JAMA. 2002;287:3127-3129
Vol. 287 No. 23,
June 19, 2002
Scientific Review and Clinical Applications
CLINICIAN'S CORNER
Vitamins for Chronic Disease Prevention in Adults
Clinical Applications
Robert H. Fletcher, MD, MSc; Kathleen M. Fairfield, MD, DrPH
Vitamin deficiency syndromes such as scurvy and beriberi are uncommon in Western societies. However, suboptimal intake of some vitamins, above levels causing classic vitamin deficiency, is a risk factor for chronic diseases and common in the general population, especially the elderly. Suboptimal folic acid levels, along with suboptimal levels of vitamins B6 and B12, are a risk factor for cardiovascular disease, neural tube defects, and colon and breast cancer; low levels of vitamin D contribute to osteopenia and fractures; and low levels of the antioxidant vitamins (vitamins A, E, and C) may increase risk for several chronicdiseases. Most people do not consume an optimal amount of all vitamins by diet alone. Pending strong evidence of effectiveness from randomized trials, it appears prudent for all adults to take vitamin supplements. The evidence base for tailoring the contents of multivitamins to specific characteristics of patients such as age, sex, and physical activity and for testing vitamin levels to guide specific supplementation practices is limited. Physicians should make specific efforts to learn about their patients' use of vitamins to ensure that they are taking vitamins they should, such as folate supplementation for women in the childbearing years, and avoiding dangerous practices such as high doses of vitamin A during pregnancy or massive doses of fat-soluble vitamins at any age.
Author/Article Information
Author Affiliations: Department of Ambulatory Care and Prevention, Harvard Medical School/Harvard Pilgrim Health Care, and Department of Epidemiology, Harvard School of Public Health (Dr Fletcher); Division of General Medicine and Primary Care, Beth Israel Deaconess Medical Center, and Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School (Dr Fairfield), Boston, Mass. Funding/Support: Dr Fairfield is supported by career development award CCDA-00-179-01 from the American Cancer Society.
Corresponding Author and Reprints: Robert H. Fletcher, MD, MSc, Department of Ambulatory Care and Prevention, Harvard Medical School/Harvard Pilgrim Health Care, 133 Brookline Ave, Sixth Floor, Boston, MA 02215 (e-mail: Robert_Fletcher@hms.harvard.edu).
Scientific Review and Clinical Applications Section Editor: Wendy Levinson, MD, Contributing Editor
© 2002 American Medical Association. All rights reserved.
------------------------------------------------------------------------
JAMA. 2002;287:3116-3126
Vol. 287 No. 23,
June 19, 2002
Scientific Review and Clinical Applications
CLINICIAN'S CORNER
Vitamins for Chronic Disease Prevention in Adults
Scientific Review
Kathleen M. Fairfield, MD, DrPH; Robert H. Fletcher, MD, MSc
Context Although vitamin deficiency is encountered infrequently in developed countries, inadequate intake of several vitamins is associated with chronic disease.
Objective To review the clinically important vitamins with regard to their biological effects, food sources, deficiency syndromes, potential for toxicity, andrelationship to chronic disease.
Data Sources and Study Selection.We searched MEDLINE for English-language articles about vitamins in relation to chronic diseases and their references published from 1966 through January 11, 2002.
Data Extraction: We reviewed articles jointly for the most clinically important information, emphasizing randomized trials where available.
Data Synthesis: Our review of 9 vitamins showed that elderly people, vegans, alcohol-dependent individuals, and patients with malabsorption are at higher risk of inadequate intake or absorption of several vitamins. Excessive doses of vitamin A during early pregnancy and fat-soluble vitamins taken anytime may result in adverse outcomes. Inadequate folate status is associated with neural tube defect and some cancers. Folate and vitamins B6 and B12 are required for homocysteine metabolism and are associated with coronary heart disease risk. Vitamin E and lycopene may decrease the risk of prostate cancer. Vitamin D is associated with decreased occurrence of fractures when taken with calcium.
Conclusions Some groups of patients are at higher risk for vitamin deficiency and suboptimal vitamin status. Many physicians may be unaware of common food sources of vitamins or unsure which vitamins they should recommend for their patients. Vitamin excess is possible with supplementation, particularly for fat-soluble vitamins. Inadequate intake of several vitamins has been linked to chronic diseases, including coronary heart disease, cancer, and osteoporosis.
Author/Article Information
Author Affiliations: Division of General Medicine and Primary Care, Beth Israel Deaconess Medical Center, and Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School (Dr Fairfield); Department of Ambulatory Care and Prevention, Harvard Medical School/Harvard Pilgrim Health Care, and Department of Epidemiology, Harvard School of Public Health (Dr Fletcher), Boston, Mass.
Funding/Support: Dr Fairfield is supported by career development award CCDA-00-179-01 from the American Cancer Society.
Corresponding Author and Reprints: Kathleen M. Fairfield, MD, DrPH, Division of General Medicine and Primary Care, Libby 330, Beth Israel Deaconess Medical Center, 330 Longwood Ave, Boston, MA 02215 (e-mail: kfairfie@caregroup.harvard.edu).
Scientific Review and Clinical Applications Section Editor: Wendy Levinson, MD, Contributing Editor
© 2002 American Medical Association. All rights reserved.