ABSTRACT
Recent efforts worldwide have resulted in a growing database of measured concentrations of chemicals in blood and urine samples taken from the general population. However, few tools exist to assist in the interpretation of the measured values in a health risk context. Biomonitoring Equivalents (BEs) are defined as the concentration or range of concentrations of a chemical or its metabolite in a biological medium (blood, urine, or other medium) that is consistent with an existing health-based exposure guideline. BE values are derived by integrating available data on pharmacokinetics with existing chemical risk assessments. This study reviews available health-based exposure guidance values for bisphenol A (BPA) from Health Canada, the United States Environmental Protection Agency (USEPA) and the European Food Safety Authority (EFSA). BE values were derived based on data on BPA urinary excretion in humans. The BE value corresponding to the oral provisional tolerable daily intake (pTDI) of 25 microg/kg-d from Health Canada is 1mg/L (1.3mg/g creatinine); value corresponding to the US EPA reference dose (RfD) and EFSA tolerable daily intake (TDI) estimates (both of which are equal to 50 microg/kg-d) is 2mg/L (2.6 mg/g creatinine). These values are estimates of the 24-h average urinary BPA concentrations that are consistent with steady-state exposure at the respective exposure guidance values. These BE values may be used as screening tools for evaluation of central tendency measures of population biomonitoring data for BPA in a risk assessment context and can assist in prioritization of the potential need for additional risk assessment efforts for BPA relative to other chemicals.
Subject(s)
Environmental Monitoring/standards , Environmental Pollutants/standards , Estrogens, Non-Steroidal/standards , Phenols/standards , Adolescent , Adult , Aged , Aged, 80 and over , Benzhydryl Compounds , Biomarkers/metabolism , Child , Environmental Exposure/standards , Environmental Exposure/statistics & numerical data , Environmental Pollutants/metabolism , Environmental Pollutants/pharmacokinetics , Environmental Pollution/statistics & numerical data , Estrogens, Non-Steroidal/metabolism , Estrogens, Non-Steroidal/pharmacokinetics , Female , Humans , Male , Middle Aged , Phenols/metabolism , Phenols/pharmacokinetics , Reference Values , Risk Assessment , Young AdultABSTRACT
Dietary guidance recommends consumption of whole grains to reduce the risk of chronic diseases including cancer and cardiovascular disease. Epidemiologic studies support the belief that whole grains are protective against cancers, especially gastrointestinal cancers such as gastric and colonic, and cardiovascular disease. Components in whole grains that may be protective are diverse and include compounds that affect the gut environment, i.e., dietary fiber, resistant starch, and other undigestible compounds in whole grains, compounds that function as antioxidants such as trace minerals and phenolic compounds, and compounds that are phytoestrogens with potential hormonal effects. Many of the protective compounds in whole grains are also in fruits and vegetables, but some plant compounds are more concentrated in whole grains, such as phenolic compounds including ferulic and caffeic acid. Other potential mechanistic effects of whole grains include binding of carcinogens and modulation of glycemic index. Clearly, the range of protective substances in whole grains is impressive, and advice to consume additional whole grains is justifiable.
