Mineral profile of weight loss related foods marketed in Spain
Introduction
Overweight and obesity are an important public health problem due to their close relationship with the rise of different chronic and non-communicable diseases worldwide. An imbalance between intake and energy expenditure is the main origin of obesity, consequently, the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Obesity Society (Jensen et al., 2014) recommend the prescription of a hypocaloric diet for obese or overweight people. One successful approach for weight loss tested in several clinical trials is the daily substitution of one or more meals with low-calorie products (Ard et al., 2019). Therefore, meal replacement and/or low calorie products may provide favourable results in a weight management intervention since they have similar attrition rates to conventional dieting (Gulati et al., 2017).
In recent days consumers are aware of the importance of low calorie foods to prevent overweight, not only as an obesity treatment but also as a way to control snacking, since the obesity problem is best described as an issue of systematic caloric overconsumption, with the consumption of snacks as an increasingly important contributor (Shelley, 2012). In this sense, different low-calorie snacks that supplement a balanced and healthy diet are available on the market, such as cereal bars, cereal cakes and meal replacement shakes (Hartmann, Siegrist, & van der Horst, 2013). For example, meal replacement beverages are usually consumed as part of a reduced-calorie diet, but compared with cereals bars or cakes they have a weaker satiety effect, reduced dietary compensation, and greater subsequent energy intake (Mattes, 2006; Rufián-Henares et al., 2002, Cassady et al., 2012).
At the ingredient level, there are clear differences between cereal bars, cereal cakes and meal replacement shakes. Cereal bars are made with different grains, ranging from oat to barley or rice, with wheat being the most common (Orecchio et al., 2014, Rufián-Henares et al., 2006). As famous as cereal bars, or perhaps more, are the increasingly ubiquitous cereal cakes. They are made, like many different breakfast cereals, of corn, rice, barley, quinoa, rye, buckwheat or even a combination of the above cereals (Delgado-Andrade et al., 2007, Islam et al., 2017). However, the main difference with respect to cereal bars is the higher salt content of cereal cakes. A diet high in salt has long been shown to increase blood pressure and consequently put one at increased risk of cardiovascular diseases (He & MacGregor, 2011). Finally, food replacement shakes designed to supplant foods are composed of milk proteins and a cocktail of vitamins and minerals (Rufián-Henares, García-Villanova, & Guerra-Hernández, 2001), so that a micronutrient deficiency should not be reached due to the consumption of these foods.
Irrespective of the type of weight loss product, their quality is determined by different indicators like microbiological safety, sensory attributes, and nutritional value, among others (Rufián-Henares et al., 2006, Rufián-Henares et al., 2006). For many years, the attention of producers and consumers was mainly focused on the sensory properties and low amount of calories, but lately nutritional value has also become an important aspect (Rybicka & Gliszczynska-Swiglo, 2017). In this sense, foods and water provide the major proportion of the daily intake of minerals in human beings. Foods can also be contaminated with trace metals by the introduction of mechanized farming, the increasing use of chemicals, food processing, etc. (Matos-Reyes, Cervera, Campos, & de la Guardia, 2010). In order to decrease the adverse impact of food consumption, it is important to monitor mineral levels. Thus, mineral food composition data are important to both consumers and health professionals, and in recent years food labeling legislation has highlighted this requirement.
Due to the limited data on mineral elements content in products designed for weight loss-control, the aim of the present paper is to unravel the quality of a range of weight control products available on the Spanish market. The content of three macroelements (potassium, phosphorous and sodium), four microelements (cobalt, copper, manganese, zinc), three oligoelements (chromium, nickel, molybdenum) and twelve contaminants (antimony, arsenic, barium, beryllium, bismuth, cadmium, lead, thallium, thorium, uranium, vanadium, yttrium) is described in this study. Due to the limited data on mineral content in these products, the obtained results are an important part of their quality characteristics.
Section snippets
Chemicals
All chemical reagents used for mineral assays were of analytical grade unless otherwise stated. Such reagents were from Merck and Sigma-Aldrich (Germany).
Samples
Seventy-four foods designed for weight management were bought in local supermarkets (Granada, Spain). Each sample was obtained from three different stores, each sample belonging to a different batch. Thirty-five cereal bars were analyzed, of which 21 had chocolate in their ingredients. In the case of cereal cakes, 33 different samples were
Essential and toxic minerals content in weight loss related products
Although weight loss related products are not the main source of mineral elements for the whole population, they are an important part of a balanced diet for people under calorie-restriction (meal replacement) or for those that use these foods as appetizers.
The content expressed as median (±SD) of analyzed arsenic, barium, beryllium, bismuth, cadmium, cobalt, chromium, copper, potassium, manganese, molybdenum, sodium, nickel, phosphorus, lead, thorium, thallium, antimony, uranium, vanadium,
Conclusions
This manuscript reports for the first time the analysis of the mineral profile (22 elements) of weight loss related products marketed in Spain. The analytical methods used showed good accuracy and recovery. In general the studied samples did not exceed the legal limits for toxic elements, except chromium and lead, of which many samples exceeded such limits. Differences in the concentrations of essential and toxic elements were obtained for some types of cereal bars and cereal cakes, taking into
CRediT authorship contribution statement
Ana Zurita-Ortega: Investigation, Methodology. Ana Cervera-Mata: Investigation, Methodology, Formal analysis. Gabriel Delgado: Formal analysis, Conceptualization. Félix Zurita-Ortega: Conceptualization, Formal analysis. José Ángel Rufián-Henares: Validation, Formal analysis, Writing - review & editing, Funding acquisition. Silvia Pastoriza: Supervision, Project administration.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This study was supported by project AGL2014-53895-R from the Spanish Ministry of Economy and Competitiveness and by the European Regional Development Fund (FEDER). This paper will form part of the doctoral thesis by Ana Zurita-Ortega, conducted within the context of the “Pharmacy PhD Programme” at the University of Granada. We also acknowledge Melanie Davies for English proofreading.
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