**1. Introduction**

Chili pepper (*Capsicum* spp.) has been used in Mexico as food and a condiment for over eight centuries [1] and is an integral component of the diet and cultural identity of Mexico. Although various chili species grow wild and are cultivated in the United States of America, Mexico is the center of origin, domestication and diversification of *Capsicum annuum* L. [2, 3]. Wild variants continue diversifying (*C. annuum* var. *glabriusculum* [Dunal] Heiser & Pickersgill) and are distributed throughout the country [4, 5]. In this Mesoamerican biocultural context and using traditional management, farmers preserve and utilize a great diversity of chili landraces.

A total of slightly more than 150 landraces, occupying extensive planted surfaces and providing for great consumption, have been described in Mexico. The central and south-southeastern regions are more diverse and relevant for the in situ preservation of chilis. In these regions, approximately 80 landraces have been preserved. In Mexico, 153,565 ha are cultivated annually, resulting in an average production of 2.8 million tons of dry and fresh fruits. Annually, approximately 2 million tons of fresh and dry chilis are consumed, and in some years, imports range between 20,757 and 41,000 tons [6]. Consumption per capita in urban areas is from 8 to 9 kg, and in rural communities, it varies between 13 and 17 kg.

The health benefits of chili consumption and its active ingredients continue to be investigated using in vitro and in vitro biological models as well as theoretical and experimental models. Capsaicinoids and flavonoids are the determinant compounds of color, flavor, texture and aroma of food prepared with chilis. A common question among health specialists is whether chili consumption improves health or contributes to disease development. The chili fruit contains up to 15 or more capsaicinoid compounds. Among the majority are capsaicin, dihydrocapsaicin and nordihydrocapsaicin; in flavonoid content, quercetin, apigenin and luteolin are notable as well as some catechins and cyanidins. Thus, one does not only ingest vitamins B1 , B2 and C, minerals, carotenoids and phenols by chili consumption.

Flavonoids contain phenolic hydroxyl groups in their chemical structure and possess excellent chelating properties of iron and other transition metals—characteristics that confer on chilis a high antioxidant capacity and anti-free-radical properties, generating protection against oxidative damage [7]. Flavonoids have positive effects on health although their mechanisms of action continue to be investigated because it is difficult to quantify daily intake and their direct effects on health. Thus far, flavonoids are associated with antisclerotic, anti-inflammatory, antitumoral, antithromobogenic, antiviral and antiosteoporotic effects and may function as a preventive agent in cancer, among other effects [8–10].

Capsaicinoids are synthesized in the placenta of the fruit and are genetically determined (*Pun1* allele of pungency) by the presence of the *Pun1* or *pun1* gene with EST- or AT3-type cofactors that induce a quantitative effect of the gene and variations in the pungency of the fruit. Therefore, not all chili peppers are spicy, and various consumers consider chili varieties that carry the *pun1* recessive gene to be sweet fruits [11]. In addition, genetic or genotypic factors, crop management, cultivation environments, maturity of the fruit upon cutting, postharvest management of fruit and forms of processing or cooking the fruit for consumption influence the level of pungency and flavor at the time of consumption [12].

In the last decade, hundreds of articles have been published on the potential adverse and beneficial effects of capsaicin (8-methyl-N-vainillyl-6-nonenamide) on human health. Experimental results are controversial and require testing in humans, not only biological models. Consumption of capsaicin in chilis stimulates neuronal networks and gastric secretions and stimulation; in addition, capsaicin is considered to be a preventative agent for cancer, has lipolytic action by increasing the hydrolysis of triacylglycerol in adipocytes and is associated with antioxidant action. Direct effects as a carcinogenic agent have not been demonstrated, and recent studies have demonstrated that there is no conclusive evidence that confirms the association between consumption of extremely spicy red chili peppers and mortality in the European and North American populations [13–18].

The role of diet in health is increasingly important and warrants further investigation. Several investigators have focused their studies on the documentation of macro- and micro-nutrients, vitamins, minerals, proteins, gastronomic aspects and, recently, the functional and nutraceutical character of various bioactive compounds. Chili peppers and other species are consumed universally because these fruits confer color, flavor, aroma and texture and help preserve foods. In this work, the diversity and variety of consumed forms of chilis in Mexico, flavonoid and capsaicinoid content in the fruits and their potential health benefits, are documented based on various study results and bibliographic information. Additionally, elements of the culinary culture associated with chili in Mexico, high levels of consumption and repercussions on human health with an emphasis on flavonoids and capsaicinoids are provided.
