Magnesium supplement intake and C-reactive protein levels in adults

Previous research has indicated that dietary magnesium may be a key component in the association between diet and inflammation; however, the role of intake from magnesium supplements has not been elucidated. The objective of this study was to determine the likelihood of elevated C-reactive protein (CRP) in people taking magnesium-containing supplements of 50 mg/d or more. We examined this issue in a study sample derived from the National Health and Nutrition Examination Survey 1999-2002, a nationally representative, survey of the civilian, noninstitutionalized population of the United States. Among US adults, 25.6% were taking a magnesium supplement of at least 50 mg daily. Only 21.9% of individuals not taking supplemental magnesium met or exceeded the recommended daily allowances (RDA) for magnesium intake compared with 60.2% of adults who were taking magnesium supplements. In adjusted logistic regression analyses, people whose total daily magnesium intake was below the RDA were significantly 40% more likely to have elevated CRP regardless of whether they were taking magnesium supplements (P < .05). Among people with dietary magnesium intake less than 50% RDA, individuals taking magnesium supplements were 22% less likely to have elevated CRP. Magnesium supplement intake is associated with a lower likelihood of elevated CRP in people with low dietary magnesium intake. Prospective studies are needed to examine whether magnesium supplementation can reduce levels of CRP.