The association between healthy beverage index and sarcopenic obesity among women with overweight and obesity: a cross-sectional study.

INTRODUCTION: Sarcopenic obesity is related to changes in body composition, loss of muscle mass, and raised adipose tissue. Beverage patterns are effective with changes in health status. Therefore, the aim of this study was to investigate the association between sarcopenic obesity (SO) and the healthy beverage index (HBI) in women with overweight and obesity. METHODS: This cross-sectional study conducted on 210 overweight and obese (BMI ≥25 kg/m2) women aged 18-56 years. The measurement of skeletal muscle mass (SMM) and fat mass (FM) done by bioelectric impedance analyzer (BIA) (Inbody Co., Seoul, Korea) based on guidelines. The two lowest quintiles SMM and the two highest quintiles FM and body mass index (BMI) ≥30 are considered sarcopenic obesity in women. A validated and reliable semi-quantitative food-frequency questionnaire (FFQ) was used to evaluate the beverage dietary data. and RFS and NRFS was calculated. Biochemical assessments were quantified by standard approaches, and physical activity were evaluated by international physical activity questionnaire (IPAQ). RESULT: In this cross-sectional study, 210 overweight and obese females took part (18-56) years old). The studies were carried out using binary logistic regression. After controlling for a wide variety of confounding variables such as age, energy intake, physical activity, education, and economic status, we found a negative association between HBI and risk of SO (OR = 0.29, 95% CI = 0.35 to 1.01, P = 0.05). CONCLUSION: We observed that the odds of SO was reduced by 69% in participants with higher HBI score. More well-designed studies need to confirm our findings.

The interaction between MC4R gene variant (rs17782313) and dominant dietary patterns on depression in obese and overweight women: a cross sectional study.

BACKGROUND: Previous studies have shown that the minor allele (C allele) for melanocortin 4 receptor (MC4R) rs17782313 may be associated with depressed mood. Moreover, dietary patterns have potentially adverse effects on depression. This study investigates the interactions between the MC4R gene variant (rs17782313) and dietary patterns on depression among Iranian obese and overweight women. METHODS: A total of 289 Iranian overweight and obese women, aged 18-50 years, were enrolled in this cross-sectional study. Biochemical, anthropometric, and body composition indices were assessed in all participants. Moreover, MC4R rs17782313, by the restriction fragment length polymorphism (PCR-RFLP) method, and depression, using the 21-item Depression Anxiety Stress Scales (DASS) questionnaire, were assessed. Food intakes were assessed by completing a 147-item semi-quantitative food frequency questionnaire (FFQ). RESULTS: By the use of factor analysis, 2 major dietary patterns were extracted: healthy dietary pattern (HDP) and unhealthy dietary pattern (UDP). Binary logistic analysis showed that individuals with minor allele risk (CC) with high adherence to the unhealthy pattern increased odds for depression (OR: 8.77, 95%CI: -0.86-18.40, P: 0.07), after controlling for confounders. Also, a logical inverse relationship was observed between CT genotype and HDP on depression in the crude and adjusted models (OR: -0.56, 95% CI: -3.69-2.57, P: 0.72) (OR: -4.17, 95% CI: -9.28-0.94, P: 0.11), although this interaction was not statistically significant. CONCLUSION: According to the above findings, adherence to unhealthy food intake pattern increases odds of depression in MC4R risk allele (C allele) carriers. To confirm these findings, more studies are needed in the form of clinical trials and prospective studies with higher sample sizes.

The association between healthy beverage index and quality of life among overweight and obese women: a cross-sectional study.

BACKGROUND: Although several studies have evaluated the association between patterns of beverage consumption with different components of quality of life separately, the findings are controversial. In addition, none have examined all components of quality of life together in relation to patterns of beverage consumption. Therefore, this study was conducted to identify the association between healthy beverage index (HBI) and quality of life among overweight and obese women. METHODS: For this cross-sectional study, 210 obese and overweight women were recruited from health centers in Tehran, Iran. Using reliable and verified standard protocols, data on beverage intake, socio-demographic, physical activity, and anthropometric variables were assessed. Based on past studies, the predetermined HBI was estimated. Serum samples were used to determine biochemical characteristics, and quality of life was assessed using SF-36 questionnaires. RESULTS: There was a significant association between total QoL score with T2 tertile of HBI in the adjusted model (ß: 13.11, 95% CI: 1.52, 24.69, p-value = 0.027). General health had a significant negative association with T2 (ß: -5.83; 95% CI: - 11.48, - 0.18; p-value = 0.043) and T3 (ß: -6.20; 95% CI: - 12.37, - 0.03; p-value = 0.049). Women with greater adherence to the HBI had a higher physical functioning score, and there was a significant upward trend from the second to the third tertile (7.74 vs 0.62) (-trend = 0.036). There was a significant positive association between mental health with T3 of HBI (ß: 4.26; 95% CI: 1.51, 5.98; p-value = 0.015) and a significant increasing trend was observed with increasing tertiles (P-trend = 0.045). CONCLUSION: In conclusion, there is a significant association between total QoL score, and its components, with HBI among overweight and obese women. However, additional well-designed studies are needed to confirm these findings.

Association of Lifelines Diet Score (LLDS) and metabolically unhealthy overweight/obesity phenotypes in women: a cross-sectional study.

BACKGROUND: Previous studies have shown the association of a number of dietary quality scores with metabolically phenotypes of obesity. Recently, the Lifelines Diet Score (LLDS), which is a fully food-based score based on the 2015 Dutch dietary guidelines and underlying international literature, has been proposed as a tool for assessing the quality of the diet. Therefore, this study was performed to investigate the association between LLDS and metabolically healthy/unhealthy overweight and obesity (MHO/MUHO) phenotypes. METHODS: This study was performed on 217 women, aged 18-48 years old. For each participant anthropometric values, biochemical test and body composition were evaluated by standard protocols and methods. The LLDS was determined based on 12 components using a valid and reliable food frequency questionnaire (FFQ) containing 147 items. The metabolically healthy (MH) was evaluated using the Karelis criteria. RESULTS: Among the total participants in this study, 31.3% of the subjects were MHO while 68.7% were MUHO. After adjustment for potential confounding variables (age, energy intake, and physical activity), participants in highest LLDS tertile had a lower odds of MUHO compared with those in the lowest tertile (OR: 1.18; 95% CI: 0.23, 5.83; P-trend = 0.03). Also, after further adjustment with BMI, provided only small changes in "OR" and did not attenuate the significance (OR: 1.28; 95% CI: 0.23, 6.91; P-trend = 0.02). CONCLUSIONS: The present evidence indicates that individuals with higher adherence to the LLDS had lower odds of metabolically unhealthy (MUH).

The association between Healthy Beverage Index and psychological disorders among overweight and obese women: a cross-sectional study.

BACKGROUND AND AIMS: The Healthy Beverage Index (HBI) is a valuable technique to estimate the synergistic effects of overall beverage consumption. Several studies have evaluated the associations between HBI and beneficial changes in the health status. however, there is no study on the association between patterns of beverage consumption and mental health status. Therefore, this study sought to examine the association between HBI and psychological disorders among overweight and obese women. METHODS: 199 overweight and obese women, between the ages of 18 and 55 y, were enrolled in this cross-sectional study in Tehran, Iran. To collect beverage dietary data, a validated semi-quantitative food-frequency questionnaire (FFQ) was used. Furthermore, the DASS-21 questionnaire was used to assess psychological profile states. RESULTS: The association of total depression anxiety stress (DASS) score with healthy beverage index (HBI) tertiles in models was marginally significant (OR =: 0.78; 95% CI 0.30-2.02; P-value = 0.074; (OR = 0.77; 95% CI 0.28-2.16; P-value = 0.062), respectively. In terms of stress, anxiety, and depression, after adjusting for confounders, participants with higher HBI in the third tertile had lower odds of depression vs. the first tertile (OR = 0.99; 95% CI 0.35-2.81; P-trend = 0.040). CONCLUSION: We demonstrate that the total DASS score was associated with HBI tertiles. We also found that participants with higher HBI had lower odds of depression. However, additional well-designed studies are needed to confirm the veracity of these findings.

The Association between Healthy Beverage Index and Healthy and Unhealthy Obesity Phenotypes among Obese Women: A Cross-Sectional Study.

Background: Metabolic phenotypes are new dimensions of obesity. Two important types of these phenotypes are metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO). Studies showed that the components of the healthy beverage index (HBI) such as sugar-sweetened beverages (SSBs), milk, and fruit juices might have an association with MHO and MUO phenotypes. Methods: This cross-sectional study was performed on 210 women with the age range of 18-65 years and a body mass index (BMI) ≥25 kg/m2. The age range of the study population was the main inclusion criterion. Dietary intakes were assessed using a 147-item food frequency questionnaire (FFQ), as well as biochemistry and anthropometric parameters, in all participants. Metabolic health phenotypes were considered using the Karelis score, whilst HBI was evaluated based on 8 categories of beverages consumed. Analysis was carried out using binary logistic regression. Result: After controlling for a wide variety of confounding variables such as age, energy intake, BMI, education, physical activity, marriage, economic status, job, and supplementation, we found that the participants in the highest tertile of HBI had a lower risk of abnormal metabolic status than those in the lowest tertile (OR = 0.49; 95% CI: 0.07-3.21; P trend: 0.04), and it was not statistically significant, but we saw a significant trend. Conclusion: In conclusion, it seems that higher adherence to HBI can minimize the risk of metabolic abnormality, based on a significant trend.

Interaction between ultra-processed food intake and genetic risk score on mental health and sleep quality.

PURPOSE: Mental health and sleep quality are associated with genetics and nutrient and energy intake. The present study examined the association between ultra-processed food (UPF) intake and genetic risk score (GRS) and their interactions on mental health and sleep quality in Iranian women. METHODS: A cross-sectional study was conducted on 278 overweight and obese females aged between 18 and 56 years. According to the NOVA classification system, 37 food groups and beverages were collected using a 147-item semi-quantitative food frequency questionnaire (FFQ). The blood parameters of all participants were assessed. Mini-column kit (type G; Genall; Exgene) and the PCR-RFLP method were used to extract DNA and determine gene polymorphism, respectively. Three single nucleotide polymorphisms (SNPs), including Caveolin_1 (Cav_1), Melanocortin4 receptor (MC4R), and cryptochrome circadian regulator 1 (CRY1), were used to calculate GRS. The individual risk allele (0, 1, 2) for each SNP was calculated using the incremental genetic model. RESULTS: After controlling for confounders, a significant interaction was found for depression (ß = 0.026, 95% CI 0.003, 0.049, P = 0.028) and depression anxiety stress scales (DASS) score (ß = 0.059, 95% CI 0.001, 0.117, P = 0.046) on the NOVA classification system and GRS. CONCLUSIONS: The findings of this study showed a significant interaction between GRS and the NOVA classification system on mental disorders, including depression, DASS score and stress. There was also a significant relationship between the NOVA classification system and anxiety, DASS score, sleep quality and depression. Furthermore, a partially significant association was observed between GRS and stress. LEVEL OF EVIDENCE: Level V, cross-sectional descriptive study.

The relationship between food habits and physical activity and the IQ of primary school children.

BACKGROUND: Children's intelligence quotient (IQ) is influenced by various environmental and genetic variables. The current study aimed to determine how children's dietary choices and physical activity levels correlated with their IQ. METHODS: A total of 190 students (111 girls and 79 boys) between the ages of 8 and 10 were chosen randomly for this cross-sectional research. For all children, questionnaires were utilized to gather information on their anthropometry, socio-economic position, food habits, and 24-h memory. Children's physical activity questionnaire (CPAQ) was also used to gauge their level of physical activity. Raven's color progressive intelligence test was also used to gauge children's IQ. All the questions may be filled out online with the assistance of parents. SPSS software was used to gather and evaluate the generated data. RESULTS: Of 190 respondents, 79 (41.6%) are males, and 111 (58.4%) are girls. The results of the study showed that, a positive correlation between children's IQ and physical activity (P = 0.017, r = 0.17), if this relationship was not seen by gender. In addition, a positive correlation was observed between the IQ and food habits scores in all children (P = 0.001, r = 0.24), as well as by gender, that is, male (P = 0.04, r = 0.23) and female (P = 0.006, r = 0.26), which indicates that children with better food habits were associated with higher IQ. CONCLUSION: It was shown that elementary school children's IQ, food habits, and degree of physical activity are all positively correlated.

The relationship between the intake of branched-chain and aromatic amino acids and individuals' sleep quality based on body mass index, gender, and age.

Sleep disorder is a relatively common problem that causes chronic conditions such as obesity, diabetes, and cardiovascular diseases. It is believed that diet regulates sleep. So, investigating the relationship between branched-chain amino acids (BCAAs) and aromatic amino acids intake with sleep quality based on age, gender and Body Mass Index (BMI) is important. A total of 172 males and females aged 18-65 participated in this study. The questionnaires were given online to them, included demographic information, food frequency questionnaire (FFQ), International Physical Activity Questionnaire, and Pittsburgh Sleep Quality Index. The Chalder fatigue scale (CFQ) was also used to measure the extent and severity of fatigue. The intake of amino acids was investigated by FFQ. The relationship between amino acids intake and sleep quality was investigated using Pearson's test. The results showed that intake of energy, macronutrients, and some micronutrients had a significant relationship with the quality of sleep of men compared to that of women (P < 0.05). No difference in sleep duration was observed between the two genders. There was a significant, positive association between sleep duration and the intake of BCAA (CC = 0.205, P = 0.031) and aromatic amino acids (CC = 0.22, P = 0.02) in the participants with normal BMI. Significant differences were seen in the intake of BCAA according to BMI which these differences were between lean and obese people, lean and overweight people, obese and normal, and overweight people. It demonstrated that in individuals with normal BMI, amino acids, protein, and carbohydrate intake may affect sleep duration and with modification of these factors sleep quality may get better. More study is needed to confirm these findings.

Investigation the interaction of dietary fat quality indices and the MC4R gene in metabolically healthy and unhealthy overweight and obese women.

Obesity has become a common global problem. Some obese people can be metabolically healthy. Gene-environment interaction can be important in this context. This study aimed to assess the interaction between dietary fat quality indices and the Melanocortin 4 receptor (MC4R) gene in metabolically healthy and unhealthy overweight and obese women. This cross-sectional study was conducted on 279 women with overweight and obesity. The definition of metabolically healthy and unhealthy phenotypes was done according to Karelis criteria. Dietary assessment was done using a 147-item validated semi-quantitative food frequency questionnaire and dietary fat quality was assessed by cholesterol-saturated fat index (CSI) and the ratio of omega-6/omega-3 (N6/N3) essential fatty acids. MC4R was genotyped by polymerase chain reaction-restriction fragment length polymorphism technique. A generalized linear model was used to evaluate the interaction between dietary fat quality indices and the MC4R gene in both crude and adjusted models. Study subjects with higher ratio of N6/N3 had higher homeostatic model assessment for insulin resistance (HOMA IR) index (P = 0.03) and other variables showed no difference according to the tertile of CSI and N6/N3. Participants with the C allele of MC4R rs17782313 had lower height (P < 0.001) and higher HOMA index (P = 0.01). We found that the CC genotype of MC4R interacts with the N6/N3 ratio on the metabolically unhealthy phenotype in the crude model (ß = 9.94, CI 2.49-17.39, P = 0.009) and even after adjustment for all confounders (ß = 9.002, CI 1.15-16.85, P = 0.02, ß = - 12.12, CI 2.79-21.46, P = 0.01). The data of this study can justify one inconsistency observed in society, regarding dietary recommendations about metabolic health status. Those with CC genotype, are more likely to have an unhealthy phenotype with an increase in N6/N3 as one fat quality indices than those who do not have CC genotype. We found the interaction of dietary fat quality indices such as N6/N3 and the MC4R gene in metabolically unhealthy overweight and obese women.

The association between cholesterol/saturated fat index (CSI) and quality of sleep, and circadian rhythm among overweight and obese women: a cross-sectional study.

BACKGROUND: The decline in sleep quality is one of the main public health problems affecting the global population. Some studies have shown that a high-fat diet may be linked to changes in circadian rhythm and sleep quality. The cholesterol/saturated fatty acid index (CSI) determines the amount of cholesterol and saturated fatty acid (SFA) in people's dietary patterns and can affect the quality of sleep and circadian rhythm. However, to date, no studies have investigated the effect of this index on these two variables. Therefore, our aim was to investigate the relationship between CSI on circadian rhythm and sleep quality in obese and overweight women. METHOD: This cross-sectional study included 378 adult women who were obese or overweight. Using accepted techniques, anthropometric measurements, blood pressure readings, and biochemical variables were evaluated. A validated and trustworthy semi-quantitative food frequency questionnaire (FFQ 147 items) was used to gauge dietary intake. The CSI was measured to find out how much cholesterol and saturated fats were in the diet. Additionally, to assess circadian rhythm and sleep quality, respectively, the valid morning-evening questionnaire (MEQ) and Pittsburgh sleep quality index (PSQI) questionnaires were utilized. RESULT: The results of the multinomial logistic regression model of our analysis showed that a significant association was observed between circadian rhythm status with CSI score, and participants with one higher unit of CSI had a 7.3% more chance of being in the eveningness group than being in morningness category in the crude model (OR: 1.07; 95% CI 1.00, 1.14; P = 0.026). This association remains marginally significant when adjusting for age, energy intake, BMI, job status, thyroid, and smoking status (OR = 1.08; 95% CI 1.00, 1.16; P = 0.051). The binary logistic regression model showed that after controlling for potentially confounding variables, there was no significant association between sleep quality with CSI score, however, those with one higher unit of CSI had 1.6% more chance of having sleep problems (OR: 1.01; 95% CI 0.96, 1.06; P = 0.503). CONCLUSION: Our results indicated a direct marginally significant association between CSI with evening type in overweight and obese women. Future studies are needed to clarify the precise link between circadian rhythm and sleep behavior with fatty acid quality index.

Inflammatory biomarkers in overweight and obese Iranian women are associated with polyphenol intake.

BACKGROUND: The evidence shows that obesity is associated with chronic inflammation in obese subjects. Polyphenols are a complex group of plant secondary metabolites that may play a role in reducing the risk of obesity and obesity-related diseases. Given the scarcity of evidence on the association between inflammatory markers and dietary polyphenols intake in overweight/obese Iranian women, the current study aims to investigate this link. METHOD: The present cross-sectional study was conducted on 391 overweight and obese Iranian women aged 18-48 years (body mass index (BMI) ≥ 25 kg/m2). A 147-item food frequency questionnaire (FFQ) was used to assess dietary intake, as well as anthropometric indices including weight, height, waist circumference (WC), and hip circumference (HC) and biochemistry parameters including triglyceride (TG), total cholesterol (Chole), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), serum glutamic pyruvic transaminase (SGPT), serum glutamic-oxaloacetic transaminase (SGOT), galactin-3 (Gal-3), monocyte chemoattractant protein-1 (MCP-1), transforming growth factor beta (TGF-ß), interleukin-1 beta (IL_1ß), plasminogen activator inhibitor-1 (PA-I), serum leptin concentrations, and C-reactive protein of high sensitivity (hs-CRP) in all participants. The inflammatory markers were assessed using the enzyme-linked immunosorbent assay (ELISA). RESULT: The findings revealed a significant negative association between flavonoids intake and MCP-1 (P = 0.024), lignans intake and MCP-1 (P = 0.017), and Gal-3 (P = 0.032). These significant associations were observed between other polyphenols intake and IL_1ß (P = 0.014). There was also a significant positive association between other polyphenol intake and TGF-ß (P = 0.008) and between phenolic acid intake and TGF-ß (P = 0.014). CONCLUSION: Our findings suggest that a high polyphenol intake may help individuals to reduce systemic inflammation. Further large studies involving participants of different ages and genders are highly warranted.

Does the Mediterranean diet reduce the odds of diabetic nephropathy in women? A case-control study.

Background: In recent decades, the prevalence of chronic diseases such as diabetes is increasing. One of the major complications of diabetes is diabetic nephropathy (DN), so it is important to find a way that can delay or control the onset of DN. Therefore, in this study, we investigated the relationship between the Mediterranean diet (MED) and the odds of DN. Methods: This case-control study was performed among 210 women (30-65 years) who were referred to the Kowsar Diabetes Clinic in Semnan, Iran. Biochemical variables and anthropometric measurements were assessed. The food frequency questionnaire (FFQ) was used to calculate dietary intakes. Data from dietary intakes based on the FFQ were used to evaluate the MED score. Logistic regression was used to examine the associations. Results: Our results showed that in the crude model with higher adherence to the MED (OR: 0.272; 95% CI: 0.154, 0.481; P = 0.001), the odds of DN has reduced by 73%, and in model 1, after controlling for potential confounders, with higher adherence to the MED (OR: 0.239; 95% CI: 0.128, 0.447; P = 0.001), the odds of DN has reduced by 76% compared to low adherence. Also, in model 1, significant associations were observed between high consumption of grains (OR: 0.360; 95% CI: 0.191, 0.676; P = 0.001), legumes (OR: 0.156; 95% CI: 0.083, 0.292; P = 0.001), vegetables (OR: 0.273; 95% CI: 0.149, 0.501; P = 0.001), fruits (OR: 0.179; 95% CI: 0.093, 0.347; P = 0.001), fish (OR: 0.459; 95% CI: 0.254, 0.827; P = 0.01), and reduced odds of DN (P < 0.05). Conclusion: We observed that with higher adherence to the MED, the odds of DN had reduced through mechanisms. However, additional studies are needed to confirm these findings.

Interaction between caveolin-1 polymorphism and dietary fat quality indexes on visceral adiposity index (VAI) and body adiposity index (BAI) among overweight and obese women: a cross-sectional study.

BACKGROUND AND AIMS: Caveolin-1 (CAV-1) in adipocyte tissue and other body parts possesses numerous biological functions. In the present study, we sought to investigate the interaction between CAV-1 polymorphism and dietary fat quality indexes on visceral adiposity index (VAI) and body adiposity index (BAI) among overweight and obese women. METHODS: This study was conducted on 386 women aged 18-48 years old. Biochemical measurements were assessed by standard protocols. We used a food frequency questionnaire (FFQ) to calculate the dietary intake and the indexes of dietary fat quality intake. Anthropometric values and body composition were measured by standard methods. Finally, the CAV-1 genotype was measured using the PCR-RFLP method. RESULTS: We found marginally significant differences between AA and GG genotypes of waist-to-hip ratio (WHR) (P = 0.06) and BAI (P = 0.06) of participants after adjusting for potential confounders. For dietary intakes, after adjusting with the energy intake, mean differences in biotin (P = 0.04) and total fiber (P = 0.06) were significant and marginally significant, respectively. The interaction between two risk alleles (AA) with omega-6 to omega-3 ratio (W6/W3) on BAI, after adjustment for potential confounders (age, physical activity, energy intake, education), was marginally positive (ß = 14.08, 95% CI = - 18.65, 46.81, P = 0.07). In comparison to the reference group (GG), there was a positive interaction between the two risk alleles (AA) with W6/W3 ratio on VAI (ß = 2.81, 95% CI = 1.20, 8.84, P = 0.06) in the adjusted model. CONCLUSIONS: We found that there might be an interaction between CAV-1 genotypes with dietary quality fat indexes on VAI and BAI among overweight and obese women.

The effects of L-carnitine supplementation on glycemic markers in adults: A systematic review and dose-response meta-analysis.

Background and aims: Hyperglycemia and insulin resistance are concerns today worldwide. Recently, L-carnitine supplementation has been suggested as an effective adjunctive therapy in glycemic control. Therefore, it seems important to investigate its effect on glycemic markers. Methods: PubMed, Scopus, Web of Science, and the Cochrane databases were searched in October 2022 for prospective studies on the effects of L-carnitine supplementation on glycemic markers. Inclusion criteria included adult participants and taking oral L-carnitine supplements for at least seven days. The pooled weighted mean difference (WMD) was calculated using a random-effects model. Results: We included the 41 randomized controlled trials (RCTs) (n = 2900) with 44 effect sizes in this study. In the pooled analysis; L-carnitine supplementation had a significant effect on fasting blood glucose (FBG) (mg/dl) [WMD = -3.22 mg/dl; 95% CI, -5.21 to -1.23; p = 0.002; I 2 = 88.6%, p < 0.001], hemoglobin A1c (HbA1c) (%) [WMD = -0.27%; 95% CI, -0.47 to -0.07; p = 0.007; I 2 = 90.1%, p < 0.001] and homeostasis model assessment-estimate insulin resistance (HOMA-IR) [WMD = -0.73; 95% CI, -1.21 to -0.25; p = 0.003; I 2 = 98.2%, p < 0.001] in the intervention compared to the control group. L-carnitine supplementation had a reducing effect on baseline FBG ≥100 mg/dl, trial duration ≥12 weeks, intervention dose ≥2 g/day, participants with overweight and obesity (baseline BMI 25-29.9 and >30 kg/m2), and diabetic patients. Also, L-carnitine significantly affected insulin (pmol/l), HOMA-IR (%), and HbA1c (%) in trial duration ≥12 weeks, intervention dose ≥2 g/day, and participants with obesity (baseline BMI >30 kg/m2). It also had a reducing effect on HOMA-IR in diabetic patients, non-diabetic patients, and just diabetic patients for insulin, and HbA1c. There was a significant nonlinear relationship between the duration of intervention and changes in FBG, HbA1c, and HOMA-IR. In addition, there was a significant nonlinear relationship between dose (≥2 g/day) and changes in insulin, as well as a significant linear relationship between the duration (weeks) (coefficients = -16.45, p = 0.004) of intervention and changes in HbA1C. Conclusions: L-carnitine could reduce the levels of FBG, HbA1c, and HOMA-IR. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier: CRD42022358692.