Chronic diseases, most notably diabetes, cancer, cardiovascular diseases, neurodegenerative diseases, thyroid diseases, and allergic diseases are major causes of death, disability, and a lower quality of life in various populations. Oxidative stress, defined as an imbalance between the production of pro-oxidants (reactive oxygen, nitrogen, and chlorine species) and the body’s production of antioxidants (enzymatic, eg, superoxide dismutase, glutathione peroxidase, catalase, and non-enzymatic, eg, glutathione, uric acid, melatonin, metal-binding proteins, bilirubin, polyamines), plays an important role in the pathogenesis of these diseases. Lifestyle modifications, including a healthy diet, are a major therapeutic strategy in preventing and treating chronic diseases. Dietary antioxidants such as polyphenols, eg, flavonoids (flavones, flavonols, theaflavins, catechins, proanthocyanidins, flavanones, anthocyanidins, and isoflavones) and non-flavonoids (phenolic acids, stilbenes, and lignans), antioxidant vitamins (C, E, A, carotenoids) and minerals (Se, Mn, Zn, Cu, Fe) can support the action of endogenous antioxidants in alleviating the negative effects of oxidative stress [1].

A new approach to a healthy diet is to asses dietary total antioxidant capacity (DTAC), because the whole diet contains various antioxidants with additive or synergistic effects. Several assays are available to measure antioxidants in foods, but the largest database is based on the FRAP (ferric ion-reducing antioxidant potential) method. Dietary FRAP has been shown to positively correlate with well-known indicators of a healthy diet [2]. Moreover, habitual antioxidant intake is significantly positively associated with the lifestyle and socioeconomic status of the population [3]. However, individual diet modification in terms of higher antioxidant intake can improve the clinical parameters of patients with metabolic syndrome (MetS), even before pharmacological treatment [4]. Paulis and Giorgio [5], in a report on three cases, demonstrated the positive effect of combined therapy involving oral intake of antioxidants and pharmacological treatment in urological diseases. Similarly, Candellone et al.[6] indicated that antioxidant supplementation (vitamin E, curcumin, resveratrol, quercetin) has a synergistic effect on the course of pharmacological treatment of thyroid diseases in both animals and humans. In the Bialystok PLUS population in Poland, a higher quartile of DTAC, after adjustment for confounding variables, was significantly associated with a reduced odds ratio for the prevalence of prediabetes, and was inversely associated with HOMA-IR in a multivariate linear regression model. Moreover, DTAC was positively related to individual dietary antioxidants (polyphenols, antioxidant vitamins, and minerals). It was found that reduced DTAC may be considered an additional risk factor for developing type 2 diabetes mellitus (T2DM)[7].