A Triple-blind randomized controlled trial on the effects of turmeric versus ginger on inflammatory biomarkers in patients with COVID-19

Abstract

Inflammation and immune mediators exacerbate COVID-19; turmeric and ginger possess antiviral and anti-inflammatory properties that may mitigate this response. This study compared the effects of turmeric and ginger on inflammatory markers in patients with COVID-19. This triple-blind randomized clinical trial enrolled 144 COVID-19 outpatients at Kowsar Hospital (Semnan, Iran) in 2021. Participants were randomly allocated to group C (turmeric), group G (ginger), or group P (placebo) using blocked randomization and consumed three 500 mg tablets daily for five days (15 tablets total). Inflammatory markers—lactate dehydrogenase (LDH), C-reactive protein (CRP), white blood cell count (WBC), and erythrocyte sedimentation rate (ESR)—were measured at baseline and on day 6. LDH and WBC levels did not differ significantly among groups (p = 0.349 and p = 0.663, respectively). Changes in CRP and ESR varied significantly across groups (p < 0.001), with greater reductions observed in the turmeric and ginger groups compared to the placebo group (p < 0.001), and no difference between the turmeric and ginger groups (CRP: p = 0.263; ESR: p > 0.99). Turmeric and ginger exerted equivalent anti-inflammatory effects; therefore, either agent may serve as a complementary therapy alongside standard treatment to reduce CRP and ESR in COVID-19 outpatients. Trial registration Iranian Registry of Clinical Trials, Trial No IRCT20120109008665N14. Registered 31/08/2021.

Introduction

The World Health Organization declared COVID-19 a global pandemic on March 11, 2020, marking it as a substantial threat to global public health¹. As of October 9, 2022, more than 626 million individuals in over 195 countries have been infected, and more than 6 million have died worldwide. In Iran, over 7 million cases and more than 486 thousand deaths have been reported².

Most infected individuals develop respiratory symptoms ranging from mild to moderate severity³. Diagnosis relies on clinical symptoms, and individuals presenting those symptoms are classified as suspected cases⁴. Laboratory findings also help confirm the diagnosis. Elevated liver enzymes accompany changes in complete blood count in 37% of patients, as well as increased erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), serum ferritin, and interleukin-6 levels. Many patients also exhibit elevated D-dimer, lactate dehydrogenase (LDH), creatine kinase (CK), alanine aminotransferase (ALT), and aspartate aminotransferase (AST)^5–7.

Several factors predict poor prognosis in COVID-19, including lymphopenia, thrombocytopenia, and elevated inflammatory markers such as interleukin-6, ferritin, and ESR^7–9. Inflammatory and immune mediators exacerbate COVID-19, and enhancing immune function represents a therapeutic goal⁵. Therapeutic approaches draw on similarities between SARS-CoV-2 and related coronaviruses, yet robust clinical evidence for effective COVID-19 treatments remains lacking⁵.

Identifying natural compounds with well-characterized mechanisms, interactions, and safety profiles for the prevention and treatment of COVID-19 is crucial. Studies have suggested that natural compounds such as curcumin and ginger possess activity against SARS-CoV-2¹⁰. Supplementation with medicinal natural products, either alone or in combination with conventional therapies, may harness antiviral and anti-inflammatory properties to enhance host immunity and alleviate symptoms of upper respiratory tract infections^11,12.

Turmeric and ginger are notable for their antiviral and anti-inflammatory properties^13,14 and have garnered research interest due to their accessibility and ease of administration. Turmeric, the dried rhizome powder of Curcuma longa, has long served as a medicinal agent or supplement in Asia. More than 300 preclinical studies have demonstrated the safety and potential benefits of curcumin^15,16. Curcumin exhibits anti-inflammatory¹⁷, anticancer¹⁸, antioxidant¹⁷, and antidepressant properties¹⁹ and has demonstrated antiviral activity against HIV, hepatitis C virus, human cytomegalovirus, Epstein–Barr virus, and influenza A virus²⁰.

Previous studies also linked curcumin to antiviral effects against the 2003 SARS-CoV²¹. Given the more than 80% genomic similarity between SARS-CoV and SARS-CoV-2, curcumin’s potential efficacy against COVID-19 is enhanced²². Zahedipour et al. suggested that curcumin may reduce COVID-19 symptoms by inhibiting viral activity, modulating inflammatory and immune responses, accelerating the resolution of pulmonary edema, and influencing fibrosis pathways²³. Curcumin also exerts anticoagulant effects via anti-platelet aggregation; as SARS-CoV-2 infection can trigger disseminated intravascular coagulation, curcumin may mitigate this complication²⁴.

Ginger (Zingiber officinale Roscoe; Zingiberaceae) belongs to the same plant family as turmeric and cardamom²⁵ and has been investigated for antimicrobial, antiviral, anticancer, antioxidant, antidiabetic, nephroprotective, hepatoprotective, analgesic, anti-inflammatory, and immunomodulatory effects attributed to its phenolic constituents^26,27. Although its anti-inflammatory mechanisms remain unclear, ginger’s anti-inflammatory properties may confer health benefits. Ginger also contains anti-influenza factors; for example, it induces tumor necrosis factor-alpha (TNF-α), a recognized anti-influenza cytokine²⁸. Given its immunostimulatory and antiviral activities, including efficacy against H1N1 influenza, ginger may be a suitable dietary supplement for COVID-19 patients²⁹. By inducing mucosal interferon β secretion, ginger may help alleviate symptoms of viral colds, including fever and cough²⁶.

Despite demonstrated benefits, some studies report conflicting results. For example, Pawar et al. (2021) in China found that oral curcumin with piperine as an adjunctive therapy for COVID-19 yielded variable outcomes, with specific symptoms improving more in the control group than in the curcumin group³⁰. Similarly, Saber-Moghaddam et al. (2021) reported that oral nanocurcumin administration in hospitalized patients with mild to moderate COVID-19 did not alter blood CRP levels³¹.

Given the severe complications of COVID-19 and the demonstrated antiviral and anti-inflammatory properties of curcumin and ginger, these compounds warrant further investigation. However, conflicting data exist on their clinical and laboratory effects, and to date, no study has directly compared the efficacy of turmeric and ginger on inflammatory biomarkers in COVID-19 outpatients. This study, therefore, aimed to evaluate the effects of these two herbal compounds on inflammatory biomarkers in COVID-19 outpatients.

Materials and methods

Study design

This parallel, randomized, triple-blind clinical trial was conducted at Kowsar Hospital affiliated with Semnan University of Medical Sciences in Semnan, Iran, from November 20, 2021, to June 30, 2022. Patients, prescribing physicians, outcome assessors, and the statistician were blinded to treatment allocation. The trial enrolled patients with mild COVID-19 who presented to the specialized outpatient clinic and continued home treatment at the physician’s discretion. All methods were performed in accordance with the relevant guidelines and regulations outlined in the Declaration of Helsinki. The Ethics Committee of Semnan University of Medical Sciences approved the protocol (IR.SEMUMS.REC.1400.105), and the Iranian Clinical Trials Center registered the study on August 31, 2021 (IRCT20120109008665N14). Data collection began after coordinating with two specialist physicians and adhering to institutional protocols.

Study sample

Sample size calculations utilized preliminary data from 10 participants per group, along with the observed means and standard deviations of changes in LDH, CRP, WBC, and ESR. Applying a 95% confidence level and 80% power, the sample size equation for comparing means across more than two independent groups indicated required group sizes of 44, 12, 38, and 25; we therefore enrolled 44 participants per group to meet all parameters (Eq. 1).

1

A total of 144 participants met inclusion criteria: age ≥ 18 years; informed voluntary consent; confirmed COVID-19 diagnosis based on clinical symptoms, fever, chest computed tomography consistent with COVID-19, complete blood count changes with lymphocytopenia, and positive PCR; absence of chronic liver disease, cholecystitis, or peptic ulcer disease; no allergy to turmeric or ginger; female participants nonpregnant and nonlactating; no use of anti-inflammatory medications (e.g., colchicine, tocilizumab); and willingness to continue participation. Participants who withdrew consent after enrollment were excluded.

Study groups

Sampling used convenience and purposive methods. The principal research assigned participants to Group C, Group G, or Group P by block randomization (block size = 6) using sealed envelopes obtained from www.sealedenvelope.com. Of 165 physician-referred individuals, 13 withdrew consent after pill receipt, eight were excluded for allergy to turmeric or ginger, and five discontinued medications due to gastrointestinal symptoms and hot flashes (three in group G, two in group C). Four participants were hospitalized following clinical deterioration, and seven who improved declined follow-up testing. Ultimately, 43 participants, each in groups C and G, and 42 in group P, completed the protocol (Fig. 1).

Fig. 1.

Consort flowchart of the study.

Study intervention

Principal investigator explained the study objectives and methodology during an introductory session, established rapport, and obtained written informed consent prior to the commencement of the intervention. Participants then visited an infectious disease specialist or pulmonologist, who confirmed the COVID-19 diagnosis based on clinical symptoms, positive PCR results, or mild pulmonary involvement on a chest CT scan. The specialist referred eligible patients to the researcher in an adjacent room. The researcher administered a questionnaire on demographics and medical history and provided instructions on pill administration. All participants received standard COVID-19 treatment in addition to the study intervention.

Group C (turmeric group) received package C, containing fifteen 500 mg turmeric (Curcuma) pills. The package was intended for five days, and patients were instructed to take three pills daily—one in the morning, one at noon, and one in the evening—before meals.

Group G (ginger group) received package G, containing fifteen 500 mg ginger (Zingiber) pills. The package was intended for five days, and patients were instructed to take three pills daily—one in the morning, one at noon, and one in the evening—before meals.

Group P (placebo group) received package P, containing fifteen placebo pills. The package contained fifteen pills intended for use over five days, and patients were instructed to take three pills daily—one in the morning, one at noon, and one in the evening—before meals. The placebo was manufactured by Dineh Pharmaceutical Company (Iran) and contained PVP, Avicel, and starch; the tablets were colorless.

The principal investigator (PI) provided each participant in all three groups with two referral letters signed and stamped by the attending physician, specifying the start and end dates of the five-day pill regimen for laboratory testing at Khatam Clinic in Semnan.

The PI instructed participants to fast before starting the pill regimen and to visit the Khatam Clinic laboratory the day after receiving the referral letter to undergo a baseline blood test free of charge without completing the regular admission process. The PI collected participants’ contact numbers and called each patient the following morning to confirm attendance at the laboratory, review pill-administration instructions, and answer any questions regarding dosage timing or test procedures.

During the subsequent five days, the PI contacted participants multiple times daily to reinforce adherence to the three-times-daily pill schedule.

Upon completing the pill regimen, participants returned to the Khatam Clinic laboratory to provide post-treatment blood samples, thereby concluding the study protocol.

Outcomes

The primary outcome comprised changes in CRP, ESR, LDH, and WBC levels from baseline to five days after the initial blood test.

Data analysis

Data analysis followed an intention-to-treat (ITT) approach using SPSS version 24, with significance set at p < 0.05. Descriptive statistics included absolute and relative frequencies presented in frequency tables and percentages. Data normality was assessed using the Kolmogorov–Smirnov test. We compared categorical variables with the Chi-square test and continuous variables across groups using the Kruskal–Wallis test or one-way analysis of variance, as appropriate. Between-group comparisons of median (Interquartile Range; IQR) changes in inflammatory markers before and after intervention employed the Wilcoxon and Paired t-test. Pairwise comparisons were conducted with Bonferroni-adjusted post-hoc tests.

Results

Demographic characteristics of participants

The trial enrolled 144 outpatients with mild COVID-19. In the turmeric group, two participants did not receive the allocated intervention due to side effects; two participants discontinued the intervention due to hospitalization; and one participant refused to undergo a second blood test. In the ginger group, three participants did not receive the allocated intervention due to side effects; one participant discontinued the intervention due to hospitalization; and one participant refused to undergo a second blood test. In the placebo group, one participant discontinued the intervention due to hospitalization; and five participants refused to undergo a second blood test. Ultimately, 128 patients completed the study. The mean ages of the turmeric, ginger, and placebo groups were 37.3 ± 15.1, 45.6 ± 14.0, and 40.6 ± 12.9 years, respectively. There was a significant difference in mean ages among the groups (p = 0.023). Females comprised the majority in each group. Sex distribution, body mass index (BMI), marital status, occupation, comorbidities (diabetes, heart disease, hypertension, hyperlipidemia, lung disease), and symptom duration did not differ significantly among groups (Table 1).

Table 1.

Baseline characteristics of samples, turmeric, ginger and placebo groups.

Group Characteristics		Turmeric	Ginger	Placebo	P-Value
		N (%)	N (%)	N (%)
Gender	Male	21(48.8)	17(3905)	17(40.5)	0.632 a
	Female	22(51.2)	26(60.5)	25(59.5)
Marital status	Single	11(25.6)	5(11.6)	7(16.7)	0.233 a
	Married	32(74.4)	38(88.4)	35(83.3)
Underlying conditions	Yes	37(86)	30(69.8)	34(81)	0.167 a
	No	6(14)	13(30.2)	8(19)
Duration of symptoms (day)	1–5	26(60.5)	27(62.8)	33(78.6)	0.065b
	6–10	17(39.5)	14(32.6)	9(21.4)
		Mean ± SD	Mean ± SD	Mean ± SD
Age (years)		37.3 ± 15.1	45.6 ± 14	40.6 ± 12.9	0.023c
BMId		24.6 ± 3.7	25.5 ± 4.2	25.5 ± 3.5	0.463c

^a Chi-square; ^b Kruskal-Wallis test; ^c ANOVA test; ^d Body mass index; P < 0.05 was considered significant in all cases.

Inflammatory markers

Turmeric group experienced a median reduction in LDH of 24.0 (IQR 58.0), the ginger group 19.0 (IQR 81.0), and the placebo group 10.0 (IQR 111.0). Kruskal–Wallis analysis did not detect a significant difference in LDH reduction among groups (p = 0.349) (Table 2).

Table 2.

Median (IQR)^a of inflammatory factors in turmeric, ginger and placebo groups pre-intervention and end of study measurements.

Group Inflammatory factors		Before	After	Difference	P-Value
		Median(IQR)	Median(IQR)	Median(IQR)
Turmeric	WBC	4.8(2.7)	6.9(3.6)	1.30(3.10)	0.004 b
	ESR	13.0(15.0)	7.0(11.0)	5.00(8.00)	< 0.001 b
	CRP	7.0(10.0)	2.0(3.0)	4.00(8.00)	< 0.001 b
	LDH	345.0(101.0)	328.0(53.0)	24.00(58.00)	0.002 c
Ginger	WBC	5.9(2.8)	7.5(3.3)	1.40(3.90)	0.002 b
	ESR	21.0(16.0)	12.0(9.0)	6.00(11.00)	< 0.001 b
	CRP	12.0(17.0)	3.0(5.0)	9.00(13.00)	< 0.001 b
	LDH	358.0(85.0)	358.0(93.0)	19.00(81.00)	0.024 c
Placebo	WBC	5.9(4.2)	7.8(4.6)	1.45(4.55)	< 0.001 b
	ESR	15.5(15.0)	13.5(14.0)	0.75(12.00)	0.037 b
	CRP	5.0(11.0)	7.5(13.0)	2.50(7.00)	0.696 b
	LDH	368.0(129.0)	368.0(109.0)	10.0(111.0)	0.491 c

^a Interquartile Range ^b Wilcoxon test; ^c Paired t-test; P < 0.05 was considered significant in all cases.

Turmeric group exhibited a median CRP reduction of 4.0 (IQR 8.0), the ginger group 9.0 (IQR 13.0), and the placebo group showed a median CRP increase of 2.50 (IQR 7.0). Kruskal–Wallis analysis revealed significant differences in CRP changes among groups (p = 0.001) (Table 2); post hoc Bonferroni-adjusted comparisons indicated significant differences between turmeric and placebo (p = 0.001) and between ginger and placebo (p = 0.001), with no difference between turmeric and ginger (p = 0.263) (Table 3).

Table 3.

Pairwise comparisons of the mean difference scores of inflammatory factors before and after the intervention between research groups.

Groups	CRP		ESR
	Mean Difference	P-Value a	Mean Difference	P-Value a
Turmeric vs. Ginger	−3.6	0.263	−0.74	> 0.99
Turmeric vs. Placebo	5.3	0.001	5.04	0.002
Ginger vs. Placebo	8.9	0.001	5.78	< 0.001

^a Bonferroni post hoc test; P values were corrected for pairwise comparisons between the groups; P < 0.05 was considered significant in all cases.

The median WBC increase was 1.30 (IQR 3.10) in the turmeric group, 1.40 (IQR 3.90) in the ginger group, and 1.45 (IQR 4.55) in the placebo group. Kruskal–Wallis analysis did not detect significant differences in WBC changes among groups (p = 0.663) (Table 2).

Turmeric group experienced a median ESR reduction of 5.0 (IQR 8.0), the ginger group 6.0 (IQR 11.0), and the placebo group 0.75 (IQR 12.0). Kruskal–Wallis analysis revealed significant differences in ESR changes among groups (p < 0.001) (Table 2); post hoc Bonferroni-adjusted comparisons indicated significant ESR reductions in the turmeric versus placebo groups (p = 0.002) and the ginger versus placebo groups (p < 0.001), with no difference between turmeric and ginger (p > 0.99) (Table 3).

Discussion

Ginger (Zingiber officinale) and turmeric (Curcuma longa) are well-established functional foods frequently used as spices, teas, dietary supplements, and natural remedies, recognized for their anti-inflammatory, immunomodulatory, and analgesic properties. Extensive preclinical and clinical studies have individually documented the anti-inflammatory efficacy of these compounds^32–36.

The findings of this trial provide evidence supporting the beneficial effects of turmeric and ginger in reducing inflammatory markers, specifically CRP and ESR, in outpatients with mild COVID-19. The statistically significant reductions observed in both markers, compared to placebo, underscore the anti-inflammatory potential of these herbal supplements and suggest possible utility in managing inflammatory consequences associated with viral infections.

Elevated CRP and ESR levels are established markers of inflammation and commonly observed in viral illnesses, including COVID-19^37,38. The results of the current study confirm that turmeric and ginger significantly reduce these inflammatory markers, aligning with previous evidence detailing their anti-inflammatory mechanisms. Curcumin, the active constituent in turmeric, exerts anti-inflammatory effects primarily by inhibiting nuclear factor-κB (NF-κB), a critical transcription factor involved in regulating pro-inflammatory cytokines³⁹. By suppressing NF-κB activity, curcumin potentially decreases the secretion of inflammatory mediators, such as interleukins and tumor necrosis factor-alpha (TNF-α), thereby attenuating inflammatory responses³⁸.

Similarly, ginger exerts its anti-inflammatory properties through multiple pathways. Its bioactive constituents, notably 6-gingerol and 6-shogaol, reduce the production of pro-inflammatory cytokines and inhibit cyclooxygenase-2 (COX-2), a key enzyme frequently upregulated during inflammatory processes⁴⁰. Additionally, these compounds enhance antioxidant defenses, thereby mitigating oxidative stress and consequent tissue injury, which may explain the observed reductions in CRP and ESR in the current study⁴¹. Moreover, certain ginger-derived bioactive compounds exhibit strong affinity for the SARS-CoV-2 spike protein, potentially interfering with its binding to host angiotensin-converting enzyme 2 (ACE-2) receptors^42,43.

These observations align with previous research demonstrating potent and dose-dependent anti-inflammatory activities of hydroalcoholic extracts of Curcuma longa and Zingiber officinale, both individually and in combination⁴⁴. Srinivasan et al. confirmed the anti-inflammatory efficacy of turmeric-derived curcuminoids, particularly in reducing oxidative stress, a critical component of inflammatory processes⁴⁵.

The multifaceted anti-inflammatory properties of these agents largely stem from their antioxidant capacity, closely linked to their phenolic compounds, notably flavonoids. Additionally, phenolic compounds possess antimicrobial effects, potentially inhibiting microorganisms that may delay the healing process⁴⁶.

Furthermore, kidneys play an essential role in eliminating inflammatory mediators such as cytokines and acute-phase proteins. Existing literature highlights curcumin’s potential protective effects against renal injury, attributed to its anti-inflammatory and antioxidant mechanisms, as indicated in a recent systematic review⁴⁷.

Consistent with the findings of the current study, Hassaniazad et al. (2021) reported reduced CRP levels among patients receiving nano-curcumin during the second week of treatment; however, the difference compared with placebo was not statistically significant, with elevated CRP (> 2+) observed in 5% of patients in the nano-curcumin group versus 20% in the placebo group⁴⁸. Pawar et al. (2021) found that 90% of patients with mild COVID-19 who received curcumin combined with piperine maintained stable CRP levels, which was significantly greater than the 50% in the control group³⁰. Conversely, Ahmadi et al. (2021) noted a decrease in CRP in patients administered nano-curcumin after two weeks, but the difference compared with the placebo remained nonsignificant⁴⁹. Saber-Moghaddam et al. (2021) similarly observed no significant differences in CRP levels between the nano-curcumin and control groups at multiple assessment points, including discharge³¹. Honarkar Shafie et al. (2021) also detected no significant group differences in high-sensitivity CRP (hs-CRP), reporting normalized values post-treatment⁵⁰. Additionally, Mahluji et al. (2013) demonstrated significant reductions in serum TNF-α, IL-6, and CRP levels following oral ginger supplementation among patients with type 2 diabetes⁵¹.

Our results indicated no significant changes in WBC counts or LDH levels following turmeric or ginger intervention compared with placebo. This finding may reflect participants’ baseline clinical status, as patients with mild COVID-19 generally exhibit stable leukocyte counts during the early stages of the disease⁵². The absence of significant WBC alterations across all three groups is consistent with the findings reported by Honarkar Shafie et al. (2021), who also noted no meaningful differences in WBC counts between the nano-curcumin and placebo cohorts⁵⁰. Askari et al. (2022) similarly observed a significant rise in WBC only in their placebo group, with borderline significance in the intervention arm, a finding likely reflecting previously documented associations between elevated leukocyte counts and severe COVID-19 cases⁵³.

The absence of significant changes in LDH levels—a marker reflecting tissue injury and cellular damage—suggests that although turmeric and ginger might modulate inflammatory responses, they do not directly mitigate cellular damage during the initial stages of mild COVID-19 infection. This suggests that these herbal agents may selectively influence specific inflammatory pathways rather than broadly impacting immune cell proliferation or cellular injury markers, such as LDH⁵⁴. Researchers have suggested that unchanged WBC and LDH levels could reflect that the inflammatory response in mild COVID-19 is not solely linked to these biomarkers, or that treatment duration and dosage might require optimization to observe more substantial effects.

Furthermore, the current study found no statistically significant differences between turmeric and ginger, suggesting that they have similar mechanisms of action against inflammation in mild COVID-19. This finding supports the potential interchangeability of turmeric and ginger as complementary therapeutic agents, particularly among patients who prefer natural interventions for managing inflammation. Prior studies have also noted the synergistic benefits of combining multiple herbal compounds to alleviate inflammatory conditions⁵⁵.

However, clinical evidence regarding ginger remains limited, possibly due to the low water solubility and poor absorption of its phenolic constituents. Ethanol has been proposed as an optimal solvent to maintain ginger’s bioactive compounds (56, 57). Similarly, curcumin’s low bioavailability and poor absorption pose significant obstacles to its clinical applications⁵⁸, prompting research into nano-formulated curcumin to enhance delivery and efficacy⁵⁹. Nevertheless, these solvent-based formulations were not utilized in the current study.

Although the study demonstrated that turmeric and ginger have comparable effects on inflammatory biomarkers (ESR, CRP, LDH, WBC) in COVID-19 outpatients, the significant age differences between the study groups may have confounded the results. Given that age is a well-established factor influencing inflammatory responses and biomarker levels, the absence of an analysis addressing the potential impact of age constitutes a limitation. Future research should therefore consider controlling for age or conducting subgroup analyses to more accurately elucidate how age may modulate the effects of these interventions on inflammatory markers.

The clinical implications of our findings are particularly relevant for adjunctive therapies in the treatment of COVID-19. Given the ongoing nature of the pandemic, investigating safe and effective complementary approaches remains crucial. Turmeric and ginger, widely accessible and generally considered safe, represent promising options for patients aiming to manage inflammation associated with COVID-19.

Limitations of the study

This study has several limitations. First, no follow-up was performed beyond one week after treatment completion, precluding the assessment of longer-term outcomes compared with placebo. Second, participant adherence posed significant challenges, primarily due to the unconventional packaging of medication required to maintain blinding, which caused reluctance among some participants. Despite reassurance from specialists regarding drug validity and direct oversight of the protocol, several patients declined medication and subsequently withdrew from the study. Additionally, obtaining follow-up blood samples proved challenging; after experiencing symptom improvement within five days, several participants were unwilling to return to the laboratory for testing, leading to further exclusions. To mitigate dropout, home visits were conducted to obtain blood samples from some participants, ensuring study continuity.

Conclusion

The findings indicate that turmeric and ginger significantly reduced ESR and CRP levels, but had no notable effect on LDH and WBC levels. Additionally, no significant differences were observed between the turmeric and ginger interventions. Thus, supplementation with turmeric or ginger could serve as a complementary therapy alongside standard pharmacological treatments for managing inflammatory markers in mild COVID-19 cases. Future studies with larger sample sizes, varying dosages, and extended follow-up periods are recommended further to validate the therapeutic potential of these natural compounds.

Abbreviations

COVID-19

Coronavirus disease 2019

LDH

Lactate dehydrogenase

CRP

C reactive protein

WBC

White blood cell

WHO

World Health Organization

CK

Creatine Kinase

ALT

Alanine transaminase

AST

Aspartate transaminase

IL-6

Interlukine-6

SARS

Severe acute respiratory syndrome

CAM

Complementary and Alternative Medicine

HIV

Humane Immunodeficiency Virus

PVP

Polyvinylpyrrolidone

BMI

Body mass index

IQR

Interquartile Range

Author contributions

ZS, MRA, and HB conceived and designed the study. ZS and HB collected, input, and checked the data. RG analyzed the data. ZS and HB draft the manuscript. HB and MRA revised the manuscript, and HB submitted the manuscript. All authors read and approved the final manuscript.

Funding

This study was funded by the Research and Technology Administration of Semnan University of Medical Sciences, Semnan, Iran (Grant no: 1891).

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

Under the guidance of principles of the World Medical Association Declaration of Helsinki, it was taken into the first consideration to respect participants’ rights and to protect their health and rights. The Ethics Committee of Semnan University of Medical Sciences, Semnan, Iran, approved this study (code: IR.SEMUMS.REC.1400.105). Participants were provided with information about data confidentiality, voluntary participation, and their freedom to withdraw from the study. Then, written informed consent for participation was obtained from all of them.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.