Diet and Health

hese days when the conversation turns to diet, the question is not so much what we should eat as what we shouldn't. Deficiency diseases are almost history. Scientists have identified 19 vitamins, minerals, and other nutrients needed for good health; and our foods are laced with supplements to make sure that we get them.

Our problem today is not too little but too much—too much fat, salt, sugar...too much of whatever the latest study has chosen to attack. We now get so much advice on what foods to avoid that it's tempting to simply throw up your hands and forget the whole thing. Unfortunately, that's not a realistic option.

Some 34 million Americans are now classified as “obese”—that is, 20 percent or more above their ideal weight. And with obesity comes increased risk of heart disease, diabetes, stroke, and some forms of cancer.

Indeed, according to the American Cancer Society, 50 percent of cancers in women and 30 percent in men may be related to diet. Worse yet, an estimated 67 million Americans, 1 out of 4, now have some form of heart disease, and several of the leading risk factors for heart disease, including high cholesterol, obesity, diabetes, and high blood pressure, can all be aggravated by diet.

Eating a well­balanced healthy diet really can be a life­saver. But deciding what's healthy is no easy task when we're faced with an almost daily onslaught of often controversial, sometimes even contradictory, nutritional information. To help sort through the conflicting claims, here's a quick review of the basic facts we know today.

The Carbohydrate Craze

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Carbohydrates, along with proteins and fats, provide the energy we need from our diets. In fact, carbohydrates provide most of the calories your body uses. As an easily available source of energy, carbohydrates are an ideal “fuel for fitness” for both the recreational and professional athlete.

Because carbohydrates yield only 4 calories per gram, they are essential to any weight control program. This idea runs counter to earlier theories about dieting, where the first things to get ousted from the diet were those “fattening” breads, potatoes, and pastas. High­carbohydrate foods are actually low in fat—unless you add fat in cooking or at the table.

Foods high in carbohydrates are a staple of diets both for diabetics and for those who want healthy hearts. High in nutrients, these foods also add fiber to the diet, which helps control both blood sugar and blood cholesterol levels.

Except for the carbohydrate found in milk, almost all carbohydrates come from plants. Unfortunately, when it comes to nutritional value, not all carbohydrates are created equal. There are two types: simple and complex. Although both provide 4 calories per gram, they have distinctly different functions.

Simple Carbohydrates

Structurally, simple carbohydrates consist of 1 or 2 sugar units linked together. This makes them an easy­to­absorb source of energy. Most simple carbohydrates, often referred to as simple sugars, have one appealing trait in common—sweetness. Common forms of simple carbohydrates are sucrose (table sugar), glucose (dextrose), fructose (fruit sugar), lactose (milk sugar), and maltose (malt sugar). Other forms of these sugars are honey, corn syrup, maple syrup, and any type of “sugar,” such as brown sugar, confectioner's sugar, and beet sugar. Simple sugars provide calories, but few vitamins and minerals.

Is sugar, with its minimal nutrient contribution, really the “health culprit” it is made out to be? Throughout history, sugar has been blamed for everything from obesity and diabetes to hyperactivity in children. Yet the only disorder sugar has ever been firmly linked to is tooth decay.

THE FAMED “FOOD PYRAMID”

This government-developed diagram reflects the latest consensus on healthy diet. Carbohydrates—represented by the broad slab supporting the pyramid—are definitely in. Fat—shown in the little capstone at the peak—is unquestionably out. Not that a little fat is bad, mind you. The problem is that almost all of us get far too much of it. If you make no other change in your diet, you should at least consider cutting out most of the fat.

Although most people believe that “sugar makes you gain weight,” evidence favors fat as the main cause of obesity. Many foods thought of as “sweets” are in fact high­fat foods that happen to have sugar in them—for example, ice cream and pastries. Fat, not sugar, contributes most of the calories in these foods. Some weight watchers, however, think that sugar triggers eating binges. If it has this effect on you, you may need to limit sugar for behavioral, rather than nutritional, reasons.

Believe it or not, researchers have not conclusively linked sugar intake to the development of diabetes, heart disease, or behavioral changes. Usually other factors—fat intake, obesity, or some social or psychological situation—offer a more likely explanation. The best argument against including too much sugar in your diet is one of priority. Sugars often displace more healthful foods: a candy bar displaces a piece of fruit, soda displaces milk. But so long as it is not at the expense of more nourishing foods, there's no harm in including some sugar in your diet.

Complex Carbohydrates

The majority of calories in your diet come from complex carbohydrates, often referred to as starches. Foods rich in complex carbohydrates are grains (bread, rice, pasta and cereal), some fruits, and some vegetables, notably beans and potatoes. Unlike simple sugars, complex carbohydrates consist of long chains of sugar units linked together.

Before they can be absorbed, these sugars must be split apart, and this means they are more gradually absorbed into the bloodstream. Complex carbohydrates, therefore, provide a more lasting source of energy. This is particularly important for athletes fueling up for an event.

Fiber

Unlike the “empty calories” provided by simple sugars, the foods that contain complex carbohydrates come stocked with vitamins and minerals. If you choose whole grains and unprocessed fruits and vegetables, you will also increase your intake of another increasingly important dietary component—fiber.

While most people know that fiber is good for them, many are not sure of exactly what it is or why it's so healthy. Simply stated, dietary fiber (or roughage) is the part of a plant that cannot be digested by the human body. There are two different types: water­soluble fiber and water­insoluble fiber. Most plant foods contain varying amounts of both types. Each, according to certain health claims, has specific benefits, so you should know which foods contain each one.

Until a few years ago, the principal focus was on water­insoluble fiber, the type found primarily in fruits, vegetables, and whole grains (wheat, seeds, beans, and brown rice). Insoluble fiber softens the stool and stimulates the digestive tract. For this reason, it alleviates constipation, hemorrhoids, and diverticulosis, another intestinal disorder. Some studies also suggest that it may decrease the risk of colon cancer, possibly by speeding the passage of cancer­causing agents through the colon.

Water­soluble fiber has been in the spotlight lately, because it is apparently able to lower blood cholesterol levels. It is also of particular interest to diabetics; it slows the absorption of sugar into the bloodstream, thus reducing the need for insulin or other diabetes medications. Advertising campaigns of recent years would lead one to believe that oat bran is the only source of this valuable fiber, but many other foods, like barley, fruits, vegetables, and beans, can provide soluble fiber while adding variety to your diet.

How beneficial is a high­fiber diet? Since it is also typically low in fat, and because those who choose to follow it are individuals who readily modify their life­style, it is difficult to determine exactly which factor is helping them. Regardless, more and more studies point to the benefits of a high­fiber diet. At present, fiber intake among Americans is estimated at about 12 grams per day. Most experts agree that we should at least double our daily fiber intake to about 20 or 30 grams. It is not necessary to specifically target soluble or insoluble fiber sources, as both are easily included in a diet that is high in fiber overall.

As for the benefits of a high­carbohydrate diet in general, numerous studies suggest that it may help control obesity, diabetes, and cardiovascular disease. Most likely, this is due not just to the health effects of carbohydrates, but also to the presumed replacement of high­fat foods with high­carbohydrate substitutes. Carbohydrates provide about 45 percent of calories in men, 46 percent in women. About a quarter of these calories came from simple sugars. Authorities recommend that you get more than 50 percent of your calories from carbohydrates, with emphasis on the complex variety.

How Important is Protein?

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Protein is necessary for the growth, maintenance, and repair of every cell in the body. It is present in countless forms throughout the body—as part of enzymes, hormones, antibodies, oxygen carriers, bones, muscle, hair, and skin, to name a few. Unlike the fuel­providing carbohydrates, proteins are the building blocks that provide structure and perform vital functions. However, when needed, proteins can break down to provide energy—4 calories per gram.

Small units called amino acids unite to form the structure of proteins. Altogether there are 20 common amino acids. They mix and match in thousands of different combinations to make up specific proteins. Since your body cannot manufacture nine of these amino acids, you must get them from your diet. Proteins in your food provide them, with the most concentrated sources coming from animal products—meat, chicken, fish, dairy products, and eggs. However, it is also possible to get protein from plants such as beans, nuts, and grains. In fact, most of the people in the world get their protein from vegetable sources for either cultural or economic reasons.

Animal versus Plant Proteins

Proteins from meat, poultry, fish, and dairy foods are called complete proteins because they furnish all the amino acids needed for growth. Most plant proteins, on the other hand, are incomplete: Except for the soy bean, no single plant provides all nine essential amino acids. (Soy, though complete, is still considered inferior to animal proteins.) You can, however, meet your daily requirements by consuming a variety of plant proteins over the course of each day. For example, the amino acids from beans taken at one meal can complement the amino acids from rice eaten at another meal that day. Other examples are peanut butter and wheat bread, or macaroni and cheese. (In the latter case, the essential amino acids from the animal product, cheese, allow the body to better use the amino acids in the macaroni.)

Dietary protein deficiencies in this country are relatively rare. When they do occur, they are usually the result of a disease that causes loss of appetite or loss of large amounts of protein from the body.

Excess dietary protein is a much more common problem. Government surveys estimate that the average American consumes about 100 grams of protein per day—almost twice the recommended daily allowance (RDA) of 50 grams for women and 63 grams for men. Excess protein taxes the body physiologically. Once it's digested and absorbed, end products of protein metabolism are excreted in the urine; so any excess places extra burden on the kidneys. Nor does excess protein build muscles. It is either burned as energy or stored—not as muscle, but as fat. Many athletes, particularly those involved in strength training, believe that to build muscle you need more protein. In fact, Americans already get more than enough; and exercise, not extra protein, is the only way to increase muscle size and strength.

Fat: The Danger in our Diet

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If the media have drummed nothing else into us about diet, the message about fat is clear: It's bad for you! It causes obesity. It raises your cholesterol. It causes heart disease. It may even contribute to development of cancer.

But if it is all that bad, why is it part of our natural diet chain? Despite its bad press, fat does contribute to many important bodily functions. It provides the body with essential fatty acids (linoleic and linolenic acids) needed for normal reproduction and growth, as well as for production of prostoglandin, a hormonelike compound that helps regulate blood pressure, blood clotting, and inflammation. On a practical level, fat cushions bones and vital organs, protects the body from extreme temperatures, carries fat­soluble nutrients, and serves as an important energy reserve. Though fat reserves have become the bane of modern times, their original purpose was to sustain early humans through times of famine.

At 9 calories per gram, fat remains an important storehouse of calories to be tapped for sustained work and exercise. After a 20­minute aerobic workout, the body begins to deplete its carbohydrate stores. At this point, fat steps in to provide an almost endless source of fuel.

For those who are not physically active, however, high intakes of fat lead to obesity. Fat requires few calories for its metabolism—it “slides” right into storage at little expense to the body. With carbohydrates, on the other hand, it takes a significant number of calories to convert excess amounts into fat for storage. While we need only about 1 percent to 2 percent of our calories from linoleic acid (the most essential fatty acid) to prevent a deficiency, the average American gets about 37 percent of total calories from fat. The good news is that this is down from a high of 41 percent of calories in 1977.

So what should your fat intake be? The consensus among experts is to get no more than 30 percent of your calories from fat. Where that fat comes from also matters quite a bit. Certain types of fat are more likely to raise blood cholesterol, high levels of which are associated with an increased incidence of atherosclerosis, in which cholesterol­containing plaques build up on the inside of artery walls, causing progressive narrowing.

The term dietary fat really encompasses three types: polyunsaturated, monounsaturated, and saturated. Saturation refers to the chemical structure of a particular fat. In general, the more saturated a fat is, the more solid it is.

Polyunsaturated Fats

These fats are liquid at room temperature. They are found in plant oils, including sunflower, safflower, soybean, sesame seed, and corn oil. They also appear in cold­water fish like tuna, salmon, and mackerel. Polyunsaturated fats help lower blood cholesterol levels, and when found in fish oils act as a blood thinner, decreasing the risk of life­threatening blood clots forming in the arteries of the heart. Our present intake of polyunsaturated fat averages about 7 percent of total calories. The recommended amount is up to 10 percent of total calories.

Monounsaturated Fats

These fats are also found in fish oils, as well as in olive oil, peanut oil, canola oil, and avocado. Initial interest in monounsaturated fats arose in part from research revealing that in Mediterranean countries, where olive oil is plentiful in the diet, the incidence of cardiovascular disease is low. Many experts now think that if you substitute monounsaturated fat for saturated fat in your diet, you can lower your cholesterol level. There is also a theory that monounsaturates may be even better than polyunsaturated fats at lowering blood cholesterol. Though we presently consume about 14 percent of our calories as monounsaturates, well within the recommended range of 10 percent to 15 percent, there is a possibility that higher intakes will be recommended in the future.

Saturated Fats

This type, usually solid at room temperature, comes most often from animal sources, for example, meats and whole­fat dairy products. Some vegetable fats, notably palm oil and coconut oil, are also saturated. While animal fat is usually easy to see and therefore often trimmed away, vegetable fats are more likely to be hidden in certain foods, such as baked goods and milk chocolate.

Another widely consumed, though often unrecognized, form of saturated fat is hydrogenated vegetable fat. Many manufacturers take unsaturated fats, like soybean oil, and solidify them through a process called hydrogenation, creating products like margarine. Unfortunately, this process reduces their polyunsaturated content.

Saturated fats have a well­earned reputation as the villains of the American diet. Studies from countries the world over show that the more saturated fat people eat, the greater their chances of developing coronary artery disease. Saturated fats may actually raise blood cholesterol levels more than dietary cholesterol itself. Why this happens is not clear. One theory is that saturated fats suppress the receptors in the liver that clear the blood of the low­density lipoprotein (LDL) cholesterol that sticks to artery walls. Another theory is that saturated fat stimulates production of LDL cholesterol in the liver.

Cholesterol

The best rule to follow with cholesterol is the less of it, the better. Like fat, some cholesterol is necessary for good health, for it is a vital component of cell membranes, nerves, and hormones. But, unlike fat, our liver produces all we require; we don't need any cholesterol at all in our diet.

Nevertheless, we get plenty. Many common foods contain cholesterol, some much more than others. Remember this: Because cholesterol is made by the liver, only animal products contain cholesterol. It is not a problem in peanut butter, margarine, or vegetable oil. Cholesterol is most abundant in eggs and organ meats (after all, cholesterol is made in the liver), but some cholesterol is found in all animal products. Even seafood, particularly shrimp, contains some cholesterol, though with its low saturated fat content, shrimp is no longer considered as “forbidden” as it was in the past.

Some people seem more sensitive to high intakes of dietary cholesterol than others. For everyone, however, experts recommend an intake of no more than 300 milligrams of cholesterol per day. Current daily intakes average about 370 milligrams, with women averaging a bit less.

As for recommended levels of blood cholesterol, the National Cholesterol Education Program (NCEP) has established guidelines to help identify those at risk of cardiovascular disease based on their blood levels of total and LDL cholesterol. Total blood cholesterol is actually made up of two components: low­density lipoprotein (LDL) and high­density lipoprotein (HDL). The more abundant form is LDL cholesterol. Excessive levels of LDL are associated with increased risk of cardiovascular disease. High levels of HDL, on the other hand, tend to prevent the disease. So, the lower your total and LDL cholesterol and the higher your HDL cholesterol, the better. According to NCEP guidelines, a desirable total blood cholesterol level is less than 200 milligrams per deciliter of blood; a desirable LDL level, less than 130 milligrams per deciliter. Your HDL cholesterol level should exceed 35 milligrams per deciliter. If your HDL is greater than 60, you're lucky—you have a negative risk factor for cardiovascular disease.

Fat and the Cancer Connection

The link between fat intake and cancer is controversial, particularly when it comes to breast cancer. Though we know little about why breast cancer develops, some have speculated that diet might initiate the disease. Breast cancer is common in countries where women have high average intakes of total and saturated fat, animal protein, and total calories. As dietary fat intake increases, so do the estrogen levels in a woman's tissues, and some studies have implicated estrogen in the development of breast tumors. For the same reason, obesity in postmenopausal women is thought to increase the risk. Excessive dietary fat has also been implicated in the development of cancer of the colon.

While we lack conclusive data on this subject, the mere suggestion of a potential link between dietary fat and breast cancer lends support to recommendations for a low-fat diet for all women. Keeping to a low-fat—particularly a low-saturated-fat, low-cholesterol—diet also helps lower LDL cholesterol. According to the NCEP, less than 10 percent of your calories should come from saturated fat, and possibly less than 7 percent. HDL—the only good cholesterol—is not found in any foods and it can't be added to your diet. The only way to get more of it is to exercise.

Despite all the bad news, who will deny that fat lends flavor, aroma, and a sense of satisfaction to meals? Fat is here to stay, and it can be enjoyed in moderation. For the best ways to work a healthy amount of fat into your diet see “The Bottom Line” at the end of this chapter.

Value Of Vitamins

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Our bodies use vitamins to regulate crucial functions within the cells. Since the first vitamin was identified around the turn of the century, our knowledge of these essential dietary elements has been changing almost daily. Early treatment of vitamin deficiencies resulted in amazing—almost “miraculous”—improvements in health. Sailors, for example, no longer died from scurvy, and children going blind from vitamin A deficiency abruptly regained their sight. Except for vitamins D and K, which the body is able to manufacture, vitamins must be obtained from the diet. Though needed in only small amounts, they play an indispensable role in storage and production of energy, and assist in tissue formation.

At this time, we know of 13 essential vitamins. They are classified as either water soluble or fat soluble, depending on how they are transported and stored. This distinction is important. Because the water component of the body turns over frequently, you have to replenish water­soluble vitamins daily. On the other hand, fat­soluble vitamins are stored in fat and tend to stay with you. This makes it possible to overload on fat­soluble vitamins if you take them in large, potentially toxic, amounts. But it also means that fat­soluble vitamins do not have to be taken daily.

Water­Soluble Vitamins

Included in the water­soluble group are vitamin C and the B complex vitamins. Though deficiencies are relatively rare in the United States, recent research has brought several of these vitamins back into the limelight.

Vitamin C, also known as ascorbic acid, strengthens bone and blood vessels, aids in iron absorption, and promotes wound healing. Contrary to popular belief, there is no conclusive evidence that vitamin C prevents or speeds recovery from a cold. Studies done on this issue seem to be prone to the “placebo effect”—people are influenced by what they think helps, whether it does or not. The recommended daily allowance (RDA) of vitamin C is 60 milligrams, 100 milligrams if you smoke (smokers have lower blood levels of vitamin C than nonsmokers). From 4 to 8 ounces of orange juice will supply this amount of vitamin C. Other good sources of vitamin C are citrus fruits, strawberries, cantaloupe, tomatoes, broccoli, potatoes, sweet potatoes, and greens.

Abuse of vitamin C supplements is common; the most frequent side effects are nausea, abdominal cramps, and diarrhea. Large amounts of vitamin C can also interfere with the accuracy of certain lab tests. Theoretically, huge doses over a prolonged period could also cause kidney stones.

Niacin, thiamine, and riboflavin are important players in the processes that produce energy from nutrients. These B vitamins are widely available from dairy products, meats, fish, poultry, whole grain or enriched breads and cereals, and nuts. Although most people in developed countries get adequate amounts, alcoholics are an exception. They tend to have vitamin­deficient diets and, in the case of thiamine, lose too much in their urine.

Megadoses of niacin, sometimes prescribed for its cholesterol­lowering properties, can cause niacin flush, a hot, tingling sensation in the skin that sometimes makes the therapy intolerable. Megadoses of vitamins, defined as 10 times the RDA, act more as drugs than as nutrients. It's wise to avoid self­prescribing them.

Folic acid, another of the B­complex vitamins, is required for the formation of all new cells. Along with B ₁₂ , it is particularly involved in production of red blood cells. A deficiency of either of these vitamins can cause anemia. B ₁₂ also helps maintain the protective covering of the nervous system; a deficiency becomes apparent when nerves and muscles malfunction. B ₁₂ is found only in animal products: meat, fish, poultry, eggs, and dairy products, leaving strict vegetarians at risk of deficiency. Folic acid is most plentiful in liver, leafy green vegetables (like spinach, broccoli, and asparagus), beans, and seeds; it is also found in whole grains, pork, poultry, shellfish, and citrus fruits.

Recently, folic acid deficiency has been shown to play a central role in development of the neural tube defects anencephaly and spina bifida. Anencephaly is the absence at birth of all or a major part of the brain. In spina bifida, a portion of the spinal column does not completely close. Many spina bifida victims, even after surgery, have trouble walking and suffer bowel and bladder problems. Significant evidence indicates that adequate folic acid intake before conception and into early pregnancy can reduce the baby's chances of a neural defect. Evidence is so compelling that now the U.S. Public Health Service, recognizing the need for folic acid before a woman even knows she's pregnant, states that anyone who may become pregnant should get at least 0.4 milligram (400 micrograms) of folic acid each day. For women who have a history of a neural tube defect in a previous pregnancy and who hope for another child, physicians may prescribe an even higher dose of 4 milligrams of folic acid daily. Women on birth control pills also need higher doses, in case the pills fail.

Vitamin B ₆ is involved in numerous processes: red blood cell formation, release of glucose (sugar) from its storage forms, and conversion of the amino acid tryptophan into niacin. Deficiency rarely occurs alone, but usually accompanies multiple B complex deficiencies. Signs of deficiency include neurologic problems, skin rash, and anemia. B ₆ is widely available in meat, fish, poultry, beans, fruit, whole grains, and green vegetables.

The last two B vitamins, biotin and pantothenic acid, play important roles in the body's use of carbohydrate, protein, and fat. Since both are widespread in the food supply, healthy people with ordinary diets are not at risk of deficiency.

Fat­Soluble Vitamins

Vitamin A was the first fat­soluble vitamin to be identified. It is probably the most diverse in its functions, which include roles in vision, immune and stress responses, energy production, blood production, maintenance of the nervous system and numerous other body tissues, and normal growth and reproduction. Often, its presence in food is obvious. Its active form, retinol, is yellow and is found in butter and eggs. Other less obvious sources of retinol are cheese, fortified milk, cream, fortified margarine, and liver. Vitamin A's precursor (so­called because it is converted to vitamin A in the body) is beta carotene. A bright orange color, beta carotene is found in apricots, cantaloupes, squash, carrots, sweet potatoes, and pumpkins. Other good sources of beta carotene are broccoli and leafy greens like spinach.

Vitamin A deficiency affects the ability of the skin and the linings of the internal organs to resist cancer, particularly of the skin, lung, bladder, and pharynx. Beta carotene has other health­promoting properties linked to its antioxidant characteristics (see the next section of this chapter).

While adequate intakes of vitamin A are vital for good health, excessive use of active vitamin A supplements such as retinol can be dangerous. Symptoms of vitamin A toxicity are headache, vomiting, hair loss, dryness of the mucous membranes, bone abnormalities, and liver damage. Toxicity usually occurs only after long­term megadoses amounting to 15,000 micrograms of retinol (50,000 international units [IU]) in adults and 6,000 micrograms (20,000 IU) of retinol in infants and children. Such doses are not usually obtained from food alone.

Beta carotene is not known to cause toxicity, primarily because your body will stop converting it to vitamin A when needed levels are reached. Instead, the beta carotene is stored in fatty tissues, so that an accumulation under your skin can tint it orange. Although unbecoming, this condition is not harmful. It fades when you decrease your beta carotene intake.

Vitamin D ranks with calcium as crucial protection for your bones. Vitamin D helps maintain blood calcium levels by regulating the absorption of calcium in the digestive system and its excretion in the urine. Best sources of vitamin D are butter, fortified milk, fortified margarine, eggs, and liver. It is also produced by our intestinal bacteria, and is manufactured by skin exposed to sunlight. The average person needs only 10 to 15 minutes in the sun each day. Keep in mind that sunscreen blocks vitamin D synthesis.

The most obvious signs of vitamin D deficiency are bone abnormalities. In children, vitamin D deficiency causes the abnormal bone growth called rickets. Though no longer common, the disease has long been known to respond to treatment with cod liver oil, which we now know is high in vitamin D. Adult rickets or osteomalacia, is most often seen in women with low calcium intakes and little sun exposure who have repeated pregnancies and breast­feed their babies. In this instance, calcium is withdrawn from the bone but not replaced. These women can benefit from extra calcium and vitamin D. A number of studies suggest that increased intakes of vitamin D may also improve calcium absorption in elderly people and some victims of osteoporosis. Use care with vitamin D supplements, however, as it is the most potentially toxic vitamin. Avoid doses significantly above the RDA.

Vitamin E, classified as an antioxidant, is especially important to the lungs, and the red blood cell membranes. Vitamin E also protects white blood cells, which play a major role in the immune system's defense against disease.

The leading sources of vitamin E are polyunsaturated vegetable oils, followed by green leafy vegetables, wheat germ, whole grains, nuts, and seeds. If you have the typical intake of fat, you will rarely suffer vitamin E deficiency unless you have a disorder that interferes with fat absorption.

Vitamin K, the last of the fat­soluble vitamins, helps blood to clot. Without vitamin K, wounds would bleed for dangerously long periods of time, and surgery would be impossible. Bacteria in the intestine can synthesize vitamin K, and because of this, deficiencies are rare. Due to its role in helping blood to clot, those who take blood­thinning medications should avoid excessive amounts of vitamin K (primarily found in green leafy vegetables and liver.) On the other hand, people taking antibiotics may need more. Vitamin K toxicity is not a problem.

The Antioxidant Story

Recently, anitoxidants have become a media buzzword. These nutrients—mainly vitamin E, vitamin C, and beta carotene—are thought to ward off disease and slow the aging process. Along with other substances known as antioxidant enzymes and scavengers, these vitamins seem to protect the body's cells from the damaging effects of oxygen. They do this by neutralizing so­called free radicals,—unstable oxygen by­products that can damage cell DNA, proteins, carbohydrates, and fats. Normal body processes, such as breathing and digesting food, produce free radicals. Environmental pollutants, such as cigarette smoke, also produce them. They can cause severe damage to cell structures.

Under normal conditions, the body's own antioxidant enzymes and scavengers remove or deactivate free radicals. But if levels of free radicals get too high to handle, the body may need reinforcement with antioxidant vitamins.

While the role that free radicals play in disease and aging is not completely understood, some scientists believe they either cause or accelerate the progression of age­related diseases. In cancer, free radicals may damage DNA, thus promoting the disease. In cardiovascular disease, oxidation of LDL cholesterol may be a first step in development of arterial plaque. Some speculate that Parkinson's and other neurologic diseases are in part caused by the effects of free radicals on nerve tissue. And cataracts may result from free­radical damage to the lens of an eye.

Vitamin E is the premier antioxidant. It also supports the immune system, blocks formation of nitrosamines (suspected carcinogens), and repairs damaged cell membranes. In some research studies, it has been shown to protect against various forms of cancer.

High intakes of beta carotene are also thought to lower the risk of cancer, particularly of the lung, but also of the breast, cervix, uterine lining, gastrointestinal tract, and oral cavity. And Vitamin C is believed to defend against cancer in several ways:

• It deactivates free radicals;
• It boosts immune function;
• It may help detoxify cancer-causing substances, such as pesticides, heavy metals, and industry­produced hydrocarbons, and may prevent formation of the cancer- causing nitrosamines.

Vitamin C is most strongly associated with protection against gastrointestinal, breast, and cervical cancer. However, many studies of both vitamin C and beta carotene involved diets with numerous other nutrients and fiber, so there's a possibility that the protective effects result from a number of dietary influences working together.

In cardiovascular disease, both vitamins C and E interfere with the oxidation of LDL cholesterol, with vitamin C having the stronger effect. One large study showed that women with a daily vitamin E intake of greater than 100 IU had a 36 percent lower risk of heart attack than those with intakes of less than 30 IU daily. Beta carotene also seems to play a role in reducing the risk of heart attack and stroke. All three antioxidant vitamins affect blood platelet aggregation, which causes formation of blood clots. By reducing the platelets' “stickiness,” the antioxidants make the platelets less likely to adhere to the inside of blood vessels and to each other, thus reducing the chance of life-threatening blood clots.

The Latest Cancer Fighters: Phytochemicals

Also hot in current nutritional news are the phytochemicals, naturally occurring substances in plants thought to possess disease­fighting properties. Research into phy-tochemicals has helped fuel the recent push to increase our intakes of garlic, broccoli, and similar vegetables classified as cruciferous.

The phytochemicals' potential role against cancer and heart disease has sparked a flurry of research. Cruciferous vegetables, notably broccoli, cauliflower, cabbage, and brussels sprouts, are rich sources of indoles, the basic components of many biologically active substances like serotonin and tryptophan. Indoles may stimulate enzymes that break down carcinogens into harmless substances. They appear to be particularly protective against stomach and intestinal cancers. Cruciferous vegetables are also high in fiber, and beneficial in preventing colon cancer.

A compound found in garlic extracts, allyic sulfide, is thought to protect against cancer, as well as inhibiting cholesterol synthesis and thereby reducing the risk of arterial plaque. In addition, parsley, carrots, citrus fruit, berries, cucumbers, cruciferous vegetables, peppers, squash, yams, tomatoes, eggplant, and soy products contain flavonoids, a group of substances that may act to block receptors for hormones that promote cancer. Other phytochemicals—phenolic acid, coumarin, isothiocyanates, and catechin—are also under study as disease fighters.

Questions that still need answers, for phytochemical and antioxidants alike include: “How much should I take?” and “What combinations will give me the best effect?” Although there does seem to be a role for these nutrients—possibly in amounts well above their recommended daily allowances—the jury is still out as to whether supplements are warranted and safe. Until we have answers, the most practical advice is to follow current recommendations and increase intakes of all fruits and vegetables. The National Cancer Institute is now promoting the “5­A­Day Plan”—eat at least 5 servings of fruits and vegetables each day, at least one high in vitamin C, one high in vitamin A, and one high in fiber; include cruciferous vegetables several times each week.

Minerals: A Woman's
Special Needs

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Like vitamins, minerals provide mandatory support for certain life­sustaining functions. They regulate reactions like nerve transmission, blood clotting, and oxygen transport. Most important, minerals provide structure to the body in the form of bones. There are 60 minerals in the body, but 7 predominate, namely calcium, phosphorous, magnesium, potassium, sodium, chlorine, and sulfur. All others—needed in tiny amounts—are called trace minerals. Quantity does not necessarily dictate importance, however. Iron, for example, is needed in only trace amounts, but is involved in one of the body's most vital functions—the transport of oxygen.

Four key minerals you, as a woman, particularly need to maintain your health are calcium, iron, potassium, and sodium.

Calcium

Most Americans, particularly women, do not get enough calcium. The adult body contains about 1200 grams of calcium. Only 1 percent is found inside cells and body fluids, where it plays a part in nerve conduction, muscle contraction, and blood clotting. The remaining 99 percent is stored in bones and teeth. While we think of the skeleton as a stable structure, it is actually in a constant state of turnover—calcium is deposited and withdrawn throughout our lives. In childhood and adolescence, more calcium is deposited than withdrawn. Later in life the reverse occurs. Calcium levels in the blood must remain within a certain range. Specialized hormones that regulate calcium levels will “rob” the bones of calcium if necessary. Vitamin D, and possibly lactose, the sugar in dairy products, aid the absorption of calcium in the intestine.

By far the most concentrated sources of calcium are milk, and milk products. There are smaller amounts in dark green leafy vegetables, broccoli, calcium­processed tofu, sardines, salmon (including the bones), and some fortified cereals.

Osteoporosis, a disease in which the bones become brittle and porous, strikes women more often than men, frequently causing bone fractures. Osteoporosis affects about 25 million Americans in all, and often progresses for years undetected. For the many older women who suffer fractures, the disease can mean loss of independence, and for 12 percent to 20 percent, even death.

One major risk factor for osteoporosis is continually low calcium intake. The less calcium you consume early in life, the less bone you have to spare as you get older. Bone density reaches its peak around age 30 to 35 and remains fairly stable until middle age. After menopause, bone loss speeds up for the first 5 to 10 years, with the total loss reaching 10 to 15 percent.

This bone loss results from a decline in estrogen, which prior to menopause helps to maintain proper calcium levels. Lower estrogen levels also somewhat inhibit digestion of calcium. After menopause, estrogen replacement therapy can slow this process. (For more information, see chapter 30, “Holding Back Osteoporosis.”)

Calcium intake in early life builds up bone reserves before menopause. Yet even later in life, increasing calcium intake may slow the rate of bone loss, particularly in older women 5 to 20 years into menopause. The ideal amount of calcium needed is unknown and probably varies from woman to woman. Many believe the current RDA of 800 milligrams for both men and women is too low. The National Institutes of Health recommend 1,000 milligrams per day for men and premenopausal women, 1,500 milligrams for most postmenopausal women, and 1,000 milligrams per day for postmenopausal women treated with estrogen.

Calcium also appears to exert a positive effect on high blood pressure in some people. Exactly how is unknown, and it's premature to make any specific dietary recommendations concerning this. It's another good reason, however, for making sure you get at least the recommended allowance in your daily diet.

Lactose Intolerance. If you are one of the many women who suffer from lactose intolerance, eating dairy products may give you painful bloating, gas, and diarrhea. Lactose intolerance is caused by a deficiency of the enzyme lactase, which breaks down milk sugar into digestible sugars. As undigested lactose passes through the digestive tract, intestinal bacteria consume it for energy, producing gas and other intestinal irritants. The degree of lactose intolerance varies. Some people cannot eat any dairy products at all, others can tolerate small amounts taken with other foods. For some, a lactase supplement taken before consuming any dairy products solves the problem. Aged cheese and yogurt with active cultures are often easier to digest because bacteria have already broken down most of the lactose during fermentation.

If you are one of those who just will not eat dairy products, you should consider calcium supplements to make up the difference. The many calcium supplements available differ in the amount of elemental calcium they provide. Calcium carbonate, for example, is about 40 percent calcium, whereas calcium lactate is only about 13 percent, and calcium gluconate only 9 percent. Purity is another concern. Although bone meal and dolomite (calcium magnesium carbonate) are 31 percent and 22 percent calcium respectively, they may also contain lead or other toxic metals. While it is difficult to overdose on calcium from foods, the same cannot be said of supplements. The safe upper limit seems to be about 2,500 milligrams per day. Anyone at risk of developing kidney stones, however, should limit daily intake to no more than 1,000 milligrams.

Which form of calcium is best? In general, calcium carbonate seems to come closest to dietary calcium in absorbability, but, like any other supplement, it lacks the other nutrients plentiful in dairy products that help build bones.

In most people, supplements are absorbed better when taken between meals. If you are elderly, however, the stomach acid needed for digestion may be more plentiful when food is present, so it's best to take the supplements at mealtime.

Iron

Another major dietary concern for women, iron is the blood-building mineral. It plays an important role in transport of oxygen throughout the body. It is also thought to help the body use beta carotene, and aids in clearing fats from the blood. Most iron in the body is stored in the oxygen­carrying proteins hemoglobin and myoglobin, found in the blood and muscles, respectively. The less iron your body has already stored, the more dietary iron you will absorb. Other factors that govern absorption are the form of iron and the presence of other nutrients. Inadequate intake or excessive loss from bleeding can cause iron­deficiency anemia, a condition in which the body is unable to absorb enough iron from marginal supplies. Anemic red blood cells contain too little hemoglobin and therefore deliver too little oxygen to the cells. Symptoms of anemia are fatigue, apathy, lowered resistance to infection, and decreased exercise tolerance.

The principal sources of dietary iron are meat, eggs, vegetables, and iron­fortified cereals. Iron from vegetables and grains is absorbed more readily in the presence of Vitamin C or meat. You can readily meet your daily need by having orange juice with iron­fortified cereal, or a baked potato with your steak. On the other hand, substances called phytates (found in whole grains and beans) interfere with iron absorption, as do substances in coffee, tea, bran, calcium phosphate, and antacids.

Even under the best conditions, iron is poorly absorbed from food. In fact, a healthy woman absorbs only about 10 percent of the iron in her food, absorbing the most from meats. In the United States, iron deficiency is most likely to occur in children, women in their childbearing years, and those who are pregnant. Even if you are convinced you're anemic, however, you should not take iron supplements without the advice of a physician. Iron toxicity can be serious—even fatal; so it's important to store iron supplements well away from children. The recommended daily allowance, or RDA, is 10 milligrams for men and older women, and 15 milligrams for women during childbearing years. If you are pregnant, double your intake to 30 milligrams per day. Because women generally eat less than men, they need to pay special attention to including high­iron foods in their diets. A tip—if you use cast iron pans in cooking, you will increase your iron intake because iron from the pan leeches into the food.

Potassium

This indispensable mineral is necessary for muscle contraction, nerve transmission, and proper functioning of the heart and kidneys. It also helps maintain fluid balance in the cells. While more than 90 percent of potassium is absorbed in the digestive tract, changing the amount in your diet will not significantly change potassium levels in the blood. The kidneys tightly regulate how much potassium is in the blood by reabsorbing what they need and spilling what they do not in the urine. Tight control is vital, because large fluctuations in blood potassium levels affect heart rhythms.

Potassium regulation is so efficient that under normal conditions deficiency is never a problem. When it does happen, it is usually due to the excessive loss of potassium that occurs with prolonged vomiting, chronic diarrhea, laxative abuse, or use of diuretic medications. Often referred to as “water pills,” diuretics are commonly prescribed to treat high blood pressure. These medications flush excess water out of the system and often potassium along with it. Because of this side effect, a diet rich in high­potassium foods is recommended to offset losses caused by diuretics. Potassium is widely available in our food, the best sources being oranges, orange juice, bananas, potatoes, dried fruits, yogurt, milk, meat, and poultry. Do not take potassium supplements without a doctor's supervision.

Although there is no official RDA for potassium, the minimum requirement is estimated at 1,600 to 2,000 milligrams per day. Some studies indicate that potassium may lower blood pressure in certain individuals; higher intakes may thus be beneficial.

Sodium

Better known as salt, sodium is the chief regulator of fluid in the body. Like potassium, sodium is eliminated by the kidney. Sodium deficiency, although unusual, can result from the kind of heavy, persistent sweating that occurs during prolonged exercise in hot weather.

Sodium is all too plentiful in our diets. The average American consumes between 4,000 and 5,800 milligrams of sodium per day. Contrast this with the recommended intake of 2,400 milligrams per day, and the minimum requirement of only 500 milligrams, and you can see that most of us consume at least twice the sodium considered healthy. One­third of this occurs naturally in foods, one­third is added during processing, and one­third is added during cooking or at the table.

Aside from table salt, the biggest contributors of sodium to our diets are cured meats, including ham, bacon, sausages, frankfurters, and luncheon meats; cheese; pickles; canned and frozen foods (unless marked “no added salt” or “low sodium”); commercial pasta, potato and rice dishes; salty snacks; and “fast foods.”

The main problem with sodium is its effect on blood pressure. High blood pressure affects about 60 million Americans. It is a major risk factor for both heart attack and stroke, as it causes injury to the linings of arteries, which in turn makes cholesterol plaques likely to form. High blood pressure usually displays no outward symptoms. Because of its silent onset, many people have the condition without knowing it. From adolescence through age 45, men are more likely to have high blood pressure than women. After 45, the reverse holds true.

Blood pressure is a measure of the force that blood exerts on the inside of the artery walls. The amount of fluid in the circulatory system affects this. Sodium causes fluid retention; so the more sodium in the blood, the more fluid there will be, too .

The evidence correlating sodium with high blood pressure is not clear­cut. For years researchers have associated high intakes of salt (or sodium chloride, which is a compound of sodium and chlorine) with elevations in blood pressure. Recently it has become less clear whether the culprit is the sodium or the chlorine.

Most people get rid of excess salt by excreting it in the urine. However, some salt­sensitive individuals (people with kidney disease, those whose parents have high blood pressure, blacks, and those over age 50), definitely undergo an increase in blood pressure from eating salty foods. For these people, salt restriction is likely to help control blood pressure. Because it is hard to tell who is salt­sensitive and who isn't, everyone with high blood pressure is advised to cut back on salt.

Should You Take A Supplement?

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Nearly 4 out of 10 adults in the United States take vitamin and mineral supplements regularly. We spend more than $2.5 billion on them annually. They are the third largest product category sold over­the­counter.

Supplement use, according to surveys, is heaviest among people who have one or more health problems; but some who describe their health as very good or excellent are also avid users. Supplement users tend to be especially health conscious. They also are likely to believe that marginal vitamin deficiencies are more common than generally thought.

Arguments against supplements focus not on daily multivitamins, but on the hazards of high­dose supplements. High doses of any nutrient may be dangerous; and toxic levels differ from one person to another. Indeed, since it is easily misdiagnosed, supplement overdose could be more common than we realize. Confusing the matter further is the lack of scientific data establishing a reasonable margin of safety for the average adult.

It's also true that nutrients are generally absorbed better from food than from pills. Foods contain an array of nutrients that facilitate each other's absorption, while individual supplements must go it alone. If you stick to a well­balanced diet, you can obtain all the vitamins, minerals, fiber, calories, and other substances—presently known and yet to be discovered—that you need to maintain good health.

The only people who really need to consider a supplement are those who are malnourished (dieters, some of the elderly, people with illnesses affecting their appetites), people with impaired digestion, those on medications that block the body's use of a nutrient, sick people with extra nutritional requirements, pregnant women, vegetarians, women with heavy menstrual bleeding, and women at risk of osteoporosis. If you fall into one of these groups, or decide you want a supplement to improve general health, base your choice on fact, not hype. Check with your doctor if you have any doubt, and choose a supplement that provides nutrient amounts close to the recommended allowances. Avoid megadoses (doses 10 times or more than the RDA), particularly of vitamins A and D. Opt for a brand made by a reputable manufacturer, whose production standards are likely to be well­regulated. (A recently described disorder called eosinophilia­myalgia syndrome was traced to a contaminant in an amino acid suplement, L­tryptophan, manufactured in Japan.) You need not buy the most expensive brand. Store brands may be just as good and cheaper. Steer clear of supplements whose advertisers make outrageous claims of benefits for a specific ailment or for “stress.”

Your Changing Needs Throughout Life

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Nutrient needs of men and women do not differ appreciably until adolescence. Growth accelerates in girls beginning around 10 or 11 years of age, peaking at about age 12.

Adolescence

At this stage, girls acquire a larger amount of body fat than boys in preparation for childbearing. This rapid growth significantly increases the need for all nutrients, but particularly for protein, calcium, and iron. The developing young woman needs calcium to support bone growth and to build up calcium deposits as a defense against osteoporosis later in life. She must also replace the iron lost from menstruation in order to avoid anemia. In short, this is not the moment to switch from milk to soda, as so many teenagers do.

Adolescence is also a high­risk time for anorexia nervosa, a condition 10 times more common in girls than boys. Girls with this problem starve themselves and often overexercise, all in reaction to a distorted body image that makes them overestimate their weight. A related disorder, bulimia, combines recurrent food binges with self­induced vomiting and excessive laxative use. (For more on these distressing disorders, turn to Chapter 34.)

Just as sad as a 12­year­old worrying about her weight are the social and emotional effects of adolescent obesity. Many teens consume a high­fat diet of “fast foods” and snacks needlessly high in calories. If you keep low­fat snack foods handy, and try to encourage exercise, you may be able to prevent an overweight child from becoming an obese adult.

Pregnancy

The nutritional demands of pregnancy are extraordinary both for healthy development of the baby, and to maintain the health of the mother­to­be. Indeed, a developing baby will get the nutrients it needs for growth at the mother's expense, if necessary. Daily calorie demands increase by 300 calories in an adult mother­to­be, more in a pregnant teen, who needs to support her own continued growth along with that of her baby. Ideal weight gain is about 2 to 4 pounds during the first 3 months and about 1 pound per week thereafter. Women who are overweight at the beginning of pregnancy should gain less, but at least a total of 16 to 24 pounds. Underweight women should gain more. When you are pregnant, try to avoid too many high­fat, empty­calorie foods. They'll put on extra pounds that may be difficult to lose later.

Protein needs during pregnancy increase from the usual 50 grams per day to a total of 60. However, many women in the United States already get this much or more in their usual diets. You can get this amount from four 8­ounce glasses of milk (32 grams of protein) and 4 ounces of meat, fish, poultry, or cheese (28 grams of protein).

A pregnant woman's recommended daily allowance of folic acid to support both the baby's growth and her own increasing blood volume is twice the usual. Don't forget that folic acid deficiency can cause serious birth defects. At least 400 micrograms per day is now recommended for anyone even contemplating pregnancy. Prenatal vitamins easily supply this amount.

Remember, too, that if the mother doesn't get plenty of calcium, her baby will simply withdraw what it needs for its own bone and teeth development from her bones. The recommended allowance for calcium during pregnancy and while breastfeeding is 1,200 milligrams per day—hence the recommendation for 4 daily servings of milk or milk products.

The baby's development and increased maternal blood volume also boost the need for iron. With the RDA doubling to 30 milligrams per day, many pregnant women need to supplement their high­iron foods with additional iron. Pregnancy means the need for additional fluids, too—about an extra 2 quarts per day. Breastfeeding mothers continue to need extra nutrients, including calcium, to produce milk for the growing infant. Producing milk requires about 750 extra calories a day.

The Later Years

From middle age onward, your focus needs to turn to a heart­healthy diet, high in fiber, and low in fat to help with weight control. The way you eat at 30, 40, and 50 can make a big difference in your quality of life later on. While some weight gain with age may be normal, there is much you can do to stay trim. Limiting fat intake to less than 30 percent of your daily calories is an excellent start; and cutting back on fat is the easiest way of holding down total calories, too: Every gram of fat you trim from your diet saves you 9 calories. Remember that your future bone health relies on continued intakes of calcium and vitamin D, particularly after menopause. And given all the known and suspected health benefits of fruits and vegetables, plan on making them a major part of your diet—at least 5 servings per day.

Nutr itional n eeds cont inue to c hange for women ov er 50, bu t by how much is uncertain . At pres ent, reco mmended d aily allo wances ar e the sam e for ev eryone in this age group, b ut indivi dual need s may dif fer. For example, stomach a cid secr etion, wh ich aids digestion , decreas es with a ge in som e people, but not in others . < /p>

< small> Dehydr ation becomes more comm on as we age. The elderly may have a less se nsitive t hirst mec hanism, p ay less a ttention to it, or simply have more trouble getti ng to a glas s of wate r when th ey want o ne. The r esult can be leth argy, mus cle weakn ess, and constipat ion, symp toms ofte n written off as “nor mal” in the e lderly. T he standa rd 6 to 8 glasses of fluid per day i s as imp ortant to the elde rly as to anyone e lse.

The Bott om Line</ font>

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Here are the steps you need to take to keep your diet healthy:

(1) Put your low­fat diet into practice by pinpointing sources of fat. Butter, margarine, vegetable oil, lard, shortening, mayonnaise, salad dressings, gravies, cream, sour cream, and cream sauces are almost exclusively fat. Other foods like meats, cheese, nuts, snack foods, ice cream, milk chocolate, and many baked and fried foods derive many of their calories from fat. Your goal is to keep total fat­derived calories below 30 percent on average. If you hit 40 percent one day, balance it out with 20 percent the next. Short of calculating out everything you eat, the best approach is to:

• Limit added fats, or substitute low­fat or fat­free alternatives, like low­fat mayonnaise or fat­free salad dressing.
• Trim visible fat from meat, and remove skin from poultry.
• Grill, roast, bake, barbecue, broil, stir­fry, microwave, or poach foods, but don't deep fry. (Frying foods drastically increases calories.)
• Use nonstick pans or nonstick spray if frying. Sauté in broth instead of oil.
• Choose lean cuts of meat like beef round.
• Use skimmed milk instead of whole milk or cream in recipes.
• Skim fat from homemade soups.
• Order fast­food burgers and grilled chicken sandwiches without their mayonnaise­based sauces.
• Opt for cereal, bagels, or English muffins for breakfast. Croissants and commercially­made muffins are usually loaded with fat.
• Try fat­free cream cheese, jam, jelly, or fruit spread on bagels or toast.
• Snack on low­fat pretzels, rice or corn cakes, animal crackers, fruit, or dry cereal.
  Keep high­fat snacks out of the house. Better still, skip snacks.
• Read labels. Ingredients are listed according to quantity, from the highest to the lowest. New labeling laws require useful information, such as the amount of saturated fat in an item and the percentage of fat­derived calories it contains.
• When determining grams of fat consumed, pay attention to serving sizes. You may be eating 2 servings or more.

(2) Keep cholesterol intake to less than 300 milligrams per day.

(3) Eat 5 or more servings of fruits and vegetables per day, especially those high in vitamin C, vitamin A, beta carotene, and fiber. In general, a serving is 1 small piece of fruit, half a cup of cooked or canned fruits and vegetables, or 1 cup raw.

(4) Increase your intake of complex carbohydrates, especially whole grains. Experts recommend 6 or more servings of foods like bread, rice, pasta, cereal, and beans.

(5) Watch the size of your protein portion. Most women need a daily intake of only about 6 ounces (cooked) of meat, chicken, fish, or a substitute like cheese or eggs. Excess protein can mean extra fat, and high amounts of protein may increase calcium losses in the urine.

(6) Drink alcohol in moderation. Excessive drinking is linked to osteoporosis. If you're pregnant, avoid alcohol entirely.

(7) Limit daily salt intake to 6,000 milligrams, preferably less. Watch your intake of salty, processed foods. Season with butter­flavored granules, lemon, vinegar, broth, wine, garlic, herbs, and spices instead of salt. (Your risk of developing high blood pressure increases with age.)

(8) Adopt a high­calcium diet for life. Skim milk provides calcium and vitamin D without the fat and calories.

(9) Do not overdo supplements. Pills are no match for the nutrients found in food. Megadoses of vitamins act more like drugs than nutrients, and can even be dangerous.

(10) Keep an eye on your iron intake. Many women rely on iron­fortified cereals to contribute iron to their diets. You may need iron supplements during pregnancy, when increased needs exceed what even a high­iron diet can provide.

(11) If you're in your childbearing years, get at least 0.4 milligram (400 micrograms) of folic acid daily to reduce the risk of having a child with a neural tube defect. Excellent sources are spinach, broccoli, chickpeas, romaine lettuce, wheat germ, and fortified breakfast cereals (25 percent of the US RDA per ounce). If you're pregnant, take a folic acid supplement.