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Influenza and Cold Prevention by Stained Tea Catechin on Throat Mucosa

Health and Wellness

The route and timing of initiation of upper respiratory tract infections, such as influenza and colds, are difficult to observe because the causative virus is not visible to the naked eye. Even individuals who are vaccinated, wash their hands, and wear a mask can become infected.
Kao has focused on the mucous membrane of the pharynx (throat), one of the inherent biological barriers in humans, for considering new preventive methods. Previous studies by our researchers revealed that tea catechin remained in the throat mucosa of mice and there exerted an antiviral effect. It is thus considered that by utilizing the action of chemical binding between mucin, the main component of throat mucosa, and tea catechin, and by retaining a greater quantity of tea catechin in the mucosa for a longer period, it is possible that the mucosal barrier (antiviral capability) can be further enhanced (Fig. 1).


Figure 1. Image showing improved mucosal barrier (antiviral capability) caused by tea catechin

Investigation of a method for retaining a large amount of tea catechin in the mucosa confirmed that greater viscosity caused by xanthan gum (thickener) increased the amount of tea catechin adsorbed on throat mucosa (Fig. 2).


Figure 2. Amount of tea catechin adsorbed on model pharyngeal mucosa

In a subsequent study, the group that consumed drinks containing tea catechin and increased viscous three times a day for three months had a 50% lower incidence of cold syndrome, as defined by WHO, than subjects who consumed drinks without tea catechin (placebo group). Furthermore, the risk of onset was statistically reduced by about 50% as compared to that noted in the placebo group (Fig. 3).


Figure 3. Effects of tea catechin that is increased viscosity on incidence of influenza and colds

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