Prime Time (21 page)

For vegetarians, tofu, which is made from soybeans, is an excellent source of high-quality, complete protein, healthy soybean oil, and calcium, while also being low in calories and carbohydrates, with no cholesterol. Legumes such as garbanzo beans (chickpeas), black beans, navy beans, lentils, black-eyed peas, and other mature, dried beans contain good amounts of protein, but they still need to be combined with a grain to be equivalent to a complete, high-quality soy or animal protein.

Vitamins and Minerals

Vitamins—unlike protein, carbohydrates, and fat—are not a source of energy. They are catalysts for the biochemical reactions that take place in the body. Since vitamins are not manufactured by the human body, we must eat foods that supply them, or take vitamin supplements.

Like vitamins, minerals are needed for many bodily functions, especially as building blocks for tissue and as regulators of metabolic processes. We need different kinds of minerals for good health and growth, some in relatively large quantities and some, known as trace minerals, in minute amounts.

The minerals that are needed in higher amounts are calcium, potassium, sodium, magnesium, and phosphorus. The trace minerals include iron, copper, zinc, manganese, chromium, selenium, vanadium, and molybdenum.

If we all ate the recommended amounts of fruits, vegetables, and other nutrient-rich foods, we probably would not need most vitamin and mineral supplements. The Dietary Guidelines for Americans advise us to get our vitamins and minerals directly from foods because foods also contain more than nine hundred naturally occurring substances—such as fiber, carotenoids, flavonoids, polyphenols, anthocyanins, isoflavones, resveratrol, and protease inhibitors, the phytonutrients described earlier—that may protect us from chronic health problems.

That said, most of us don’t eat such healthful diets, and as we age and our appetites diminish, we can find it hard to consume enough food to provide the necessary nutrients. On top of that, most of the fruits and vegetables sold in supermarkets are transported long distances and stored before being put on sale. That gap from field to table results in nutrient loss and, in some instances, may require that we take a multivitamin and/or mineral supplement and consume certain fortified foods.

Vitamins are either water-soluble or fat-soluble. The water-soluble vitamins—C and the B family—are not stored in the body, so we must eat foods that provide them every day. The fat-soluble vitamins—A, D, E, and K—are stored in the fatty tissues and are absorbed and used by the body only if we eat appropriate amounts of fat with our meals.

Because of their low intake of protein and because they don’t absorb it well, many older people suffer from a deficiency of B
₁₂
, which causes anemia and neurologic disorders. The Dietary Guidelines recommend that people over fifty consume foods to which vitamin B
₁₂
has been added, such as fortified cereals, or take the crystalline form of vitamin B
₁₂
supplements.

By age eighty, 35 percent of men and women suffer from a wearing out of the intestinal lining. This causes lower levels of acid secretion, leading to a decreased absorption of folic acid, iron, calcium, and vitamins B
₆
and B
₁₂
. To counter this, obtain folic acid by eating uncooked leafy vegetables, yeast, and fruits daily, supplemented with 400 micrograms of folic acid.

VITAMIN A

Liver, fish oils, eggs, and whole milk are sources of vitamin A, but the best sources (free of cholesterol and saturated fat) are carrots, sweet potatoes, and dark leafy green vegetables. Plants don’t actually contain vitamin A itself but, rather, carotenoid precursors that the body can turn into vitamin A. Vitamin A is important for good eyesight and a strong immune system,
but people should not take supplements that contain vitamin A itself because it can build up to a toxic level in the liver. On the other hand, beta-carotene and other carotenoids are safe at any dose.

VITAMIN D

Vitamin D is necessary for our bodies to absorb calcium from food, to strengthen bones, and to prevent fractures. Recent research shows that 50 percent of women over fifty in the United States are deficient in vitamin D. That is dangerous for a host of reasons.

We are designed to get vitamin D from the sun. In fact, anyone living north of a line drawn between Los Angeles and Atlanta is almost certainly not getting enough vitamin D from sunlight during much of the year. Modern lifestyle changes—including more indoor activities and sunscreen usage—have reduced or eliminated sun exposure for just about everyone, especially older people, causing unprecedented vitamin D deficiency, rickets, and bone breaks in children and adults alike. Compounding the problem of reduced sun exposure is the fact the there are so few food sources for vitamin D. An adequate intake simply cannot be obtained from food. Hence, a supplement is necessary for most people, especially since we know that too much sun exposure—normally the main source of vitamin D—is correlated with skin cancer.

Poor bone health is not the only consequence of inadequate Vitamin D. Evidence is starting to show that vitamin D may be important for every cell and every organ in your body, and that a deficiency may contribute to a host of diseases, from the common cold and the flu to cancer, hypertension, insulin-dependent diabetes, and even multiple sclerosis.

How much vitamin D is enough? That’s debatable, as even the scientists cannot decide!

Foods with vitamin D are fortified milk and oily fish from the sea (such as salmon and mackerel), egg yolks, liver, and fish liver oil. It is difficult to get enough vitamin D from food sources alone, so people up to age seventy should supplement with
at least
600 IU daily. For those over seventy, 800 units daily is recommended, with a safe upper limit of 4,000 units. To find out what
you
should be taking, get your vitamin D blood levels tested at your next doctor’s appointment. Blood levels of at least 32 to 40 nanograms per milliliter or higher are recommended. When choosing a supplement, look for vitamin D
₃
(cholecalciferol), not D
₂
(ergocalciferol). You can usually get vitamin D as part of a calcium supplement.

CALCIUM

Sources of calcium are dairy products, broccoli, kale, and collards, as well as calcium-fortified foods like orange juice, soy milk, breakfast cereals, and tofu. Assuming we are getting about 700 milligrams of calcium from our daily diet—a big assumption for most people—doctors recommend that in order to help protect our bones, we should supplement this with 500 milligrams of calcium. The new guidelines from the Institute of Medicine recommend a total of 1,200 milligrams of calcium for women fifty-one and older and men seventy-one and older. Too much calcium can result in kidney stones and heart disease; the institute says that the upper limit of safety for men and women over fifty-one is 2,000 milligrams. Calcium supplements need to be taken along with 800 to 1,000 IU of vitamin D—or more—to help with absorption and to reduce bone loss and prevent fractures. (More on calcium in
Appendix IV
.)

I used to think that vitamin E, vitamin C, and selenium were the antioxidant supplement superstars. I was wrong! There are, in fact, no well-controlled trials showing that supplementing our diets with vitamin E or selenium does any good … and it may do harm.

VITAMIN C

Vitamin C is an important antioxidant, synthesizes collagen, helps boost iron absorption, and plays a role in our hormonal and nervous systems. The recommended dietary allowance is 75 milligrams per day for adult women and 90 milligrams per day for men. When a person eats up to 120 milligrams daily, 80 to 90 percent is absorbed. As supplemental vitamin C intake goes up, absorption declines. There is no evidence that older people need megadoses, and everyone should avoid doses greater than 2,000 milligrams daily, which may cause diarrhea, nausea, abdominal cramps, and nosebleeds.

Food sources include citrus fruits, peaches, strawberries, peppers, broccoli, Brussels sprouts, papayas, kohlrabi, mangoes, pineapple, kiwifruit, peppers, cauliflower, cabbage, kale, potatoes, asparagus, and raspberries.

Both vitamin and mineral supplements (with the exception of calcium) should be taken with meals. This way they are absorbed into the system more efficiently and are digested more easily.

Water

Water is the largest single constituent of the human body and makes up two-thirds of our body weight. It is required for almost every function, from digestion to regulating our temperature to transporting nutrients to removing bodily wastes. It’s good for mental function, aerobic power, endurance, physical work capacity, the heart, and the bowels. Many older men and women complain about constipation; much of the time, it’s because they don’t drink enough water. Too little water may also increase the risk of painful kidney stones.

Drink plenty of fluids. The National Academy of Sciences’ most recent report stated that most adults naturally, based on thirst, consume enough fluid from a combination of foods, such as fruits, vegetables, and grains (from which we get about one-third of our water), and beverages, so most people don’t need to focus on a particular amount. Though the scientists made no specific water recommendation, they concluded that the elderly may experience a diminished sense of thirst. Their recommendations for an adequate daily intake is nine cups for women over fifty and thirteen cups for men; this refers to
total beverages,
including water, milk, juice, coffee, and tea.

While drinking water may or may not curb the appetite, it’s good for you! And there is plenty of evidence that eating water-containing
foods,
such as fruits, vegetables, and soups (low-calorie and broth-based, of course),
will
curb your appetite, reducing what you eat at meals, and thus your overall calorie intake. So, if you’re trying to lose weight, eat a piece of fruit—for instance, an apple or some berries—or a salad or broth-based veggie soup before a meal to curb your appetite. Or turn your meals into soups or salads by adding veggies or broth. You’ll feel full with fewer calories, and studies show that it may save you from eating 100 excess calories—and that could keep you from gaining several pounds in one year.

We need to learn to eat smaller meals and snack only when necessary. Our blood sugar tends to drop at certain times of the day. To avoid grabbing the nearest cookie or doughnut to satisfy our craving and keep us from feeling dizzy, we should always eat a balanced breakfast and lunch, each composed of, ideally, about one-fourth to one-third of our day’s caloric needs. Also, be prepared to have midmorning and afternoon snacks on hand, such as red grapes, an apple, a low-fat piece of string cheese, yogurt, some unsalted nuts, or raisins. Apples vary greatly in flavor, so try different ones until you find varieties whose flavors appeal to you. I’m partial to the Honeycrisp, Stayman, Gala, and Fuji varieties. Foods grown locally and in season, picked at peak ripeness, have more flavor and nutrition, making them more enjoyable and healthier. Choosing them also means you’re using fewer natural resources, and helping to save the environment.

When I’m away from home, I carry tasty and filling snack foods with me. The natural sugar in the fruits and proteins will raise my blood sugar level, appease my hunger the natural way, and give me energy without the high jolt of refined sugar and the precipitous drop that follows.

When to Eat

It’s a good idea to distribute your meals, calories, and nutrients evenly through the day. This way, you fuel your body in a way that improves your nutrient absorption (particularly protein) and your concentration; stabilizes your blood sugar, your mood, and your energy; and reduces cravings. For most people, that means: Don’t skip breakfast! Studies show that people who eat more food earlier in the day end up consuming fewer overall calories, and vice versa; people who eat more of their food later in the day tend to consume more overall calories, which may explain why people who skip breakfast are often fatter, according to the studies. As a bonus, people who eat breakfast take in more essential nutrients than people who don’t, and people who lose and maintain weight never skip breakfast! If you don’t feed yourself properly during the day, you’ll be more prone to overeating later, and to impulsively choosing less healthy foods. So eat a good, balanced breakfast and lunch, have planned healthy snacks in between, and snack only lightly in the evening … at least three hours before you go to bed. Don’t snack after dinner if you can avoid it, and if you must, choose something light, such as herbal tea, a serving of veggies or fruit, or a cup of yogurt or hot cocoa made with skim or soy milk.

One final word of advice: Never go to a restaurant or shop for food when you’re hungry. Instead, try eating an apple and drinking a glass of water before you go, and always shop with a list so you won’t find yourself improvising in the fatty-food aisles.

You will find more details about a healthy diet in
Appendix IV
.

CHAPTER 8

You and Your Brain: Use It or Lose It

“Can’t you give me brains?” asked the Scarecrow.

     
“You don’t need them,” said the Wizard. “You are learning something every day. A baby has brains, but it doesn’t know much. Experience is the only thing that brings knowledge and the longer you are on earth the more experience you are sure to get.”