Patient information: Diet and health
Last literature review version 18.2: May 2010 | This topic last updated: January 23, 2009
HEALTHY DIET OVERVIEW — The food choices we make can have an important impact on our health. However, expert opinions about which and how much of these foods is best continues to change as new research is completed.
This topic summarizes the research about 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", section on 'Choosing a diet'.)
FRUITS AND VEGETABLES — A number of studies have demonstrated important health benefits of eating fruits and vegetables.
The National Cancer Institute recommends a goal of five servings of fruits or vegetables per day.
FIBER — Eating a diet that is high in fiber can decrease the risk of coronary heart disease and stroke by 40 to 50 percent . 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".)
The recommended amount of dietary fiber is 20 to 35 grams of fiber per day. Many breakfast cereals 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).
FAT — High blood cholesterol levels increase the risk of coronary heart disease. Eating foods lower in certain types of fat and cutting back on foods that contain cholesterol can lower cholesterol levels and reduce the risk of coronary heart disease. (See "Patient information: High cholesterol and lipids (hyperlipidemia)".)
The type of fat consumed appears to be more important than the amount of total fat. Saturated fats and trans fats should be avoided.
When considering a low fat diet, it is important not to replace fat with carbohydrates. Increases in carbohydrate intake may lower levels of high density lipoprotein (HDL) cholesterol (good cholesterol), which actually increases the risk of coronary heart disease.
FOLATE — 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 colon cancer or heart disease.
ANTIOXIDANTS — 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.
No recommendations can yet be made regarding the use of vitamin C to prevent coronary heart disease (CHD).
Vitamin E supplements, either alone or in combination with other antioxidant vitamins, are of no benefit in preventing prevention of CHD. Studies have also failed to show that supplements of vitamins E and C decrease the risk of stroke. The American Heart Association does recommend, however, that a healthy diet include foods high in antioxidants, such as fruits, vegetables, and whole grains.
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). Calcium from food sources and supplements appears to slightly increase the risk of prostate cancer, although it may help to protect against colon cancer.
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 1500 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".)
Experts recommend that adults consume a total of 800 International Units (IU) of vitamin D each day. This dose appears to reduce bone loss and the number of bone fractures in older women and men. Milk is the primary dietary source of dietary vitamin D, containing approximately 100 IU per cup. Infants and children also need vitamin D. (See "Patient information: Starting solid foods during infancy".)
ALCOHOL — 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".)
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. 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.
CALORIE RECOMMENDATIONS — The total number of calories a person needs depends upon the following factors:
We provide a calculator to help you estimate how many calories you should eat every day based your current weight and activity level (for women (calculator 1) and for men (calculator 2).
GENERAL RECOMMENDATION FOR A HEALTHY DIET — Eat a lot of vegetables, fruits, whole grains, and a limited amount of red meat. Eat at least five servings a day of fruits and vegetables. More is even better. Tips for achieving this goal include:
Trans fats and saturated fats should be avoided. Monounsaturated and polyunsaturated fats should be used instead. Tips to accomplish this include:
Get enough folate every day (400 micrograms per day). Tips for achieving this goal include:
Avoid excessive alcohol intake. Tips for achieving this goal include:
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 every four months 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
Patient information: Weight loss treatments
Patient information: High fiber diet
Patient information: High cholesterol and lipids (hyperlipidemia)
Patient information: Calcium and vitamin D for bone health
Patient information: Starting solid foods during infancy
Patient information: Risks and benefits of alcohol
Professional level information
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
The following organizations also provide reliable health information.
Use of UpToDate is subject to the Subscription and License Agreement.
1. Joshipura, KJ, Hu, FB, Manson, JE, et al. The effect of fruit and vegetable intake on risk for coronary heart disease. Ann Intern Med 2001; 134:1106.
2. World Cancer Research Fund, American Institute for Cancer Research. Food, Nutrition and the Prevention of Cancer: A Global Perspective. American Institute for Cancer Research, Washington, DC 1997.
3. Wolk, A, Manson, JE, Stampfer, MJ, et al. Long-term intake of dietary fiber and decreased risk of coronary heart disease among women. JAMA 1999; 281:1998.
4. Negri, E, Franceschi, S, Parpinel, M, La Vecchia, C. Fiber intake and risk of colorectal cancer. Cancer Epidemiol Biomarkers Prev 1998; 7:667.
5. Hu, FB, Stampfer, MJ, Manson, JE, et al. Dietary fat intake and the risk of coronary heart disease in women. N Engl J Med 1997; 337:1491.
6. Ascherio, A, Rimm, EB, Giovannucci, EL, et al. Dietary fat and risk of coronary heart disease in men: Cohort follow up study in the United States. BMJ 1996; 313:84.