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The effects of grape seed extract supplementation on cardiovascular risk factors, liver enzymes and hepatic steatosis in patients with non-alcoholic fatty liver disease: a randomised, double-blind, placebo-controlled study

BMC Complementary Medicine and Therapies volume 24, Article number: 192 (2024) Cite this article

Abstract

Background

Despite the high antioxidant potential of grape seed extract (GSE), very limited studies have investigated its effect on non-alcoholic fatty liver disease (NAFLD). Therefore, this study was conducted with the aim of investigating the effect of GSE on metabolic factors, blood pressure and steatosis severity in patients with NAFLD.

Methods

In this double-blind randomized clinical trial study, 50 NAFLD patients were divided into two groups of 25 participants who were treated with 520 mg/day of GSE or the placebo group for 2 months. The parameters of glycemic, lipid profile, blood pressure and steatohepatitis were measured before and after the intervention.

Results

The GSE group had an average age of 43.52 ± 8.12 years with 15 women and 10 men, while the placebo group had an average age of 44.88 ± 10.14 years with 11 women and 14 men. After 2 months of intervention with GSE, it was observed that insulin, HOMA-IR, TC, TG, LDL-c, ALT, AST, AST/ALT, SBP, DBP and MAP decreased and QUICKi and HDL-c increased significantly (p-value for all < 0.05). Also, before and after adjustment based on baseline, the average changes indicated that the levels of insulin, HOMA-IR, TC, TG, LDL-c, SBP, DBP, MAP in the GSE group decreased more than in the control group (p for all < 0.05). Furthermore, the changes in HDL-c were significantly higher in the GSE group (p < 0.05). The between-groups analysis showed a significant decrease in the HOMA-β and AST before and after adjustment based on baseline levels (p < 0.05). Moreover, the changes in QUICKi after adjustment based on baseline levels were higher in the GSE group than in the control group. Also, between-groups analysis showed that the severity of hepatic steatosis was reduced in the intervention group compared to the placebo group (P = 0.002).

Conclusions

It seems that GSE can be considered one of the appropriate strategies for controlling insulin resistance, hyperlipidemia, hypertension and hepatic steatosis in NAFLD patients.

Trial Registration

The clinical trial was registered in the Iranian Clinical Trial Registration Center (IRCT20190731044392N1). https://irct.behdasht.gov.ir/trial/61413. (The registration date: 30/03/2022)

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Introduction

Hepatosteatosis is defined as fat accumulation in the liver, comprising more than 5–10% of liver weight. Non-alcoholic fatty liver disease (NAFLD) is a term used to describe fatty liver disease that does not involve alcohol consumption. NAFLD encompasses a spectrum from benign steatosis to nonalcoholic steatohepatitis with inflammation (NASH) and liver cirrhosis [1]. Notably, NAFLD has significantly increased liver-related mortality, ranking as the 12th most common cause of death worldwide [2]. The global prevalence of NAFLD is reported to be 32.4%, and in Iran, this number reaches 40.8% [3]. Also, projections indicate that NAFLD will become the leading cause of death in Asia by 2030 [4].

The prevailing hypothesis regarding NAFLD pathogenesis is the multiple-hit hypothesis. According to this hypothesis, the initial trigger for NAFLD development is insulin resistance. Simultaneously, serum free fatty acids accumulate and transfer to hepatocytes, leading to increased hepatic lipogenesis from beta oxidation, ultimately resulting in steatosis [5]. Additionally, NAFLD disrupts vascular endothelium and serves as a primary marker of atherosclerosis. It is suggested that patients with fatty liver exhibit reduced vascular vasodilation compared to control subjects without steatosis [6]. NAFLD is considered a hepatic manifestation of metabolic syndrome, and its treatment primarily targets this syndrome. Conversely, the beneficial effects of polyphenols on metabolic syndrome have been demonstrated in numerous studies [7, 8].

Grape seed extract (GSE) is a food source rich in antioxidant potential, containing various polyphenols, including proanthocyanidins. Studies have reported that GSE significantly affects metabolic factors [9, 10]. Research has demonstrated that GSE’s anti-metabolic syndrome effects result from increased expression and concentration of adiponectin, inhibition of adipogenesis, and stimulation of lipolysis [10, 11]. Animal studies have confirmed that GSE treatment reduces fasting blood sugar (FBS), serum insulin, and HbA1c in diabetic rats. Furthermore, the positive effects of GSE on systolic blood pressure (SBP) are associated with increased production of nitric oxide and reduced expression of endothelin-1 [7].

Additionally, GSE has been shown to reduce the production of reactive oxygen species and inflammatory markers, as well as protect the liver against high-fat diets [12]. Numerous studies have investigated the effect of GSE on cardiovascular risk factors, and thus far, two studies have been conducted on NAFLD patients [13, 14]. However, none of the studies conducted on NAFLD patients have investigated insulin levels, homeostasis model assessment (HOMA-IR), homeostasis model assessment of beta-cell function (HOMA-β), quantitative insulin sensitivity check (QUICKi) index, atherogenic index of plasma (AIP), or blood pressure.

Therefore, the hypothesis of the present study was that GSE supplementation may play a beneficial role in improving NAFLD, as opposed to having no effect. Due to the confirmed beneficial effects of GSE on components of metabolic syndrome and the lack of sufficient randomized clinical trials (RCTs) evaluating the effects of GSE on metabolic factors in NAFLD patients, this study aimed to determine the effects of GSE supplementation on glycemic status, lipid profile, AIP, blood pressure, liver enzymes, and hepatic steatosis.

Materials and methods

Study design and population

This interventional study adhered to the ethical guidelines outlined in the 1975 Declaration of Helsinki and received approval from the Ethics Committee of Ahvaz Jundishapur University of Medical Sciences (Ethical Code: IR.AJUMS.REC.1400.704). The study was also registered with the Iran Clinical Trials Registry (registration code: IRCT20190731044392N1). Written informed consent was obtained from all patients at the study’s initiation.

We followed the CONSORT standard flow diagram (Fig. 1) to conduct this randomized controlled trial. In this double-blind randomized controlled trial study, fifty patients with NAFLD were selected from those referred to the clinic of Shohadaye Hindijan Hospital between April and December 2022. The severity of hepatic steatosis in these patients was determined by a radiologist who was unaware of the study groups, using 3 to 5 MHz ultrasound. Hepatic steatosis was categorized into four groups based on liver echogenicity: Absent (score 0) (representing the normal condition), Mild (score 1) (characterized by echogenicity similar to the renal cortex), Moderate (score 2) (indicating a visible portal vein), and Severe (score 3) (associated with an invisible portal vein) [15, 16].

The inclusion criteria comprised moderate to severe steatosis detected via ultrasonography at the trial’s outset, age between 20 and 60 years, BMI between 25 and 35 kg/m², and patient willingness to participate in the study. Exclusion criteria included pregnancy and lactation, smoking, use of other food supplements, probiotics, or anti-inflammatory drugs, immunosuppressive drug use, and the presence of chronic diseases such as chronic liver disease, diabetes, kidney failure, thyroid disorders, and anemia, as well as adherence to special diets.

Randomization and blinding

In this study, 50 patients were randomly divided into two supplement groups (n = 25) and a placebo group (n = 25) by assigning three-digit codes using Random Allocation Software (RAS) (Fig. 1). Allocation concealment was used for concealment. This work was done using opaque envelopes sealed with a random sequence (sequentially numbered, sealed, opaque envelopes). In this method, each of the generated random sequences (3-digit codes) was recorded on a card, and the cards were placed in the envelopes in order. To maintain a random sequence, the outer surface of the envelopes was numbered in the same order. Finally, the lid of the letter envelopes was glued, and they were placed in a box. The 3-digit codes were also mentioned on the supplement and placebo cans. At the time of participant registration, based on the order of arrival of eligible participants, the envelopes were opened in order, revealing the allocated group for each participant. In fact, each patient received a can containing a 3-digit code according to the code registered on the envelope, and the patients were placed in their respective groups. Coding was performed by a researcher outside the study. Both the researcher and patients were blinded during the study. Additionally, the type of intervention remained blind for the person performing the laboratory tests.

Intervention

The patients in the supplement group received two tablets containing 260 mg of GSE daily (made by the Shari company, Iran) during their morning and evening snacks. Meanwhile, the patients in the control group received two 260 mg placebo tablets daily (produced by the Faculty of Pharmacy, Ahvaz Jundishapur University of Medical Sciences, Iran). These placebo tablets contained cellulose, silicon dioxide, magnesium stearate, and starch, and were similar in terms of shape, color, taste, and size to the supplement tablets. The duration of the study and the prescribed dose of GSE were determined based on previous studies [13, 17]. Patients were instructed at the start of the study to adhere to their regular diet and exercise routine. Additionally, patients were reminded to take supplements or placebo. Patient compliance was evaluated by counting the tablets after 2 months. Subjects who consumed less than 10% of the tablets were excluded. Possible side effects of GSE were evaluated during the study.

Assessment of anthropometric indices

At the beginning of the study, the weight of each patient was measured with light clothes and with an accuracy of 100 g using a Seca scale (Germany), and the height of each patient was measured with a Seca height meter in a standing position without shoes using a height meter with an accuracy of 0.5 cm. Furthermore, waist circumference (WC) was measured with a tape measure with an accuracy of 0.5 cm while standing and in the narrowest part and in the area between the last rib and the iliac crest. Hip circumference (HC) was also measured while standing and at the widest circumference of the hip. The body mass index (BMI) of patients was calculated using the formula (dividing weight (kg) by height squared (m²)). To estimate WHR, WC was divided by HC. All measurements were performed by a trained expert.

Biochemical evaluation

After fasting for 12 h, blood was collected and centrifuged at 2500 rpm for 10 min. The serum samples were frozen immediately at -80 °C until analyzed. The levels of liver enzymes (AST and ALT) were measured by colorimetric method using Parsazmun kits (Tehran, Iran). Total cholesterol (TC), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-c) levels were evaluated using enzymatic kits (Pars Azmun, Iran). To calculate low-density lipoprotein cholesterol (LDL-C), the Friedewald formula was used. FBS level was assessed via the enzymatic colorimetric method using glucose oxidase, and insulin levels were measured by an insulin ELISA kit (Monobind, USA). HbA1c was measured by the HPLC method with a Ds5 device. The homeostasis model assessment [HOMA-IR], Homeostasis model assessment of beta-cell function (HOMA-β), and quantitative insulin sensitivity check (QUICKi) index were calculated according to the following formula: HOMA-IR = [FBS (mmol/L) fasting insulin (µIU/mL)]/22.5, QUICKi = 1/[log (I0) + log (G0)], and HOMA- β = [360 fasting insulin (µIU/mL)]/[FBS (mg/dL)63]. Furthermore, the atherogenic index of plasma (AIP) was calculated as log (TG/HDL-c) [18]. These measurements were obtained at pre-intervention and after 2 months of monitoring.

Assessment of physical activity, food intake and blood pressure

At the beginning of the study and at the end of eight weeks, a 3-day food record (two non-holiday days and 1 holiday day) and physical activity intensity according to Metabolic Equivalents (MET) were assessed using a physical activity questionnaire (IPAQ) [19]. The information obtained through the 3-day food record questionnaire was analyzed using Nutritionist 4 (Nut 4) software. SBP and diastolic blood pressure (DBP) were measured using an automatic oscillometric device on the right arm after five minutes of rest in a sitting position with an accuracy of 2 mmHg, both at the beginning and end of the study. Blood pressure was measured twice, and its average was recorded. The pulse pressure (PP) and mean arterial pressure (MAP) were computed using the following formula: PP = SBP-DBP, MAP= (SBP + 2DBP)/3 [20].

Sample size

The sample size was determined based on insulin levels as the main result. According to a study by Taghizadeh et al., study [21], with α = 0.05, 90% power, and assuming a probable 25% dropout rate, the sample size was estimated to be 25 participants per group. The sample size formula considering σ1 = 25.2, σ2 = 23.4, µ1 = 1.8, µ2 = -23.4 is presented below.

(\(n=\frac{{\left({z}_{1}- \frac{\alpha }{2}+ {z}_{1}-\beta \right)}^{2}\left({{\delta }_{1}}^{2}+{{\delta }_{2}}^{2}\right)}{{({\mu }_{1}- {\mu }_{2})}^{2}}\))

Statistical analysis

The normality of data distribution was evaluated by the Kolmogorov-Smirnov test. Paired sample t-test or Wilcoxon test were used to compare intragroup changes in variables, and the comparison between the studied variables of the two GSE and placebo groups was done using the independent sample t-test. Analysis of covariance (ANCOVA) was used to evaluate the variables between two groups after adjusting for baseline. All values ​​were reported based on the mean ± standard deviation. Based on the dropout rate of participants, the intention-to-treat (ITT) method was utilized. Missing values were imputed by calculating the median of the available data for each variable with missing values. Data analysis was done using SPSS23 software. P < 0.05 was considered statistically significant.

Results

In the present study, 74 patients with NAFLD were investigated, of which 50 patients met the conditions for inclusion in the study. Finally, 50 patients with NAFLD were divided into one of the two groups: GSE or placebo. During the intervention, one participant in the intervention group with GSE and two in the placebo group were excluded from the study due to lack of interest in continuing the study. Nevertheless, after using the ITT method, at the end, 25 people in each group were subjected to statistical analysis. No side effects were reported in the patients during the consumption of GSE supplements or placebo.

Fig. 1
figure 1

Stages of clinical trial progress

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Basic characteristics

All data showed normal distributions. The mean age of the participants in the GSE group was 43.52 ± 8.12 years, consisting of 15 women and 10 men. In comparison, the placebo group had a mean age of 44.88 ± 10.14 years, with 11 women and 14 men. Average anthropometric indexes, age, sex, and the severity of liver steatosis did not differ significantly at the beginning (Table 1) (P ≥ 0.05). According to the BMI patients, both groups were in the first-degree obesity category (31.80 ± 5.17 in the placebo group and 32.35 ± 4.34 in the GSE group). Also, race, education, occupation and medications (data not shown) were examined, and no significant difference was observed between the two groups (P ≥ 0.05). The intake of energy and macronutrients (shown in Table 2) had no statistically significant differences in the two groups (P ≥ 0.05).

Table 1 The characteristics of subjects at baseline
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Table 2 Mean ± SD of energy, macronutrients, and micronutrients intake at baseline and post- intervention
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GSE and glycemic parameters

At baseline, there was no significant difference between the mean serum concentrations of the glycemic parameters (P ≥ 0.05). As shown in Tables 2 and 3 months of supplementation with GSE had no significant effect on FBS and HbA1c levels (P ≥ 0.05), while the average insulin levels and HOMA-IR and QUICKi in the intervention group with GSE improved significantly (14.26 ± 3.26 vs. 12.29 ± 2.26, p = 0.01; 3.35 ± 0.88 vs. 2.83 ± 0.60, p = 0.01; 0.32 ± 0.01 vs. 0.33 ± 0.01, p = 0.002). Also, the between-group analysis showed that the average changes in insulin serum levels and HOMA-IR and HOMA-β indices in the intervention group with GSE were significantly lower than the control group (0.97 ± 0.52 vs. 0.90 ± 0.03, p = 0.04; 57.80 ± 21.16 vs. 53.97 ± 11.14, p = 0.04). After adjusting the data based on baseline levels, it was observed that the significance of insulin and HOMA-IR increased (p = 0.002, p < 0.001 respectively), but HOMA-β was not statistically significance. We also found that the QUICKi index became statistically significant after adjustment for baseline levels (p = 0.001).

GSE and lipid profile

At baseline, the lipid profiles (TG, TC, LDL-c, HDL-c, and VLDL) of the intervention and control groups did not differ significantly (P ≥ 0.05). The paired sample t-test analysis showed that the average levels of TC, TG, LDL-c, and LDL/HDL ratio in the GSE group decreased significantly (191.14 ± 23.70 vs. 182.58 ± 21.59, p < 0.001; 158.84 ± 34.26 vs. 173.24 34.26 ± 34.36 vs. 158.84 ± 34.26, p < 0.001; 23.21 ± 113.21 vs. 101.89 ± 22.88; p < 0.001; 0.67 ± 2.69 vs. 2.13 ± 0.58, p < 0.001, respectively) and the average HDL-c level increased (43.28 ± 8.34 vs. 48.91 ± 7.32, p < 0.001). Also, we found that the average AIP index in the intervention group improved significantly (0.15 ± 0.60 vs. 0.14 ± 0.50, p = 0.01).

Between groups analysis also showed that the average changes of TC, TG, and LDL-c in the intervention group with GSE had a significant difference from the control group (− 8.56 ± 9.44 vs. 6.54 ± 21.58, p = 0.002; -14.10 ± 16.16 vs. 1.32 ± 32.36, p = 0.002, p = 0.03; − 11.31 ± 10.53 vs. 5.22 ± 22.55, p = 0.002). Also, the average HDL-c changes were significantly higher than the control group (5.63 ± 7.32 vs. 1.05 ± 4.70, p = 0.004). Investigating the average changes of AIP and LDL/HDL ratio also showed that they were significantly lower in the intervention group (-0.09 ± 0.06 vs. -0.008 ± 0.09, p < 0.001; -0.56 ± 0.46 vs. 0.07 ± 0.62, p < 0.001). After adjusting the results based on the baseline levels, no significant difference was found and it was observed that the difference in the changes of TG, TC, LDL-c, HDL-c, LDL, HDL and AIP levels between the two groups was significant (P < 0.001, p = 0.01, p < 0.001, p < 0.001, p < 0.001, p < 0.001) (Table 4).

Table 3 Glycemic status at baseline and post-intervention
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Table 4 Lipid profile and AIP and at baseline and post-intervention
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GSE and blood pressure

At the beginning of the study, the baseline blood pressure of the patients in the two groups was not significantly different (p > 0.05). However, after 2-month of intervention with GSE, we observe that the mean arterial pressure (MAP), SBP and DBP in the intervention improved significantly (108.40 ± 11.06 vs. 95.60 ± 7.37, p < 0.001; 132.80 ± 13.39 vs. 118.00 ± 9.12, p < 0.001; 97.60 ± 9.25 vs. 84.40 ± 8.20, p < 0.001) while these results were not seen in the control group. On the other hand, the between-group results also showed that the average changes in MAP, SBP and DBP were significantly lower than the control group (-13.73 ± 7.09 vs. 0.40 ± 7.02, p < 0.001; 8.22 ± 14.80 vs. -9.78 ± 0.40, p < 0.001; -14.40 ± 7.94 vs. 6.72 ± 0.80, p < 0.001). After adjusting the results, it was observed that the changes in the average MAP, SBP and DBP between the two groups were significant (p for all < 0.001) (Table 5).

GSE and liver enzymes and severity of hepatic steatosis

We found that the levels of ALT and AST decreased after 2-month of supplementation with GSE (34.87 ± 8.70 vs. 24.28 ± 8.61, p < 0.001; 21.40 ± 3.80 vs. 18.75 ± 4.08, p = 0.02). Moreover, the mean levels of AST/ALT significantly rose following supplementation. The results of the independent sample t-test between groups also showed significant changes in AST/ALT and ALT in the intervention group compared to the control group (-10.59 ± 4.85 vs. -1.26 ± 7.04, p < 0.001), while this significant difference was not seen in the AST enzyme (p > 0.05). However, after adjusting the AST changes based on its baseline level, a significant difference was observed between the two groups (P = 0.03) (Table 5).

According to the ultrasound, performed at the beginning of the study, none of the participants had normal hepatic steatosis. On the other hand, by comparing the baseline of hepatic steatosis between the intervention and placebo groups, no significant difference was seen between the two groups (p > 0.05). By performing the Wilcoxon test, it was observed that 60% of patients with moderate and severe steatosis reached normal or mild steatosis (P < 0.001). Also, at the end of the study, the chi-square test showed a significant difference in the severity of hepatic steatosis between the two groups (P = 0.002) (Table 5).

Table 5 Blood pressure markers, Liver enzymes and hepatic steatosis at baseline and post-intervention
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Discussion

There have been limited studies of supplementing with GSE in NAFLD patients. As a result of this study, positive effects of GSE on average insulin level, insulin resistance, lipid profile, blood pressure and severity of hepatic steatosis were seen in patients with NAFLD. NAFLD is a disease associated with metabolic disorders in a vicious cycle [22]. Studies have shown that insulin resistance is one of the main causes of NAFLD [23], and that the oxidative stress created in NAFLD can play a role in increasing insulin resistance, lipid disorders [24] and hypertension [25]. The association of GSE with metabolic disorders has been reported in various studies. Controlling each of the metabolic variables can play an important role in preventing NAFLD.

GSE and glycemic parameters

Dysfunction of insulin causes damage to the pathway of carbohydrates and fats, which provides the basis for the flow of fatty acids to the liver, increases the synthesis and storage of triglycerides, and finally increases the levels of inflammation and steatosis in the body [23]. Therefore, the control of insulin resistance can be considered one of the important solutions to improving NAFLD. As a result of the present study, we observed a decrease in average insulin levels and an improvement in HOMA-IR, HOMA-β, and QUICKi with GSE supplementation. In line with the results of our study, human studies have also observed the improvement of average insulin levels and insulin resistance index (HOMA-IR or HOMA-β) in the group supplemented with GSE [21, 26, 27]. Our investigation observed a mean difference in HOMA-IR of -0.52 ± 0.97 post-intervention. The minimal clinically important difference (MCID) for HOMA-IR has been reported to vary across different studies, with values ranging from 0.26 [28] to specific cut-off values like 3.63 [29] for identifying diabetes mellitus. This variability underscores the importance of context-specific considerations when interpreting changes in HOMA-IR levels. While the observed mean difference falls below the commonly reported MCID thresholds, the clinical relevance of this change warrants further exploration, especially in the context of our study population.

In addition, in the animal study conducted by Bao et al., a decrease in insulin levels, FBS, and HbA1c was seen in diabetic rats treated with GSE [7]. The lack of effect of GSE on FBS and HbA1c in the present study could be attributed to the normal levels of HbA1c variables and FBS in the baseline state. Different mechanisms for the effect of GSE on glycemic parameters have been reported in the previous studies. It has been said that the phenols in GSE can increase the expression of proteins related to the insulin signaling pathway and the expression of glycogen synthase mRNA [9]. On the other hand, the proanthocyanidins present in the GSE can be effective in improving the glycemic profile by increasing pancreatic glutathione and decreasing lipid peroxidation as well as total nitrate/nitrite levels in the pancreas [30]. According to the unadjusted and adjusted analysis, there was a significant decrease in insulin and HOMA-IR between the two groups. However, HOMA-β and QUICKi showed significant differences between groups before and after adjustment. Contrary to the findings, in a study conducted on patients with metabolic syndrome for 4 weeks, there was no significant difference in HOMA-IR and average insulin in the intervention group with freeze-dried grape powder compared to the control group [31]. The difference in the duration of the study and the type of intervention may have been effective factors on the results. Almost similar findings were observed in studies demonstrating an improvement in the effects of GSE on insulin levels and insulin resistance. It has been shown that GSE can be effective in improving insulin secretion by inhibiting dipeptidyl peptidase 4 in the intestine and increasing the activity of GLP-1 [32].

GSE and lipid profile

It was seen in the present study that taking 520 mg/day of GSE is effective in improving TC, TG, LDL-c and HDL-c levels. In addition, AIP was used to show the predictive capacity of lipid profiles for cardiovascular disease. The findings of this study showed that receiving 2 months of GSE can have positive results on the AIP index.

In various studies, the relationship between dyslipidemia and NAFLD has been reported. A cohort study conducted in Iran showed high levels of TC, LDL/HDL ratio and low HDL in patients with NAFLD [33]. Insulin resistance, by causing dyslipidemia, can lead to increased oxidative stress and lipid peroxidation, all of which contribute to NAFLD [34]. Yogalakshmi et al. suggested that grape seed proanthocyanidins can stimulate enzymes involved in β-oxidation of lipids by affecting the peroxisome proliferator-activated receptor α. PPARs are high-potential targets for NAFLD therapy [35]. In confirmation of these findings, human studies confirmed the hypoglycemic, hypolipidemic, and anti-atherogenic effects of GSE [13, 36]. However, in a study conducted on 40 female volleyball players, no significant difference was found in the lipid profile levels between the two intervention groups with GSE and the placebo group [37]. In one of the meta-analysis studies, the reduction of LDL-c and TG levels with the consumption of GSE has been reported, and on the other hand, it has been stated that receiving an amount of less than 300 mg of GSE for less than 10 weeks probably does not affect HDL-c and TC [38]. Therefore, the positive effects seen in the present study may be due to the higher dose of GSE prescribed in the study. Also, the type of intervention group or the basic levels of lipid profiles may be the reasons for the difference between the results of this study and other studies. The anti-hyperlipidemic effect of GSE suggests that the high antioxidant potential caused by proanthocyanidin can prevent cholesterol accumulation by scavenging free radicals and inhibiting LDL-c oxidation. It has been reported that GSE can lead to the inhibition of enzymes effective in the digestion of fats and prevent micellization of cholesterol by bile acid [39]. In the present study, before and after adjusting the results, the levels of LDL, HDL, TG, and TC showed a significant difference in the between-groups analysis. Contrary to these studies, Odai et al. showed that the consumption of 200 and 400 mg/day of GSE for 12 weeks does not create a significant difference in HDL and LDL levels between the intervention and control groups [17]. However, in another study conducted on obese or overweight adult individuals, lipid parameters and AIP were significantly improved [36].

The mean difference in LDL cholesterol of -11.31 ± 10.53 seen in our study surpasses the MCID reported for LDL cholesterol, which stands at 3.87 mg/dl [40]. Although the MCID for TC remains unspecified in our search results, the notable reduction in LDL cholesterol post-intervention accentuates the favorable impact of the treatment on lipid parameters. This marked decrease underscores a potential beneficial effect on cardiovascular risk, warranting attention in the management of dyslipidemia. Additionally, it has been shown that the MCID for TG varies depending on the study duration. At 6 months, a decrease of 0.30 mmol/L is considered a clinically meaningful benefit, surpassing the MCID threshold of 0.09 mmol/L [28]. Similarly, at 12 months, a decrease of 0.32 mmol/L is also deemed beneficial, exceeding the MCID of 0.09 mmol/L [28]. The mean difference of TG before and after the intervention in our study was observed to be -14.10 ± 16.16 mg/dl. This considerable reduction signifies a noteworthy positive impact on lipid profiles, highlighting the effectiveness of the GSE intervention in managing TG levels within the studied population. GSE can be effective in improving lipid profile levels by reducing acyl-coenzyme A, cholesterol acyltransferase and inhibiting microsomal triglyceride transfer protein, and increasing fatty acid oxidation [41].

GSE and blood pressure

Another important finding is that GSE intervention leads to a decrease in MAP, SBP and DBP in patients with NAFLD. Studies have shown that the prevalence of hypertension in patients with NAFLD exceeds 40% [42]. It is suggested that inflammation in NAFLD can increase the iNOS / eNOS ratio, which leads to endothelial dysfunction, increased insulin resistance, and oxidative stress [25, 43]. Additionally, chronic inflammation has been observed to upregulate the renin-angiotensin system (RAS) in NAFLD [44].

Studies have reported that the primary mechanism of lowering blood pressure by GSE is due to the stimulation of nitric oxide release and its anti-inflammatory and antioxidant properties [45, 46]. Additionally, a humane investigation of healthy individuals conducted by Schön et al., revealed that a 4-month intervention with 300 mg GSE could successfully lower blood pressure. It was demonstrated that GSE is effective in reducing soluble intercellular adhesion molecule-1 (sICAM) and endothelin-1 secretion [47]. The sICAM and endothelin-1 are implicated in the activation or damage of cells such as platelets and endothelium and could be associated with high blood pressure [48]. Moreover, in a clinical trial conducted with doses of 200 mg and 400 mg of GSE in patients with high blood pressure, it was observed that MAP, DBP, and SBP were significantly lower with the administration of a higher dose of GSE than in the control group [17].

The alterations in blood pressure parameters post-intervention revealed compelling findings. A substantial decrease in SBP by -14.80 ± 8.22, DBP by -14.40 ± 7.94, and MAP by -13.73 ± 7.09 was noted. While the specific MCID for blood pressure in our search results remains unspecified, previous research suggests that even a modest reduction of 2 mmHg in SBP could translate to a significant decrease in cardiovascular mortality risk [49]. The substantial reductions observed in our study signal promising implications for cardiovascular health and underscore the potential clinical significance of the intervention on blood pressure management. The valuable effects of the intake of GSE on blood pressure could be explained by its decrease of the cell damage caused by free radicals and improved endothelial function through an increase in enhancing nitric oxide bioactivity [50]. Similarly, Mas-Capdevila et al., reported that GSE can be effective on blood pressure by downregulating the expression of the main endothelial vasoconstrictor, ET-1, and inducing the upregulation of the NO-enhancer Sirt-1 mRNA [51]. However, despite these findings, no significant effect of GSE on SBP and DBP was seen in some studies [17, 52] which might be the reason for the difference between the results of these studies and the present study, the duration of the intervention, the difference in doses used in studies or the sample size. It has also been shown that GSE can be effective in reducing blood pressure with its anti-obesity effects in addition to reducing cardiac output [53].

GSE and liver enzymes and severity of hepatic steatosis

In addition to the above-mentioned variables, this study evaluated the severity of hepatic steatosis using ultrasound. The findings showed that receiving the GSE supplement at a rate of 520 mg per day for two months could effectively reduce the severity of hepatic steatosis and improve liver enzyme levels. In line with this study, human and animal studies have revealed a significant decrease in liver enzymes and the severity of liver steatosis after the intake of GSE [13, 54]. Considering the high antioxidant potential of GSE and the role of inflammation and oxidative stress in NAFLD, GSE affects the severity of hepatic steatosis by reducing inflammatory factors such as hs-CRP, TNF-α, and oxidative stress (MDA), as well as increasing antioxidant enzymes (SOD and CAT) [55, 56]. However, no significant effect on liver enzymes was observed in interventions made with grape products on patients with high blood pressure or obese individuals [57, 58]. The difference in intervention subjects can be one of the reasons for the differing results. Between-group analysis in this study showed a significant decrease in liver enzyme levels and the severity of hepatic steatosis in the GSE group compared to the control group. Similar findings have been observed in several studies showing the reductive effects of GSE on lipid metabolism. It is indicated that GSE can suppress lipogenesis and increase hepatic beta-oxidation by affecting the gene expression of hepatic lipid droplet proteins, sterol regulatory element-binding protein 1c (SREBP-1c), and peroxisome proliferator-activated receptor-α (PPAR-α) [59].

Among the strengths of the present study, we can mention the more accurate method of the present study and the evaluation of the variables such as Insulin levels, HOMA-IR, HOMA-β, QUICKi index, WC, HC, WC/HC, blood pressure variables and atherogenic index of plasma (AIP). Also, in the section of statistical methods, many confounding factors were considered, and the ITT method was used to compensate for the missing items. The study limitations include a small sample size and short duration, highlighting the need for future studies to address these constraints. Moreover, ultrasound’s limitation in distinguishing between steatosis and steatohepatitis without liver biopsy is acknowledged, despite its common use as an initial diagnostic tool for hepatic steatosis in suspected NAFLD patients. While ultrasound proves highly effective in detecting steatosis when over 33% of hepatocytes are affected, its reliability diminishes in cases of mild fatty infiltration [60].

Conclusion

According to the results of the present study, it can be said that the supplementation of GSE for 2 months can be effective in improving the lipid profile, insulin resistance, blood pressure, and the severity of hepatic steatosis in patients with NAFLD. Therefore, the supplementation of GSE can be considered as a therapeutic solution to improve the symptoms of patients with NAFLD. Although more research is needed to validate these findings, our study does indicate some early positive impacts in patients with NAFLD.

Data availability

The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy restrictions.

Abbreviations

BMI:

body mass index

WC:

waist circumference

HC:

hip circumference

FBS:

fasting blood sugar

HbA1c:

glycosylated hemoglobin

HOMO-IR:

homeostasis model assessment of insulin resistance

QUICKi:

quantitative insulin sensitivity check index

HOMA-β:

homeostasis model assessment of β-cell function

TG:

triglyceride

TC:

total cholesterol

HDL-c:

high-density lipoprotein cholesterol

LDL-c:

low-density lipoprotein cholesterol

VLDL:

very low density lipoprotein

ELISA:

enzyme linked immunosorbent assay

References

  1. Hormati A, Shakeri M, Iranikhah A, Afifian M, Sarkeshikian SS. Non-alcoholic fatty liver disease. Govaresh. 2018;23(4):203–12.

    Google Scholar 

  2. Younossi Z, Stepanova M, Ong JP, Jacobson IM, Bugianesi E, Duseja A, et al. Nonalcoholic steatohepatitis is the fastest growing cause of hepatocellular carcinoma in liver transplant candidates. Clin Gastroenterol Hepatol. 2019;17(4):748–55. e3.

    Article  PubMed  Google Scholar 

  3. Riazi K, Azhari H, Charette JH, Underwood FE, King JA, Afshar EE, et al. The prevalence and incidence of NAFLD worldwide: a systematic review and meta-analysis. Lancet Gastroenterol Hepatol. 2022;7(9):851–61.

    Article  PubMed  Google Scholar 

  4. Salehisahlabadi A, jadid h. The prevalence of non-alcoholic fatty liver disease in Iranian children and adolescents: a systematic review and Meta-analysis. J Sabzevar Univ Med Sci. 2018;25(4):487–94.

    Google Scholar 

  5. Buzzetti E, Pinzani M, Tsochatzis EA. The multiple-hit pathogenesis of non-alcoholic fatty liver disease (NAFLD). Metabolism. 2016;65(8):1038–48.

    Article  CAS  PubMed  Google Scholar 

  6. Theofilis P, Vordoni A, Nakas N, Kalaitzidis RG. Endothelial dysfunction in nonalcoholic fatty liver disease: a systematic review and Meta-analysis. Life (Basel). 2022;12(5).

  7. Bao L, Zhang Z, Dai X, Ding Y, Jiang Y, Li Y, et al. Effects of grape seed proanthocyanidin extract on renal injury in type 2 diabetic rats. Mol Med Rep. 2015;11(1):645–52.

    Article  CAS  PubMed  Google Scholar 

  8. Amiot MJ, Riva C, Vinet A. Effects of dietary polyphenols on metabolic syndrome features in humans: a systematic review. Obes Rev. 2016;17(7):573–86.

    Article  CAS  PubMed  Google Scholar 

  9. Asbaghi O, Nazarian B, Reiner Ž, Amirani E, Kolahdooz F, Chamani M, et al. The effects of grape seed extract on glycemic control, serum lipoproteins, inflammation, and body weight: a systematic review and meta-analysis of randomized controlled trials. Phytother Res. 2020;34(2):239–53.

    Article  CAS  PubMed  Google Scholar 

  10. Wei S, Zheng Y, Zhang M, Zheng H, Yan P. Grape seed procyanidin extract inhibits adipogenesis and stimulates lipolysis of porcine adipocytes in vitro. J Anim Sci. 2018;96(7):2753–62.

    Article  PubMed  PubMed Central  Google Scholar 

  11. Söğütlü İ, Mert N, Mert H, Mis L, Yılmaz HC, İrak K. The effects of grape seed extract on insulin, adiponectin and resistin levels in diabetic rats. Turkish J Agriculture-Food Sci Technol. 2021;9(4):709–13.

    Article  Google Scholar 

  12. El Ayed M, Kadri S, Mabrouk M, Aouani E, Elkahoui S. Protective effect of grape seed and skin extract against high-fat diet-induced dyshomeostasis of energetic metabolism in rat lung. Lipids Health Dis. 2018;17(1):1–9.

    Google Scholar 

  13. Mojiri-Forushani H, Hemmati A, Khanzadeh A, Zahedi A. Effectiveness of Grape Seed Extract in Patients with Nonalcoholic Fatty Liver: A Randomized Double-Blind Clinical Study. Hepatitis Monthly. 2022(In Press).

  14. Khoshbaten M, Aliasgarzadeh A, Masnadi K, Farhang S, Tarzamani MK, Babaei H, et al. Grape seed extract to improve liver function in patients with nonalcoholic fatty liver change. Saudi J Gastroenterology: Official J Saudi Gastroenterol Association. 2010;16(3):194–7.

    Article  Google Scholar 

  15. Ferraioli G, Soares Monteiro LB. Ultrasound-based techniques for the diagnosis of liver steatosis. World J Gastroenterol. 2019;25(40):6053–62.

    Article  PubMed  PubMed Central  Google Scholar 

  16. Vehmas T, Kaukiainen A, Luoma K, Lohman M, Nurminen M, Taskinen H. Liver echogenicity: measurement or visual grading? Comput Med Imaging Graph. 2004;28(5):289–93.

    Article  PubMed  Google Scholar 

  17. Odai T, Terauchi M, Kato K, Hirose A, Miyasaka N. Effects of grape seed proanthocyanidin extract on vascular endothelial function in participants with prehypertension: a randomized, double-blind, placebo-controlled study. Nutrients. 2019;11(12):2844.

    Article  PubMed  PubMed Central  Google Scholar 

  18. Bazyar H, Moradi L, Zaman F, Zare Javid A. The effects of rutin flavonoid supplement on glycemic status, lipid profile, atherogenic index of plasma, brain-derived neurotrophic factor (BDNF), some serum inflammatory, and oxidative stress factors in patients with type 2 diabetes mellitus: a double‐blind, placebo‐controlled trial. Phytother Res. 2023;37(1):271–84.

    Article  CAS  PubMed  Google Scholar 

  19. Craig CL, Marshall AL, Sjöström M, Bauman AE, Booth ML, Ainsworth BE, et al. International physical activity questionnaire: 12-country reliability and validity. Med Sci Sports Exerc. 2003;35(8):1381–95.

    Article  PubMed  Google Scholar 

  20. Smeltzer SC, Bare BG, Hinkle JL, Cheever KH. Brunner and Suddarth’s textbook of medicalsurgical nursing 12th edition. Philadelphia: Lipincott Williams & Wilkins; 2010.

    Google Scholar 

  21. Taghizadeh M, Malekian E, Memarzadeh MR, Mohammadi AA, Asemi Z. Grape seed extract supplementation and the effects on the biomarkers of oxidative stress and metabolic profiles in female Volleyball players: a Randomized, Double-Blind, placebo-controlled clinical trial. Iran Red Crescent Med J. 2016;18(9):e31314–e.

    Article  PubMed  PubMed Central  Google Scholar 

  22. Abebe G, Ayanaw D, Ayelgn Mengstie T, Dessie G, Malik T. Assessment of fatty liver and its correlation with glycemic control in patients with type 2 diabetes mellitus attending Dessie Comprehensive Specialized Hospital, Northeast Ethiopia. SAGE Open Med. 2022;10:20503121221124762.

    Article  PubMed  PubMed Central  Google Scholar 

  23. Méndez-Sánchez N, Arrese M, Zamora-Valdés D, Uribe M. Current concepts in the pathogenesis of nonalcoholic fatty liver disease. Liver Int. 2007;27(4):423–33.

    Article  PubMed  Google Scholar 

  24. Tangvarasittichai S. Oxidative stress, insulin resistance, dyslipidemia and type 2 diabetes mellitus. World J Diabetes. 2015;6(3):456–80.

    Article  PubMed  PubMed Central  Google Scholar 

  25. Ogresta D, Mrzljak A, Cigrovski Berkovic M, Bilic-Curcic I, Stojsavljevic-Shapeski S, Virovic-Jukic L. Coagulation and endothelial dysfunction Associated with NAFLD: current status and therapeutic implications. J Clin Translational Hepatol. 2022;10(2):339–55.

    Article  Google Scholar 

  26. Mohammad A, Shahnaz T, Sorayya K. Effect of 8 weeks’ supplementation grape seed extract on insulin resistance in Iranian adolescents with metabolic syndrome: a randomized controlled trial. Diabetes Metabolic Syndrome: Clin Res Reviews. 2021;15(1):197–203.

    Article  CAS  Google Scholar 

  27. Irandoost P, Ebrahimi-Mameghani M, Pirouzpanah S. Does grape seed oil improve inflammation and insulin resistance in overweight or obese women? Int J Food Sci Nutr. 2013;64(6):706–10.

    Article  CAS  PubMed  Google Scholar 

  28. Goldenberg JZ, Day A, Brinkworth GD, Sato J, Yamada S, Jönsson T et al. Efficacy and safety of low and very low carbohydrate diets for type 2 diabetes remission: systematic review and meta-analysis of published and unpublished randomized trial data. BMJ. 2021;372.

  29. Horáková D, Štěpánek L, Janout V, Janoutová J, Pastucha D, Kollárová H, et al. Optimal homeostasis model assessment of insulin resistance (HOMA-IR) cut-offs: a cross-sectional study in the Czech population. Medicina. 2019;55(5):158.

    Article  PubMed  PubMed Central  Google Scholar 

  30. El-Alfy AT, Ahmed AAE, Fatani AJ. Protective effect of red grape seeds proanthocyanidins against induction of diabetes by alloxan in rats. Pharmacol Res. 2005;52(3):264–70.

    Article  CAS  PubMed  Google Scholar 

  31. Millar CL, Duclos Q, Garcia C, Norris GH, Lemos BS, DiMarco DM, et al. Effects of freeze-dried grape powder on high-density lipoprotein function in adults with metabolic syndrome: a randomized controlled pilot study. Metab Syndr Relat Disord. 2018;16(9):464–9.

    Article  CAS  PubMed  Google Scholar 

  32. González-Abuín N, Martínez-Micaelo N, Margalef M, Blay M, Arola-Arnal A, Muguerza B, et al. A grape seed extract increases active glucagon-like peptide-1 levels after an oral glucose load in rats. Food Function J. 2014;5(9):2357–64.

    Article  Google Scholar 

  33. Mansour-Ghanaei R, Mansour-Ghanaei F, Naghipour M, Joukar F. Biochemical markers and lipid profile in nonalcoholic fatty liver disease patients in the PERSIAN Guilan cohort study (PGCS), Iran. J Family Med Prim Care. 2019;8(3):923–8.

    Article  PubMed  PubMed Central  Google Scholar 

  34. Akhtar DH, Iqbal U, Vazquez-Montesino LM, Dennis BB, Ahmed A. Pathogenesis of Insulin Resistance and atherogenic dyslipidemia in nonalcoholic fatty liver disease. J Clin Translational Hepatol. 2019;7(4):362–70.

    Google Scholar 

  35. Yogalakshmi B, Sreeja S, Geetha R, Radika MK, Anuradha CV. Grape seed Proanthocyanidin rescues rats from steatosis: a comparative and Combination Study with Metformin. J Lipids. 2013;2013:153897.

    Article  PubMed  PubMed Central  Google Scholar 

  36. Yousefi R, Parandoosh M, Khorsandi H, Hosseinzadeh N, Madani Tonekaboni M, Saidpour A, et al. Grape seed extract supplementation along with a restricted-calorie diet improves cardiovascular risk factors in obese or overweight adult individuals: a randomized, placebo‐controlled trial. Phytother Res. 2021;35(2):987–95.

    Article  CAS  PubMed  Google Scholar 

  37. Taghizadeh M, Malekian E, Memarzadeh MR, Mohammadi AA, Asemi Z. Grape seed extract supplementation and the effects on the biomarkers of oxidative stress and metabolic profiles in female Volleyball players: a Randomized, Double-Blind, placebo-controlled clinical trial. Iran Red Crescent Med J. 2016;18(9):e31314.

    Article  PubMed  PubMed Central  Google Scholar 

  38. Anjom-Shoae J, Milajerdi A, Larijani B, Esmaillzadeh A. Effects of grape seed extract on dyslipidaemia: a systematic review and dose-response meta-analysis of randomised controlled trials. Br J Nutr. 2020;124(2):121–34.

    Article  CAS  PubMed  Google Scholar 

  39. Downing LE, Edgar D, Ellison PA, Ricketts ML. Mechanistic insight into nuclear receptor-mediated regulation of bile acid metabolism and lipid homeostasis by grape seed procyanidin extract (GSPE). Cell Biochem Funct. 2017;35(1):12–32.

    Article  CAS  PubMed  Google Scholar 

  40. Momin ES, Khan AA, Kashyap T, Pervaiz MA, Akram A, Mannan V et al. The effects of Probiotics on cholesterol levels in patients with metabolic syndrome: a systematic review. Cureus. 2023;15(4).

  41. Zern TL, West KL, Fernandez ML. Grape polyphenols decrease plasma triglycerides and cholesterol accumulation in the aorta of ovariectomized guinea pigs. J Nutr. 2003;133(7):2268–72.

    Article  CAS  PubMed  Google Scholar 

  42. Ng CH, Wong ZY, Chew NWS, Chan KE, Xiao J, Sayed N, et al. Hypertension is prevalent in non-alcoholic fatty liver disease and increases all-cause and cardiovascular mortality. Front Cardiovasc Med. 2022;9:942753.

    Article  PubMed  PubMed Central  Google Scholar 

  43. Zanotto TM, Quaresma PG, Guadagnini D, Weissmann L, Santos AC, Vecina JF, et al. Blocking iNOS and endoplasmic reticulum stress synergistically improves insulin resistance in mice. Mol Metabolism. 2017;6(2):206–18.

    Article  CAS  Google Scholar 

  44. Zhao Y-C, Zhao G-J, Chen Z, She Z-G, Cai J, Li H. Nonalcoholic fatty liver disease: an emerging driver of hypertension. Hypertension. 2020;75(2):275–84.

    Article  CAS  PubMed  Google Scholar 

  45. Afshari G, Zahedi Khorasani M, Dianat M, Sarkaki A, Badavi M. Therapeutic effects of the grape seed extract on lead-Induced hypertension and aortic responsiveness in rats. Iran Heart J. 2019;20(3):36–46.

    Google Scholar 

  46. Chen F, Wang H, Zhao J, Yan J, Meng H, Zhan H, et al. Grape seed proanthocyanidin inhibits monocrotaline-induced pulmonary arterial hypertension via attenuating inflammation: in vivo and in vitro studies. J Nutr Biochem. 2019;67:72–7.

    Article  CAS  PubMed  Google Scholar 

  47. Schön C, Allegrini P, Engelhart-Jentzsch K, Riva A, Petrangolini G. Grape seed extract positively modulates blood pressure and perceived stress: a Randomized, Double-Blind, placebo-controlled study in healthy volunteers. Nutrients. 2021;13(2).

  48. Glowinska B, Urban M, Peczynska J, Florys B. Soluble adhesion molecules (sICAM-1, sVCAM-1) and selectins (sE selectin, sP selectin, sL selectin) levels in children and adolescents with obesity, hypertension, and diabetes. Metabolism. 2005;54(8):1020–6.

    Article  CAS  PubMed  Google Scholar 

  49. Kelley GA, Kelley KS, Stauffer BL. Walking and resting blood pressure: an inter-individual response difference meta-analysis of randomized controlled trials. Sci Prog. 2022;105(2):368504221101636.

    Article  PubMed  Google Scholar 

  50. Zhang H, Liu S, Li L, Liu S, Liu S, Mi J, et al. The impact of grape seed extract treatment on blood pressure changes: a meta-analysis of 16 randomized controlled trials. Med (Baltim). 2016;95(33):e4247.

    Article  Google Scholar 

  51. Mas-Capdevila A, Iglesias-Carres L, Arola-Arnal A, Suárez M, Bravo FI, Muguerza B. Changes in arterial blood pressure caused by long-term administration of grape seed proanthocyanidins in rats with established hypertension. Food Funct. 2020;11(10):8735–42.

    Article  CAS  PubMed  Google Scholar 

  52. mohammadipour f, cheraghipour j. The effect of grape seed extract on lipid profile and blood pressure of patients with hyperlipidemia: a randomized double blind clinical trial study. Nurs Midwifery J. 2016;14(1):1–9.

    Google Scholar 

  53. Foshati S, Nouripour F, Sadeghi E, Amani R. The effect of grape (Vitis vinifera) seed extract supplementation on flow-mediated dilation, blood pressure, and heart rate: a systematic review and meta-analysis of controlled trials with duration- and dose-response analysis. Pharmacol Res. 2022;175:105905.

    Article  PubMed  Google Scholar 

  54. Abd Eldaim MA, Tousson E, Soliman MM, El Sayed IET, Abdel Aleem AAH, Elsharkawy HN. Grape seed extract ameliorated Ehrlich solid tumor-induced hepatic tissue and DNA damage with reduction of PCNA and P53 protein expression in mice. Environ Sci Pollut Res. 2021;28(32):44226–38.

    Article  CAS  Google Scholar 

  55. Hasona N, Morsi A. Grape seed Extract alleviates Dexamethasone-Induced hyperlipidemia, lipid peroxidation, and hematological alteration in rats. Indian J Clin Biochem. 2019;34(2):213–8.

    Article  CAS  PubMed  Google Scholar 

  56. Şehirli Ö, Ozel Y, Dulundu E, Topaloglu U, Ercan F, Şener G. Grape seed extract treatment reduces hepatic ischemia-reperfusion injury in rats. Phytotherapy Research: Int J Devoted Pharmacol Toxicol Evaluation Nat Prod Derivatives. 2008;22(1):43–8.

    Article  Google Scholar 

  57. Zunino SJ, Peerson JM, Freytag TL, Breksa AP, Bonnel EL, Woodhouse LR, et al. Dietary grape powder increases IL-1β and IL-6 production by lipopolysaccharide-activated monocytes and reduces plasma concentrations of large LDL and large LDL-cholesterol particles in obese humans. Br J Nutr. 2014;112(3):369–80.

    Article  CAS  PubMed  Google Scholar 

  58. Vaisman N, Niv E. Daily consumption of red grape cell powder in a dietary dose improves cardiovascular parameters: a double blind, placebo-controlled, randomized study. Int J Food Sci Nutr. 2015;66(3):342–9.

    Article  CAS  PubMed  Google Scholar 

  59. Yogalakshmi B, Sreeja S, Geetha R, Radika MK, Anuradha CV. Grape seed proanthocyanidin rescues rats from steatosis: a comparative and combination study with metformin. J Lipid. 2013;2013:153897.

    Article  Google Scholar 

  60. Jessica KD, Quentin MA, Stuart M. Non-alcoholic fatty liver disease: a practical approach to diagnosis and staging. Frontline Gastroenterol. 2014;5(3):211.

    Article  Google Scholar 

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Acknowledgements

We would like to appreciate the staff of Shohadaye Hindijan hospital, participants and the Student Research Committee, Ahvaz Jundishapur University of Medical Science, for providing the financial support (00s108).

Funding

This research work was financially supported by Student Research Committee of Ahvaz Jundishapur University of Medical Sciences (00s108).

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Authors and Affiliations

  1. Student Research Committee, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

    Parisa Ghanbari, Roghayeh Alboebadi & Hamidreza Razmi

  2. Department of Internal Medicine, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

    Davoud Raiesi

  3. Nutrition and Metabolic Diseases Research Center, Clinical Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

    Ahmad Zarejavid

  4. School of Medical and Life Sciences, Sunway University, Sunway City, Malaysia

    Mostafa Dianati

  5. Department of Complex Genetics and Epidemiology, School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, Netherlands

    Mostafa Dianati

  6. Department of Public Health, Sirjan School of Medical Sciences, Sirjan, Iran

    Hadi Bazyar

  7. Student Research Committee, Sirjan School of Medical Sciences, Sirjan, Iran

    Hadi Bazyar

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Contributions

P-GH: all steps of research and writing the manuscript, DR: clinical supervision and conception or design, RA and A-ZJ: acquisition, analysis, or interpretation of data and statistical analysis, MD: Revised the manuscript and statistical consulting, HR: corresponding author, supervision and all steps of research and writing the manuscript, HB: co-corresponding author, supervision and all steps of research.

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Correspondence to Hamidreza Razmi or Hadi Bazyar.

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At the beginning of the study, a written informed consent was obtained from patients. This parallel intervention study conformed to the ethical guidelines of the 1975 Declaration of Helsinki and was approved by the Ethics Committee of Ahvaz Jundishapur University of Medical Sciences (Ethical Code: IR.AJUMS.REC.1400.704 and registration code of Iran clinical trials: IRCT20190731044392N1).

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Ghanbari, P., Raiesi, D., Alboebadi, R. et al. The effects of grape seed extract supplementation on cardiovascular risk factors, liver enzymes and hepatic steatosis in patients with non-alcoholic fatty liver disease: a randomised, double-blind, placebo-controlled study. BMC Complement Med Ther 24, 192 (2024). https://doi.org/10.1186/s12906-024-04477-3

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BMC Complementary Medicine and Therapies

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