Extended Abstract
1. Introduction
Overweight and obesity are growing metabolic diseases [1]. Studies have shown that being overweight and obese is associated with impairment in serum lipids and lipoproteins, such as Low-Density Lipoprotein (LDL), Very Low-Density Lipoprotein (VLDL), Total Cholesterol (TC), Triglycerides (TG) and High-Density Lipoprotein (HDL) [4, 5] which are the risk factors for cardiovascular diseases. Obesity has also been shown to release pre-inflammatory cytokines such as IL-6 from adipose tissue. High serum IL-6 levels increase the hepatic synthesis of C-reactive protein (CRP) [6]. CRP has been shown to be a non-specific biomarker of inflammation, independent of other traditional risk factors, predicting cardiovascular diseases, especially in women, and has been shown that blood CRP levels in obese people are higher than in normal weight people, and have a positive relationship with Body Mass Index (BMI) [7].
Recent evidence suggests that certain food components, such as spices, may play a key role in preventing or treating obesity and related metabolic disorders [6]. Curcumin, the active ingredient in turmeric, has low toxicity and has a wide range of pharmacological functions, including antioxidant, anti-inflammatory, antimicrobial and anti-cancer effects [9 ،8]. It has a positive effect on lipid profile by reducing inflammation, regulating cholesterol homeostasis, reducing LDL, lipid peroxidation, and increasing HDL [10, 11]. 
However, studies such as Baum et al. have also shown that taking curcumin has no significant effect on serum cholesterol and TG concentrations [14]. Moreover, several studies have reported conflicting effects of curcumin on anthropometric indicators (body weight, BMI and waist-to-hip ratio). Some studies have shown a significant effect of curcumin consumption on body composition in addition to its anthropometric characteristics [15, 16]. In contrast, some studies have not reported its any significant effect [17-19].
Since weight management strategies are important for improving the mental and physical health of obese and overweight people, and reviewing the previous studies showed that their findings are highly ambiguous, more research is needed. In this regard, this study aimed to investigate the effect of 6 weeks of nanocurcumin supplementation on lipid profile, CRP level and anthropometric characteristics of overweight girls.
2. Materials and Methods
This is a quasi-experimental study with pretest/posttest design. The subjects were 24 overweight students with a mean age of 22.48±1.64 years and BMI of 27.53±3.29 kg/m2. After receiving written consent from the subjects, they were randomly divided into two groups of supplement (n=12) and placebo (n=12). Supplement group consumed 80 mg nano-curcumin capsule daily for 6 weeks, while placebo group received a capsule containing starch daily. Anthropometric indicators including body weight, BMI and Waist-To-Hip Ratio (WHR) were measured before and after the intervention and blood samples were collected to measure components of lipid profile (LDL, TC, TG, and HDL) and CRP level. Data were analyzed by dependent and independent t-tests. The significance level was set at P≤0.05.
3. Results
The statistical results related to anthropometric characteristics in pretest and posttest phases are presented in Table 1. No significant between-group and within-group differences were observed in terms of anthropometric characteristics as well as in lipid profile and CRP level (P>0.05) (Table 2).

4. Discussion
The results of the present study showed that 6 weeks of nano-curcumin supplementation had no significant effect on lipid profile, CRP level, and anthropometric indicators (weight, BMI and WHR) in overweight girls. This is consistent with the results of Mohammadi et al. [17], but is against the results of Di Pierro et al. [22]. One of the reasons for this discrepancy is that although the subjects in both studies were overweight, the samples in Di Pierro et al.’s study had metabolic syndrome, and during the 30-day supplementation period and 30 days before it, there were interventions in the lifestyle of the subjects such as 500 kcal of calorie restriction per day and 210 minutes of physical activity per week, while in the present study, subjects had no caloric restriction and regular physical activity.

The exact mechanism by which curcumin may affect body weight and BMI is not yet known; however, it has been reported that curcumin regulates the Janus Kinase (JNK), which has been shown to play a key role in the pathogenesis of obesity [8, 25]. Curcumin may also inhibit the 11βHSD1 enzyme, which activates cortisol [26]. Higher concentrations of cortisol in fat cells cause central obesity [27]. Curcumin also reduces obesity by inhibiting fat differentiation in the early stages by suppressing the Peroxisome proliferator-activated receptor c (PPAR-c) and by increasing the protein kinase activated by monophosphate following lipolysis [26]. Moreover, previous studies have shown that curcumin supplementation may reduce energy expenditure [8, 28].
Other results from the present study showed improvements in lipid profile (decreased TC, TG, LDL and increased HDL) after 6 weeks of nanocurcumin supplementation, although these changes were not significant. This is consistent with the results of Sohaei et al. [30]. Studies have shown that curcumin prevents the formation of oxygen free radicals and is effective in reducing the progression and complications of inflammation and hyperlipidemia. Curcumin also inhibits the activity of Fatty Acid Synthase (FAS) and enhances the oxidation of β-fatty acids, thus leading to an effective reduction in fat reserves, and using this mechanism, curcumin can regulate lipid metabolism [35].

The present study showed an improvement in serum CRP levels after 6 weeks of nanocurcumin supplementation; however, the changes were not significant. This is consistent with the results of of Sohaei et al. [30], but is against the results of Shadkam et al. [3], and Holt et al. [36].  The reasons for the inconsistency of the results are probably the duration of study, type and dose of curcumin supplementation. Concentrations, conditions, and cell types, as well as the uptake and distribution of curcumin in tissues, are also important for its biological activity [35, 38].
5. Conclusion
The short-term use of nanocurcumin supplementation did not lead to significant changes in the anthropometric characteristics, lipid profile, and CRP level in overweight girls. Therefore, long-term use and different doses of this supplement are recommended.
Ethical Considerations
Compliance with ethical guidelines
This study obtained its ethical approval from the Research Ethics Committee of Shahid Chamran University of Ahvaz (Code: EE.96.24.3.85899.scu.ac.ir) and is a clinical trial registered by Iranian Registry of Clinical Trials (Code: IRCT20180927041150N1).
Funding
This article is financially supported by the Research Vice Chancellor of Shahid Chamran University of Ahvaz.
Authors' contributions
Conceptualization, methodology and sampling: Fatemeh Fakhri; Data analysis: Fatemeh Fakhri and Somayyeh Fakhri; Writing and review: Fatemeh Fakhri, Saeid Shakeryan, and Ali Akbar Alizadeh; Supervision and project administration: Somayyeh Fakhri.
Conflicts of interest
The authors declare no conflict of interest