Subtropical fruits grown in Spain and elsewhere: A comparison of mineral profiles

Highlights

• Sub-tropical fruits are a proper but not well-explored source of micronutrients.

• The content of Ca, P, Na and K of Spanish and international fruits was studied.

• The mineral content of national fruits was comparable to the international ones.

• The P and K concentration was noticeably higher in the international fruits.

• A fruit serving contributes up to 10% of the daily intake of K in adult population.

Abstract

Large quantities of essential minerals are present in subtropical fruits, which constitute a valuable, if relatively unknown, source of dietary micronutrients, and consumption of these foods is tending to increase. Our aim in this study was to investigate the mineral composition (Ca, P, Na and K) of Spanish-grown subtropical fruits in comparison with that of similar fruits sourced elsewhere. The contribution of these fruits to total daily mineral intake per capita in Spain and to mineral intake per regular fruit size was also estimated. The results obtained showed the mineral content of the Spanish-origin samples to be comparable to that of those from other countries, except for avocados, in which the concentrations of P and K were noticeably higher in the non-Spanish fruits (530 vs. 196 and 5260 vs. 3664 mg/kg, respectively). The contribution of subtropical fruits to daily mineral intake in adults was estimated to be 2–7% for Ca and P, approximately 10% for K and negligible for Na. In conclusion, subtropical fruits of Spanish origin present a balanced mineral composition and the consumption of these fruits is recommended as a means of increasing the intake of essential minerals (especially in a population such as that of Spain, where there is considerable room for improvement in dietary patterns).

Introduction

Many studies have demonstrated that the consumption of fruits and vegetables is associated with improved human health. Thus, individuals who eat five or more daily servings of fruits and vegetables have a decreased risk of developing a wide variety of cancer types, particularly those of the gastrointestinal tract (Gescher et al., 1998). Other studies have shown that fruits and vegetables alleviate the effects of Alzheimer’s disease (Planas et al., 2004), diabetes, obesity and metabolic syndrome (Devalaraja et al., 2011), due to the bioactive components in these foods. It has also been reported that the consumption of kiwifruit can lower blood triglyceride levels by 15%, compared with a control group (Duttaroy and Jorgensen, 2004). The latter study also reported that consuming two or three kiwifruits per day for 28 days reduces the platelet aggregation response to collagen. Similarly, the consumption of mango, among other fruits, provides significant amounts of bioactive compounds with antioxidant effects (Liu, 2003). In general, exotic fruits have several bioactive components with potential health benefits, including anti-diabetic, anti-obese, anti-oxidant and anti-inflammatory activities (Dembitsky et al., 2011). In this study, therefore, we provide a detailed description of these fruits, as an essential first step in assessing their content of nutrients and bioactive components (Samadi-Maybodi and Shariat, 2003, Montoya et al., 2016).

Mineral micronutrients are involved in numerous biochemical processes and an adequate intake of these minerals is essential to the prevention of deficiency-related diseases (Leterme et al., 2006). The risk of nutritional deficiency, and of associated pathologic conditions, depends on a wide range of factors, including the magnitude of dietary intake, processing practices, the presence of substances that could reduce or increase mineral bioavailability, and the physiologic and health condition of the individual (Barberá et al., 1992). For example, calcium is very important in human nutrition due to its direct relationship with bone mass (Shim and Kim, 2015), while inadequate potassium and sodium intake are both related to the development of hypertension (Perez and Chang, 2014). In this sense, kiwifruit has been demonstrated to decrease bone resoption (Katsumata et al., 2015). Although diets high in fruits and vegetables are rich in vitamins, minerals and dietetic fibre, and are directly linked to a decreased risk of disease, in the last 30 years their global consumption has decreased (Retamales, 2011). Thus, in Spain, fruit intake per capita (Ministerio de Agricultura, Alimentación y Medio Ambiente, 2014) during 2014 was 284 g/day, well below the 400 g/day recommended by FAO and WHO (FAO/WHO, 2003). Therefore, greater consumption of fruits and vegetables should be encouraged.

Tropical fruits are rich in various mineral species, and so they constitute an important source of these micronutrients (Galán, 2006). Tropical fruit crops are commonly produced in the geographical zone extending from latitudes 30° south to 30° north, where climatic conditions are appropriate, with average temperatures of around 27 °C, low differences in photoperiod and high levels of humidity (Almeida et al., 2009). Subtropical zones, on the other hand, have hotter summers and colder winters, greater differences in photoperiod and less humidity. In Spain, regions such as the Canary Islands and parts of Andalusia fall into this category, where weather conditions are suitable for the cultivation of subtropical fruits (Galán and Ferré, 2005). One such area is that of the “Tropical Coast”, which straddles the provinces of Granada and Málaga, and contains the towns of Almuñécar, Itrabo, Jete, Lentejí, Los Guájares, Molvízar, Motril, Salobreña, Otívar, Benaudalla and Vélez (in western Granada province) and those of Algarrobo, Frigiliana, Nerja, Torrox and Vélez-Málaga (in eastern Málaga province) (Diputación de Granada, 2007).

The aim of this study is to investigate the mineral micronutrient composition of a group of subtropical fruits grown in the above area of southern Spain, and to compare it with the corresponding composition of imported counterparts, marketed in the same region, to determine the influence of the origin and type of fruit in this respect. We also analyse the contribution of the daily consumption of these fruits to overall mineral intake, and the contribution per regular fruit size. Therefore, because of the increased consumption of these fruits in Spain, they become a god source of minerals in the daily diet.