Dr Adam Carey, chair of ESSNA pointed out that the study, which also found 9% of the 52 protein powder samples had blocked lysine values exceeding 20%, did not reference any comparisons made with other non-dairy protein sources, which would have a higher damage percentage.
“Dairy processing has for a long time been acknowledged as one of the least damaging processes, in terms of damage to amino acids, compared to other protein sources where, for example, fibrous components require more processing to extract the protein,” he said.
“Since dairy processing only involves a series of membrane filtrations at controlled temperatures, the damage is comparatively minimal.
“For example, unpublished data has previously found that lysine can be found damaged at 24% in rolled oats, 45% in puffed rice, 36% in wheat bran, just to name a few.
“Therefore the ~10% presented by this study for dairy protein sources, considered in this context, is actually extremely low.”
The study, performed at the University of Seville and included over 5,000 individuals, also noted the highest concentrations of blocked lysine found in whey hydrolysates and peptides (12%).
In addition, the research team found the lowest concentrations were recorded by serum and casein isolates.
As indicated on the label?
The study also suggested that the content of carbon hydrates as shown on the label could be an "indirect but useful" indication of the thermal damage done to milk serum supplements.
“During the preparation of powdered protein supplements, the thermal treatment involved can reduce the nutritional value of the product, an aspect that, until now, has received little research attention,” said the University of Seville’s Antonio Sánchez.
“Lysine, an amino acid involved in this reaction, is transformed into other compounds that are not biologically usable.
“In addition, according to the thermal treatment received, changes can be produced in the protein structure, which means that these supplements are less digestible for the body."
Study ‘highlights whey protein benefits and advantages’
Dr Carey argued that the study provided no new information to suggest that whey protein suffered from any excessive or untoward degradation, which would compromise its beneficial effects.
“Indeed, whey manufacturers have made a concerted effort to use low-temperature, gentle processing methods so as to maintain the integrity, nutritional and functional properties of their products and they have been proudly promoting these processing techniques for decades.
“Given all of the above, ESSNA is of the strong opinion that this research, if taken in proper context, relative to other foods, actually highlights the benefits and advantages of using whey protein.”
During their manufacture, PPS may undergo chemical or enzymatic processes such as heat treatment (evaporation) or by other methods (ultrafiltration) to achieve the concentration required.
Along with a heat-treated drying stage, these steps can produce the partial denaturation of the proteins promoting undesirable reactions that can affect nutritional properties.
Also, PPS are sometimes stored for long periods, which further impairs their nutritional properties.
‘With food processing, there is always loss’
Despite the findings, the research team added that the consumption of protein supplements did not raise any health concerns provided that the product complied with quality controls, was purchased via approved channels and was manufactured to standardised specifications.
"There are increasingly more cases in which the consumption of supplements means, unknown to the consumer, the consumption of substances that can have adverse effects on their health,” said Sánchez.
“Therefore, nutritional evaluation must be the first step when advising sportspeople on diet strategies or the use of supplements."
Dr Carey added, “It is no secret that in every type of food processing procedure, damage is incurred to nutrients – this is not just an issue of the sports nutrition industry.
“With food processing, there is always loss; such as a loss of Vitamin C when something is juiced and left standing, and in this case, Maillard reactions, which happen even when an apple or a banana is cut and not eaten immediately.
“The fact is there will be blocked Lysine in any form of processed protein food.”
Published online: doi.org/10.1016/j.lwt.2018.06.047
“Quality analysis of commercial protein powder supplements and relation to characteristics declared by manufacturer.”
Authors: A.J. Sánchez-Oliver, Contreras-Calderón, J.M.Puya-Braza, E.Guerra-Hernández