Possible involvement of lipids in the effectiveness of kombu in individuals with abnormally high serum triglyceride levels

In Japan, Kombu (Laminaria japonica), which is a type of seaweed, is considered to be a foodstuff with health-promoting benefits, and Japanese people actively incorporate Kombu into their diets. Previously, we reported that the frequent intake of Kombu reduced the serum triglyceride levels of subjects with abnormally high serum triglyceride levels. In the current human study, we performed metabolomic analysis of serum lipids, and then the molecular species profiles of phosphatidylcholines (PC), phosphatidylethanolamines (PE), lysophosphatidylcholines (LPC), lysophosphatidylethanolamines (LPE), and free fatty acids (FFA) were evaluated. As a result, it was found that there were no marked differences between the lipid profiles obtained before and after the intake of Kombu for 4 wk in all subjects. In the subjects with abnormal serum triglyceride levels, the intake of Kombu improved the subjects’ molecular species profiles in terms of their serum levels of the diacyl and acyl forms of PC, PE, LPC, and LPE, and FFA. Furthermore, the intake of Kombu also tended to increase the serum levels of both the plasmanyl and plasmenyl forms of PC and PE in these subjects. The lipid alterations observed in our study might be related to the functionality of Kombu. Furthermore, it is important to evaluate the quality of lipids as well as the quantity of lipids in various types of research, including food functionality studies.