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

Dietary energy density, metabolic parameters, and blood pressure in a sample of adults with obesity

BACKGROUND

Several previous studies revealed the role of dietary energy density (DED) in developing obesity and related disorders. However, the possible role of DED in triggering cardiometabolic risk factors of individuals with obesity has not been studied yet. This study aimed to evaluate the association between DED and anthropometric parameters, blood pressure, and components of metabolic syndrome (MetS) (such as glycemic markers, lipid profile, and blood pressure) among individuals with obesity.

METHODS

In this cross-sectional study, we included 335 adults with obesity (BMI ≥ 30 kg/m²) aged 20-50 years in Tabriz and Tehran, Iran. Dietary intake was assessed by a validated semi-quantitative Food Frequency Questionnaire (FFQ), including 168 food items; then, DED was calculated. MetS was defined based on the guidelines of the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III). Enzymatic methods were used to assess serum lipids, glucose, and insulin concentrations. Blood pressure was measured by sphygmomanometer and body composition by bioelectrical impedance analysis (BIA).

RESULTS

Participants in the higher tertiles of DED had more intake of carbohydrate, dietary fat, saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), and meat, fish, poultry (MFP). Increasing the DED in both methods had no association with systolic blood pressure (SBP), fasting blood sugar (FBS), low-density lipoprotein cholesterol (LDL-C), insulin, triglyceride (TG), and homeostatic model assessment of insulin resistance (HOMA-IR) even after adjustment for confounders. However, diastolic blood pressure (DBP) decreased in second tertile of DED I (β = 0.921, P = 0.004). The quantitative insulin-sensitivity check index (QUICKI) in second tertile of both DED methods had significant positive association with DED. In the second tertile of DED II, while total cholesterol (TC) significantly decreased (P crude = 0.036, P adjusted = 0.024), high-density lipoprotein cholesterol (HDL-C) increased (β = 1.096, p = 0.03). There was no significant changes in biochemical parameters in third tertile of DED I and II even after adjustment for covariates. Also, higher tertiles of DED was associated with reduced prevalence of MetS.

CONCLUSION

High DED was associated with lower levels of blood pressure and TC but elevated levels of HDL and QUICKI independent of such confounders as age, BMI, sex, and physical activity. Further longitudinal studies are warranted to better elucidate casual associations.

Association of n-3 polyunsaturated fatty acid intakes with juvenile myopia: A cross-sectional study based on the NHANES database

Aim

Inflammation is involved in the development of myopia. n-3 polyunsaturated fatty acids (n-3 PUFAs) have vasodilating and anti-inflammatory effects, which may be involved in controlling myopia. It is of great significance to explore the relationship between n-3 PUFA intakes and juvenile myopia in order to control and alleviate myopia among teenagers through dietary intervention.

Methods

Sociodemographic data, information of nutrient intakes, cotinine, PUFAs, and eye refractive status of 1,128 juveniles were extracted from the National Health and Nutrition Examination Survey (NHANES) database in this cross-sectional study. PUFAs contained total polyunsaturated fatty acid (TPFAs), alpha-linolenic acid, octadecatetraenoic acid, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA). Covariates were screened by comparison among groups of normal vision, low myopia, and high myopia. The association between n-3 PUFA intakes and the risk of juvenile myopia was evaluated using univariate and multivariate logistic regression analyses with odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Among the juveniles, 788 (70.68%) had normal vision, 299 (25.80%) had low myopia, and 41 (3.52%) had high myopia. There were significant differences in average EPA and DHA intakes among the three groups, and mean DPA and DHA intakes in the normal vision group were lower than those in the low myopia group (P < 0.05). After adjustment for age, gender, TPFAs, and cotinine, a high dietary intake of EPA (≥11 mg/1,000 kcal) in juveniles seemed to be associated with the risk of high myopia (OR = 0.39, 95% CI: 0.18-0.85), while no significant associations were identified between n-3 PUFA intakes and the risk of low myopia.

Conclusion

A high dietary intake of EPA may be associated with a decreased risk of high myopia among juveniles. A further prospective study is needed to validate this observation.

Longitudinal Association of Dietary Energy Density with Abdominal Obesity among Chinese Adults from CHNS 1993–2018

Few studies have explored the longitudinal association between dietary energy density and waist circumference and abdominal obesity in adults in China. This study aimed to analyze the relationship between dietary energy density and waist circumference and abdominal obesity in Chinese residents aged 18–64. Using data from the CHNS from 1993 to 2018, 25,817 adult residents aged 18 to 64 were selected for the study. Three consecutive 24-h dietary recalls and home-weighed seasonings were used to assess food intake. A multilevel model was used to analyze the relationship between dietary energy density and waist circumference and abdominal obesity. The results showed that compared with the lowest dietary energy density group, females had an increased risk of abdominal obesity (OR = 1.16, 95% CI: 1.05, 1.29), and females’ waist circumference increased significantly by 0.24 cm (95% CI: 0.39–1.09) in the highest dietary energy density group. No association between dietary energy density and waist circumference and abdominal obesity was observed in males. This study shows that higher dietary energy density is significantly associated with females’ waist circumference and abdominal obesity. Further research on high dietary energy density and abdominal obesity will provide scientific basis for the effective control of abdominal obesity.