Authors' objectives:

The aim of this study was to update the chapter from the 1996 Guide to Clinical Preventive Services examining the effectiveness of counseling to promote a healthy diet and to assist the US Preventive Services Task Force in making recommendations on this topic.

Authors' results and conclusions: The relationships between dietary patterns and health outcomes have been examined in a wide range of observational studies. Few randomized trials have examined the effect of dietary interventions on health outcomes. The majority of studies show that persons consuming diets high in fruits, vegetables, fish, and whole grains or fiber and low in saturated and trans-unsaturated fats have lower rates of coronary heart disease and some forms of cancer. Similarly strong evidence supports the relationship between dietary intake of calcium and the risk of low bone mineral density. High intake of dietary sodium and low intake of dietary potassium are associated with higher blood pressure levels and increased incidence of hypertension. Efforts to reduce sodium intake and increase potassium have shown moderate effects on blood pressure, with greater effects seen in African-Americans and persons with hypertension. Several brief, valid dietary assessment instruments are feasible for the primary care setting. Although these instruments have not been evaluated as to their impact on health outcomes, they serve an important role of identifying dietary counseling needs and monitoring change over time. Many of these instruments are designed for specific patient populations or nutrients. We identified 33 articles examining the effect of nutritional counseling in primary care patients. Among primary care patients, nutrition counseling can produce modest improvements in saturated and total fat consumption, as well as fruit and vegetable consumption. The evidence is insufficient to determine the effectiveness of counseling in changing consumption of whole grains or fiber, calcium, sodium, or fish. Intensive interventions are more likely to produce large changes, but typical strategies pursued in primary care settings tend to be of lower intensity and produce smaller changes. Interventions using mailed or computer-generated materials appeared moderately effective, particularly in increasing fruit and vegetable consumption. Isolating the effect of a single counseling approach as more or less effective is made difficult by the tendency for counseling interventions to test multiple approaches simultaneously. Studies employing 3 or more well-proven counseling elements were more effective than those employing fewer elements.

Authors' recommendations: Diets low in saturated and trans-unsaturated fat and high in fruits, vegetables, fish, and whole grains are associated with better health outcomes. Counseling patients can improve dietary behaviors, including reduction in dietary total and saturated fat and increases in fruit and vegetable intake. More intensive counseling and counseling directed to higher-risk patients have generally produced larger changes than less intensive interventions delivered to low-risk populations.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.ahrq.gov/clinic/uspstf/uspsdiet.htm

Year Published: 2002

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: United States

Organisation Name: Agency for Healthcare Research and Quality

Contact Address: Center for Outcomes and Evidence Technology Assessment Program, 540 Gaither Road, Rockville, MD 20850, USA. Tel: +1 301 427 1610; Fax: +1 301 427 1639;

Contact Name: martin.erlichman@ahrq.hhs.gov

Contact Email: martin.erlichman@ahrq.hhs.gov

Copyright: Agency for Healthcare Research and Quality (AHRQ)