Damien Belobrajdic
CSIRO Health and Biosecurity

Australian mushrooms and their potential health benefits of lowering blood cholesterol
Mushrooms are one of the few foods that are high in β-glucan, a type of dietary fibre well recognised for its blood cholesterol lowering properties. At present a high-level health claim related to β-glucan and cholesterol lowering is authorised by Food Standards Australia New Zealand, but the claim is only applicable to oat and barley foods. It is not clear whether mushroom β-glucan has similar cholesterol lowering properties as oats and barley as they contain differing forms of β-glucan.

In this study we quantified the amount of β-glucan in raw and cooked Australian mushrooms and showed that the β-glucan content of fresh Agaricus bisporus mushrooms (0.3 – 0.7%) was much lower than oats (6.9%) while Pleurotus mushrooms contained 3.2% (Oyster) and 3.7% (Shimeji) β-glucan. This equates to consuming 150 – 300 g raw A. bisporus or 30 g raw Pleurotus mushrooms to achieve 1 g of β-glucan (amount required per serving of oats or barley for a high-level health claim related to cholesterol lowering).

We also evaluated whether these mushroom varieties affected bile acid binding capacity, the primary cholesterol lowering mechanism for β-glucan. Using an in vitro (laboratory-based) assay, the bile acid binding capacity of A. bisporus mushrooms (29 - 36%) was equivalent to raw oats (36%) whereas Oyster mushrooms had significantly lower (22%) bile acid binding capacity than oats. Thus, this study provides preliminary evidence that the β-glucan from A. bisporus has similar bile acid binding capacity on a per g basis compared to oats and supports further investigation in humans.

Dr. Damien Belobrajdic
Damien is a Senior Research Scientist for CSIRO Health and Biosecurity, Adelaide. He graduated with a PhD in Nutritional Physiology from Adelaide University in 2004 and has primarily focused his research efforts on determining the nutritional and health benefits of cereals and dietary fibres such as β-glucan, resistant starch and fructans. He currently leads multidisciplinary research projects that investigate how food and food components modulate gut and metabolic health, particularly focused on identifying plant varieties and food products high in fibre and quality proteins.