## 4 Discussion
The impact of the habitual dietary consumption of selected antioxidants in various foods, as well as of pure compounds supplementation, suggests its positive impact on cardiovascular risk factors such as obesity or blood pressure [21]. However, the observational studies and the interventional studies' results are not consistent. It could be the result of the fact that for supplementation purposes usually pure compounds are used, while in the habitual consumption assessment, they are a part of a mixture of multiple antioxidative agents. Such conclusions have already been raised when referring to apples [42]. Dwarf kiwi has not been widely tested in humans, however, in vitro and animal model studies results are promising [34; 35; 36; 37; 38]. That is why we decided to assess the impact of apples and dwarf kiwi supplementation on clinical laboratory metabolic parameters among humans with excessive body mass. The results of our pilot study showed that in the overall group, supplementation led to a significant drop in ALT levels. ALT is one of the routine parameters to assess liver functions in the clinical practice. Its level rises in the course of liver damage, so this observation can suggest the possible hepatotoxicity potential of this intervention. However, more detailed tests would be needed to further confirm this preliminary conclusion, as liver malfunction can be the result of multiple factors, including the metabolic dysfunction-associated fatty liver disease. What is more, in the placebo group, we observed a significant elevation of amylase level which was not present in the supplementation group. Amylase is the enzyme produced by the pancreas and it is the laboratory marker of pancreas dysfunction. Its level rises in the course of pancreas damage, so this observation could also indirectly suggest the possible pancreas-protective potential of the intervention. However, similarly, more detailed laboratory and imaging tests would be needed to confirm this preliminary suggestion. Moreover, these observations are in line with the results of the animal model studies in which _Actinidia_ supplementation protected the liver in rats with hypercholesterolemiaemia [37]. What is more, when the participants were divided into subgroups, the analysis revealed a significant impact of supplementation on lipid profile, which was not observed in the placebo group. However, the nature of this improvement differed among the subgroups. In the women subgroup, supplementation led to significant total cholesterol and non-HDL levels decrease. Moreover, the possible hepatotoxicity potential as described above was also stronger in women. On the other hand, in men, supplementation led to a significant triglyceride level decrease. These results are consistent with the results from the mentioned above animal model study which also showed that dwarf kiwi supplementation presents hepatotoxicity potential together with lipid profile improvement [37]. There are no other studies available regarding the metabolic impact of dwarf kiwi supplementation. As already mentioned, excessive body mass can lead to serious metabolic complications, such as dyslipidemia or diabetes. They are both important cardiovascular risk factors, which is why looking for methods of their improvement is crucial in terms of public health efforts [3; 10]. Lipid profile assessment is focused on different lipoprotein fractions, due to their chemo-physical and biological properties. Total cholesterol is composed of the main fractions HDL and non-HDL, which gathers LDL altogether with VLDL cholesterol. HDL is responsible for cholesterol transport, mainly from tissues to the liver, which is then responsible for its metabolism and elimination. At the same time, non-HDL acts contrary to this and transports cholesterol mainly to peripheral tissues, including the artery wall and partially to the liver. Penetration and accumulation of cholesterol in the vascular wall leads to local inflammation and the development of atherosclerosis.