• Users Online: 62
  • Print this page
  • Email this page


 
 
Table of Contents
ORIGINAL ARTICLE
Year : 2020  |  Volume : 8  |  Issue : 1  |  Page : 9-13

The effect of vitamin C on toxic metals, antioxidant minerals, oxidative stress, and lipid profile of automobile workers


1 Department of Chemical Pathology, Chukwuemeka Odumegwu Ojukwu University, Awka, Nigeria
2 Department of Chemical Pathology, Nnamdi Azikiwe University, Nnewi, Nigeria
3 Department of Human Biochemistry, Nnamdi Azikiwe University, Nnewi, Nigeria
4 Department of Chemical Pathology, School of Medical Laboratory Technicians, Iyienu Mission Hospital, Ogidi, Anambra, Nigeria

Date of Submission15-May-2020
Date of Decision24-May-2020
Date of Acceptance31-May-2020
Date of Web Publication30-Jun-2020

Correspondence Address:
Dr. Chikaodili Nwando Obi-Ezeani
Department of Chemical Pathology, Chukwuemeka Odumegwu Ojukwu University, Awka, Anambra
Nigeria
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/JIHS.JIHS_12_20

Rights and Permissions
  Abstract 


Context: Automobile workers (AMWs) are exposed to lots of toxic chemicals with associated adverse health consequences. The adverse health effects are mainly attributed to oxidative stress, however, antioxidant vitamins may aid in ameliorating these adverse effects. Aim: The aim of this study was to examine the effect of Vitamin C supplementation on toxic metals, antioxidant minerals, oxidative stress, and lipid profile of AMWs. Settings and Design: Twenty-nine AMWs and 30 controls aged 19–55 years were recruited for this study. Subsequently, 27 AMWs received 500 mg Vitamin C tablets daily for 2 months. Subjects and Methods: Five milliliters of fasting blood samples was collected before intervention and at 1- and 2-month intervals for biochemical analyses. Blood lead (Pb), cadmium (Cd), selenium (Se), and zinc (Zn) were analyzed using atomic absorption spectrophotometer, malondialdehyde (MDA) and total antioxidant capacity (TAC) were measured spectrophotometrically, total cholesterol (TC), high-density lipoprotein (HDL), and triglyceride (TG) were measured enzymatically, whereas MDA/TAC, low-density lipoprotein (LDL), very LDL (VLDL), and non-HDL (nHDL) were calculated. Statistical Analysis: Data were analyzed, and statistical significance was set at P < 0.05. Results: The mean levels of Pb, Cd, MDA, MDA/TAC ratio, TC, LDL, VLDL, TG, and nHDL were significantly higher, whereas Se and Zn were significantly lower in AMWs compared to controls (P < 0.05). After 2 months of supplementation, Pb and TG levels decreased significantly, whereas Se, Zn, and HDL levels increased significantly compared to their values at 1 month and baseline (P < 0.05). MDA, MDA/TAC, TC, LDL, VLDL, and nHDL decreased progressively, whereas TAC level increased progressively from baseline to 2 months of Vitamin C intake (P < 0.05). Conclusion: Vitamin C reduced blood lead and oxidative stress, improved antioxidant defense, and may modulate dyslipidemia and adverse cardiovascular outcomes in AMWs.

Keywords: Antioxidant, lipid profile, oxidative stress, toxic metals, Vitamin C


How to cite this article:
Obi-Ezeani CN, Dioka CE, Meludu SC, Onuora IJ. The effect of vitamin C on toxic metals, antioxidant minerals, oxidative stress, and lipid profile of automobile workers. J Integr Health Sci 2020;8:9-13

How to cite this URL:
Obi-Ezeani CN, Dioka CE, Meludu SC, Onuora IJ. The effect of vitamin C on toxic metals, antioxidant minerals, oxidative stress, and lipid profile of automobile workers. J Integr Health Sci [serial online] 2020 [cited 2020 Sep 30];8:9-13. Available from: http://www.jihs.in/text.asp?2020/8/1/9/288681




  Introduction Top


Automobile workers (AMWs) are occupationally exposed to an array of hazardous substances including toxic metals, heavy metal contaminated dust, fumes, and polycyclic aromatic hydrocarbons [1] which adversely affect their health by altering various biological and biochemical processes; these adverse health effects are mainly attributed to oxidative stress. Oxidative stress is an imbalance between oxidants and antioxidants which could result to various pathological conditions including cancers, cardiovascular diseases, and others. These toxic chemicals or substances are known to increase the generation of reactive oxygen species (ROS) and consequently oxidation of biomolecules including proteins, lipids, and nucleic acids. Lipid peroxidation which enhances oxidative stress as well as altered lipid parameters is known to increase the risk of cardiovascular diseases (CVDs), however, dietary supplements including antioxidant vitamins may play a vital role in the prevention or reduction of CVD risk in this group of workers.

VC, also known as ascorbic acid, is naturally present in many fruits and vegetables such as oranges, watermelon, pineapple, and grapefruit and also available as a dietary supplement in the form of tablets, capsules, or suspensions. It is a vital nutrient and antioxidant that scavenges free radicals, protecting against oxidative damage. VC is one of the essential vitamins in humans since they lack the enzyme L-gulonolactone oxidase required in the last step of its synthetic pathway.[2] Vitamin C may help prevent or delay the development of some diseases in which oxidative stress plays a causal role by limiting the damaging effects of the free radicals through its antioxidant activity.

Since oxidative stress and dyslipidemia are contributing factors to the development of cardiovascular disorders (CVDs), maintenance of appropriate antioxidant status, lipids and lipoprotein levels as well as reduction of oxidative stress, especially in high-risk individuals, is paramount. Studies have evaluated VC effect on some biochemical parameters in apparently healthy individuals and certain disease conditions, however, none has been carried out on AMWs. This study, therefore, examined the levels of toxic metals, antioxidant minerals, oxidative stress markers, and lipid profile of AMWs and the subsequent effect of VC supplementation.


  Subjects and Methods Top


Study participants and design

Fifty-nine male individuals aged between 19 and 55 years made up of 29 AMWs and 30 age-matched occupationally unexposed controls in Emene, Enugu, were recruited for this study. The AMWs were recruited on voluntary basis after written informed consent was obtained. Subsequently, 27 out of the 29 workers received 500 mg Vitamin C tablets (Mason Natural, USA) daily for a period of 2 months.

Blood sample collection

Five milliliters of fasting blood samples was collected from all participants before the intervention and at 1- and 2-month intervals for biochemical analyses. 3 mL of the blood sample was transferred into K2EDTA tubes for blood lead (Pb), cadmium (Cd), selenium (Se) and zinc (Zn) analysis while 2 mL was transferred into plain tubes and centrifuged. The sera obtained were then used for malondialdehyde (MDA), total antioxidant capacity (TAC), total cholesterol (TC), high-density lipoprotein (HDL) and triglyceride (TG) analysis. Low-density lipoprotein (LDL), very LDL (VLDL) were estimated.

Inclusion/exclusion criteria

Apparently healthy consenting male participants aged 19–55 years who have worked in the automobile workshop for 1 year or more were included in the study, whereas participants with any history of chronic diseases such as diabetes and heart disease or on any vitamin, mineral, herbal supplement, or lipid-lowering drugs were excluded from the study.

Ethical consideration

This study was approved by Nnamdi Azikiwe University Teaching Hospital Research Ethics Committee with approval number NAUTH/CS/66/Vol.10/20/2017/021 and conformed to all the ethical requirements of the Helsinki Declaration.

Biochemical analyses

Blood metals (Pb and Cd) and trace elements (Se and Zn) analyses were conducted using Varian AA240 atomic absorption spectrophotometer (USA) according to the method of the American Public Health Association.[3]

MDA was determined using colorimetric method described by Gutteridge and Wilkins.[4] TAC was determined using ferric-reducing ability of plasma method as described by Benzie and Strain,[5] and MDA/TAC ratio was calculated. TC, HDL, and TG were determined by enzymatic colorimetric method as described by Roeschlaw et al.,[6] Grove,[7] and Fossati and Prencipe,[8] respectively. LDL and VLDL were estimated by calculation according to the formula given by Friedewald et al.[9] Non-HDL (nHDL) was estimated by calculating the difference between TC and HDL.

Statistical analysis

The Statistical Package for the Social Sciences (SPSS) version 23.0 (SPSS Inc, Chicago, IL, USA) was used for statistical analysis. The variables were expressed as mean ± standard deviation; the independent Student's t-test and paired t-test were used to assess the mean difference between two unrelated and related variables, respectively. The level of significance was considered at P < 0.05.


  Results Top


In [Table 1], the mean blood Pb, Cd, and serum MDA and MDA/TAC ratio were significantly higher, whereas the mean blood Se and Zn were significantly lower in the AMWs when compared to the control group (P < 0.05). The mean serum TAC level in the AMWs did not differ significantly from the controls (P = 0.072).
Table 1: Toxic metals, antioxidant minerals, and oxidative stress markers of automobile workers and controls

Click here to view


In [Table 2], the mean levels of TC, LDL, VLDL, TG, and nHDL were significantly higher in the AMWs when compared to the controls (P < 0.05), however, the mean HDL level in the AMWs was not significantly different from the controls (P = 0.321).
Table 2: Lipid profile parameters of automobile workers and controls

Click here to view


In [Table 3], the blood Pb, Cd, Se, and Zn levels after 1 month of Vitamin C supplementation did not differ significantly from their baseline values (P > 0.05). However, after 2 months of supplementation, the mean blood Pb level decreased significantly, whereas the mean Se and Zn levels increased significantly (P < 0.05) compared to their values at 1 month and baseline. The mean levels of blood Cd did not differ significantly from baseline to 2 months of Vitamin C intake (P > 0.05). The mean levels of MDA and MDA/TAC ratio decreased progressively, whereas the mean TAC level increased progressively from baseline to 2 months of Vitamin C intake.
Table 3: Toxic metals, antioxidant minerals, and oxidative stress markers of automobile workers at different stages of Vitamin C supplementation

Click here to view


In [Table 4], the mean levels of TC, LDL, VLDL, and nHDL decreased progressively from baseline to 2 months of Vitamin C intake. The mean levels of HDL and TG after 1 month of Vitamin C supplementation did not differ significantly from their baseline values (P = 0.266 and P = 0.052, respectively), however, HDL level increased significantly, whereas TG decreased significantly after 2 months of supplementation when compared to their values at 1 month and baseline (P < 0.05).
Table 4: Lipid profile parameters of automobile workers at different stages of Vitamin C supplementation

Click here to view



  Discussion Top


The present study examined the levels of toxic metals, antioxidant minerals, oxidative stress markers, and lipid profile of AMWs and the subsequent effect of Vitamin C supplementation. Higher blood lead and cadmium levels were observed in the AMWs, which suggest higher exposure of this group of workers to these toxic metals. These findings correspond with those of Bal et al.[10] and Obi-Ezeani et al.[11] who also reported a similar increase in blood lead and cadmium levels, respectively, in humans occupationally exposed to these toxic metals.

Lead and cadmium have been reported to alter biochemical indices [12] and consequently disrupting various biochemical processes including antioxidant defense system through inhibition of various enzymes as well as displacement of antioxidant minerals resulting in oxidative stress which triggers the adverse health outcomes. Accordingly, the present study showed significant alterations in the measured biochemical indices of AMWs which may have possibly resulted from exposure to these metals.

The lower levels of blood selenium and zinc in the AMWs observed in this study may be attributed to the ability of the toxic metals to displace or interfere with the metabolism of these antioxidant minerals otherwise known as trace elements [13] at various levels including intestinal absorption, distribution in tissues, and biological functions.[14] This corresponds with the reports of Dioka et al.[15] and Basu et al.[16] who, respectively, observed significant reductions in blood zinc and selenium levels in workers exposed to lead. Adejumo et al.[17] in their study on occupationally exposed automotive workers in Benin City, however, reported a higher blood zinc level which they attributed to inhalation of welding fumes containing zinc oxide during welding of galvanized materials or oral intake of contaminated foods in the auto repair workshops.

These antioxidant minerals form vital components of the antioxidant enzymes, and as such, reductions in these essential elements invariably result in the inhibition of antioxidant enzymes and consequently excessive production of ROS, oxidative stress, and tissue damage.[18]

This study also observed higher MDA and MDA/TAC ratio in the AMWs which is suggestive of oxidative stress in these workers. MDA is a product of lipid peroxidation, whereas TAC measures the cumulative antioxidant activity in a biological sample, and both were used to evaluate the oxidative stress level in these workers. MDA/TAC ratio was used as an index of oxidative stress status.[19] Although the TAC level did not differ from the controls, the elevated MDA level may indicate lipid peroxidation from enhanced generation of ROS which impairs the antioxidant system [20] as evidenced by the higher MDA/TAC ratio observed in these workers. Adekola et al.[21] had earlier reported a similar increase in MDA levels in male automechanics in Ibadan, Nigeria.

Significant elevations in the levels of TC, LDL, VLDL, TG, and nHDL were also observed in the AMWs, and this may be attributed to the adverse effects of lead and cadmium on lipid metabolism [22] as they have been shown to alter normal lipid and lipoprotein fractions through lipid peroxidation,[23] thereby increasing the risk of CVD in these workers. It may equally be attributed to the ability of these metals to enhance the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme in cholesterol biosynthesis, thereby enhancing cholesterol synthesis. Studies on exposure to these toxic metals have equally demonstrated similar alterations in lipid profile parameters.[24],[25]

This study recorded a significant reduction in blood lead level in the AMWs after 2 months of Vitamin C intake, and this reduction may be attributed to increased urinary elimination of lead which subsequently reduces blood and tissue levels of this metal. Blood cadmium levels were, however, not altered by Vitamin C supplementation, and this may probably be due to the inability of the given dose (500 mg) to effectively reduce the metal ions in blood, or that Vitamin C may not be an appropriate agent for the reduction of blood cadmium in the exposed persons.

Vitamin C supplementation was also found to increase the blood selenium and zinc levels in these workers after 2 months of intake, and this may be related to the action of this antioxidant vitamin in reducing the blood lead level in the AMWs and subsequently increasing the levels of these trace elements. Other researchers likewise reported that Vitamin C enhances the expression of antioxidant enzyme activity,[26],[27] which possibly increased zinc and selenium levels.

Vitamin C supplementation equally improved oxidative stress markers in the AMWs as depicted in the progressive reduction in serum levels of MDA and MDA/TAC ratio with a corresponding increase in serum TAC level from baseline to 2 months as observed in this study. This may be due to the antioxidant nature of this vitamin which acts by forming less reactive compounds with ROS or reducing free radical reactions, oxidative stress, and lipid peroxidation and consequently improving antioxidant status.[28] The findings from this study are in agreement with the reports of El-Tohamy and El-Nattat [29] who reported a protective effect of Vitamin C against heavy metal-induced oxidative stress.

The present study also recorded significant reductions in the elevated serum levels of TC, LDL, VLDL, and nHDL after 1 and 2 months of Vitamin C supplementation. Serum TG and HDL levels, however, reduced and increased, respectively, after 2 months in the AMWs. These results indicate that Vitamin C may be involved in the maintenance of normal lipid and lipoprotein levels which could be attributed to its ability to activate 7α-hydroxylase, the enzyme that enhances the conversion of plasma cholesterol to bile acid, and subsequently improving cholesterol levels.[30] The reduced serum TG level may be from enhanced uptake and removal of VLDL from plasma which is facilitated by this vitamin.[31]


  Conclusion Top


This study, therefore, suggests that Vitamin C may represent a potential dietary supplement for reducing blood lead and oxidative stress, improving antioxidant defense, and modulating dyslipidemia and adverse cardiovascular outcomes in AMWs.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Khan AA, Safeena I, Idrees M, Dad A, Gul K, Akbar H. Effect of automobile workshop on the health status of automechanics in N.W.F.P. Pakistan. Afr J Environ Sci Technol 2010;4:192-200.  Back to cited text no. 1
    
2.
Nishikimi M, Yagi K. Molecular basis for the deficiency in humans of gluconolactone oxidase, a key enzyme for ascorbic acid biosynthesis. Am J Clin Nutr 1991;54:12035-85.  Back to cited text no. 2
    
3.
American Public Health Association. Direct Air-Acetylene Flame Method Standard Methods for the Examination of Metals in Blood. 20th ed. Washington DC: American Public Health Association; 1995.  Back to cited text no. 3
    
4.
Gutteridge JM, Wilkins S. Copper dependent hydroxyl radical damage to ascorbic acid reactive products. FEBS Lett 1982;137:327-30.  Back to cited text no. 4
    
5.
Benzie IF, Strain JJ. The ferric reducing ability of plasma (FRAP) as a measure of “antioxidant power”: The FRAP assay. Anal Biochem 1996;239:70-6.  Back to cited text no. 5
    
6.
Roeschlaw P, Bernt E, Gruber JW. Enzymatic determination of total cholesterol in serum. J Clin Chem Clin Biochem 1974;12:226-403.  Back to cited text no. 6
    
7.
Grove TH. Effect of reagent pH on determination of HDL-C by precipitation with sodium- phosphotungstate-magnesium. Clin Chem 1979;25:560.  Back to cited text no. 7
    
8.
Fossati P, Prencipe L. Serum triglycerides determined colorimetrically with an enzyme that produces hydrogen peroxide. Clin Chem 1982;28:2077-80.  Back to cited text no. 8
    
9.
Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem 1972;18:499-502.  Back to cited text no. 9
    
10.
Bal C, Buyuksekerci M, Alaguney ME, Gunduzoz M, Hocaoglu A, Gungor OY, et al. The trace element pattern in occupational lead exposed workers. The Turk J Occup Environ Med Saf 2015;2:20.  Back to cited text no. 10
    
11.
Obi-Ezeani CN, Dioka CE, Meludu SC, Onuora IJ, Usman SO. Effect of green tea supplementation on blood cadmium and male sex hormone levels in automobile workers in Emene, Enugu State, Nigeria. J Adv Med Med Res 2018;27:1-7.  Back to cited text no. 11
    
12.
Orisakwe OE, Nwachukwu E, Osadolor HB, Afonne OJ, Okocha CE. Liver and kidney function tests amongst paint factory workers in Nkpor, Nigeria. Toxicol Ind Health 2007;23:161-5.  Back to cited text no. 12
    
13.
Matović V, Buha A, Bulat Z, Dukić-Ćosić D. Cadmium toxicity revisited: Focus on oxidative stress induction and interactions with zinc and magnesium. Arh Hig Rada Toksikol 2011;62:65-76.  Back to cited text no. 13
    
14.
Al-Fartosy AJM, Shanan SK, Awad NK. Biochemical study of the effects of some heavy metals on oxidant/antioxidant status in gasoline station workers, Basra-Iraq. Int J Sci Res Publ 2017;7:83-93.  Back to cited text no. 14
    
15.
Dioka CE, Orisakwe OE, Adeniyi FA, Meludu SC. Liver and renal function tests in artisans occupationally exposed to lead in mechanic village in Nnewi, Nigeria. Int J Environ Res Public Health 2004;1:21-5.  Back to cited text no. 15
    
16.
Basu R, Biswas A, Biswas K, Mukhopadhyay A, Talapatra SN, Ray SS, et al. An attempt to search the health status of garage workers – A neglected part in India. Int J Adv Res 2015;3:1466-71.  Back to cited text no. 16
    
17.
Adejumo BI, Isu MO, Uchuno GA, Dimkpa U, Emmanuel A, Oke OM, et al. Serum levels of lead, zinc, cadmium, copper and chromium among occupationally exposed automotive workers in Benin City. Int J Environ Pollut Res 2017;5:70-9.  Back to cited text no. 17
    
18.
Ahamed M, Siddiqui MK. Low level lead exposure and oxidative stress: Current opinions. Clin Chim Acta 2007;383:57-64.  Back to cited text no. 18
    
19.
Kocyigit A, Armutcu F, Gurel A, Ermis B. Alterations in plasma essential trace elements selenium, manganese, zinc, copper, and iron concentrations and the possible role of these elements on oxidative status in patients with childhood asthma. Biol Trace Elem Res 2004;97:31-41.  Back to cited text no. 19
    
20.
Flora G, Gupta D, Tiwari A. Toxicity of lead: A review with recent updates. Inter Discip Toxicol 2012;5:47-58.  Back to cited text no. 20
    
21.
Adekola SA, Charles-Davies MA, Onifade AA, Okoli SU. Oxidative stress biomarkers and their relationship with male automechanics in Ibadan, Nigeria. Br J Med Med Res 2016;12:1-11.  Back to cited text no. 21
    
22.
Zhou Z, Lu YH, Pi HF, Gao P, Li M, Zhang L, et al. Cadmium Exposure is Associated with the Prevalence of Dyslipidemia. Cell Physiol Biochem 2016;40:633-43.  Back to cited text no. 22
    
23.
Olisekodiaka MJ, Igbeneghu CA, Onuegbu AJ, Oduru R, Lawal AO. Lipid, lipoproteins, total antioxidant status and organ changes in rats administered high doses of cadmium chloride. Med Princ Pract 2012;21:156-9.  Back to cited text no. 23
    
24.
Sharmar SV, Kumar P, Atam V, Verma A, Murthy RC. Lipid profiles with increased blood lead levels: Risk of cardiovascular disease in battery workers of Lucknow City. J Indian Acad Forensic Med 2012;34:328-31.  Back to cited text no. 24
    
25.
Obi-Ezeani CN, Dioka CE, Meludu SC, Onuora IJ, Usman SO, Onyema-Iloh OB. Blood pressure and lipid profile in automechanics in relation to lead exposure. Indian J Occup Environ Med 2019;23:28-31.  Back to cited text no. 25
[PUBMED]  [Full text]  
26.
Kathore V, Shete AN, Zingade US, Bansode DG. The effect of Vitamin C on serum superoxide dismutase and blood sugar levels in type 2 diabetes mellitus. Int J Health Sci Res 2014;4:94-100.  Back to cited text no. 26
    
27.
Assaikkutti A, Bhavan PS, Vimala K, Karthik M, Cheruparambath P. Effect of different levels dietary Vitamin C on growth performance, muscle composition, antioxidant and enzyme activity of fresh water prawn, Macrobrachium macolmsonii. Aquacult Rep 2016;3:229-36.  Back to cited text no. 27
    
28.
Ghanwat G, Patil AJ, Patil J, Kshirsagar M, Sontakke A, Ayachit RK. Effect of Vitamin C supplementation on blood lead level, oxidative stress and antioxidant status of battery manufacturing workers of Western Maharashtra, India. J Clin Diagn Res 2016;10:BC08-11.  Back to cited text no. 28
    
29.
El-Tohamy MM, El-Nattat WS. Effect of antioxidant on lead-induced oxidative damage and reproductive dysfunction in male rabbits. J Am Sci 2010;6:264-72.  Back to cited text no. 29
    
30.
Eteng MU, Ibekwe HA, Amatey TE, Bassey BJ, Uboh FU, Owu DU. Effect of Vitamin C on serum lipids and electrolyte profile of albino Wistar rats. Niger J Physiol Sci 2006;21:15-9.  Back to cited text no. 30
    
31.
Hasegawa N, Niimi N, Odani F. Vitamin C is one of the lipolytic substances in green tea. Phytother Res 2002;16 Suppl 1:S91-2.  Back to cited text no. 31
    



 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

Top
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
Abstract
Introduction
Subjects and Methods
Results
Discussion
Conclusion
References
Article Tables

 Article Access Statistics
    Viewed593    
    Printed37    
    Emailed0    
    PDF Downloaded72    
    Comments [Add]    

Recommend this journal