Maintaining Good Nutrition
Good nutrition is necessary for keeping the body functioning normally, maintaining a healthy weight, and preventing disease. If disease develops, good nutrition helps minimize the effects. People never outlive the need for good nutrition.
Good nutrition involves consuming a variety of foods in appropriate amounts. No one food provides all the substances the body needs (nutrients) for good health: protein, carbohydrates, fats, vitamins, minerals, fiber, and many others. Consuming enough water is also important. Water is necessary for all of the body's functions, including moving nutrients into cells and removing waste products from cells.
 See the figure A Daily Food Pyramid for Older People.
For older people, following standard nutritional recommendations, such as those of the standard daily food pyramid and recommended dietary allowances (RDAs), may not always be wise. Older people who try to follow these recommendations may gradually gain weight or develop a nutritional deficiency. Research has not determined the best diet for older people. Changes in diet, based on the way the body changes as it ages, may be beneficial. A different daily food pyramid has been developed with these changes in mind.
How Aging Affects Nutritional Needs
Calories: Older people tend to be less active and to use less energy. As people age, body fat tends to increase, and muscle tissue tends to decrease. Muscle tissue burns more calories than fat. So the aging body burns fewer calories, and weight may be gained. Therefore, older people may need to consume fewer calories to avoid gaining too much weight. However, if older people remain physically active, they may need as many calories as they did when younger. Calories are the measure of how much energy foods contain. All of the calories needed by the body come from carbohydrates (sugars and starches), fats, and proteins. Fats have about twice as many calories per gram as carbohydrates and proteins.
When people need to consume fewer calories, getting all the nutrients they need—particularly vitamins and minerals—is more difficult. They should choose foods that are rich in nutrients but not high in calories. Whole-grain cereals and whole-grain breads that are fortified with vitamins, such as folic acid (folate), are good choices. Fruits and vegetables that are deeply colored (such as strawberries, peaches, broccoli, spinach, and squash) tend to contain more nutrients than those that are less deeply colored.
Some foods that are high in sugar or fat (and thus high in calories) do not contain many vitamins and minerals. These foods are sometimes called empty-calorie foods. Examples are candy bars, doughnuts, cookies, and certain fried foods. Some fried foods contain many nutrients. But frying adds calories, and the nutrient it adds the most of is saturated fat. People should limit the amount of empty-calorie and fried foods they eat. Alcoholic beverages also contain many calories and few nutrients.
Carbohydrates: Older people should follow the standard nutritional recommendations for carbohydrates. Some foods contain complex carbohydrates. Examples are whole-grain cereals, breads, and pasta as well as peas, beans, brown rice, and many vegetables. Other foods contain simple or refined carbohydrates. Examples are ice cream, candy, syrups, jellies, and sodas. White rice, white bread, and other foods made with white flour also contain simple or refined carbohydrates. Foods containing complex carbohydrates are better choices because they are digested more slowly and are less likely to be converted to fat. These foods also tend to contain more fiber, vitamins, and minerals. A diet high in simple or refined carbohydrates increases the risk of obesity and diabetes.
Fats: The most important consideration is what type of fat is consumed. People of all ages should consume less saturated fat and less partially hydrogenated fat (trans fatty acids). These fats should provide no more than 10% of daily calories. Saturated fats are found in meat, butter, and whole-milk dairy products. Trans fatty acids are found in margarine, shortening, and many processed foods, such as cookies, crackers, doughnuts, and chips.
When possible, monounsaturated fats and polyunsaturated fats, particularly omega-3 fats, should be substituted for saturated fats and trans fatty acids. These fats may help protect the heart. Monounsaturated fats are found in avocado, olive, and peanut oils and in peanut butter. Polyunsaturated fats are found in canola, soybean, and many other liquid vegetable oils. Omega-3 fats are found in flaxseed and in certain fish, such as mackerel, salmon, and albacore tuna.
Some experts also recommend limiting the amount of total fat to no more than 30% of daily calories. When reducing the amount of fat in the diet, people must be careful about what foods they eat instead. Replacing fatty foods with foods that contain simple or refined carbohydrates can also cause weight gain.
Protein: As people age, they tend to lose muscle, because the level and activity of some hormones decrease and because they exercise less. Muscle may also be lost if older people do not consume enough protein.
Lean meat is a good source of protein. But for some older people, certain types of meat are hard to chew. Meat may also be expensive. Protein sources that are easier to chew and may be less expensive include fish, poultry, dairy products, and eggs. Peanut butter, beans, soy products, and nuts are also good sources of protein. These foods can provide enough protein for people who choose not to eat animal products.
Fiber: As people age, food moves more slowly through the digestive tract. Part of the reason is that older people become less physically active and drink less fluids. Eating enough fiber can help counter this slowing. Fiber, sometimes called roughage, provides bulk to stool. The increased bulk helps food move through the digestive tract. Fiber also helps prevent constipation and diverticular disease.
Fiber has other benefits. Some types of fiber slow the body's absorption of sugar and cholesterol after a meal. Fiber-rich foods are low in calories and tend to produce a feeling of fullness. So they can help people eat fewer calories. Good sources of fiber are high-fiber breakfast cereals (such as bran cereals), whole-grain breads and pastas, brown rice, and whole fruits and vegetables (with skins, if possible). Prunes, apples, and pears are good sources of fiber. Meat and dairy foods do not contain fiber.
About 20 to 30 grams of fiber should be consumed daily. An average serving of fruit, vegetable, or cereal contains 2 to 4 grams of fiber. Consequently, older people should eat 8 to 12 servings of these foods daily. Fiber supplements, such as psyllium, are also available. But getting fiber from foods is preferable.
Vitamins and minerals: As people age, some vitamins and minerals become more important. Consuming enough calcium (which is used to build bones) and vitamin D (which helps the body absorb calcium) is important. Fortified milk is a good source of both calcium and vitamin D. Other sources of calcium include other dairy products and juices fortified with calcium. Dark green vegetables such as turnip greens and collard greens contain calcium, but calcium in vegetables may be harder for the body to use. Older people often need to take supplements of calcium and vitamin D, because getting enough from the diet is difficult.
Older people absorb and store some vitamins and minerals differently. For example, many people cannot absorb vitamin B12 from food well. So people who consume the recommended daily amount of vitamin B12 in foods may not get enough of it into the body. Taking vitamin B12 supplements may be necessary.
Getting enough vitamins and minerals from foods is usually preferable to getting them from supplements. Foods, unlike supplements, contain other substances necessary for good health. However, always eating a healthy, well-balanced diet is difficult. So taking a multivitamin that contains the recommended daily allowances for vitamins and minerals, in addition to trying to eat a healthy diet, is a good idea.
Water: Older people are more likely to become dehydrated for many reasons. Consequently, older people need to make a conscious effort to drink enough fluids rather than wait until they feel thirsty. Water, fruit or vegetable juices, and caffeine-free coffee and tea are good choices. Alcoholic beverages and caffeinated coffee, tea, and sodas may make people urinate more, so they are less advisable.
How Disorders and Drugs Change Nutritional Needs
Disorders or drugs may change the body's nutritional needs or change the body's ability to meet those needs. They can decrease appetite or interfere with the absorption of nutrients.
Diuretics (used to treat high blood pressure) cause the body to excrete more water, increasing the risk of dehydration. So a person taking a diuretic, particularly during hot weather, may need to drink more fluids.
People with certain disorders sometimes need to follow a special diet. For example, a low-fat diet may be recommended for people who have had a heart attack or stroke. A low-salt diet may be recommended for people who have high blood pressure or heart failure. A low-protein diet may be recommended for people who have a kidney disorder. However, older people who follow such diets may be forced to give up foods they enjoy and to eat less of foods that contain nutrients they need. As a result, they may lose weight or develop a nutritional deficiency. They may need to take supplements. For some people (particularly very frail older people), limiting fat, salt, or protein may not be appropriate.
Screening for Adequate Nutrition
Many health care practitioners routinely check older people to determine whether their nutrition is adequate. Often, a careful description of what a person eats helps most. So practitioners may ask what the person typically eats in a day and how active the person is. Questions related to shopping for, preparing, and eating foods are also important. Problems with these tasks can result in nutritional deficiencies. Practitioners may ask about the person's mood. Feeling depressed, anxious, or stressed can affect what a person eats. A blood or urine sample may be taken, so that levels of nutrients may be measured.
Weight and height are measured. From these measurements, the body mass index (BMI) can be calculated. BMI is a single number that adjusts weight for height. It indicates whether a person is underweight, normal weight, overweight, or obese.
Estimating how much fat and muscle a person has (body composition) can help determine whether nutrition is adequate. In a test called bioelectric impedance analysis, the resistance of body tissues to the flow of a very low-voltage electrical current is measured. (The voltage is so low that it cannot be felt.) Body fat and bone resist the flow much more than does muscle tissue. By measuring the resistance to the current, health care practitioners can estimate the percentage of body fat. This test takes only about 1 minute. A simple but less accurate way to estimate body composition involves two measurements. A health care practitioner measures around a person's arm, leg, or waist. Then the thickness of fat under the skin, usually at the back of the upper arm, is measured with a caliper. But the most accurate way to estimate body composition is immersion in a water-filled tank, an expensive and cumbersome method rarely used for older people.
 See the table Body Mass Index.
Reading Food Labels
To eat a healthy diet, people need to know what they are eating. Reading food labels can help people make good choices. Food labels define a serving and state how many servings are in a container.
Labels are required to provide the number of calories and the amounts of certain nutrients in each serving.
Labels list the amounts for fat, cholesterol, salt (sodium), and carbohydrates (including fiber and sugars) by weight (in grams or milligrams) and as a percentage. The amount for protein is given only by weight. The percentage indicates what proportion of the total recommended daily amount of a nutrient is provided in a serving. The percentages are based on a diet of 2,000 calories a day. So they vary somewhat depending on how many calories are consumed each day.
Food labels list the amount of total and saturated fat and the number of calories supplied by fat in the food. Listing the amounts of cholesterol and salt (sodium) helps people, especially those with certain disorders, control how much salt and cholesterol they consume.
Food labels must list vitamins A and C and the minerals calcium and iron. Other vitamins and minerals are often listed.
The ingredients of a food are listed in order of weight. The ingredient with the greatest weight is listed first. Whether the food contains trans fatty acids can usually be checked by reading this list. They are usually described as hydrogenated oils or partially hydrogenated oils.
See the table How Much is a Serving?
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