Comparison between omega-3 and omega-6 polyunsaturated fatty acid intakes as assessed by a food frequency questionnaire and erythrocyte membrane fatty acid composition in young children.

OBJECTIVE: We conducted a dietary validation study in youth aged 1-11 years by comparing dietary intake of omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) as assessed by a parent-completed semiquantitative food frequency questionnaire (FFQ) over time to erythrocyte membrane composition of the same fatty acids. DESIGN: The study population included youth aged 1-11 years who were participants in the Diabetes Autoimmunity Study in the Young (DAISY), a longitudinal study in Denver, Colorado that is following a cohort of youth at risk for developing type I diabetes. Four hundred and four children who had erythrocyte membrane fatty acid data matched to an FFQ corresponding to the same time frame for a total of 917 visits (matches) were included. PUFA intake was expressed both as g/day (adjusted for total energy) and as percent of total fat intake. We used mixed models to test the association and calculate the correlation between the erythrocyte membrane estimates and PUFA intake using all records of data for each youth. RESULTS: Intakes of total omega-3 fatty acids (beta=0.52, P<0.0001, rho=0.23) and marine PUFAs (beta=1.62, P<0.0001, rho=0.42), as a percent of total fat in the diet, were associated with percent of omega-3 and marine PUFAs in the erythrocyte membrane. Intakes of omega-6 PUFAs (beta=0.04, P=0.418, rho=0.05) and arachidonic acid (beta=0.31, P=0.774, rho=0.01) were not associated. CONCLUSIONS: In these young children, an FFQ using parental report provided estimates of average long-term intakes of marine PUFAs that correlated well with their erythrocyte cell membrane fatty acid status.

Lead content of calcium supplements.

CONTEXT: Substantial quantities of lead have been reported in some over-the-counter calcium supplement preparations, including not only bone-meal and dolomite, but also over-the-counter natural and refined calcium carbonate formulations. Examination of this issue is warranted given recent increases in physician recommendations for calcium supplements for prevention and treatment of osteoporosis. OBJECTIVES: To determine the lead content of calcium supplements and to quantify the lead exposure from popular brands of calcium in dosages used for childhood recommended daily allowance, osteoporosis, and phosphate binding in dialysis patients. DESIGN AND SETTING: Analysis of lead content in 21 formulations of nonprescription calcium carbonate (including 7 natural [ie, oyster shell] and 14 refined), 1 brand of prescription-only calcium acetate, and 1 noncalcium synthetic phosphate binder conducted in March 2000. MAIN OUTCOME MEASURES: Lead content, assayed using electrothermal atomic absorption, expressed as micrograms of lead per 800 mg/d of elemental calcium, per 1500 mg/d of calcium, and for a range of dosages for patients with renal failure. Six microg/d of lead was considered the absolute dietary limit, with no more than 1 microg/d being the goal for supplements. RESULTS: Four of 7 natural products had measurable lead content, amounting to approximately 1 microg/d for 800 mg/d of calcium, between 1 and 2 microg/d for 1500 mg/d of calcium, and up to 10 microg/d for renal dosages. Four of the 14 refined products had similar lead content, including up to 3 microg/d of lead in osteoporosis calcium dosages and up to 20 microg/d in high renal dosages. No lead was detected in the calcium acetate or polymer products. Lead was present even in some brand name products from major pharmaceutical companies not of natural oyster shell derivation. CONCLUSIONS: Despite increasingly stringent limits of lead exposure, many calcium supplement formulations contain lead and thereby may pose an easily avoidable public health concern. JAMA. 2000;284:1425-1429.