widespread reporting of the findings, the UK's National Health Service (NHS) were also concerned that "the way the researchers added together hazards from different metals to produce a final score for individual wines may not be particularly meaningful". Commentators in the US questioned the relevance of seafood-based THQ assessments to agricultural produce, with the TTB, responsible for testing imports for metal ion contamination, have not detected an increased risk. George Solas, quality assessor for the Canadian Liquor Control Board of Ontario (LCBO) claimed that the levels of heavy metal contamination reported were within the permitted levels for drinking water in tested reservoirs. Whereas the NHS also described calls for improved wine labeling as an "extreme response" to research which provided "few solid answers", they acknowledged the authors call for further research to investigate wine production, including the influence that grape variety, soil type, geographical region, insecticides, containment vessels and seasonal variations may have on metal ion uptake. Chemical composition Natural phenols and polyphenols Although red wine contains many chemicals under basic research for their potential health benefits, resveratrol has been particularly well studied and evaluated by regulatory authorities, such as the European Food Safety Authority and US Food and Drug Administration which identified it and other such phenolic compounds as not sufficiently understood to confirm their role as physiological antioxidants. Resveratrol Red wine contains an average of 1.9 (±1.7) mg of trans-resveratrol per liter. For comparison, dietary supplements of resveratrol (trans-resveratrol content varies) may contain as much as 500 mg. Resveratrol is a stilbenoid phenolic compound found in wine produced in the grape skins and leaves of grape vines. The production and concentration of resveratrol is not equal among all the varieties of wine grapes. Differences in clones, rootstock, Vitis species as well as climate conditions can affect the production of resveratrol. Also, because resveratrol is part of the defence mechanism in grapevines against attack by fungi or grape disease, the degree of exposure to fungal infection and grape diseases also appear to play a role. The Muscadinia family of vines, which has adapted over time through exposure to North American grape diseases such as phylloxera, has some of the highest concentrations of resveratrol among wine grapes. Among the European Vitis vinifera, grapes derived from the Burgundian Pinot family tend to have substantially higher amounts of resveratrol than grapes derived from the Cabernet family of Bordeaux. Wine regions with cooler,