Introduction
The metabolic syndrome (MetS) is a collection of metabolic abnormalities, including central obesity, dyslipidemia, hypertension, and insulin resistance.(Reference Rochlani, Pothineni and Kovelamudi1) Approximately 40–46 per cent of world’s adult population have the risk factor for MetS.(Reference Alberti, Zimmet, Shaw and Grundy2) The prevalence of MetS in the Asia-Pacific region varies by region, age group, and gender, with 25% of the population affected.(Reference Ranasinghe, Mathangasinghe and Jayawardena3) MetS is strongly associated with increased risk of cardiovascular disease (CVD) and type 2 diabetes (T2D).(Reference Kalan Farmanfarma, Kaykhaei and Adineh4) Consequently, the increasing prevalence of MetS worldwide has become a significant public health concern.(Reference Farmanfarma, Kaykhaei and Mohammadi5,Reference Naghipour, Joukar and Nikbakht6)
Lifestyle changes, such as quitting smoking, increasing physical activity, and especially reducing consumption of processed meat and sugar-sweetened beverages (SSBs), have been shown to be effective in preventing and treating MetS.(Reference Pérez-Martínez, Mikhailidis and Athyros7,Reference Kim, Chung and Kim8) In this study, our primary objective is to investigate the relationship between beverage quality and the prevalence of MetS, aiming to uncover potential dietary factors that could influence metabolic health. Beverage consumption is a critical aspect of dietary habits and is associated with MetS. The type and amount of beverages consumed can significantly affect overall nutrient intake and health outcomes.(Reference Duffey and Popkin9) Previous studies have shown that SSBs are positively associated with MetS and its components.(Reference Shin, Kim and Ha10,Reference Crichton, Alkerwi and Elias11) Conversely, some studies have shown that higher consumption of non-caloric beverages such as tea and coffee is associated with a lower risk of MetS and its components.(Reference Grosso, Stepaniak and Micek12,Reference Marventano, Salomone and Godos13) However, another study found no significant association between coffee consumption and MetS.(Reference Wong, Wong and Zhang14)
Nevertheless, there is no consensus on how to define and measure healthy beverage consumption. Some studies have used a simple classification of SSBs versus non-SSBs, while others have taken a more comprehensive approach, such as the healthy beverage score (HBS) or the healthy beverage index (HBI).(Reference Duffey and Davy15,Reference Di Pietro, Baldassarre and Cichelli16) HBS and HBI are scoring systems that assign points to different beverage types based on their health benefits, including nutrient content and potential health benefits. Higher scores indicate higher consumption of healthier beverages such as water, tea, and low-fat milk and lower consumption of less healthy beverages such as SSBs. Therefore, they can be appropriate tools for evaluating the quality of beverage consumption and its association with various diseases, as they comprehensively consider both the quality and quantity of all beverage types and utilise a complex scoring system.(Reference Di Pietro, Baldassarre and Cichelli16,Reference Hedrick, Myers and Zoellner17)
To date, few studies have examined the association between HBI and MetS, while most studies focusing on the effects of only one type of beverage, and no research has yet examined the association between HBS and MetS. Recently, M.Nouri et al. demonstrated that maybe a higher HBI score is related to a lower risk of MetS.(Reference Nouri, Shateri and Rezaei18) Also, another cross-sectional study found that higher HBI can be related with lower risk factors of MetS among over weigh and obese individuals.(Reference Jahanbazi, Abbasalizad Farhangi and Tousi19) However, the big difference with the current study is that we additionally evaluated HBS to receive more comprehensive results and we encompassed a more diverse population.
Methods
Participants and study design
This study was conducted according to the guidelines laid down in the Declaration of Helsinki, and all procedures involving human subjects were approved by the local ethics committee of Shiraz College of Medical Sciences (code: IR.SUMS.SCHEANUT.REC1402.002). Written informed consent was obtained from all subjects, and they are accessible.
The study population included adults who participated in the Shiraz University of Medical Sciences Employees’ Health Cohort Study (SUMS EHCS), conducted between 2018 and 2019, is a comprehensive research endeavour designed to provide insights into various aspects of employee health. This longitudinal study encompasses a diverse range of participants from different occupational backgrounds within the university setting. With meticulous attention to detail and adherence to rigorous research protocols.
Under the guidance of Dr. Masoumi, a renowned expert in the field of nutrition, the SUMS EHCS places particular emphasis on dietary factors and beverage intake in relation to overall health outcomes. Dr. Masoumi’s expertise ensures that the study design incorporates robust methodologies for the collection and analysis of dietary data, thereby enhancing the validity and reliability of the findings. The cohort study included participants aged 20 to 65 who were officially or contractually employed at Shiraz College of Medical Sciences. After excluding 1,170 individuals who either had missing data on any MetS components, struggled to understand the questions, did not participate in the survey, were menstruating or pregnant, or reported a daily energy intake outside the range of 800 to 4,200 kcal, A total of 3,380 participants were included in the statistical analysis.
Anthropometric assessment
Anthropometric measures, including weight, height, body mass index (BMI), waist circumference (WC), and hip circumference (HC), are essential for evaluating obesity and its association with MetS. Weight was measured with minimal clothing and no shoes on a scale with an accuracy of 0.1 kg. Height was measured using a standard method with an accuracy of 0.1 cm while participants stood with shoulders, hips, and legs against the wall, without shoes. BMI was calculated by dividing weight by height squared (kg/m2). WC was measured at the narrowest part of the WC and HC was measured at the widest part of the hip using a rigid tape with an accuracy of 1.0 cm.(Reference Madden and Smith20) In addition, body composition data were obtained using the BIA InBody 770.(Reference Waterland, Travisano and Tahiliani21)
Dietary intake, HBI and HBS
Food intake information was collected using a modified semi- 125 item food frequency questionnaire (FFQ) based on Iranian foods. The validity and reliability of the questionnaire had been confirmed in previous internal and external studies.(Reference Willett, Sampson and Stampfer22,Reference Ahmadijoo, Eftekhari and Masoumi23) Trained interviewer (A.Torabi Ardekani) administered the questionnaire, and participants reported their consumption of each food item daily, weekly, monthly, or annually during the past year. Energy and nutrient intakes were calculated using the adapted version of NUTRITIONIST IV for Iranians (version 7.0; N-Squared Computing, Salem, OR, United States).
Beverage intake was determined using the FFQ about food beverage like tea, coffee, high-fat and low-fat milk, soda, fruit juices, and additional questions on water intake in different seasons. HBS and HBI were calculated based on beverage consumption according to methods previously published by Dufey and Davy.(Reference Duffey and Davy15) HBI divided beverages consumed into eight groups, including water, tea, coffee without sugar, low-fat milk, high-fat milk, natural fruit juices, SSBs, diet beverages, and alcoholic beverages. The index was reported on a scale of 0 to 100, with a higher value indicating healthier beverage consumption. In the Iranian population, in which alcoholic and diet beverages were not consumed, the final HBI value ranged from 0 to 90.(Reference Ayoubi, Yaghoubi and Pahlavani24) The HBS included seven components that were classified as adequate intake (low-fat milk, tea, and coffee without sugar) and moderate intake (high-fat milk, SSBs, diet beverages, fruit juice, and alcoholic beverages). Each component was assigned a score from 1 to 4 depending on consumption, resulting in a total score from 7 to 28. Because data on the consumption of alcoholic beverages and diet drinks were not available in this study, the HBS ranged from 5 to 20.(Reference Hu, Anderson and Crews25)
Covariates
Covariates included sex, age, education level, marital status, number of children, smoking history, hookah use, drug and alcohol use, and clinical illness. Data on chronic diseases and medication use were also collected. Socioeconomic status (SES) was assessed using a well-being index (WI) based on household items and amenities through principal component analysis (PCA). The WI was divided into tertiles, with the first tertile representing the lowest income category and the last tertile representing the highest income category.
Physical activity
Physical activity data were collected using the International Physical Activity Questionnaire (IPAQ), which assesses the frequency and intensity of various activities. Participants were categorised into three activity levels: light, moderate, and intense.(Reference Vasheghani-Farahani, Tahmasbi and Asheri26)
MetS and biochemical assessment
MetS was defined according to National Cholesterol Education Program (NCEP) Adult Treatment Panel criteria III (ATP III) and requires the presence of at least three of the following five components: central obesity, elevated triglycerides, decreased high-density lipoprotein (HDL) cholesterol, elevated blood pressure, and elevated fasting blood glucose. Blood pressure was measured with a blood pressure monitor after at least 15 minutes of rest, and fasting blood samples were collected for biochemical analyses, including fasting blood glucose and lipid profile.(Reference Huang27)
Statistical analysis
Statistical analysis was performed with SPSS software (version 26.0, Inc, Chicago, IL), and a significance level of P < 0.05 was considered statistically significant. Because of the nonnormal distribution of variables in the population, nonparametric tests were performed. Baseline characteristics were compared with Mann-Whitney and chi-square tests for continuous and categorical variables, respectively. SES was indicated by the PCA-derived wealth index.(Reference Djalalinia, Saeedi Moghaddam and Sheidaei28) The Mann-Whitney test was used to compare intake of macronutrients and HBI components between groups with and without MetS. Univariate logistic regression was used to assess the relationship between the tertiles of HBI and HBS with the probability of MetS. Multivariate analysis was performed using the backward LR method to account for the effects of confounding variables (variables with P < 0.25 in the univariate analysis assume cofounder in multivariate analysis). Univariate and multivariate analyses were also performed to assess the relationship between HBI and HBS tertiles with each component of MetS.
Results
This cross-sectional study included a total of 3,380 participants, of whom 876 had MetS and 2,504 did not. Table 1 shows the demographic and baseline information of the two groups separately. The median age in the MetS group was 45 years, whereas it was 44 years in the without MetS group. The median BMI was 25.71 in the MetS group and 28.39 in the group without MetS.
Table 1. The basic characteristic of the study population
Abbreviation: BMI, body mass index; WC, waist circumference; HC, hip circumference; SBP, systolic blood pressure; DBP, diastolic blood pressure; HDL-c, high density lipoprotein cholesterol; MUFA, mono unsaturated fatty acid; PUFA, poly unsaturated fatty acid; HBS, healthy beverage score; HBI, healthy beverage index; SES, socioeconomic status.
1Using Mann–Whitney for abnormal continuous variables.
2 Using chi-square test for categorical variables.
Values are median (IQR) for continuous and percentage for categorical variables.
Table 2 shows the mean energy intake in the MetS population, which was approximately 2146 kcal compared to 2035 kcal in the without MetS group. When the HBI components were examined, the median SSB intake was 33.86 cc in the MetS group and 24.10 cc in the without MetS group, and the difference was statistically significant. In addition, the total energy intake of beverages was 115.39 kcal in the MetS group and 106.88 kcal in the group without MetS. While, the median intake of high-fat milk was the same in both groups (65.53 ml), but the interquartile range was significantly higher in the MetS group, indicating higher consumption of high-fat milk in individuals with MetS. Also, participants with MetS had higher coffee and tea consumption than the group without MetS.
Table 2. Dietary nutrient intake and Healthy beverage index components between population with and without Metabolic Syndrome
Using Mann–Whitney for abnormal continuous variables.
Values are median (IQR).
Compared with the first tertile, there was a significant association between the last tertile of HBI and a lower odds ratio (OR) for MetS (OR = 0.66, 95% CI: 0.54–0.81; P < 0.001). After adjustment for confounding factors, the third tertile of HBI was significantly associated with a 40% lower risk for MetS compared with baseline (OR = 0.60, 95% CI: 0.48–0.74, P < 0.001) (Table 3). In Table 4, participants in the second tertile of HBS had a 30% lower risk for MetS compared with the first tertile. After adjustment for confounding factors, higher HBS in the second and third tertiles was significantly associated with lower odds of MetS compared with baseline (second tertile: OR = 0.64, 95% CI: 0.52–0.79, P < 0.001; third tertile: OR = 0.80, 95% CI: 0.65–0.97, P = 0.030).
Table 3. Associations between study variables with healthy beverage index in total population
SES, socioeconomic status.
Missing values in each variable were excluded from the analyses.
Using backward LR method for multivariate analysis.
Significant values are shown in bold.
Confounders: Age, BMI, Energy, Gender, SES, Smoke exposure, Alcohol use, Education, Medication or Supplementation.
Table 4. Associations between study variables with healthy beverage Score in total population
SES, socioeconomic status.
Missing values in each variable were excluded from the analyses.
Using backward LR method for multivariate analysis.
Adjusted for variables with P value <0.25 in univariate analysis.
Significant values are shown in bold.
Confounders: Age, BMI, Energy, Gender, SES, Smoke exposure, Alcohol use, Education, Medication or Supplementation.
The association between HBI tertiles and MetS components was assessed. After adjustment for confounding factors, the association between the third tertile of HBI and lower levels of Blood pressure and WC remained significant (OR = 0.64, 95% CI: 0.52–0.79, P < 0.001) (OR = 0.70, 95% CI: 0.54–0.91, P = 0.009) (Supplemental Table 1). Supplemental Table 2 shows data on each component of the MetS and their relationship with HBS. Overall, there was a significant association between the second tertile of HBS and a 21% lower risk of hypertension compared with baseline (OR = 0.79, 95% CI: 0.64–0.97, P = 0.025).
Discussion
This study examined 3,380 employees of SUMS and found that higher adherence to healthy beverage patterns, as measured by HBI and HBS, was associated with a lower risk of MetS. In addition, higher HBI and HBS levels both were associated with lower blood pressure levels, and only higher HBI was associated with lower WC.
In line with findings of the current study, a previous research have shown that consuming healthy beverages such as water, tea, coffee, and low-fat milk and reducing the consumption of SSB can reduce the risk of MetS.(Reference Mena-Sánchez, Becerra-Tomás and Babio29,Reference Yamagata30) However, in this study, the overall beverage pattern was assessed using the HBI and HBS which represent the quality and quantity of beverage intake based on nutrient content. A recent systematic review and meta-analysis by A.Cabrejas et al. found a positive association between higher consumption of SSB and increased risk of MetS.(Reference Muñoz-Cabrejas, Guallar-Castillón and Laclaustra31) Also, a study by J.Mattei et al. demonstrated that replacing one serving of soda with homemade fruit juice could reduce the likelihood of MetS by 30% in the Hispanic population.(Reference Mattei, Malik and Hu32) In addition, a cohort study with a 6-year follow-up found that moderate coffee consumption may be associated with a lower risk of MetS.(Reference Corbi-Cobo-Losey, Martinez-Gonzalez and Gribble33) However, another cohort study with 14 years of follow-up showed no significant association between coffee, tea, alcohol, and diet cola consumption and MetS risk.(Reference Appelhans, Baylin and Huang34) Another study discovered that elevated HBI were linked to higher risk of MetS among men, whereas a reduced risk of MetS was observed among women; and the researchers proposed that the identical beverages may fulfil distinct functions in males and females.(Reference Liu, Zhu and Dong35) As you can see, there is still no consensus on the specific effects of different beverages on the MetS, and it is important to consider the complex interactions between different beverage types and their effects on health. The beneficial effects of healthy beverage patterns on the MetS can be attributed to several mechanisms. First, lower consumption of SSB has been consistently associated with decreased risk of obesity, CVD, and MetS in previous studies.(Reference Neelakantan, Park and Chen36) Second, higher consumption of low-fat milk has been associated with a preventive effect against MetS.(Reference Mena-Sánchez, Becerra-Tomás and Babio29) Third, lower total energy intake from beverages may reduce the risk of MetS and its components.(Reference Seo, Kim and Kwon37)
Also, the present study has unveiled a noteworthy correlation between higher adherence to HBI and HBS with diminished blood pressure levels. The implications of these findings are particularly significant, given that hypertension is a prominent risk factor for CVD, the primary cause of global mortality.(Reference Mahdavi-Roshan, Salari and Ghorbani38) This observation aligns with previous research that has underscored the salutary impact of specific beverages on blood pressure regulation.(Reference Hu, Anderson and Crews25) For instance, a comprehensive meta-analysis of randomised controlled trials has revealed that the consumption of green tea significantly mitigates both systolic and diastolic blood pressure.(Reference Peng, Zhou and Wang39) In a prospective study conducted by L.Chen et al., it was discerned that a reduction in the intake of SSBs by one serving is correlated with a 1.8 mmHg decrease in systolic blood pressure and a 1.1. mmHg decrease in diastolic blood pressure in adults with prehypertension or stage 1 hypertension(Reference Chen, Caballero and Mitchell40) On the other hand, a meta-analysis of cohort studies has indicated an absence of significant association between coffee consumption and hypertension risk.(Reference Han, Oh and Myung41) An intriguing outcome of a study by A.Miranda et al. posits that the beneficial effects of coffee consumption against hypertension are exclusive to the non-smoking demographic.(Reference Miranda, Goulart and Benseñor42) The potential mechanisms underpinning the positive influence of higher adherence to HBI and HBS on blood pressure encompass the presence of bioactive compounds, such as polyphenols and caffeine. These compounds have been demonstrated to enhance endothelial function, attenuate inflammation, and stimulate vasodilation.(Reference Di Pietro, Baldassarre and Cichelli16) Another plausible explanation pertains to hydration status, which is recognised as a crucial determinant in blood pressure regulation. Increased consumption of water and other low-sugar beverages may facilitate the release of atrial natriuretic peptide (ANP) and augment right atrium pressure.(Reference Ruskoaho, Lang and Toth43) Furthermore, the intake of natural fruit juice, rich in magnesium and potassium, can contribute to blood pressure reduction.(Reference Liu, Zhu and Dong35) Beyond these specific beverages, the overall quality and quantity of an individual’s beverage consumption may also influence blood pressure regulation because, it is possible that the components of HBI or HBS exert synergistic effects with each other.
This study also found a negative association between higher adherence to HBI and WC, indicating healthier body composition and lower risk of chronic diseases such as diabetes and CVD.(Reference Mohammadifard, Nazem and Sarrafzadegan44) This finding is consistent with other studies that have reported a protective effect of higher adherence to HBI against abdominal obesity.(Reference Rasaei, Hosseininasab and Shiraseb45,Reference Gholami, Samadi and Soveid46) Conversely, a national cross-sectional study in Chinese children and adolescents found no significant association between SSBs consumption and overall obesity.(Reference Gui, Zhu and Cai47) One possible explanation for the inverse association between HBI and WC is that healthy beverages are usually low in calories and sugar, which may help people maintain a healthy weight and prevent central obesity. In addition, consumption of healthy beverages such as water and tea may promote feelings of satiety(Reference Burls, Price and Cabello48) and reduce consumption of high-calorie sugary beverages, which are known to contribute to weight gain and obesity.(Reference Malik, Schulze and Hu49)
This study has several strengths, including novelty in choosing the title, access to a large and valid sample of a cohort study, adjustment for confounding factors, and assessment of the MetS and its individual components. However, there are limitations to note. First, the cross-sectional design prevents the identification of a cause-and-effect relationship. Second, the food intake frequency questionnaire relies on participants’ long-term memory, which may introduce recall bias. Finally, while our research design adhered to rigorous methodologies and employed standardised procedures for data collection and analysis, inherent biases or confounding factors may have influenced the outcomes. Additionally, the study population comprised individuals from a specific demographic or clinical setting, which may limit the generalisability of our results to the broader population.
Conclusion
In conclusion, a higher proportion of healthy beverage patterns, as measured by HBI and HBS, was associated with lower MetS risk, particularly lower blood pressure levels. Further studies are needed to confirm the association of HBI and HBS with MetS in different populations.
Supplementary material
The supplementary material for this article can be found at https://doi.org/10.1017/jns.2024.65
Acknowledgements
This article results from a research project approved by the local ethics committee of Shiraz College of Medical Sciences. This research has been done for the master thesis. We would like to thank the students and professors who helped us in this research.
Authorship
K L, M N and S M designed the study. A A and F A collected the data; M N, K L, and M Z analysed the data; K L interpreted the results; K L and S M conceived and designed the study. K L, Z M and Z G wrote the manuscript. All authors discussed the results and revised the manuscript. All authors read and approved the final manuscript.
Financial support
This study was conducted without external funding.
Competing interests
Dr. Masoumi, the corresponding author of this article, also served as the principal designer of the Shiraz University of Medical Sciences Environmental Health Cohort Study (SUMS EHCS). This dual role as both the corresponding author and the study designer may present a potential conflict of interest. However, steps have been taken to ensure that the study design, data collection, analysis, and interpretation of the results were conducted with the utmost integrity and transparency, independent of any personal interests.
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