Specific micronutrient concentrations are associated with inflammatory cytokines in a rural population of Mexican women with a high prevalence of obesity

Dietary Energy Density Is Associated with Biomarkers of Chronic Diseases-A Cross-Sectional Study of School-Aged Children in Rural Mexico

Background

Dietary energy density (DED) is associated with chronic disease markers in adults. However, results in children are still controversial.

Objective

To evaluate the DED of children and its association with obesity and biomarkers of chronic disease.

Methods

In this cross-sectional study, we recruited 284 children (6-10 y) from rural Mexico. Dietary intake was assessed using three 24-h recalls. DED was calculated for "foods only" (DEDfo) and for "foods and beverages" (DEDfb). Weight, height, and body fat percent (dual-energy X-ray absorptiometry) were measured. Inflammatory cytokines, lipid profile, leptin, and insulin resistance were determined from a fasting blood sample.

Results

DEDfo was 1.91 ± 0.36 kcal/g and DEDfb was 1.36 ± 0.31 kcal/g. Higher DEDfo and DEDfb were associated with higher risk to have insulin resistance [odds ratio (OR) = 3.92, 95% confidence interval (CI): 1.66, 9.22, P < 0.01; OR = 3.51, 95% CI: 1.25, 9.87, P = 0.02, respectively]. Higher DEDfo was associated with higher risk of higher leptin levels (OR = 3.17, 95% CI: 1.01, 10.23). Also, DEDfo and DEDfb were associated with higher concentrations of cholesterol (β = 11.67, 95% CI: 1.81, 19.53, P = 0.03; and β = 11.74, 95% CI: 2.69, 20.74 P = 0.01, respectively) and higher odds of having high insulin concentrations (OR = 2.52, 95% CI: 1.26, 5.06, P = 0.01; and OR = 2.95, 95% CI: 1.30, 6.70, P = 0.01). DEDfo and DEDfb were not associated with any measure of obesity and inflammatory cytokines in the adjusted models.

Conclusions

DED was associated with higher leptin and cholesterol concentrations, and having insulin resistance, but not with any measure of obesity or inflammation. Reducing DED may reduce risk of cardiovascular disease and improve insulin sensitivity in school-aged children.

Zinc Transporter ZnT1 mRNA Expression Is Negatively Associated with Leptin Serum Concentrations but Is not Associated with Insulin Resistance or Inflammatory Markers in Visceral Adipose Tissue

The aim of this study was to evaluate the relationship between biomarkers of chronic inflammation, insulin resistance, and zinc transporter ZnT1 expression in human visceral adipose tissue. Visceral adipose tissue obtained from 47 adults undergoing laparoscopic surgery for cholecystectomy was used to analyze ZnT1 mRNA expression by RT-qPCR. ZnT1 mRNA levels were compared between subjects with normal weight, overweight, and obesity. A significantly lower ZnT1 expression was observed in overweight and obesity compared with normal-weight subjects (p = 0.0016). Moreover, subjects with normal weight had significantly higher serum zinc concentration (97.7 ± 13.1 mg/L) than subjects with overweight (87.0 ± 12.8 mg/L) and obesity (83.1 ± 6.6 mg/L) (p = 0.002). Pearson test showed a positive correlation between serum zinc concentrations and ZnT1 mRNA expression in visceral adipose tissue (r = 0.323; p = 0.031) and a negative correlation with body mass index (r =  - 0.358; p = 0.013). A linear regression model was used to analyze the associations between ZnT1 mRNA expression and serum zinc levels, insulin resistance (HOMA2-IR), serum adipokines (leptin and adiponectin), and serum inflammation biomarkers (tumor necrosis factor alpha, interleukin-6, and C-reactive protein). Interestingly, leptin concentrations were negatively associated with ZnT1 mRNA expression (p = 0.012); however, no significant associations were found for the rest of the analyzed variables. Future research is needed to analyze the causality of negative association between ZntT1 expression in visceral adipose tissue and leptin.

Association between plasma and dietary trace elements and obesity in a rural Chinese population

Trace elements may play an important role in obesity. This study aimed to assess the plasma and dietary intake levels of four trace elements, Mn, Cu, Zn and Se in a rural Chinese population, and analyse the relationship between trace elements and obesity. A cross-sectional study involving 2587 participants was conducted. Logistic regression models were used to analyse the association between trace elements and obesity; restricted cubic spline (RCS) models were used to assess the dose-response relationship between trace elements and obesity; the weighted quantile sum (WQS) model was used to examine the potential interaction of four plasma trace elements on obesity. Logistic regression analysis showed that plasma Se concentrations in the fourth quartile (Q4) exhibited a lower risk of developing obesity than the first quartile (Q1) (central obesity: OR = 0·634, P = 0·002; general obesity: OR = 0·525, P = 0·005). Plasma Zn concentration in the third quartile (Q3) showed a lower risk of developing obesity in general obesity compared with the first quartile (Q1) (OR = 0·625, P = 0·036). In general obesity, the risk of morbidity was 1·727 and 1·923 times higher for the second and third (Q2, Q3) quartiles of dietary Mn intake than for Q1, respectively. RCS indicated an inverse U-shaped correlation between plasma Se and obesity. WQS revealed the combined effects of four trace elements were negatively associated with central obesity. Plasma Zn and Se were negatively associated with obesity, and dietary Mn was positively associated with obesity. The combined action of the four plasma trace elements had a negative effect on obesity.

Mineral elements and adiposity-related consequences in adolescents with intellectual disabilities

BACKGROUND

Patients with intellectual disabilities are shown to have a limited capacity for cooperation, communication,and other biological consequences, which significantly require a specialized interest in healthcare professionals worldwide.

AIM

In this respect, the present study was designed to evaluate the levels mineral elements, and their correlation with oxidative stress markers and adiposity markers; leptin (L), adiponectin (A), and L/A ratio in adolescents with intellectual disabilities.

METHODS

A total of 350 schoolchildren aged (12-18 years) were randomly invited to participate in this prospective, observational study. Only 300 participants agreed to participate in this study. According to Intelligence quotients scores (IQ) measured by WISC-III, the participants were classified into two groups; the healthy control group (no = 180; IQ = 90-114); and the moderate intellectual disability (MID) group (no = 120; IQ = 35-49). Adiposity markers; body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), physical activity scores, adipokines biomarkers; leptin, adiponectin, L/A ratio, oxidative stress, and plasma mineral elements were evaluated by prevalidated questionnaires, inductively coupled plasma-mass spectrometry (ICP-MS), colorimetric, and immunoassay techniques.

RESULTS

Intellectual disability of moderate type was reported in 40% of the studied populations most of them are men aged 12-18 years (66.6% for men vs. 33.3 for females). Obesity was shown to be associated with the degree of intellectual disability of the students. There was a significant (P = 0.001) increase in the BMI, WHR, and WHtR scores as obesity markers with poor physical activity (P = 0.01) in students with poor disability compared to healthy controls (HC). The levels of leptin (P = 0.001), adiponectin (P = 0.01), and L/A ratio (P = 0.01) as adiposity biomarkers were significantly increased in students with MID compared to healthy controls. Also, oxidative stress measured by malondialdehyde (MDA) (P = 0.01) and total antioxidant capacity (TAC) (P = 0.01) were significantly increased in students with MID compared to healthy control subjects. In addition, mineral elements were shown to be linked with intellectual disability. The data showed that the levels of Fe, Mn, Zn, Hg, Pb, Ca, Cr, Mg, and Ni significantly (P = 0.001) increased, and the levels of Al, Na, K, Cu, and Zn/Cu ratio significantly (P = 0.001) decreased in subjects with MID compared to healthy controls. Correlation analysis concluded that changes in mineral elements significantly correlated with adiposity markers, oxidative stress, and the scores of intellectual disability (WISC III-IQ score).

CONCLUSION

The intellectual disability of moderate type (MID) was associated with abnormal changes in the levels of essential mineral elements and adipokines and increased levels of cellular oxidative stress. Thus, evaluating plasma mineral elements and adipokines levels could be a potential diagnostic parameter for diagnosing MID.

The association between vitamin C dietary intake and its serum levels with anthropometric indices: A systematic review and meta-analysis

BACKGROUND

studies showed inflammatory background of overweight and obesity. Prevalence of weight disorders has dramatically increased over the past few decades. Vitamin C is an antioxidant and may be associated with weight disorders. This study aims to systematically review the relationship between dietary and serum vitamin C levels with anthropometric indices.

METHODS

A systematic search was conducted in Medline database (PubMed), Scopus, Embase, Web of Science, Cochrane library and Google Scholar up to the end of August 2021. All observational studies that assessed the relationship between dietary or circulating vitamin C levels and body mass index (BMI) and waist circumference (WC) on adults were included. The quality of included studies was assessed using the National Institute of Health quality assessment tool.

RESULTS

Among 11,689 studies, 47 and 37 articles were included in the systematic review and meta-analysis, respectively. There was an inverse significant correlation between WC and serum vitamin C levels (r = -0.28, 95% CI: -0.35,-0.21, I² = 14.2%) and between BMI and serum vitamin C levels (r = -0.17, 95% CI: -0.25, -0.09, I² = 72.8%). Higher vitamin C consumption was significantly associated with lower BMI. There were no significant differences in serum vitamin C levels between normal-weight and overweight subjects, but serum vitamin C levels were significantly higher in obese subjects in comparison with normal-weight subjects.

CONCLUSION

Results showed that both dietary and serum vitamin C levels were inversely associated with BMI and WC. More well-designed clinical trials are needed to assess the effect of vitamin C supplementation in prevention and treatment of obesity.

Relationship of Serum Zinc Levels with Cardiometabolic Traits in Overweight and Obese Schoolchildren from Mexico City

Zinc (Zn) participates as a cofactor for many enzymes in the cellular metabolism, and its serum levels have been associated with different metabolic diseases, especially obesity (OB). Nevertheless, its associations are not clear in the children population. The objective of this study is to evaluate the association between serum Zn levels (SZn) with overweight/obesity status (OW/OB), as well as its cardiometabolic traits in a population of children in Mexico City. Anthropometrical data (body mass index z score (BMIz)), demographic variables (age and sex), and cardiometabolic traits (total cholesterol (TC), high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc), triglycerides (TG), fasting plasma glucose (FPG), and insulin) were analyzed in this cross-sectional study. SZn were measured by inductively coupled plasma mass spectrometry (ICP-MS). The population included 210 children from Mexico City (girls (n = 105) and boys (n = 105)) between ages 6 and 10 years. Normal-weight (NW) schoolchildren had higher SZn concentrations (66 µg/dL; IQR: 48 to 91) compared to OW or OB schoolchildren (61 µg/dL; IQR: 45 to 76). The data showed a significant negative association between SZn and BMIz without sex exclusion (r =  - 0.181 and p = 0.009). The boy's population did not show an association between the SZn and BMIz compared to the girl's population which showed a significant negative association (r =  - 0.277 and p = 0.004). In addition, other associations were found between SZn and TC (boys (r = 0.214 and p = 0.025), LDLc (boys (r = 0.213 and p = 0.029), and TG (girls (r =  - 0.260 and p = 0.007)). Moreover, 38.6% of the total children in our population study had Zn deficiency (ZnD). NW schoolchildren had higher SZn concentrations compared to OW or OB schoolchildren. A diet low in Zn can be a factor to evaluate in the development of childhood OB in Mexico. However, further studies need to be performed on the children Mexican population to replicate and confirm our findings.

The Effect of Dietary Intake and Nutritional Status on Anthropometric Development and Systemic Inflammation: An Observational Study

(1) Background: Daily caloric intake should aim to reduce the risk of obesity or poor anthropometric development. Our study objective was to analyze the association between food consumption, inflammatory status and anthropometric development; (2) Methods: We performed a prospective observational analytical research during September 2020 and April 2021 on a group of 160 healthy subjects, aged between 6 and 12 years old, by analyzing food ingestion, the basal metabolic rate, anthropometric development and the inflammatory status; (3) Results: IL-6 was significantly correlated to the sum of skinfolds, along with both serum proteins and triglycerides. The skin folds were significantly correlated with the caloric intake and with total fat intake, next to saturated and trans fats. Unlike the skin folds, the body weight was significantly correlated with the caloric intake along with some vitamins, such as Vitamin A and Vitamin B12. Inactive mass increased with excessive folic acid, Vitamin E, Vitamin K and saturated fat intake; (4) Conclusions: The inflammatory status was influenced by the ingestion of micronutrients, total serum lipids and proteins. The anthropometric development was associated with the ingestion of carbohydrates, energy balance and energy intake. We can conclude that daily menu and nutrition imbalances can influence both the risk of obesity and the inflammatory status.

Reduced plasma carotenoids in individuals suffering from metabolic diseases with disturbances in lipid metabolism: a systematic review and meta-analysis of observational studies

This review summarises the association between serum carotenoids, serum retinoids and dietary intake outcomes with obesity/overweight and individuals with metabolic diseases with disturbances in lipid metabolism. Observational studies reporting dietary intakes and serum concentrations of carotenoids and retinol were collected from Medline and Web of Science. Mean differences were calculated between "cases" (classified as obese, overweight or having a metabolic disease with disturbances in lipid metabolism; i.e. non-alcoholic fatty liver disease, type 2 diabetes, dyslipidaemia or metabolic syndrome) and "comparator group" (classified as normal weight healthy individuals) and summarised in meta-analyses. Significant summary measures were observed for most serum provitamin A and non-provitamin A carotenoids. Studies reporting total serum carotenoids had shown the greatest decrease (-0.28 µmol/l [-0.33, -0.23], p<.001, I²=62.5%, n = 7). There were no significant summary measures for dietary outcomes, suggesting a physiological role of low serum carotenoids in the development of obesity and associated diseases.

Are there differences in nutrient intake of Brazilian adults according to weight status?

It was assessed the intake and prevalence of inadequate nutrient intake according to weight status among Brazilian adults from urban areas (n=16,198) evaluated in the Brazilian National Dietary Survey (NDS - 2008-2009), that obtained food records from two non-consecutive days. The prevalence of inadequate nutrient intake according to weight status was estimated based on Brazilian and international recommendations, in which usual intake was estimated applying the National Cancer Institute method. From 14 nutrients evaluated, six differed according to weight status in men, and only two among women. For men, the mean proportion of energy derived from lipids and saturated fat and mean intake of cholesterol, zinc, and vitamin B12 were greater among those with excess weight compared to those with normal weight; the inverse was observed for dietary fiber. Mean sodium intake was greater and proportion of energy from added sugar intake was lower among obese women compared to overweight ones. Strategies to encourage food consumption with high micronutrient density should be targeted to adult population regardless of their weight status.

Effect of nutrient intakes on anthropometric profiles among university students from a selected private University in Klang Valley, Malaysia

BACKGROUND

Dietary composition is the cornerstone of weight management. This study aimed to investigate the effect of nutrient intakes on anthropometric profiles among university students.

METHODS

This cross-sectional study was conducted among 411 students aged 18-29 years, purposive sampled from a selected private university in Klang Valley, Malaysia. Anthropometric profiles were measured. Nutrient intakes were assessed by 3-day 24-hour diet recalls.

RESULTS

Respondents on average had adequate macronutrient intakes, however, total consumption of dietary fiber and micronutrients were fell short of recommended levels. Significant negative associations were found between body mass index (BMI) and all the macronutrients, calcium, thiamine, riboflavin and niacin. Body fat percentage was significantly associated with all the macronutrients, calcium, zinc, thiamine and niacin. Significant inverse associations were also found between waist circumference and carbohydrate, fiber, thiamine, riboflavin and niacin. Visceral fat showed significant inverse associations with carbohydrate, fat, fiber, thiamine, riboflavin and niacin. Further, after adjusting for sex, gender and race, BMI was associated with niacin (β=-0.161, p=0.027). Body fat percentage was also found significantly associated with niacin (β=-0.180, p=0.002) and riboflavin (β=-0.132, p=0.014).

CONCLUSION

Micronutrients, especially B vitamins, are important in weight management among the young adults.

The association between serum zinc level and overweight/obesity: a meta-analysis

PURPOSE

The association between serum zinc level and overweight/obesity remains controversial. Hence, we performed a meta-analysis to summarize the relationships.

METHODS

A systematic literature search was performed in PubMed, Web of Science and Embase for relevant English articles up to April 20, 2018. The pooled standardized mean difference (SMD) with 95% confidence interval (CI) was calculated with the random-effect model.

RESULTS

For children and adults, the results showed that serum zinc level was significantly lower in the cases compared to controls ([SMD (95% CI): - 1.13 (- 2.03, - 0.23), Z = 2.45, P for Z = 0.014; I² = 97.1%, P for I² < 0.001] and [SMD (95% CI): - 0.41 (- 0.68, - 0.15), Z = 3.03, P for Z = 0.002; I² = 62.9%, P for I² = 0.009], respectively). The difference of serum zinc level between overweight adults and controls was not statistically significant [SMD (95% CI): - 0.09 (- 0.27, 0.09), Z = 0.97, P for Z = 0.334; I² = 0.0%, P for I² = 0.411]. In subgroup analyses, a lower serum zinc level in obese children compared with non-obese controls was observed [SMD (95% CI): - 2.14 (- 3.20, - 1.09)], and the SMD differ significantly between obese adults and controls in the case-control studies [SMD (95% CI): - 0.49 (- 0.90, - 0.08)].

CONCLUSION

Our meta-analysis suggested that the serum zinc level was significantly lower in obese children and adults. More large observational studies are required to confirm these results in future research.

Exploration of the Inter-Relationships Between Obesity, Physical Inactivity, Inflammation, and Low Back Pain

STUDY DESIGN

Retrospective analysis wherein 103 patients were considered, and 76 patients were included: 49 were classified as chronic non-specific low back pain (CNSLBP) (Study group) and 27 had identifiable cases of specific chronic low back pain (LBP) (Control group).

OBJECTIVE

Elucidate markers of systemic inflammation in patients with CNSLBP.

SUMMARY OF BACKGROUND DATA

Mechanisms of LBP are poorly understood. Pro-inflammatory cytokines are increased in obesity and involved with pain modulation; we previously proposed a theoretical model of their mediating role in LBP.

METHODS

Demographic information was acquired via questionnaire, chart review, and blood test data. Univariate analysis identified factors associated with CNSLBP and markers of systemic inflammation. A receiver operating curve and Youden Index were used to select optimal cut-off points for elevated C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Multivariable logistic regression analysis calculated the adjusted strength of relationship between factors that were proposed in our theoretical model for CNSLBP.

RESULTS

Unadjusted CRP was significantly correlated with ESR (R = 0.63, P < 0.0001) and body mass index (BMI) (R = 0.38, P = 0.0015). Physically inactive patients had significantly higher CRP (6.1 vs. 1.2, P = 0.0050). ESR was significantly correlated with number of comorbidities (R = 0.34, P = 0.0047), BMI (R = 0.38, P = 0.0014), and age (R = 0.36, P = 0.0026). Physically inactive patients (10.4 vs. 3.6, P = 0.0001) and females (11.2 vs. 6.4, P = 0.0422) had significantly higher ESR. Adjusted analyses indicated significant relationships between physical inactivity and markers of systemic inflammation (adjusted odds ratios for ESR and CRP: 15.9, P = 0.0380; 15.2, P = 0.0272, respectively), and between elevated CRP and CNSLBP (adjusted odds ratio: 8.0, P = 0.0126).

CONCLUSION

Systemic inflammation may act as a mediator for physical inactivity and obesity in the pathogenesis of CNSLBP.

LEVEL OF EVIDENCE

2.

Intestinal parasites: Associations with intestinal and systemic inflammation

The aim of the present study was to evaluate associations between intestinal parasitic infection with intestinal and systemic inflammatory markers in school-aged children with high rates of obesity. Plasma concentrations of C-Reactive Protein (CRP), leptin, TNF-α, IL-6 and IL-10 were measured as systemic inflammation markers and count of stool leukocytes as marker of intestinal inflammation in 291 children (6-10 years). Intestinal parasitic infection was measured by stool examination. Logistic regression analyses were performed to determine the odds of having high inflammatory markers for each parasite or group of parasites as compared to parasite-free children while adjusting for sex, age, mother's educational level and percentage of body fat. The prevalence of soil-transmitted helminths and intestinal protozoa infections was 12% and 36%, respectively. Parasitic infection was not associated with CRP, IL-6, IL-10 or TNF-α. Children infected with Ascaris lumbricoides (aOR: 5.91, 95% CI: 1.97-17.70) and Entamoeba coli (aOR: 8.46, 95% CI: 2.85-25.14) were more likely to have higher stool leucocytes than parasite-free children. Children with multiple infections (aOR: 10.60, 95% CI: 2.85-25.14) were more likely to have higher leptin concentrations than parasite-free children. Intestinal parasitic infection was not associated with systemic inflammation, but was associated with intestinal inflammation. Having multiple infections were associated with higher leptin concentrations.

Zinc, iron and vitamins A, C and e are associated with obesity, inflammation, lipid profile and insulin resistance in Mexican school-aged children

The objective of this cross-sectional study was to evaluate the relationship between micronutrient status and obesity, lipids, insulin resistance and chronic inflammation in children. Weight, height, waist circumference and body composition (dual-energy X-ray absorptiometry (DEXA)) were determined in 197 school-aged children. Lipids, glucose, insulin, C-reactive protein (CRP), zinc, iron and vitamins A, C and E were analyzed in blood. Vitamin C and vitamin E:lipids were negatively associated with Body Mass Index (BMI), waist-to-height ratio (WHR) and body and abdominal fat (p < 0.05). Vitamin A was positively associated with BMI, BMI-for-age, WHR and abdominal fat (p < 0.05). Iron and vitamin E:lipids were negatively associated with insulin (p < 0.05). Vitamins A, C and E and iron were negatively associated with CRP (p < 0.05). Interaction analysis showed that children who were overweight and obese who also had low concentrations of vitamin A had higher CRP and lower triglycerides (p < 0.1), children with low vitamin E had significantly lower glucose and triglycerides (p < 0.1) and higher low-density lipoprotein (LDL) concentrations (p < 0.05), and children with low zinc concentrations had higher insulin resistance compared with children with adequate weight (p < 0.05). In conclusion, low vitamin C concentration and vitamin E:lipids were associated with obesity. Furthermore, low concentrations of zinc, vitamins A and E in children who were overweight and obese were associated with lipids, inflammation and insulin resistance.

Micronutrient intake and the presence of the metabolic syndrome

Background:

Dietary micronutrients have been proposed to protect against oxidative damage and related clinical complications.

Aims:

We aimed to compare the micronutrient intake between individuals with and without metabolic syndrome (MS).

Materials and Methods:

This cross-sectional study included 3800 men and women who were aged between 35 and 65 years. The diagnosis of the MS was based on International Diabetes Federation criteria. Dietary intake of participants was assessed using a questionnaire for 24 h dietary recall. Student's t-test and Mann–Whitney U-tests were used for comparing the micronutrient intake of subjects with or without the MS and the odds ratio for the presence of the MS was calculated for each micronutrient by control for total energy intake adjusted by the residue method.

Results:

The mean age of MS subjects and the control group was 48.8 ± 7.9 years and 47.6 ± 7.6 years, respectively. Energy-adjusted intake of vitamin E (P < 0.05), B2 (P < 0.01), and B12 (P < 0.05) was higher in normal women compared with women with MS. Energy-adjusted intake of vitamin B1 was significantly higher in women with MS. After logistic regression analysis, no significant association between micronutrient intake and MS was shown.

Conclusion:

We found no significant association between micronutrient intake and MS.

Serum IL-12 is increased in Mexican obese subjects and associated with low-grade inflammation and obesity-related parameters

Interleukin-(IL-) 12 has been recently suggested to participate during development of insulin resistance in obese mice. Nevertheless, serum IL-12 levels have not been accurately determined in overweight and obese humans. We thus studied serum concentrations of IL-12 in Mexican adult individuals, examining their relationship with low-grade inflammation and obesity-related parameters. A total of 147 healthy individuals, 43 normal weight, 61 overweight, and 43 obese subjects participated in the study. Circulating levels of IL-12, tumor necrosis factor-alpha (TNF-α), leptin, insulin, glucose, total cholesterol, and triglyceride were measured after overnight fasting in all of the study subjects. Waist circumference and body fat percentage were recorded for all the participants. Serum IL-12 was significantly higher in overweight and obese individuals than in normal weight controls. Besides being strongly related with body mass index (r = 0.5154), serum IL-12 exhibited a significant relationship with abdominal obesity (r = 0.4481), body fat percentage (r = 0.5625), serum glucose (r = 0.3158), triglyceride (r = 0.3714), and TNF-α (r = 0.4717). Thus, serum levels of IL-12 are increased in overweight and obese individuals and show a strong relationship with markers of low-grade inflammation and obesity in the Mexican adult population. Further research is needed to understand the role of IL-12 in developing obesity-associated alterations in humans.

Association between circulating ascorbic acid, α-tocopherol, 25-hydroxyvitamin D, and plasma cytokine concentrations in young adults: a cross-sectional study

BACKGROUND

Inflammation and oxidative stress are associated with the development of numerous chronic diseases. Circulating ascorbic acid, α-tocopherol, and 25-hydroxyvitamin D (25(OH)D) may help reduce concentrations of pro-inflammatory cytokines through their antioxidant and anti-inflammatory properties. These micronutrients may act synergistically, and they may have different anti-inflammatory effects, but previous studies have assessed the link between each of these micronutrients and inflammation in isolation without controlling for the other micronutrients. Our objective was to examine the association between circulating concentrations of ascorbic acid, α-tocopherol, and 25(OH) D and a panel of pro-inflammatory cytokines in an ethnically diverse population of young adults.

METHODS

Participants (n = 1,007) from the Toronto Nutrigenomics and Health study provided fasting blood samples for biomarker measurements and were subsequently categorized into tertiles for each micronutrient based on their circulating concentrations. We conducted Pearson's correlation analyses across all micronutrients and cytokines. The associations between individual micronutrients and cytokines were examined using analysis of covariance with age, sex, waist circumference, ethnicity, physical activity, season of blood collection, total cholesterol, hormonal contraceptive use among women, and the other two micronutrients as covariates.

RESULTS

We observed weak micronutrient-cytokine correlations, moderate correlations between certain cytokines, and strong correlations between specific cytokines, particularly interleukin 1- receptor antagonist (IL-1RA), interferon-γ (IFN-γ), and platelet-derived growth factor BB (PDGF-bb). After full covariate adjustment, circulating α-tocopherol was inversely associated with IFN-γ and regulated upon activation normal T-cell expressed and secreted (RANTES). We observed an unexpected positive association between ascorbic acid and IFN-γ. 25(OH)D was not associated with altered concentrations of any inflammatory biomarkers.

CONCLUSIONS

These findings suggest that α-tocopherol, but not ascorbic acid or 25(OH)D, is inversely associated with inflammation in healthy young adults.