ABSTRACT
BACKGROUND@#Chemical intolerance (CI) is a chronic condition characterized by recurring and severe symptoms triggered by exposure to low levels of odorous or pungent substances. The etiology of CI has been a controversial subject for a long time. The aim of this review is to summarize findings on the neurological processing of sensory information during and after exposure to low levels of odorous or pungent substances in individuals with CI, focusing on the brain function and networks.@*METHODS@#Scientific studies on CI published between 2000 and 2019 in academic peer-reviewed journals were systematically searched using medical and scientific literature databases. Only peer-reviewed articles reporting original research from experimental human studies directly associated with CI, and involving related neurological responses or brain imaging after exposure to odorous or pungent substances (i.e., in chemical provocation tests), were considered.@*RESULTS@#Forty-seven studies were found to be eligible for a full-text review. Twenty-three studies met the selection criteria and were included in this review. Evidence indicated that differences between subjects with CI and healthy controls were observed by brain imaging during and after exposure to odorous or pungent substances. Differences in brain imaging were also observed between initial exposure and after exposure to these substances. Neurological processing of sensory information after exposure to extrinsic stimuli in the limbic system and related cortices were altered in subjects with CI. A previous documentable exposure event was likely to be involved in this alteration.@*CONCLUSIONS@#This review documents consistent evidence for the altered neurological processing of sensory information in individuals with CI. Further neurophysiological research exploring the processing of extrinsic stimuli and cognition of sensation through the limbic system and related cortices in CI, and the appearance of symptoms in individuals with CI, are required.
ABSTRACT
Objective: We previously reported the immune-enhancing behavior of fucoidan, a sulfated polysaccharide extracted from Gagome kombu (GKF), both in vitro and in animal studies. In the present study, we evaluated the immune efficacy and safety of GKF in healthy Japanese adults.Methods: In this randomized, double blind, placebo-controlled study, 30 subjects who ingested GKF (200 mg/day) or placebo for 4 weeks were enrolled. For evaluation of efficacy, phytohemagglutinin-stimulated cytokine production in whole blood cells was measured. For evaluation of safety, blood chemistry analysis, hematological analysis, and urinalysis were conducted.Results: Almost all cytokine production decreased in samples from the placebo group during the test period. Ingestion of GKF for 4 weeks significantly suppressed the decrease in production of the T helper 1 (Th1)-type cytokines interferon-γ and interleukin-12 as well as the Th1:Th2 ratio. There were no adverse clinical changes in blood analysis and urinary analysis, and no serious symptom was observed.Conclusion: These results indicate that GKF is a useful and safe food ingredient to support immune function.