The correlation between serum inflammatory, antioxidant, glucose handling biomarkers, and Dietary Antioxidant Index (DAI) and the role of DAI in obesity/overweight causation: population-based case-control study.

BACKGROUND: Obesity is a multifactorial disease, and about 40% of world adults are overweight, and about 20% are obese. Diet is one of the most important factors in the causality of obesity. The interactions between the diet and gut microbiota or chronic inflammation pathways highlight the importance of its various aspects in the incidence and prevalence of obesity. At the same time, diet is a combination of several antioxidants that are needed together for the body's antioxidant system. The Dietary Antioxidant Index (DAI) is a valid nutritional tool, and its correlation has been studied concerning total antioxidant capacity and malondialdehyde. The study aimed to examine the relationship between the DAI and the odds of obesity. We hypothesized that a higher DAI score indicating a predominantly antioxidant diet has a protective effect against odds of obesity. METHODS: In this population-based case-control study, 812 participants with a higher body mass index (BMI) than 25 were selected as the case group. Also, 793 participants with BMI in the range of 17.9-24.9 were selected as the control group. A valid and reliable 124-item food frequency questionnaire (FFQ) was used to assess dietary intake. Based on FFQ data, we summed up the standardized intake of the major dietary antioxidants, including vitamin A, E, C, selenium, zinc, and manganese, to calculate DAI. RESULTS: In a multivariable adjusting model, there was a significant association between DAI (as a continuous variable) and BMI (odds ratio (OR) = 0.95; 95% CI: 0.92-0.99; P value = 0.02). Also, there was a significant association between DAI (as a categorized variable) and body surface area with multivariable adjusting model (OR = 0.79; 95% CI: 0.64-0.98; P value = 0.04). CONCLUSION: In conclusion, the DAI can accurately predict some serum antioxidant and anti-inflammatory levels along with glucose handling markers.

The Association Among Maternal Index of Nutritional Quality, Dietary Antioxidant Index, and Odds of Miscarriage Incidence: Case-Control Study.

OBJECTIVE: Miscarriage is a pregnancy condition in which the fetus or embryo naturally dies before being able to survive independently. According to studies, diet and dietary factors are associated with the risk of miscarriage (pregnancies <20 weeks). A 168-item semi-quantitative feed frequency questionnaire was used to estimate the Dietary Antioxidant Index (DAI) and the Index of Nutritional Quality (INQ). We aimed to assess the relationship between INQ and DAI with odds of miscarriage. METHOD: In summary, 135 Iranian women with a history of three or more miscarriages were included. We calculated the INQ using the following formula: INQ = consumed amount of a nutrient per 1,000 kcal/Recommended Dietary Allowance of that nutrient per 1,000 kcal. We standardized each dietary vitamins/minerals by subtracting the global mean and dividing the result by the universal standard deviation to compute DAI. We computed the DAI by summing up the standardized intakes of these vitamins and minerals and equal weight. RESULTS: Regression models were used to extract the odds ratios (ORs) and 95% confidence intervals (CIs) in crude and multivariate adjustments. Controls significantly had higher INQ of vitamin B12, niacin, vitamin D, vitamin E, vitamin C, and zinc. Modeling INQs of vitamin D (OR: 0.004, 95% CI, 0.00-0.025) and B12 (OR: 0.04, 95% CI, 0.005-0.41) as a continuous variable showed a significant and protective effect in multivariate adjustment. Modeling DAI as a categorical variable showed a significant protective effect (ORDAI<0.054vs.DAI ≥0.054 = 0.43, 95% CI, 0.20-0.91). CONCLUSIONS: Recommending a diet rich in antioxidants such as vitamin E, C, zinc, and selenium and a quality diet containing vitamins B12 and D can be considered an effective strategy to reduce the odds of miscarriage in women with a history of recurrent miscarriage.

Can an anti-inflammatory diet be effective in preventing or treating viral respiratory diseases? A systematic narrative review.

Respiratory Viruses infections (RVI) such as rhinovirus, coronavirus, influenza virus, and adenovirus affect the respiratory and the immune systems. The role of nutrition in the respiratory and immune systems has been studied in some studies, and its importance is undeniable. In addition, one of the key findings in this disease is high inflammation that affects almost all patients. This systematic narrative review aims to answer the question, "Can an anti-inflammatory diet be effective in preventing or treating viral respiratory diseases?" A systematic review search was used for the articles extraction. All studies published in English from 1999 to 2020 investigating dietary inflammatory conditions and RVI were included. Food items with anti-inflammatory properties were selected based on the definition of the dietary inflammatory index (DII). We used Google Scholar, Pub Med, Scopus, Web of Science, Springer, Science Direct, Directory of Open Access Journals, Elsevier, Taylor and Francis, ProQuest, EBSCO, MEDLINE, and SciELO databases for extracting articles. Keywords were restricted by DII. Based on DII, food items/nutrients are involved in inflammation, some of which have anti-inflammatory and some inflammatory properties. Some foods/nutrients, in addition to their anti-inflammatory properties, have antioxidant, antiviral, and immune-enhancing properties. Considering the immune system's involvement, increased inflammation, and involvement of the pulmonary system in RVI and the remarkable role of the anti-inflammatory foods for counteracting them, it is recommended to use a predominantly anti-inflammatory diet along with prevention/control and treatment protocols. An anti-inflammatory diet (based on DII) includes turmeric, ginger, garlic, onions, saffron, dietary vitamin C, vitamin D, zinc, and omega-3 are recommended to reduce infection symptoms and duration.

The association between dietary antioxidant index (DAI) and nonalcoholic fatty liver disease (NAFLD) onset; new findings from an incident case-control study.

BACKGROUND: Evidence suggests an increasing global trend in non-alcoholic fatty liver disease (NAFLD) prevalence. Researchers have noted the importance of the role of dietary antioxidants in reducing the incidence of NAFLD. The dietary antioxidant index (DAI) is a valid indicator that considers the -diet's total antioxidant properties. The present study was designed and conducted to investigate the relationship between DAI and NAFLD. We hypothesized that there is a link between the DAI and the NAFLD. METHODS: This case-control study included 295 patients with NAFLD and 704 controls. The patients' dietary intake was assessed through a valid and reliable semi-quantitative food frequency questionnaire. We standardized each of vitamin A, C, E, and selenium, manganese, and zinc by subtracting the global mean and dividing by the global SD to calculate the DAI. RESULTS: Subjects with DAI score -0.46 < were at higher odds of having NAFLD compared to subjects with DAI -0.46 ≥ (ORDAI<-0.46/≥-0.46 = 0.55; 95% CI = 0.41-0.73). After adjustment for age, gender, and total energy intake (model B) a reverse and significant association was seen (ORDAI<-0.46/≥-0.46 = 0.57; 95% CI = 0.39-0.82). CONCLUSION: The role of antioxidants in reducing the odds of NAFLD is fundamental. Taking antioxidants such as vitamins A, E, C, zinc, selenium, and manganese through food can effectively reduce NAFLD odds. On the other hand, studies should examine DAI's sensitivity and specificity in various settings and outcomes to use it in clinical work.

Validation of Dietary Antioxidant Index (DAI) and investigating the relationship between DAI and the odds of gastric cancer.

BACKGROUND: Gastric cancer (GC) incidence and mortality are rapidly growing worldwide. It is estimated that more than 1,000,000 new cases are diagnosed each year, and more than 78,000 people lose their lives due to GC. The association between dietary antioxidants and GC has been shown in some studies. However, because of the discrepancy between the findings and the lack of a valid indicator, it seems necessary to design and validate the Dietary Antioxidant Index (DAI) to examine the diet's total antioxidant content. The present study aimed to survey the validity of DAI and its association with the odds of GC. METHODS: In this hospital-based case-control study, 82 patients with GC and 95 healthy controls were examined. We used a 168-item food frequency questioner to assess dietary intakes. The DAI was calculated based on the intake of vitamin A, C, E, and selenium, manganese, and zinc. We standardized each of the six vitamins and minerals by subtracting the global mean and dividing by the global standard deviation to calculate DAI. We then calculated the DAI by summing up the standardized intakes of these vitamins and minerals of the individuals with equal weight. RESULTS: We observed a significant correlation between DAI and total antioxidant capacity (TAC) after controlling for age, body mass index (BMI), energy intake, smoking and fasting blood sugar, education, total fat intake, helicobacter pylori infection, total cholesterol, and saturated fatty acid (SFA) intakes. Results obtained from modeling DAI as a continuous variable in relation to GC showed a negative association after adjustment for age and in the multivariable analysis (OR = 0.64, CI = 0.43-0.95). CONCLUSION: DAI is a valid indicator of dietary antioxidants assessments, and it can be used as a predictor of antioxidant status due to its correlation with serum antioxidant levels. The results showed that dietary antioxidants have a significant relationship with GC, which indicates the importance of antioxidants in this cancer's etiology.