Shiitake mushrooms are a functional food because that contains natural bioactive substances, such
as β-glucan and eritadenine. Using a Shiitake mushroom-enriched diet to lower plasma lipid has been
widely reported [1–4]. More recently, the role of Shiitake mushrooms in preventing body weight gain
has been reported but its mechanism was largely unknown [5]. The previous study identified that
a Shiitake mushroom-enriched diet in rats fed a high fat diet (HFD) significantly lowered plasma
triacylglycerol (TAG) and fat deposition by −55% and −35%, respectively, compared to HFD alone [5].
It has also been identified that a high dose mushroom (HD-M) enriched diet significantly increased the
ratio of faecal fat to faecal weight by +58% compared to HFD alone [6]. The β-glucan of Shiitake
mushrooms was possibly assisting faecal fat exclusion through the effects of β-glucan viscosity [7,8].
From these data it could be hypothesized that Shiitake mushrooms decrease plasma TAG, prevent fat
deposition, and prevent body weight gain via faecal fat exclusion and the accumulation of fat in
the liver