Reference Number: 393
Year: 2015
Link: Link to original paper
Health: Immune response | Inflammation
Inclusions: Mushrooms
Summary
Shiitake mushrooms are known for their benefits to health and many different medicinal properties. There have been many animal studies suggesting that they have a positive effect on the activation of our immune system and are able to reduce levels of immunosuppressive compounds. But would they have the same effect on our immune system if we add them into our baking?
One of the first studies to look at the effects of a dietary intake of shiitake mushrooms in humans was conducted in 2015. The study reviewed the effects of consuming 1-2 servings of shiitake mushrooms on a daily basis. This was specifically looking at the effects of the mushrooms on the function of one type of antibody called immunoglobulin A (IgA). Most of our IgA producing cells are found within the lining of our gut where they are able to provide some defence against infection. This was a four-week study using fifty-two participants and these were split between two groups. One group consumed one serving of shiitake mushrooms per day and the other group consumed two servings daily.
The study found that levels of IgA and other immune markers, called cytokines, were significantly greater in those that ate shiitake mushrooms every day, suggesting a more effective immune system response. Consuming these daily was also found to reduce the production of inflammatory compounds by a huge 30%. Both of these findings are thought to be due to the high ? glucan content in shiitake mushrooms. ? glucans have been shown to interact with the immune cells in the gut which then helps to activate a wide-spread immune response.
BACKGROUND: Mushrooms are widely cited for their medicinal qualities, yet very few human intervention studies have been done using contemporary guidelines.
OBJECTIVE: The aim of this study was to determine whether consumption of whole, dried Lentinula edodes (shiitake) mushrooms could improve human immune function. Primary objectives were to ascertain whether L. edodes consumption would improve ??-T cell proliferation and activation responses, quantify a dose response, and elicit cytokine secretion patterns. Secondary objectives included determining changes in natural killer T (NK-T) cell proliferation and activation, secretory immunoglobulin A (sIgA) in saliva, and C-reactive protein (CRP) in serum.
DESIGN: Fifty-two healthy males and females, aged 21-41 years, participated in a 4-week parallel group study, consuming either 5 or 10 g of mushrooms daily. Each subject had blood drawn before and after 4 weeks of daily L. edodes consumption. Saliva and serum were also collected. Peripheral blood mononuclear cells were cultured in autologous serum for 24 hours or 6 days, stained, and examined by flow cytometry.
RESULTS: Eating L. edodes for 4 weeks resulted in increased ex vivo proliferation of ??-T (60% more, p < 0.0001) and NK-T (2-fold more, p < 0.0001) cells. Both cell types also demonstrated a greater ability to express activation receptors, suggesting that consuming mushrooms improved cell effector function. The increase in sIgA implied improved gut immunity. The reduction in CRP suggested lower inflammation. The pattern of cytokines secreted before and after mushroom consumption was significantly different; consumption resulted in increased interleukin (IL)-4, IL-10, tumor necrosis factor (TNF)-?, and IL-1? levels, a decreased macrophage inflammatory protein-1?/chemokine C-C ligand 3 (MIP-1?/CCL3) level, and no change to IL-6, IL-1?, MIP-1?, IL-17 and interferon (IFN)-? levels.
CONCLUSIONS: Regular L. edodes consumption resulted in improved immunity, as seen by improved cell proliferation and activation and increased sIgA production. The changes observed in cytokine and serum CRP levels suggest that these improvements occurred under conditions that were less inflammatory than those that existed before consumption.
What does this mean for a Baker?
This study has suggested that consuming shiitake mushrooms on a daily basis may lead to a more effective immune system and reduced inflammatory responses. For this reason, we recommend trying to incorporate shiitake mushrooms into your sourdough bakes.