Elemental bioavailability in whey protein supplements

Abstract

Whey protein (WP) as a dietary supplement for athletes and gym-users is characterized by a content of high-quality amino acids. The benefits of their consumption are well-known and mainly related to the improvements of strength and body composition. Nevertheless, there is a scarce information about the risk associated to their elemental composition. The aim was to evaluate the total content and bioavailability of twenty-five elements in twenty whey protein powder samples, using Inductively Coupled Plasma Mass Spectrometry, and to evaluate the possible risk associated to the excessive daily intake of such products. Results showed that Na, K, Ca and Mg were the most predominant elements. After Hierarchical Cluster Analysis three different groups of whey protein supplements were observed. ANOVA analysis indicates that the concentration of the Na, K and Mg above mentioned elements is the key for the observed classification. The average elemental bioavailable fraction in the stomach is 45 % whereas in the intestine is 64 %. Most of the elements tested (nineteen) show gastric bioavailability higher than 60 %, being Al the lowest (37 %) and Co the highest one (76 %). According to our results, previously published data and recommendations of producers, WP samples can be considered save from the elemental composition point of view.