HEALTHY DIET OVERVIEW
The food choices we make can have an important impact on our health. However, expert opinions continue to change about which and how much of these foods is optimal.
This topic summarizes the relationships between various foods or supplements and specific health conditions, and concludes with general recommendations for following a healthy diet. A separate topic review is available about diets for weight loss. (See "Patient information: Weight loss treatments (Beyond the Basics)", section on 'Choosing a diet or new eating plan'.)
FRUITS AND VEGETABLES
A number of studies have demonstrated important health benefits of eating fruits and vegetables.
●Increased intake of fruits and vegetables is linked to a lower risk of premature death.
●Fruits and vegetables decrease the risk of cardiovascular diseases including coronary heart disease (CHD) and stroke, including death from CHD .
●High intake of fruits and vegetables also reduces the risk of developing certain kinds of cancer (including lung cancer and cancer of the gastrointestinal system). Tomato and tomato-based foods may be beneficial at lowering the risk of prostate cancer.
●At least five servings of fruits and/or vegetables should be eaten daily.
Eating a diet that is high in fiber can decrease the risk of coronary heart disease, stroke, colon cancer, and death [2,3]. Eating fiber also protects against type 2 diabetes, and eating soluble fiber (such as that found in vegetables, fruits, and especially legumes) may help control blood sugar in people who already have diabetes. (See "Patient information: High-fiber diet (Beyond the Basics)".)
The recommended amount of dietary fiber is 25 grams per day for women and 38 grams per day for men. Many breakfast cereals, fruits, and vegetables are excellent sources of dietary fiber. By reading the product information panel on the side of the package, it is possible to determine the number of grams of fiber per serving (figure 1). A list of the fiber content of a number of foods can be found in the table (table 1).
Eating foods higher in healthy fats and lower in unhealthy fats may reduce the risk of coronary heart disease.
The type of fat consumed appears to be more important than the amount of total fat. Trans fats should be avoided in favor of polyunsaturated fats, particularly those polyunsaturated fats found in fish (omega 3). Other sources of polyunsaturated fats that may be beneficial include certain oils and nuts.
Trans fats are those that are solid at room temperature, and are found in many margarines and in other fats labeled "partially hydrogenated." Another major source is oils that are maintained at high temperature for a long period, such as in fast food restaurants.
Although saturated fats (found in animal products such as cheese, butter, and red meat) have typically been viewed as unhealthy, and monounsaturated fats (found in combination with other fats in many oils) as healthy, newer evidence suggests that saturated and monounsaturated fats do not significantly increase or decrease the risk of coronary heart disease, although saturated fats raise cholesterol levels.
It is important not to replace fat with refined carbohydrates (eg, white bread, white rice, most sweets). Increases in refined carbohydrate intake may lower levels of high density lipoprotein (HDL) cholesterol (good cholesterol), which actually increases the risk of coronary heart disease.
Folate is a type of B vitamin that is important in the production of red blood cells. Low levels of folate in pregnant women have been linked to a group of birth defects called neural tube defects, which includes spina bifida and anencephaly. Vitamins containing folate and breakfast cereal fortified with folate are recommended as the best ways to ensure adequate folate intake.
However, supplements containing folate (called folic acid) are no longer recommended to reduce the risk of heart disease.
The antioxidant vitamins include vitamins A, C, E, and beta-carotene. Many other foods, especially fruits and vegetables, also have antioxidant properties. Studies have not clearly shown that antioxidant vitamins prevent cancer, and some studies show they may actually cause harm. There is no evidence to support antioxidant vitamin supplementation for individuals who do not have specific vitamin deficiencies.
CALCIUM AND VITAMIN D
Adequate calcium and vitamin D intake are important, particularly in women, to reduce the risk of osteoporosis. A healthcare provider can help to decide if supplements are needed, depending upon a person's dietary intake of calcium and vitamin D (table 2). Although the optimal level has not been clearly established, experts recommend that premenopausal women and men consume at least 1000 mg per day and postmenopausal women should consume 1200 mg per day. No more than 2000 mg of calcium should be consumed per day. (See "Patient information: Calcium and vitamin D for bone health (Beyond the Basics)".)
The current recommendation is that postmenopausal women with or at risk for osteoporosis consume at least 800 International Units of vitamin D per day. Lower levels of vitamin D are not as effective while high doses can be toxic, especially if taken for long periods of time. Although the optimal intake has not been clearly established in premenopausal women or in men with osteoporosis, 400 to 600 International units of vitamin D daily is generally suggested.
Moderate alcohol intake may reduce the risk of heart disease. However, it is not clear what amount of alcohol is best. There are some risks associated with alcohol use, including breast cancer in women; cancers of the mouth, esophagus, throat, larynx, and liver; other illnesses such as cirrhosis and alcoholism; and injuries and other trauma-related problems, particularly in men. (See "Patient information: Risks and benefits of alcohol (Beyond the Basics)".)
Based on the trade-off between these risks and benefits, the United States Dietary Guidelines recommend alcohol intake in moderation, if at all. This means no more than one drink per day for women, and up to 2 drinks per day for men. Those who do not drink alcohol do not need to start.
Drinking is discouraged for those under 40 years who are at low risk of cardiovascular disease because the risks are likely to outweigh the benefits in this group.
Calories count. Too many calories lead to weight gain and obesity. It is linked with premature death as well as an increased risk of cardiovascular disease, diabetes, hypertension, cancer, and other important diseases [4-8].
The total number of calories a person needs depends upon the following factors:
GENERAL RECOMMENDATIONS FOR A HEALTHY DIET
Eat lots of vegetables, fruits, and whole grains and a limited amount of red meat. Get at least five servings of fruits and vegetables every day. Tips for achieving this goal include:
●Make fruits and vegetables part of every meal. Eat a variety of fruits and vegetables. Frozen or canned can be used when fresh isn't convenient.
●Eat vegetables as snacks.
●Have a bowl of fruit out all the time for kids to take snacks from.
●Put fruit on your cereal.
●Consume at least half of all grains as whole grains (like whole wheat bread, brown rice, whole grain cereal), replacing refined grains (like white bread, white rice, refined or sweetened cereals).
Cut down on unhealthy fats (trans fats and saturated fats) and consume healthy fats (polyunsaturated and monounsaturated fat). Tips for achieving this goal include:
●Choose chicken, fish, and beans instead of red meat and cheese.
●Cook with oils that contain polyunsaturated and monounsaturated fats, like olive and peanut oil.
●Choose margarines that do not have partially hydrogenated oils. Soft margarines (especially squeeze margarines) have less trans fatty acids than stick margarines.
●Eat fewer baked goods that are store-made and contain partially hydrogenated fats (like many types of crackers, cookies, and cupcakes).
●When eating at fast food restaurants, choose healthy items for yourself as well as your family, like broiled chicken or salad.
Avoid sugar-sweetened beverages and excessive alcohol intake. Tips for achieving this goal include:
●Choose non-sweetened and non-alcoholic beverages, like water, at meals and parties.
●Avoid occasions centered around alcohol.
●Avoid making sugar-sweetened beverages and alcohol an essential part of family gatherings.
Keep calorie intake balanced with needs and activity level.
WHERE TO GET MORE INFORMATION
Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient information: Diet and health (The Basics)
Patient information: High-fiber diet (The Basics)
Patient information: Coronary artery bypass graft surgery (The Basics)
Patient information: Vitamin B12 deficiency and folate (folic acid) deficiency (The Basics)
Patient information: Coronary heart disease in women (The Basics)
Patient information: Vitamin supplements (The Basics)
Patient information: Can foods or supplements lower cholesterol? (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient information: Weight loss treatments (Beyond the Basics)
Patient information: High-fiber diet (Beyond the Basics)
Patient information: High cholesterol and lipids (hyperlipidemia) (Beyond the Basics)
Patient information: Calcium and vitamin D for bone health (Beyond the Basics)
Patient information: Starting solid foods during infancy (Beyond the Basics)
Patient information: Risks and benefits of alcohol (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Diet in the treatment and prevention of hypertension
Dietary and nutritional assessment in adults
Fish oil and marine omega-3 fatty acids
Lipid lowering with diet or dietary supplements
Nutrition in pregnancy
Healthy diet in adults
The following organizations also provide reliable health information.
●National Library of Medicine
●Your Disease Risk at Washington University in St. Louis
●The Hormone Foundation