Antioxidant Metabolism Pathways in Vitamins, Polyphenols, and Selenium: Parallels and Divergences

Free radicals (FRs) are unstable molecules that cause reactive stress (RS), an imbalance between reactive oxygen and nitrogen species in the body and its ability to neutralize them. These species are generated by both internal and external factors and can damage cellular lipids, proteins, and DNA. Antioxidants prevent or slow down the oxidation process by interrupting the transfer of electrons between substances and reactive agents. This is particularly important at the cellular level because oxidation reactions lead to the formation of FR and contribute to various diseases. As we age, RS accumulates and leads to organ dysfunction and age-related disorders. Polyphenols; vitamins A, C, and E; and selenoproteins possess antioxidant properties and may have a role in preventing and treating certain human diseases associated with RS. In this review, we explore the current evidence on the potential benefits of dietary supplementation and investigate the intricate connection between SIRT1, a crucial regulator of aging and longevity; the transcription factor NRF2; and polyphenols, vitamins, and selenium. Finally, we discuss the positive effects of antioxidant molecules, such as reducing RS, and their potential in slowing down several diseases.

The association of dietary antioxidant index (DAI) with breast cancer among Iranian women

Recent studies have reported that dietary antioxidants can influence the risk of breast cancer (BC). Therefore, this study aimed to investigate the association of dietary antioxidant index (DAI) with BC among Iranian women. This case-control study was conducted on 180 women with breast cancer and 360 healthy women who were referred to the cancer clinic of Shohadaye Tajrish Hospital in Tehran, Iran. A 168-item validated food frequency questionnaire (FFQ) was used to assess dietary intake. The DAI score was calculated based on the intake of antioxidant vitamins and minerals derived from the FFQ. The control group had a significantly higher intake of vitamin D (1.79±1.56 vs. 1.05±0.84 μg/d; P=0.01) and lower intake of calorie (2315±1066 vs. 2737±925 kcal/d; P=0.01), carbohydrate (311±170 vs. 402±124 g/d; P=0.01), iron (15.4±12.1 vs. 19.7±6.4 mg/d; P=0.01), thiamine (1.5±0.7 vs. 2.3±0.9 mg/d; P=0.01), niacin (18.2±9.2 vs. 24.3±7.9 mg/d; P=0.01), folic acid (465±308.7 vs. 673±205.2 μg/d; P=0.01), and selenium (82.6±41.7 vs. 98.7±40.8 μg/d; P=0.01) compared to the case group. No significant association was found between DAI with breast cancer after adjustments for age. DAI had a negative association with breast cancer after additional adjustments for BMI, the number of pregnancies, duration of breastfeeding, menopause age, and total energy intake (OR: 0.91, 95% CI: 0.90-.93, and all P<0.001). The present study identified a negative association between DAI and the risk of BC, indicating the importance of antioxidants in preventing BC. Longitudinal studies should be conducted to confirm this association.

Dietary Total Antioxidant Capacity and Odds of Breast Cancer: A Case-Control Study

Breast cancer (BC) is the most frequently diagnosed female cancer worldwide. It has been shown that oxidative stress can contribute to cancer development. Therefore, we investigated the association between dietary total antioxidant capacity (TAC) and breast cancer risk in a case-control study. This study was conducted on 136 newly diagnosed breast cancer patients and 272 hospitalized controls in Tehran, Iran. Participant habitual diet was obtained using a 168-item validated food frequency questionnaire. Dietary TAC scores were computed using two different methods: the dietary ferric reducing antioxidant potential (FRAP) method and oxygen radical scavenging capacity (ORAC). The association between dietary TAC and breast cancer risk was estimated by logistic regression. The score of DTAC calculated by ORAC method was associated with lower odds of BC, especially among premenopausal women. However, this association was not significant after controlling potential confounders (ORAC: OR Q4-Q1 = 1.01, 95% CI = 0.42-2.44, p-trend = 0.96). Estimation of DTAC by FRAP method was not associated with the risk of BC (FRAP: OR Q4-Q1 = 1.04, 95% CI = 0.53-2.05, p-trend = 0.8). There were no association detected based on menopausal status. In this study, dietary TAC was not significantly related to the odds of breast cancer.

Relationship between Dietary Total Antioxidant Capacity and the Prognosis of Amyotrophic Lateral Sclerosis

Antioxidant intake has been suggested to be associated with the prognosis of amyotrophic lateral sclerosis (ALS). This study aimed to investigate whether dietary total antioxidant capacity (DTAC) and that of major food groups are related to disease progression rate (ΔFS) and survival time in ALS patients. A total of 301 participants diagnosed with sporadic ALS according to the revised El Escorial criteria were recruited from March 2011 and followed up to the event occurrence, or the end of October 2021. Events included percutaneous endoscopic gastrostomy, tracheostomy, and death. DTAC was estimated using task automation and an algorithm based on 24 h dietary recall. ΔFS was negatively correlated with the vegetable and legume DTAC, and event-free survival was different among the tertiles of vegetables and legumes DTAC. Consistently, the risk of events was negatively associated with DTAC from vegetables and legumes. These results suggest that the intake of antioxidants, especially those derived from vegetables and legumes, has a beneficial effect on delaying disease progression and prolonging survival in patients with ALS. Further studies with large prospective cohorts and clinical trials are needed to determine whether the consumption of foods with high DTAC improves the prognosis of ALS.

Association of Dietary Total Antioxidant Capacity with Cancer Recurrence and Mortality among Breast Cancer Survivors: A Prospective Cohort Study

Antioxidants decrease the risk of breast cancer by reducing oxidative stress, but the association between dietary total antioxidant capacity (DTAC) and cancer recurrence has not yet been investigated. The present study aimed to test the hypothesis that DTAC is inversely associated with cancer recurrence and mortality in breast cancer patients. Breast cancer patients (n = 603) who underwent breast cancer surgery and a dietary survey within 5 years after surgery were recruited. This study observed disease-free survival (DFS) and mortality in breast cancer patients according to DTAC calculated based on 24-hr dietary recall. Total DTAC was significantly lower in patients with cancer recurrence than in those without. DFS was positively associated with the total DTAC (p = 0.005) and DTAC of vegetables and legumes (p = 0.001 and p = 0.010), respectively. However, total DTAC was not associated with mortality. Cox proportional hazards regression analysis showed that total DTAC (HR: 0.44, 95% CI 0.26-0.94) and DTAC of vegetables (HR: 0.30, 95% CI 0.14-0.65) and legumes (HR: 0.38, 95% CI 0.18-0.73) were inversely associated with cancer recurrence after adjusting for confounding factors. This study was the first to indicate that total DTAC and DTAC of vegetables and legumes could be beneficial in decreasing breast cancer recurrence.

Dietary Antioxidant Capacity and Serum Inflammatory Biomarkers Levels in Cancer Survivors

This study aimed to compare the dietary intake of carotenoids, tocopherols, ascorbic acid, flavonoids, and dietary total antioxidant capacity (dTAC) and to evaluate relationship of dTAC with serum inflammatory biomarkers in patients with gastrointestinal system (GIS) and non-GIS cancer. In total, 104 adult cancer survivors (52 GIS and 52 non-GIS cancer cases) were included. 24-hour dietary recalls were obtained and dTAC was calculated on the basis of oxygen radical absorption capacity (ORAC), Trolox equivalent antioxidant capacity (TEAC), total radical-trapping antioxidant parameter (TRAP), ferric reducing antioxidant potential (FRAP), and vitamin C equivalents (VCE). Serum C-reactive protein (CRP) level, neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR) were used as inflammatory biomarkers. Routinely analyzed serum CRP, neutrophil, lymphocyte, and platelet levels every day in hospital biochemistry laboratory were obtained from patients' file. There was no significant difference between patients with GIS and non-GIS cancer in terms of dietary intake of carotenoids, tocopherols, and flavonoids. While there was no significant difference between groups in terms of the mean dietary ORAC, TEAC, and FRAP, the mean TRAP of patients with GIS cancer was significantly higher than patients with non-GIS cancer. Serum inflammatory markers (CRP and NLR) were found to have an inverse relationship with dTAC.

Biomolecules Responsible for the Total Antioxidant Capacity (TAC) of Human Plasma in Healthy and Cardiopathic Individuals: A Chemical Speciation Model

(1) Background: Much effort has been expended to investigate the antioxidant capacity of human plasma, attempting to clarify the roles of both metabolic and food substances in determining defenses against oxidative stress. The relationship between the total antioxidant capacity (TAC) and the concentrations of redox-active biomolecules in the human plasma of healthy and cardiopathic individuals was investigated in the present study to develop a chemical speciation model. (2) Methods: Plasma was collected from 85 blood donors and from 25 cardiovascular surgery patients. The TAC was measured using the CUPRAC-BCS (CUPric Reducing Antioxidant Capacity — Bathocuproinedisulfonic acid) method. Biomolecule concentrations were determined via visible spectrophotometry or HPLC/RP techniques. The relationship between the TAC and the concentrations was defined by applying a multiple regression analysis. The significance of the variables was first tested, and chemical models were proposed for the two datasets. The model equation is TAC=∑iβi·Ai, where β_i and [A_i] are the electronic exchange and the molar concentrations of the i^th antioxidant component, respectively. (3) Results: The major contributions to the TAC, ~80%, come from endogenous compounds in both healthy and cardiopathic individuals, whereas the contributions from exogenous compounds were different between the two datasets. In particular, γ-tocopherol showed a different role in the chemical models developed for the two groups.

Antioxidant-Rich Diet, GSTP1 rs1871042 Polymorphism, and Gastric Cancer Risk in a Hospital-Based Case-Control Study

Background

Chronic gastritis along with Helicobacter pylori (H. pylori) infection has been implicated in inflammatory response-related genes linked to the causation of gastric cancer. Glutathione S-transferase Pi (GSTP1) plays a role in regulating oxidative stress and detoxification against carcinogenesis. In this study, we aimed to determine whether an antioxidant-rich diet is associated with gastric cancer risk and identify how this association could be altered by GSTP1 genetic variants.

Methods

This study included 1,245 participants (415 cases and 830 controls) matched for age and sex. The dietary antioxidant capacity was estimated based on the oxygen radical absorbance capacity (ORAC) incorporated with a semiquantitative food frequency questionnaire. Five single nucleotide polymorphisms (SNPs) of GSTP1 (rs1695, rs749174, rs1871042, rs4891, and rs947895) were selected among the exome array genotype data.

Results

High dietary ORAC was inversely associated with gastric cancer (hydrophilic ORAC OR _{T3vs. T1}, 95% CI = 0.57, 0.39–0.82, P = 0.004; lipophilic ORAC = 0.66, 0.45–0.95, P = 0.021; total phenolics = 0.57, 0.39–0.83, P = 0.005). The polymorphism rs1871042 increased the risk of gastric cancer (OR, 95% CI = 1.55, 1.10–2.16, P = 0.01, CT+TT vs. CC). A remarkably reduced risk of gastric cancer was observed among those who had a high dietary ORAC according to rs1871042 polymorphism (hydrophilic ORAC OR _{T3vs. T1}, 95% CI = 0.36, 0.17–0.78, P for trend = 0.013; lipophilic ORAC = 0.58, 0.37–0.93, P for trend = 0.021; total phenolics = 0.38, 0.17–0.83, P for trend = 0.019).

Conclusions

Our findings indicate that dietary ORAC intake may be inversely associated with the risk of gastric cancer altered by genetic variants of GSTP1, providing new intervention strategies for gastric cancer patients.

Dysmetabolisms Can Affect Total Antioxidant Capacity (TAC) of Human Plasma: Determination of Reference Intervals of TAC by Way of CUPRAC-BCS Method

The total antioxidant capacity (TAC) of human plasma is an index of the redox buffer capacity of this biological fluid and could be a biomarker for those disorders affecting redox status. Distinguishing physiological from pathological conditions needs a reference. Therefore, this work aims to define the reference intervals for TAC of human plasma of apparently healthy adult individuals. TAC was measured using the CUPRAC-BCS (CUPric reducing antioxidant capacity-bathocuproinedisulfonic acid) method previously optimized and tested in a clinical laboratory. A population of 500 blood donors was selected, plus an additional 222 pathological patients carrying specific defective metabolisms, namely, hyperuricemia, hyperbilirubinemia, and type 2 diabetic mellitus. The reference intervals of TAC were calculated according to international guidelines. Due to the response of a partitioning test, the reference intervals for healthy population were separately defined for male (258) and female (151) groups. The reference intervals (µmol L-1) resulted: 727-1248 for the male subgroup and 637-1048 for the female subgroup. The absence of an age effect on TAC values was verified. The reference intervals evaluated allow a discussion on some pathological conditions overloading the plasma with redox-active waste substances.

Dietary total antioxidant capacity (TAC), general and central obesity indices and serum lipids among adults: An updated systematic review and meta-analysis

Background: In the present meta-analysis, we aimed to summarize the relationship between dietary total antioxidant capacity (TAC), general and central obesity indices and lipid profile in adult population. Methods: The electronic databases of Web of Sciences, PubMed, Scopus and Cochrane library were searched for relevant studies from inception to October 2019. The effect size was indicated as weighted mean difference (WMD) and 95% confidence intervals (CI) by using random effects model. The I² index and Cochran's Q-test were used for evaluating heterogeneity. Results: From 2,469 studies identified, thirty-four studies (nineteen cross-sectional studies, thirteen cohort studies, two case-control studies) were included in the meta-analysis. According to our results, higher categories of TAC were associated with significantly lower serum triglyceride concentartions (TG; WMD: -7.58; CI: -11.42, -3.75; P < 0.001) and waist circumference (WC; WMD: -1.17; 95% CI: -1.47, -0.87; P < 0.001); while no significant change in body mass index (BMI; WMD: -0.17; 95% CI: -0.35, 0.01; P = 0.12), high density lipoprotein cholesterol (HDL-C; WMD: 0.61; 95% CI: -0.16, 1.40; P = 0.12), low density lipoprotein cholesterol (LDL-C; WMD: 1.34; 95% CI: -0.61, 3.30; P = 0.17) and total cholesterol (TC; WMD: 1.19; 95% CI: -1.46, 3.855; P = 0.37) was reported. Conclusion: Higher dietary TAC was related to reduced prevalence of central obesity, reduced WC and TG concentrations in the current meta-analysis. Moreover, subgroup analysis showed that TAC measurement index, geographical area, dietary assessment tool, health status and gender were potential sources of heterogeneity.

Association between dietary total antioxidant capacity and breast cancer: a case-control study in a Middle Eastern country

OBJECTIVE

The aim of this study was to determine the relationship between dietary total antioxidant capacity (dTAC) and risk of breast cancer among Iranian women.

DESIGN

In this hospital-based case-control study, dietary intake of participants was collected using a 168-item validated FFQ. Dietary TAC was assessed using FRAP assay considering. Logistic regression was used to obtain ORs for breast cancer across quartiles of dTAC.

SETTING

Cancer Institute, Iran.

PARTICIPANTS

We included 412 women with pathologically confirmed breast cancer and 456 apparently healthy controls.

RESULTS

Mean dTAC was 11·3 ± 5·8 for cases and 12·1 ± 7·9 for controls. A trend towards significant inverse association was seen between dTAC and odds of breast cancer in the whole population; such that after controlling for several potential confounders, individuals in the highest quartile of dTAC were 0·39 times less likely to have breast cancer than those in the lowest quartile (0·61; 95 % CI: 0·38, 0·99, P < 0·05). In the stratified analysis by menopausal status, we found that postmenopausal women with the greatest dTAC had lower odds for breast cancer, compared with those with the lowest dTAC (0·47; 95 % CI: 0·24, 0·93, P < 0·05). This association strengthened after additional adjustment for BMI (0·28; 95 % CI: 0·11, 0·72, P < 0·05). No significant association was seen between dTAC and odds of breast cancer in premenopausal women.

CONCLUSIONS

We found that dietary TAC was inversely associated with risk of breast cancer, in particular among postmenopausal women. Prospective cohort studies are needed to confirm these findings.

Dietary Inflammatory Index, Dietary Non-Enzymatic Antioxidant Capacity, and Colorectal and Breast Cancer Risk (MCC-Spain Study)

Inflammation and antioxidant capacity have been associated with colorectal and breast cancer. We computed the dietary inflammatory index (DII^®), and the total dietary non-enzymatic antioxidant capacity (NEAC) and associated them with colorectal and breast cancer risk in the population-based multi case-control study in Spain (MCC-Spain). We included 1852 colorectal cancer and 1567 breast cancer cases, and 3447 and 1486 population controls, respectively. DII score and NEAC were derived using data from a semi-quantitative validated food frequency questionnaire. Unconditional logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (95%CI) for energy-adjusted DII (E-DII), and a score combining E-DII and NEAC. E-DII was associated with colorectal cancer risk (OR = 1.93, highest quartile versus lowest, 95%CI:1.60–2.32; p-trend: <0.001); this increase was observed for both colon and rectal cancer. Less pronounced increased risks were observed for breast cancer (OR = 1.22, highest quartile versus lowest, 95%CI:0.99–1.52, p-trend: >0.10). The combined score of high E-DII scores and low antioxidant values were associated with colorectal cancer risk (OR = 1.48, highest quartile versus lowest, 95%CI: 1.26–1.74; p-trend: <0.001), but not breast cancer. This study provides evidence that a pro-inflammatory diet is associated with increased colorectal cancer risk while findings for breast cancer were less consistent.