The metal ion theory of ageing: dietary target hazard quotients beyond radicals

Metabolomics Signatures of Aging: Recent Advances

Metabolomics is the latest state-of-the-art omics technology that provides a comprehensive quantitative profile of metabolites. The metabolites are the cellular end products of metabolic reactions that explain the ultimate response to genomic, transcriptomic, proteomic, or environmental changes. Aging is a natural inevitable process characterized by a time-dependent decline of various physiological and metabolic functions and are dominated collectively by genetics, proteomics, metabolomics, environmental factors, diet, and lifestyle. The precise mechanism of the aging process is unclear, but the metabolomics has the potential to add significant insight by providing a detailed metabolite profile and altered metabolomic functions with age. Although the application of metabolomics to aging research is still relatively new, extensive attempts have been made to understand the biology of aging through a quantitative metabolite profile. This review summarises recent developments and up-to-date information on metabolomics studies in aging research with a major emphasis on aging biomarkers in less invasive biofluids. The importance of an integrative approach that combines multi-omics data to understand the complex aging process is discussed. Despite various innovations in metabolomics and metabolite associated with redox homeostasis, central energy pathways, lipid metabolism, and amino acid, a major challenge remains to provide conclusive aging biomarkers.

Heavy Metals in Seafood and Farm Produce from Uyo, Nigeria: Levels and health implications

OBJECTIVES

This study aimed to obtain representative data on the levels of heavy metals in seafood and farm produce consumed by the general population in Uyo, Akwa Ibom State, Nigeria, a region known for the exploration and exploitation of crude oil.

METHODS

In May 2012, 25 food items, including common types of seafood, cereals, root crops and vegetables, were purchased in Uyo or collected from farmland in the region. Dried samples were ground, digested and centrifuged. Levels of heavy metals (lead, cadmium, nickel, cobalt and chromium) were analysed using an atomic absorption spectrophotometer. Average daily intake and target hazard quotients (THQ) were estimated.

RESULTS

Eight food items (millet, maize, periwinkle, crayfish, stock fish, sabina fish, bonga fish and pumpkin leaf) had THQ values over 1.0 for cadmium, indicating a potential health risk in their consumption. All other heavy metals had THQ values below 1.0, indicating insignificant health risks. The total THQ for the heavy metals ranged from 0.389 to 2.986. There were 14 items with total THQ values greater than 1.0, indicating potential health risks in their consumption.

CONCLUSION

The regular consumption of certain types of farm produce and seafood available in Uyo, Akwa Ibom State, Nigeria, is likely adding to the body burden of heavy metals among those living in this region.

Metal concentrations in selected brands of canned fish in Nigeria: estimation of dietary intakes and target hazard quotients

The concentrations of metals (Cd, Pb, Ni, Cr, Cu, Co, Fe, Mn, and Zn) were determined in selected brands of canned mackerel, sardine, and tuna in Nigeria with a view to providing information on the dietary intakes of metals and lifelong health hazards associated with the consumption of these products. The concentrations of metals were determined by using atomic absorption spectrometry after acid digestion. The mean concentrations of metals in canned mackerel, sardine, and tuna were found as 0.04-0.58, 0.06-0.44, 0.32-0.83 μg/g for Cd; 0.05-2.82, 0.70-2.98, 0.23-2.56 μg/g for Pb, 1.33-11.33, <0.20-17.53, nd-34.2 μg/g for Ni, 0.49-3.79, 0.22-1.89, 0.66-14.39 μg/g for Cr, 0.33-0.92, 0.03-1.51, <0.08-1.31 μg/g for Cu, 0.11-2.17, nd-0.75, 0.14-0.50 μg/g for Co, 6.45-26.90, 6.06-53.54, 3.06-95.78 μg/g for Fe, 2.30-3.84, 0.95-21.78, 1.65-2.33 μg/g for Mn, 1.15-7.19, 3.60-17.88, 1.21-5.35 μg/g for Zn, respectively. The mean concentrations of Cd, Pb, and Fe in some of these brands of canned fish were above their permissible limits while other metals occurred at levels below their permissible limits. The estimated daily intakes of metals from consumption of 20.8 g fish per day by a 60 kg body weight adult were below the provisional tolerable daily intakes for Cd, Pb, Ni, Cr, and Cu and recommended daily intakes for Co, Fe, Mn, and Zn. The estimated target hazard quotients of the examined metals were less than 1 in the majority of the samples indicating no long-term health hazard at the present circumstance.

A survey of metal profiles in some traditional alcoholic beverages in Nigeria

The concentrations of Cd, Pb, Ni, Cr, Cu, Co, Fe, Mn, Zn, Mg, Ca, K, and Na were determined in some traditional alcoholic beverages (oil palm wine, raphia palm wine, burukutu, pito, ogogoro) consumed in southern Nigeria, with a view to providing information on the dietary intakes of essential metals and exposure of humans to toxic metals. The concentrations of these 13 elements were determined by atomic spectrometry after nitric acid/hydrogen peroxide digestion. The mean concentrations of the metals (mg/L) in the samples ranged from 0.02 to 0.05 for Cd; 0.01 to 0.19 for Pb; nd to 0.11 for Ni, nd to 0.15 for Cr; 0.09 to 0.60 for Cu; 0.01-0.08 for Co; 0.30 to 10.3 for Fe; 0.02 to 3.97 for Mn; 0.12 to 3.84 for Zn; 2.08 to 301.3 for Mg; 2.21 to 49.2 for Ca; 35.05 to 926.1 for K; 6.30-58.1 for Na. The mean concentrations of metals in these alcoholic beverages were below statutory limits for the metals in alcoholic beverages and were similar to concentrations found in other alcoholic beverages in the literature. The estimated daily intakes of metals from the consumption of these alcoholic beverages were less than 2% of the recommended dietary allowance values except for Cd and Pb. The individual and combined metals target hazard quotient values were less than 1 except for raphia palm wine and burukutu. From the estimated target hazard, no long life health concerns of metals are associated with the consumption of these alcoholic beverages.

Heavy metal ions in wines: meta-analysis of target hazard quotients reveal health risks

Background

Metal ions such as iron and copper are among the key nutrients that must be provided by dietary sources. Numerous foodstuffs have been evaluated for their contributions to the recommended daily allowance both to guide for satisfactory intake and also to prevent over exposure. In the case of heavy metal ions, the focus is often on exposure to potentially toxic levels of ions such as lead and mercury. The aim of this study is to determine target hazard quotients (THQ) from literature reports giving empirical levels of metal ions in table wines using the reference upper safe limit value. Contributions to the THQ value were calculated for seven metal ions along with total values for each wine.

Results

The THQ values were determined as ranges from previously reported ranges of metal ion concentrations and were frequently concerningly high. Apart from the wines selected from Italy, Brazil and Argentina, all other wines exhibited THQ values significantly greater than one indicating levels of risk. The levels of vanadium, copper and manganese had the highest impact on THQ measures. Typical potential maximum THQ values ranged from 50 to 200 with Hungarian and Slovakian wines reaching 300. THQ values for a sample of red and white wines were high for both having values ranging from 30 to 80 for females based on a 250 mL glass per day.

Conclusion

The THQ values calculated are concerning in that they are mainly above the safe level of THQ<1. It is notable that in the absence of upper safe limits, THQ values cannot be calculated for most metal ions, suggesting that further unaccountable risks are associated with intake of these wines.

Determination of metal ion content of beverages and estimation of target hazard quotients: a comparative study

Background

Considerable research has been directed towards the roles of metal ions in nutrition with metal ion toxicity attracting particular attention. The aim of this study is to measure the levels of metal ions found in selected beverages (red wine, stout and apple juice) and to determine their potential detrimental effects via calculation of the Target Hazard Quotients (THQ) for 250 mL daily consumption.

Results

The levels (mean ± SEM) and diversity of metals determined by ICP-MS were highest for red wine samples (30 metals totalling 5620.54 ± 123.86 ppb) followed by apple juice (15 metals totalling 1339.87 ± 10.84 ppb) and stout (14 metals totalling 464.85 ± 46.74 ppb). The combined THQ values were determined based upon levels of V, Cr, Mn, Ni, Cu, Zn and Pb which gave red wine samples the highest value (5100.96 ± 118.93 ppb) followed by apple juice (666.44 ± 7.67 ppb) and stout (328.41 ± 42.36 ppb). The THQ values were as follows: apple juice (male 3.11, female 3.87), stout (male 1.84, female 2.19), red wine (male 126.52, female 157.22) and ultra-filtered red wine (male 110.48, female 137.29).

Conclusion

This study reports relatively high levels of metal ions in red wine, which give a very high THQ value suggesting potential hazardous exposure over a lifetime for those who consume at least 250 mL daily. In addition to the known hazardous metals (e.g. Pb), many metals (e.g. Rb) have not had their biological effects systematically investigated and hence the impact of sustained ingestion is not known.