Recent analyses of the levels of metal ions in one brand of red wine and subsequent determination THQ values revealed a significant concern to health for people ingesting one 250 mL glass per day [19
]. Here we report an expansion of this result by calculating the THQ values from reported concentration ranges of metal ions in wines originating from sixteen countries [20
]. THQ values were calculated for each metal ion and for the combined metals for which oral reference doses exist. Figure displays Box-Whisker plots for the concentration ranges of these seven metal ions found in red and white wines originating in fifteen countries. The plots are given as lower and upper extremes, median and 25th
percentiles. The highest levels and largest variations in concentrations are observed for Mn (0.335 – 3.020, 0.795) and Zn (0.173 – 1.800, 0.520) ions [values in parentheses are reported for the 25th
percentile and median]. The levels of Cu ions (0.023 – 0.630, 0.150) are less with a large spread in concentration. Both the median concentrations and ranges of levels of V, Ni, Cr and Pb ions are considerably lower.
Level of metals (microgram/mL) in wines from 15 countries.
It is notable that the measured levels of metals do not necessarily reflect the risk to health as this is dependent on the upper safe limits which vary between metals. Therefore the THQ values are better measures of the levels of concern. Figure shows the THQ values determined based on the contributions of V and Cu ions. In the majority of cases the THQ values are greater than 1 causing concern for the levels of these two metal ions alone. The data are given separately for males and females with the THQ values for the latter being higher owing to smaller average size and increased average lifespan.
Ranges of THQ values for wines by country of origin based on V and Cu content (blue: THQ for females, green: THQ for males).
As anticipated from the previous study [19
], V has a large impact on the overall THQ values with values ranging up to >360 (for females) for some Hungarian and Slovakian wines. THQ values based on V for French wines range from below 60 to over 200 (for females) with Portuguese wines having a range of 100 to >140 (for females). Wines from Germany and Argentina also have a spread of THQ values based levels of V ions which are concerning. For Cu ions large variations in the contribution to overall THQ values are observed for wines from Spain, Jordan and Macedonia with upper limits of circa 70, 60 and 40 respectively for females. Lower ranges are observed for the Cu ion-based THQ value for the other seven countries with all except Argentina being of concern (THQ>1).
The contributions to the overall THQ values made by Mn, Zn and Ni ions are all concerning with the range maximum greater than 20 for Czech, Spain and Serbia for Mn ions and Greece for Zn and Ni ions (Fig ). Comparatively minor contributions are made to the overall THQ values by Pb and Cr ions (< 1 in each case with Cr, data not shown). It is notable that apart from V, the levels of metal ions in wines from Argentina have low contributions to the THQ values.
Ranges of THQ values for wines by country of origin based on Mn, Ni, Zn and Pb content (blue: THQ for females, green: THQ for males).
The total combined THQ values for wines from each country were determined based on the ranges of metal ions tabulated by Pohl (Fig ) [21
]. Results are separated by gender and are presented as THQ values corresponding to the minimum and maximum of the range for each country. THQ values corresponding to the minimum ranges of metal ions are in the order wines from Portugal > Austria > France > Spain > Czech Republic > Hungary > Germany > Serbia. Only five countries do not have minimum levels of concern in terms of THQ values >1. The maximum THQ values exhibit a somewhat different pattern with wines in the order of country as Hungary >Slovakia > France > Austria > Spain > Germany > Portugal > Greece > Czech Republic > Jordan > Macedonia > Serbia. Wines from the first two countries have maximum ranges in potential THQ values above 350 with the next five having a potential THQ value > above 100. Notably only the Argentinean and Italian wines appraised do not feature with significant maximum THQ values.
Minimum and maximum THQ values calculated for the combined metal ion content for selected wines by country of origin.
It should be noted that the THQ estimation is a risk assessment designed to avoid underestimation of the risk. Thus, it incorporates several assumptions such as ingested quantities of metal ions correspond to the quantities that are absorbed [12
]. On the contrary, many metal ions have been shown to be hazardous but do not yet have an oral reference dose. In addition, bolus dosing (e.g. binge drinking) and cross effects with other potential toxins (e.g. alcohol) are not accounted for, nor are the effects on the elderly or on the young considered. In the same vein THQ values do not reflect genetic predispositions to disease or people with clinical or sub-clinical conditions.
As the pattern of metal ions analysed varied between studies, the THQ values were calculated for selected red and white wines as a function of the contribution of each metal ion. For this part of the study wines from Portugal and the Czech Republic were chosen as the reports from these countries separated values for levels of metals in red and white wines. Figure displays the THQ values arising from the V content in red and white wines from Portugal and the Czech Republic [22
]. For wines of Portuguese origin, the THQ values were determined as 43.4 and 53.9 (white wine) and 17.8 and 22.1 (red wine) for males and females respectively. The wines originating in the Czech Republic had THQ values based on V levels of 54.8 and 68.1 (white wine) and 47.8 and 59.4 (red wine) for males and females respectively. As expected the results for the contribution of Cu levels to the overall THQ values were considerably less ranging between 5 and < 1 for males.
THQ values calculated for red and white wines based on the V and Cu content (blue: THQ for males; red: THQ for females).
The contributions to overall THQ values resulting from levels of Mn, Zn, Ni and Pb are shown in Figure for red and white wines from Portugal and the Czech Republic. The contributions from Mn are similar for all four with Zn and Ni having a rather lower contribution with no risk associated with Pb. The total THQ values are high for all of the selected red and white wines from both countries, having values ranging from 30 to 80 for females based on a 250 mL glass per day.
THQ values calculated for red and white wines based on the Mn, Zn, Ni and Pb content (blue: THQ for males; red: THQ for females).
The results from this study also question a popular belief about the health-giving properties of red wine: that drinking red wine daily protects you from heart attacks is often related to levels of anti-oxidants. However the finding of hazardous levels of metal ions which can be pro-oxidants leads to a major question mark over the protective benefits of red wine.