Journal of Indira Gandhi Institute Of Medical Sciences

: 2019  |  Volume : 5  |  Issue : 2  |  Page : 144--146

Study of ascorbic acid levels in hypothyroid patients

Ranjana Kumari1, Poonam Sinha1, Ravi Shekhar2,  
1 Junior Resident, Dept. of Biochemistry, IGIMS, Patna, Bihar, India
2 Associate Professor, Dept. of Biochemistry, IGIMS, Patna, Bihar, India

Correspondence Address:
Ravi Shekhar
Associate Professor, Dept. of Biochemistry, IGIMS, Patna


Introduction : Ascorbic acid has role in wound healing, collagen formation, enzymatic action, anti-oxidants, hormone action, synthesis of neurotransmitters etc. Thyroid hormone regulates a wide range of genes and plays a crucial role in the regulation of mitochondrial oxidative metabolism. Disorders of thyroid hormones, overt hyperthyroidism and hypothyroidism represent opposite clinical conditions. Increased concentrations of thyroid hormones result in increased production of large quantities of reactive oxygen species which enhance oxidative stress, even low concentration of thyroid hormone ie hypothyroidism has been associated with increased oxidative stress, but is controversial. This study was aimed to correlate the ascorbic acid level in patients of thyroid disorder. Material and methods : The blood samples of 150 patients were collected after the analysis of thyroid profile. The samples of the patients in the study were categorized in three groups- euthyroid, subclinical hypothyroid and overt hypothyroid based on free T3, free T4 and thyroid stimulating hormone (TSH). The ascorbic acid was estimated using 2,4-Dinitrophenyl hydrazine method. Result : The ascorbic acid levels in the patients of hypothyroid disorder was ranging from 0.43-2.60 mg/dl Conclusion : There was no correlation observed between ascorbic acid and hypothyroid disorders in the study. The dietary intake of ascorbic acid in the study group must be adequate.

How to cite this article:
Kumari R, Sinha P, Shekhar R. Study of ascorbic acid levels in hypothyroid patients.J Indira Gandhi Inst Med Sci 2019;5:144-146

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Kumari R, Sinha P, Shekhar R. Study of ascorbic acid levels in hypothyroid patients. J Indira Gandhi Inst Med Sci [serial online] 2019 [cited 2023 Mar 21 ];5:144-146
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Full Text

 Introduction :

Ascorbic acid is an essential vitamin for a variety of biological functions, like pro-oxidants, anti-oxidants, anti carcinogenic effect, activation of genes controlling several cellular transduction pathways in hypoxia, hydroxylation of amino acid residues in formation of collagen etc.[1] Oxidative stress plays a pivotal role in cellular injury. Weak defence system of the body becomes unable to counteract the enhanced reactive oxygen species generation.[2] Both hypo and hyperthyroidism promote cellular oxidative stress by influencing the intensity of oxygen reactions.[3],[4] Studies suggest that tissues may be protected from oxidant damage because of a hypo-metabolic state in hypothyroidism, but few report suggested increased oxidative stress in hypothyroidism.[5] Thus, the depletion or deficiency of anti-oxidants contributes to oxidative stress.[6]

Vitamin deficiencies are not common nowadays as these are most common food supplements. Despite the widespread availability of vitamins, their health impact knowledge, the role in the prevention and treatment of disease remain insufficiently understood.[3] Thus, the aim of the study was to evaluate ascorbic acid level and correlate it in hypothyroid patients.

 Materials and Methods :

The patients of both genders with age group 18 to 60 years requiring thyroid profile estimation attending biochemistry lab, IGIMS, Patna were included in the study. 4ml blood sample was collected in red vaccutainer. The patient’s serum was analyzed for total T3, total T4, FT3, FT4, TSH and ascorbic acid. Thyroid hormones were estimated by chemiluminescent immuno assay (CLIA) on Beckmann Coulter Access 2. The estimation of Ascorbic acid was done by 2,4-Dinitrophenyl hydrazine method (DNPH method). Ascorbic acid is oxidized by copper to form dehydroascorbic acid and diketogulonic acid. These products are treated with 2, 4, DNPH to form the derivative bis-2, 4-dinitrophenylhydrazone. This compound, in strong sulphuric acid, undergoes rearrangement to form a product with an absorption that is measured at 520 nm. The reaction is run in the presence of thiourea to provide a mildly reducing medium, which helps to prevent interference from non-ascorbic acid chromogen.[7]

The patients with TSH levels 0.35 to 5.49μIU/ml was considered as euthyroid, from 5.5μIU/ml to 10μIU/ml with free T3 & free T4 within normal range, were considered as subclinical hypothyroid patients. The patients with elevated TSH level (>10 μIU/ml) with decreased both free T3 & free T4 levels and either of the two were considered as overt hypothyroid patients. The history of patients with elevated TSH levels was taken individually to correlate the findings. Patients with infections, drug allergy, hepatic, renal, cardiac morbidity were not included in the study.


One hundred and fifty patients, comprising of 56 males and 94 females were included in the study. The male and female ratio was found to be 1:1.67. The mean age of patients in the study was 42.54 ± 13.61 years and mode was 60 years. The mean TSH value of the patients of euthyroid, sub-clinical hypothyroid and overt hypothyroid groups averaged 3.87μIU/ml, 6.88μIU/ml and 24.88μIU/ml respectively. The data was analyzed on MS excel 2007.

The serum ascorbic acid ranged from 0.6-2.0 mg/dl. In the study, the levels of ascorbic acid ranged from 0.43 - 2.60 mg/dl. The average value of ascorbic acid in euthyroid, subclinical hypothyroid and overt hypothyroid patients was 1.17 mg/dl, 1.27 mg/dl and 1.53 mg/dl respectively.{Figure 1}{Figure 2}{Figure 3}

 Discussion :

Ascorbic acid is a water soluble free radical scavenger act as non enzymatic anti-oxidants. It acts directly on O2 and OH-with the formation of semi dehydro-ascorbate (free radical) that is subsequently reduced by glutathione to generate dehydro-ascorbate and also neutralise several oxidants of blood.[4],[8] To reduce or control the delirious effect of free radicals, nature has provided human being with a set of anti oxidants. Anti-oxidant even at low concentration delays or inhibits the oxidation of substances. Thyroid hormones function by activating metabolism and promoting mitochondrial utilization of oxygen leading to excess generation of free radical. In hyperthyroid disorders, which are hyper-metabolic state, thyroid hormones promote mitochondrial oxygen utilization leading to excess generation of free radical. Hypothyroidism is a hypometabolic state with reduced utilisation of oxygen. There are multiple pathways for generation of oxidative stress like dyslipidemia, lipid peroxidation, protein glycation, autoimmunity and low grade inflammation.[9] The oxidative stress should be elevated in both hyperthyroid and hypothyroid disorders. Hypothyroidism influences the endothelial changes and it is predisposed by low level of ascorbic acid.[10] Decreased generation of oxidative stress was reported by many authors.[11],[12] All these reports strengthened the previous notion that hypothyroidism is associated with decreased oxidative stress.[9] but there is controversies regarding the presence of oxidative stress in hypothyroidism. Experiments on rats have proven that ascorbic acid has effect on thyroid activity, low dose stimulate and high dose inhibit the thyroid activity.[13] The level of anti-oxidant was mainly assessed in experimental hypothyroidism or in hyperthyroid patients. While comparing its levels with euthyroid and hypothyroid individuals, the report suggested a decreased antioxidant levels in hypothyroidism. The rise in anti oxidants in hyperthyroidism was deduced as a response to increase in oxidative stress. A lack of rise in anti-oxidant was implied as a consequence of reduced oxidative stress in hypothyroidism.[14]

Ascorbic acid is able to restore thyroid function by reducing the oxidative stress but, there is controversies regarding presence of oxidative stress in hypothyroidism. The treatment of hypothyroidism with antioxidant supplementation gives good result.

A study on benign thyroid disorder reported no association in the levels of ascorbic acid with TSH.[10] The mechanism of ascorbic acid in improvement of circulating levels of TSH and thyroid hormone is not known. But, study on hypothyroid patients associated with gastro intestinal pathology demonstrated it to help in the improving the management.[15] Ascorbic acid is able to restore thyroid function to normal in heavy metal intoxication, cadmium and lead , by preventing heavy metal induced decrease T3 and hepatic 5’ deiodination. Most of the studies suggest that Ascorbic acid has no association on hypothyroidism.[16]

 Conclusion :

Ascorbic acid has no relation on thyroid hormone levels in the study. This may be due to intake of sufficient amount of ascorbic acid in diet of the patients in the study group. The study should be conducted in larger sample size with different socio-economic strata for better result.


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