. Men who don’t get enough zinc may be temporarily infertile. Zinc deprivation can make you lose your appetite and your ability to taste food. It may also weaken your immune system, increasing your risk of infections. Wounds heal more slowly when you don’t get enough zinc.That includes the tissue damage caused by working out. In plain language: If you don’t get the zinc you need, your charley horse may linger longer. And, yes, zinc may fight the symptoms of the common cold. To date, several studies have confirmed that sucking on lozenges containing one form of zinc (zinc gluconate) shortens a cold — by a day or two. Others show no differences. Your choice. These results are for adults, not children, and the zinc tablets are meant just for the several days of your cold.
• Iodine: A moderate iodine deficiency leads to goiter (a swollen thyroid gland) and reduced production of thyroid hormones. A more severe deficiency early in life may cause a form of mental and physical retardation called cretinism.
• Selenium: Not enough selenium in your diet? Watch out for muscle pain or weakness. To protect against selenium problems, make sure that you get plenty of vitamin E. Some animal studies show that a selenium deficiency responds to vitamin E supplements. And vice versa.

Molybdenum

Molybdenum (pronounced mo-lib-de-num) is part of several enzymes that metabolize proteins. You get molybdenum from beans and grains. Cows eat grains, so milk and cheese have some molybdenum. Molybdenum also leeches into drinking water from surrounding soil. The molybdenum content of plants and drinking water depends entirely on how much molybdenum is in the soil.

Benefits of chromium

Very small amounts of trivalent chromium, a digestible form of the very same metallic element that decorates your car and household appliances, are essential for several enzymes that you need to metabolize fat. Chromium is also a necessary partner for glucose tolerance factor (GTF), a group of chemicals that enables insulin (an enzyme from the pancreas) to regulate your use of glucose, the end product of metabolism and the basic fuel for every body cell. In a recent joint study by USDA and the Beijing Medical University, adults with noninsulin-dependent diabetes who took chromium supplements had lower blood levels of sugar, protein, and cholesterol, which are all good signs for people with diabetes. In a related study, chromium reduced blood pressure in laboratory rats bred to develop hypertension (high blood pressure), a common complication in diabetes. Right now, little information exists about the precise amounts of chromium in specific foods. Nonetheless, yeast, calves’ liver, American cheese, wheat germ, and broccoli are regarded as valuable sources of this trace element.

Benefits of Fluoride

Fluoride is the form of fluorine (an element) in drinking water. Your body stores fluoride in bones and teeth. Although researchers still have some questions about whether fluoride is an essential nutrient, it’s clear that it hardens dental enamel, reducing your risk of getting cavities. In addition, some nutrition researchers suspect (but cannot prove) that some forms of fluoride strengthen bones.
Small amounts of fluoride are in all soil, water, plants, and animal tissues. You also get a steady supply of fluoride from fluoridated drinking water.

Benefits of Manganese

Most of the manganese in your body is in glands (pituitary, mammary, pancreas), organs (liver, kidneys, intestines), and bones. Manganese is an essential constituent of the enzymes that metabolize carbohydrates and synthesize fats (including cholesterol). Manganese is important for a healthy reproductive system. During pregnancy, manganese speeds the proper growth of fetal tissue, particularly bones and cartilage.
You get manganese from whole grains, cereal products, fruits, and vegetables. Tea is also a good source of manganese.

Benefits of Copper

Copper is an antioxidant found in enzymes that deactivate free radicals (pieces of molecules that can link up to form compounds that damage body tissues) and make it possible for your body to use iron. Copper also may play a role in slowing the aging process by decreasing the incidence of protein glycation, a reaction in which sugar molecules (gly = sugar) hook up with protein molecules in your bloodstream, twist the protein molecules out of shape, and make them unusable. Protein glycation may result in bone loss, high cholesterol, cardiac abnormalities, and a slew of other unpleasantries. In people with diabetes, excess protein glycation may also be one factor involved in complications such as loss of vision.
In addition, copper

• Promotes the growth of strong bones
• Protects the health of nerve tissue
• Prevents your hair from turning gray prematurely

But, no no, a thousand times, no: Large amounts of copper absolutely, and I repeat, absolutely will not turn gray hair back to its original color. Besides, megadoses of copper are potentially toxic. You can get the copper you need from organ meats (such as liver and heart), seafood, nuts, and dried beans, including cacao beans (the beans used to make chocolate).

Benefits of Selenium

Selenium was identified as an essential human nutrient in 1979 when Chinese nutrition researchers discovered that people with low body stores of selenium were at increased risk of Keshan disease, a disorder of the heart muscle with symptoms that include rapid heartbeat, enlarged heart, and (in severe cases) heart failure, a consequence most common among young children and women of childbearing age.
How does selenium protect your heart? One possibility is that it works as an antioxidant in tandem with vitamin E. A second possibility, raised by U.S. Department of Agriculture studies with laboratory rats, is that it prevents viruses from attacking heart muscle.
Here’s some exciting news: The results of a four-year study involving 1,312 patients previously treated for skin cancer strongly suggests that daily doses of selenium in amounts 3.8 times the current recommended daily allowance (RDA) (55 micrograms) may reduce the incidence of cancers of the lung, prostate, colon, and rectum. The University of Arizona study was designed to see whether taking selenium lowered the risk of skin cancer. It didn’t. But among the patients who got selenium rather than a placebo, 45 percent fewer lung cancers, 58 percent fewer colon and rectal cancers, 63 percent fewer prostate cancers, and a 50 percent lower death rate from cancer overall were recorded. Now a follow-up study will determine whether these results hold up. Although fruits and vegetables grown in selenium-rich soils are themselves rich in this mineral, the best sources of selenium are seafood, meat and organ meats (liver, kidney), eggs, and dairy products.

Iodine benefits

Iodine is a component of the thyroid hormones thyroxine and triiodothyronine, which help regulate cell activities. These hormones are also essential for protein synthesis, tissue growth (including the formation of healthy nerves and bones), and reproduction.
The best natural sources of iodine are seafood and plants grown near the ocean, but modern Americans are most likely to get the iodine they need from iodized salt (plain table salt with iodine added). And here’s an odd nutritional note: You may get substantial amounts of iodine from milk. Are the cows consuming iodized salt? No. The milk is processed and stored in machines and vessels kept clean and sanitary with iodates and iodophors, iodine-based disinfectants. Tiny trace amounts get into the products sent to the stores. Iodates are also used as dough conditioners (additives that make dough more pliable), so you’re also likely to find some iodine in most bread sold in supermarkets.

Zinc benefits

Zinc protects nerve and brain tissue, bolsters the immune system, and is essential for healthy growth. Zinc is part of the enzymes (and hormones such as insulin) that metabolize food, and you can fairly call it the macho male mineral.
The largest quantities of zinc in the male human body are in the testes, where it’s used in making a continuous supply of testosterone, the hormone a man needs to produce plentiful amounts of healthy, viable sperm. Without enough zinc, male fertility falters. So, yes, the old wives’ tale is true: Oysters — a rich source of zinc — are useful for men. By the way, women also need zinc . . . just not as much as men do.
Other good sources of zinc are meat, liver, and eggs. Plenty of zinc is in nuts, beans, miso, pumpkin and sunflower seeds, whole-grain products, and wheat germ. But the zinc in plants, like the iron in plants, occurs in compounds that your body absorbs less efficiently than the zinc in foods from animals.

Magnesium benefits

Your body uses magnesium to make body tissues, especially bone. The adult human body has about an ounce of magnesium, and three-quarters of it is in the bones. Magnesium also is part of more than 300 different enzymes that trigger chemical reactions throughout your body. You use magnesium to

• Move nutrients in and out of cells
• Send messages between cells
• Transmit the genetic code (genes and chromosomes) when cells divide and reproduce

An adequate supply of magnesium also is heart-healthy because it enables you to convert food to energy using less oxygen. Bananas are a good source of magnesium and so are many other plant foods, including dark green fruits and vegetables (magnesium is part of chlorophyll, the green pigment in plants), whole seeds, nuts, beans, and grains.

Phosphorus Benefits

Like calcium, phosphorus is essential for strong bones and teeth. For tiptop performance, you need about half as much phosphorus as calcium. Phosphorus also enables a cell to transmit the genetic code (genes and chromosomes that carry information about your special characteristics) to the new cells created when a cell divides and reproduces. In addition, phosphorus

• Helps maintain the pH balance of blood (that is, keeps it from being too acidic or too alkaline)
• Is vital for metabolizing carbohydrates, synthesizing proteins, and ferrying fats and fatty acids among tissues and organs
• Is part of myelin, the fatty sheath that surrounds and protects each nerve cell Phosphorus is in almost everything you eat, but the best sources are highprotein foods such as meat, fish, poultry, eggs, and milk. These foods provide more than half the phosphorus in a nonvegetarian diet; grains, nuts, seeds, and dry beans also provide respectable amounts.

Calcium: The bone team player

The toe bone’s connected to the foot bone. The foot bone’s connected to the anklebone. The anklebone’s connected to the knee bone. And what holds them together all the way up to the head bone is connected to your diet. Like all body tissues, bones are constantly being replenished. Old bone cells break down, and new ones are born. Specialized cells called osteoclasts start the process by boring tiny holes into solid bone so that other specialized cells, called osteoblasts, can refill the open spaces with fresh bone. At that point, crystals of calcium, the best-known dietary bone builder, glom onto the network of new bone cells to harden and strengthen the bone.
Calcium begins its work on your bones while you’re still in your mother’s womb. But it’s not the only mineral at play. You should also think zinc. Based on a survey of 242 pregnant women in Peru, where zinc deficiency is common, Johns Hopkins researchers found the babies born to women who got prenatal supplements with iron, folic acid, and zinc had longer, stronger legs bones than did babies born to women who got the same supplement minus the zinc. After you’re born, calcium continues to build your bones, but only with the help of vitamin D, which produces a calcium-binding protein that enables you to absorb the calcium in the milk Mummy feeds you. To make sure you get your D, virtually all milk sold in the United States is fortified with the vitamin. And because you may outgrow your taste for milk but never outgrow your need for calcium, calcium supplements for adults frequently include vitamin D. But vitamin D isn’t milk’s only contribution. Remember the iron in the Peruvian (and American) prenatal supplements? It isn’t there by accident. Iron increases the production of collagen, the most important protein in bone. Milk contains lactoferrin (lacto = milk; ferri = iron), an iron-binding compound that stimulates the production of the cells that promote bone growth. When researchers at the University of Auckland in New Zealand added lactoferrin from cow’s milk to a dish of osteoblasts, the bone cells grew more quickly. When they injected lactoferrin into the skulls of five lab mice, the bone at the site of the injection also grew faster, leading the team to suggest in the journal Endocrinology that lactoferrin may play a role in treating osteoporosis. No surprise to the Department of Nutrition Sciences at the University of Arizona, where a study done with scientists from the University of Arkansas and Columbia University shows that women in their 40s, 50s, and 60s who get about 18 milligrams of iron a day have stronger, denser bones than women who get less iron. What makes this intriguing is that 18 milligrams a day is more than double the current RDA (8 milligrams) for older women.
But the iron/calcium dance is a balancing act. In your body, iron and calcium appear to compete to see which one gets absorbed. So the extra iron works only for women who get about 800 to 1,200 milligrams calcium a day — women who get less and women who get more don’t seem to benefit from extra iron.
Finally, please note that the word bones begins with b — as in vitamin B12. The female sex hormone estrogen preserves bone; the male sex hormone testosterone builds new bone. As people age and their supply of sex hormones diminishes, they lose bone faster than they can levels of vitamin B12. A report in the Journal of Clinical Endocrinology and Metabolism says that researchers at the University of California, San Francisco, found that women with lower levels of this vitamin also have less dense hip bones. So to protect your bones, you need calcium, zinc, iron, and vitamins D and B12, all found most abundantly in milk, cheese, eggs, and red meat. Which sounds like a cardiologist’s nutritional high-fat, high-cholesterol nightmare — unless you edit the menu to read: skim milk, low-fat cheese, egg whites, and lean beef. Way to go.

Calcium Benefits

When you step on the scale in the morning, you can assume that about three pounds of your body weight is calcium, most of it packed into your bones and teeth.
Calcium is also present in extracellular fluid (the liquid around body cells), where it performs the following duties:

• Regulating fluid balance by controlling the flow of water in and out of cells
  
• Enabling cells to send messages back and forth from one to another
  
• Keeping muscles moving smoothly and preventing cramping

An adequate amount of calcium is important for controlling high blood pressure — and not only for the person who takes the calcium directly. At least one study shows that when a pregnant woman gets a sufficient amount of calcium, her baby’s blood pressure stays lower than average for at least the first seven years of life, meaning a lower risk of developing high blood pressure later on. Your best food sources of calcium are milk and dairy products, plus fish such as canned sardines and salmon. Calcium also is found in dark green leafy vegetables, but the calcium in plant foods is bound into compounds that are less easily absorbed by your body.

An elementary guide to minerals

The early Greeks thought that all material on Earth was constructed of a combination of four basic elements: earth, water, air, and fire. Wrong. Centuries later, alchemists looking for the formula for precious metals, such as gold, decided that the essential elements were sulfur, salt, and mercury. Wrong again.
In 1669, a group of German chemists isolated phosphorus, the first mineral element to be accurately identified. After that, things moved a bit more swiftly. By the end of the 19th century, scientists knew the names and chemical properties of 82 elements. Today, 112 elements have been identified.
The classic guide to chemical elements is the periodic table, a chart devised in 1869 by Russian chemist Dmitri Mendeleev (1834–1907), for whom mendelevium was named. The table was revised by British physicist Henry Moseley (1887–1915), who came up with the concept of atomic numbers, numbers based on the number of protons (positively charged particles) in an elemental atom.
The periodic table is a clean, crisp way of characterizing the elements, and if you are now or ever were a chemistry, physics, or premed student, you can testify firsthand to the joy (maybe that’s not the best word?) of memorizing the information it provides. Personally, I’d rather be forced to watch reruns of The Dating Game.