The ibs.GRANADA and the UGR lead a study on how cooking techniques affect the availability of copper in food and its impact on adults and children
Copper is an essential mineral for the body due to its antioxidant and anti-inflammatory effects, so reduced bioaccessibility in vulnerable populations, such as children with pathologies, could affect their growth and long-term health status.
The Granada Biosanitary Research Institute (ibs.GRANADA) and the University of Granada (UGR) have led a research on the bioaccessibility of copper, that is, on the amount of the mineral that could be absorbed in the intestine after the consumption of various foods cooked in different ways, fried, roasted, toasted, boiled, grilled or raw. The result of this work, carried out in collaboration with the Department of Pediatrics of the University of Athens, has given rise to the study entitled Do cooking techniques influence copper bioaccessibility in foods after in vitro digestion/fermentation in adults and children?, published in the magazine Food Research International. The research has been led by Dr. José Ángel Rufián Henares, researcher of the group E07-Research in Environmental Health and Children from the ibs.GRANADA and professor of the Department of Nutrition and Food Science at the University of Granada.
Copper is an essential mineral for the body due to its antioxidant and anti-inflammatory effects. Reduced bioaccessibility in vulnerable populations, such as children with pathologies, could affect their growth and long-term health status. These findings may influence future nutritional recommendations, particularly regarding appropriate cooking techniques for different types of food.
The results indicate that total copper bioaccessibility varies depending on the origin of the food (higher in those of plant origin: 52,3% compared to 44,5% in those of animal origin), food group (higher in nuts, vegetables and greens), and specific foods due to the variability of their composition and the different forms under which copper can appear in foods. It was found that bioaccessibility in the small intestine was higher than that established in the large intestine, and that in foods, considered globally, cooking increased the total bioaccessibility of copper at the expense of its increase in the large intestine. This result implies the important role of the colon microbiota in the genesis of compounds that, after fermentation, keep copper soluble facilitating greater bioaccessibility.
In plant-based foods, copper bioaccessibility in the large intestine is lower in raw form than in cooked foods, indicating that heat treatment facilitates the appearance of compounds that increase bioaccessibility. Furthermore, improving the composition of the intestinal microbiota would lead to fermentation that facilitates the formation of more soluble compounds.
In foods of animal origin, the effect of cooking techniques is more noticeable. Thus, in fried and boiled foods, copper bioaccessibility in the small intestine is lower, while in the large intestine it is higher in grilled and roasted foods, probably due to the marked protein denaturation resulting from the intense heat treatment.
Cereals containing gluten have higher values of copper bioaccessibility both in total and in the large intestine, which, together with their higher copper content, expresses the importance of avoiding recommending the consumption of gluten-free cereals in the regular diet of people who do not have gluten intolerance (celiac disease), due to the risk of suffering a nutritional deficiency in this element.
This research, funded by the European project Stance4Health and the UGR's own Research and Transfer Plan has its origin, on the one hand, in an initial demand for bioavailable quantities – physiologically usable by the human body – of essential nutrients such as copper in food and, on the other, in the social demand related to the generation of higher quality and more nutritious foods, especially aimed at more vulnerable groups such as children.
The research team, using digestion and fermentation simulation methods vitro, assessed copper bioaccessibility to optimize the nutritional quality of foods, especially those targeted at vulnerable groups such as children. Nutrient bioaccessibility in appropriate foods can help combat common childhood diseases such as obesity, celiac disease and milk protein allergy. Until now, no research had been conducted on the influence of cooking on copper bioaccessibility in such a large number of different foods (54 in total), the way they are regularly consumed, together with the stage of life (childhood versus adulthood) or the presence of diseases in children.
Differences between children and adults
The study also revealed differences in copper bioaccessibility depending on life stage and health status. In normal-weight children, bioaccessibility in the large intestine was significantly higher (37.7%) compared to healthy adults (14.1%) and children with pathologies such as celiac disease (14.6%), obesity (15.5%) and milk protein allergy (26.9%). The higher bioaccessibility in normal-weight children compared to adults, and in turn, higher in allergic children compared to celiac and obese children, is possibly related: firstly, to the growth inherent to childhood, despite a lower food and energy intake than healthy adults; and secondly to the pathology itself, which determines a specific composition of the intestinal microbiota and limits the use of copper from food. These results suggest that children with various pathologies could have limited access to the copper necessary for optimal growth and development.
Ultimately, this study represents a step forward in research on nutrient bioaccessibility and its relationship with dietary factors, cooking techniques and health conditions. Thanks to projects such as “Stance4Health”, funded by the European Union, nutritional science is advancing towards a better understanding of how to optimize diet to support public health, especially in vulnerable groups such as children. With these findings, it is hoped to contribute to healthier and more effective nutrition that can prevent diseases and promote adequate growth in childhood.
