The combined association of dietary inflammatory index and resting metabolic rate on cardiorespiratory fitness in adults

BACKGROUND

No study has examined the combined association of dietary inflammatory index (DII) of the diet and resting metabolic rate (RMR) on cardiorespiratory fitness (CRF). Therefore, we investigated the combined association between DII and RMR on CRF.

METHODS

This cross-sectional study was conducted on 270 adult subjects. The DII was calculated using a validated semi-quantified food frequency questionnaire. RMR was measured using an indirect calorimetric method. Socioeconomic status, anthropometric measures, body composition and blood pressure were documented by a trained interviewer. CRF was assessed by using Bruce protocol. Binary logistic regression was performed to find the association of CRF with DII/RMR categories in various models.

RESULTS

The participants categorized into four groups including: (1) low DII/high RMR, (2) low DII/low RMR, (3) high DII/low RMR, (4) high DII/high RMR. The mean of VO_2Max (mL/kg/min), VO_2max (L/min) and VO_2max relative to lean body mass (LBM) was lower in participants that were classified as high DII/low RMR compared to those in low DII/high RMR. After controlling for age, sex, education status, smoking status, and physical activity those who were in the high DII/low RMR group, compared to the low DII/high RMR group were 28% less likely to have higher VO_2max (ml/kg/min) (OR 0.72; 95% CI 0.18, 0.82, p = 0.04). Moreover, had 25% lower odds of VO_2max (L/min) which was significant (OR 0.75, 95% CI 0.11, 0.89, p = 0.03). In addition, were 21% less likely to have higher VO_2max (LBM) (OR 0.79; 95% CI 0.30, 0.92, p = 0.02).

CONCLUSIONS

Overall, consumption of a pro-inflammatory diet in combination with low RMR status is associated with lower odds of CRF compared to those who had anti-inflammatory diet in combination with high RMR status among Iranian healthy adults. This study suggests that researchers should focus on combined relationships rather than single pair-wise associations for having a better judgment.

Association of major dietary patterns with resting metabolic rate and body fatness in middle-aged men and women: Results from a cross-sectional study

Background: The association of dietary patterns and resting metabolic rate is still unclear. Aim: To study the relationship between the major dietary patterns, resting metabolic rate, and adiposity measures in Iranian adults. Methods: This is a cross-sectional study of 270 adults aged between 18-45 years old who lived in Tehran. Dietary intakes were achieved using food frequency questionnaire. Resting metabolic rate was measured using indirect calorimetry. Anthropometric measures were recorded using body composition analyzer. Results: Three major dietary patterns were identified by factor analysis labeled as healthy pattern (vegetables, fruits, and fruits juices, legumes, poultry, nuts, fish, egg, low fat dairy product, olive, and olive oil), mixed pattern (non-refined cereals, vegetables, vegetable oils, mayonnaise, high fat dairy product and, pickles), Western pattern (refined cereals, red or processed meat, soft drinks, sweets and desserts, Tea and coffee, salty snacks and French fries). After adjusting for covariates higher score of the Western dietary pattern was associated with lower resting metabolic rate (p = 0.023). There was significant decreasing difference in means for fat free mass across tertiles of mixed pattern when the first tertile was compared to the third tertile (p = 0.046). Higher adherence to healthy pattern was associated with lower body weight (p = 0.034), body mass index (p = 0.021), and higher resting metabolic rate (p = 0.033). Conclusions: Higher adherence to the Western dietary pattern was associated with a lower amount of resting metabolic rate. Also higher adherence to the healthy dietary pattern was associated with higher resting metabolic rate and lower body weight and body mass index. Further studies are required to examine the causal relationship between dietary patterns and resting metabolic rate.

Association between the empirical dietary inflammatory index and cardiorespiratory fitness in Tehranian adults in 2017–2018

Background

Inflammatory-related chronic diseases are increasing in Iran with high consumption of a diet containing pro-inflammatory potential and a sedentary lifestyle. The empirical dietary inflammatory index (EDII) was developed as a tool to assess dietary effects on systemic inflammation. We examined the hypothesis that specific dietary patterns reflecting systemic inflammation are associated with cardiorespiratory fitness (CRF) in Tehranian adults.

Methods

This cross-sectional study was carried out on 270 adults who are residents of Tehran. Dietary intake was assessed using a 168-item valid and reliable food frequency questionnaire. The EDII score was developed according to participant dietary intakes of 21-item pre-defined food groups. CRF was assessed by using a graded exercise treadmill test. Anthropometric measurements were assessed using standard methods. To discover the association between CRF and EDII, we used multivariable logistic regression analysis.

Results

Those who were in the third tertile of the EDII had 57% lower odds of having better VO2Max (ml/kg/min) than those in the first tertile (OR: 0.43; 95% CI: 0.16, 1.12, p = 0.01). There were no significant differences between tertiles of the EDII score in terms of VO2 (L·min) and VO2 (LBM) before and after adjusting for confounders. There was a significant decrease in VO2Max (ml/kg/min) across tertiles of the EDII after controlling for covariates (p-value = 0.04). There was a significant inverse association between the EDII score and VO2Max (ml/kg/min) (β = −0.35, p = 0.001).

Conclusions

Our finding demonstrated that a higher EDII might be associated with lower CRF in Tehranian adults. Prospective studies are needed to shed light on the causal link between the EDII and CRF.

Cross sectional determinants of VO2 max in free living Iranians: Potential role of metabolic syndrome components and vitamin D status

BACKGROUND AND AIMS

The purpose of the study was to evaluate the determinants of cardiorespiratory fitness (CRF) in Iranian adults and the potential contribution of vitamin D status.

METHODS

In this cross-sectional study 264 cases (116 men and 147 women aged 18-70 years old were participated. Maximal oxygen consumption (VO_{2 max}) was measured by the Bruce protocol utilizing treadmill exercise testing. Anthropometric data, body composition and fasting blood glucose and lipid concentrations were measured. Serum levels of 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)₂D) were assessed using enzyme-linked immunosorbent assay. Stepwise linear regression analysis was applied to determine significant predictors of VO2 peak. We tested non-linear (quadratic and cubic terms) versus linear association of adjusted (for determinants) VO2 max and vitamin D levels.

RESULTS

Multiple regression results showed that fat free mass, HDL-C and physical activity, waist circumference, age and sex were determinants of VO_{2 peak}. All of these explained the 65.3% of VO2 peak. There was a non-linear cubic association (R² = 0.03, p = 0.046) between serum 25(OH)D and adjusted VO2 peak in which 25(OH)D in people with a high 25(OH)D levels (>60 nmol/L), had better fitness and those with serum 25(OH) less than 20 nmol/L. We found no linear and non-linear associations between serum 1,25(OH)₂ D and adjusted VO_{2 max}.

CONCLUSIONS

Our results showed that waist circumference and HDL-C, as components of metabolic syndrome, contribute ∼2% to the variance in VO_{2 max}. Moreover, high concentrations of 25(OH)D but not 1,25(OH)₂ D may make additional contributions to CRF.

Mediterranean diet quality index is associated with better cardiorespiratory fitness and reduced systolic blood pressure in adults: A cross-sectional study

BACKGROUND

Literature suggests higher cardiorespiratory fitness (CRF) is inversely related to chronic diseases such as metabolic syndrome and cardiovascular disease and hypertension. The aim of this study was to assess the association of Mediterranean dietary quality index (Med-DQI) with CRF and hypertension in a sample of Iranian adults.

METHODS

This was a cross-sectional study on 270 healthy men and women, aged 18-45 years. Dietary intake and physical activity level were assessed through a validated food frequency questionnaire (FFQ); and the International Physical Activity Questionnaires (IPAQ), respectively. Cardiorespiratory fitness was assessed by using a graded exercise treadmill test. The association between Med-DQI and CRF was investigated using multiple regression models.

RESULTS

Participants in the top tertiles of Med-DQI, had higher VO2 max (mL/kg/min) (p = 0.02) and lower SBP (p = 0.01). When we controlled for age, sex, weight, smoking, physical activity and energy intake, the significant results were remained. Results of unadjusted linear regression shows that CRF was positively associated with cholesterol (p < 0.001) and fish (p < 0.001). Also, CRF was positively associated with vegetables and fruits (p < 0.001) and olive oil (p = 0.05). After adjustments for confounders, the significant associations of olive oil and cholesterol with CRF were disappeared while vegetables and fruits and total score of Med-DQI remained significant. There were no significant relations between saturated fatty acids meat, and cereals with Med-DQI.

CONCLUSIONS

Our results demonstrated that Med-DQI was associated with better CRF in Iranian adults and SBP. Further studies with interventional approaches are needed to better clarify the causal inference of these associations.

The Association of Dietary Energy Density and Body Composition Components in a Sample of Iranian Adults

Background: We aimed to investigate the association between the energy density (ED) of diet and body composition components in Iranian adults.

Methods: We conducted a cross-sectional study on 267 adults in Tehran. We obtained ED (kcal/g) using the two most common methods: ED1, ED from foods only with the exclusion of all beverages and ED2, from foods and all beverages. Body composition was measured using a multifrequency bio-impedance analysis. To find a strong association, we used both the linear and binary regression analysis in the three adjusted models.

Results: The mean of ED1 and ED2 was 1.34 ± 0.23 and 0.89 ± 0.20 kcal/g, respectively. Increasing the ED of diet in both methods was associated with a high intake of dietary fat, of saturated fatty acid (SFA), of monounsaturated fatty acid (MUFA), of polyunsaturated fatty acid (PUFA), of oleic and linoleic acids, accompanied by a low intake of fruits, vegetables, and some vitamins and minerals. There was a significant positive relationship between fat-free mass index (FFMI) and ED1 (β = 4.44, p = 0.02). However, we found no significant association between the consumption of ED1 and fat mass index (FMI) (0.28; 95% CI 0.08, 0.98; p = 0.07), and abdominal obesity (0.91; 95% CI 0.43, 1.94; p = 0.82). Also, ED2 had no association with FMI (0.86; 95% CI 0.26, 2.80; p = 0.81) and abdominal obesity (0.78; 95% CI 0.35, 1.72; p = 0.54). No significant associations were found between ED and other anthropometric indices and body composition components after considering the confounders.

Conclusion: This study supports the positive association between ED and poor dietary quality. However, our findings did not show significant associations of dietary energy density (DED) with anthropometric indices and body composition components. Further well-designed studies are required to investigate the exact link between DED and body composition.

The interaction of aging with serum 25(OH)D and 1,25(OH)2 D status on muscle strength

BACKGROUND

To investigate the combination relationship of age with serum 25-hydroxyvitamin D (25(OH) D) and 1,25-(OH)2D3 levels on muscle strength.

METHODS

We performed a cross-sectional study on 270 subjects containing 115 men and 155 women. Serum concentration of 25(OH) D and 1,25-(OH)2D3 were assessed. Hand grip strength (HGS) was measured using a digital dynamometer.

RESULTS

There was no significant difference in mean of HGS among tertiles of 25(OH)D (P = .350) and 1,25(OH)₂ D (P = .467) before and after controlling for potential confounding factors. A significant difference in HGS was found between age categories in both crude (P < .001) and adjusted models (P = .018), where mean grip strength increased in the three first age categories, but decreased in the last group (48-69 years old). There was also a significant interaction between age and 25(OH) D (P = .049) and 1,25-(OH)2D3 (P = .047) on HGS, in which the combination effect increased the mean of muscle strength up to middle age after adjusting for confounders.

CONCLUSIONS

Serum 25(OH)D and 1,25(OH)₂ D were not related to muscle strength. However, age, and combination of age with both 25(OH)D and 1,25(OH)₂ D, significantly resulted in improving in muscle strength up to middle age.

Lack of a relationship between vitamin D status and resting metabolic rate in Iranian adults

OBJECTIVES

Studies suggest a positive relationship between 25-hydroxy vitamin D (25(OH)D)) and resting metabolic rate (RMR). We aimed to determine whether this relationship was also true of populations with very low vitamin D status.

METHODS

Fat mass (FM) and fat free mass (FFM) were determined from multifrequency bioimpedance analysis (InBody 720, Korea). RMR was based on indirect calorimetry (Cortex Metalyser 3B, Germany). Fasting blood measurements of 25(OH)D concentration, glucose and triglycerides were measured. Data were analyzed separately on men and women by tertile of vitamin D status and multiple linear regression analysis.

RESULTS

Two hundred and sixty-three subjects (115 males; 148 females) with a mean age of 37 years and mean %body fat of 30.5% were studied. In women but not men, age, body weight, waist circumference, FM, and FFM increased significantly across tertiles of 25(OH)D. However, there was no difference in unadjusted or adjusted RMR across tertiles of 25OHD in both women and men. Stepwise forward regression analysis showed that age and FFM in men, age and FM in women but not by 25(OH)D, were determinants of RMR. In addition, RMR adjusted for age, sex, FM, FFM and triglyceride-glucose index did not relate to 25(OH)D when linear (r = 0, P = .98), quadratic (r = 0.008, P = .34), or cubic (r = 0.010, P = .43) relationships were tested.

CONCLUSIONS

Residual variation in RMR did not relate to vitamin D status in a group of Iranian adults with very low vitamin D status. Future studies could examine whether such a relationship holds true, after the normalization of vitamin D status.

Cardiorespiratory fitness is positively associated with both healthy and western dietary pattern in Iranian middle-aged

Background: The association between dietary patterns and cardiorespiratory fitness (CRF) is not well established. Objective: We sought to investigate association between a posteriori dietary pattern and CRF in middle-aged adults. Design: Adults (n = 276), aged 20-74 years, who were residents of Tehran, Iran were recruited. Diet was assessed by using a validated 168-item semi-quantitative food frequency questionnaire. Principal component analysis was used to derive dietary patterns. Socio-economic status, anthropometric measures, body composition, and blood pressure were recorded. CRF was assessed by using a graded exercise treadmill test. Analysis of variance and linear regression models were used to discern the association between dietary patterns and CRF. Results: Higher scores of the healthy dietary pattern had no association with VO_2max (p = 0.13). After controlling for potential confounders, VO_2max was positively associated across tertiles of healthy dietary patterns (p < 0.001). Higher adherence to the "mixed" dietary pattern was inversely related to VO_2max (p < 0.01). After adjusting for confounders, the significant association disappeared (p = 0.14). Higher scores of the "Western" dietary pattern was not associated with VO_2max (p = 0.06). However, after controlling for potential confounders, VO_2max was positively associated with the "Western" dietary pattern (p = 0.01). A positive linear association between the "healthy" dietary pattern and CRF for the total sample (R² = 0.02; p < 0.01) were presented. Conclusions: Overall, our findings suggest that higher adherence to a "healthy" and "Western" dietary pattern was positively associated with CRF. However, further studies are required to examine and clarify the causal relationship between dietary patterns and CRF.

The association of plant-based dietary patterns with visceral adiposity, lipid accumulation product, and triglyceride-glucose index in Iranian adults

BACKGROUND

We sought to investigate whether adherence to a more plant-based, and less animal-based, diet is associated with visceral adiposity, lipid accumulation product (LAP), and triglyceride-glucose index (TyG) in Iranian adults.

METHODS

This cross-sectional study was conducted on 270 adults aged between 18-75 years old. We created three plant-based diets. including an overall plant-based diet index (PDI), hPDI, and uPDI based on tertiles regarding the intake of animal- or plant-based food items obtained from a semi quantitative food-frequency questionnaire.

RESULTS

Higher hPDI was significantly associated with lower body mass index (BMI) (P-value = 0.01), lower waist circumference (P-value<0.001), and lower waist-hip ratio (P-value<0.001). A significant increase was found for high density lipoproteins (HDL) (P-trend <0.001) with a significant decrease for LAP (P-value = 0.03) in those with higher adherence to hPDI. Moreover, greater adherence to PDI was associated with a significant increase in diastolic blood pressure (DBP) (p-value = 0.01) and fat free mass (FFM) (p-value = 0.01). There were no significant associations between PDIs and TyG and VFA.

CONCLUSION

We found that a higher hPDI score was significantly associated with better anthropometric measurements. A significant increase was found for HDL and a significant decrease was found for LAP on hPDI. However, a higher PDI score was significantly associated with higher DBP and higher FFM.

Association of Dietary Patterns with Visceral Adiposity, Lipid Accumulation Product, and Triglyceride-Glucose Index in Iranian Adults

In the present study, we sought to examine the association between dietary patterns (DPs) and visceral adiposity, lipid accumulation product (LAP), and triglyceride-glucose index. This cross-sectional study was conducted on adults aged between 18–45 years old who lived in Tehran, Iran, between February 2017 and December 2018 (n = 270). DPs were derived using principal component analysis. We used analysis of variance to examine differences in continues variables across tertiles of major DPs. Subsequently, for the modeling of these relationships, and also considering the possible effect of the confounding factors, multivariate regression was used. Three DPs were identified: healthy pattern, mixed pattern, and western pattern, respectively. Compared with individuals in the lowest category of mixed pattern, those in the highest category had lower fasting blood sugar (96.26 ± 11.57 vs. 101 ± 28.66, p = 0.01). A significant association was found between healthy pattern, after adjustment for potential confounders, and odds of LAP; such that individuals in the top category of healthy pattern score were 71% less likely to have a high LAP compared with those in the lowest category (odds ratio, 0.29; 95% confidence interval, 0.10–0.81). We found that adherence to a healthy DP was associated with decreased LAP. To confirm the veracity of these findings, more studies should be conducted.