Summary

• The longest lived people are those following the traditional Mediterranean or Japanese diet, and mushrooms feature and have a place in both diets.
• Mushrooms have a range of essential nutrients, such as B vitamins and the antioxidant mineral selenium.
• Mushrooms have many other antioxidants. One in particular, ergothioneine, is found mainly in mushrooms among non-animal food sources.
• Ergothioneine has its own blood transporter, indicating that it is very important for human health.
• To achieve a long and healthy life, mushrooms have a clear role in a balanced healthy diet.

Antioxidants in mushrooms

For a long time, scientists have appreciated the antioxidant effect of fresh produce such as vegetables and fruit. Eating plenty of high antioxidant foods seems to have a role in protecting you from future disease.

Antioxidants are produced by the body and found in food. They are natural compounds that help neutralise the free radicals produced by the body. Free radicals are also quite natural, although they tend to cause damage to all parts of the body over time, hence speeding up the ageing process. For example, free radicals can damage the DNA found in the nuclei of body cells. When DNA becomes damaged, then antioxidants within the body work to correct the damage before it becomes a cancerous cell. 

If the antioxidants made by the body get overwhelmed then the antioxidants in food provide a very useful helping hand to protect the body from free radicals. Mushrooms are a rich source of antioxidants, as confirmed by laboratory analysis. In one study of 30 common vegetables, mushrooms were placed in the top five highest antioxidant levels when compared to vegetables (Pellegrini 2003; Savoie 2008). 

Not commonly appreciated is that even the unique carbohydrates in mushrooms have antioxidant properties (He 2012).

Ergothioneine

Mushrooms are very high in the powerful antioxidant ergothioneine, in amounts similar to that found in animal foods (Ey 2007). Ergothioneine is found in very few vegetables or fruit. The body does not make ergothioneine so it can only be obtained from the diet. 

An analysis of a range of foods confirmed that ergothioneine was in mushrooms, meats (especially liver and kidney), egg yolk, oat bran, wheat germ and some beans and onion. It was not found in other vegetables or fruit (Ey 2007). 

A study determining the ergothioneine levels in different mushrooms found that both white and brown button mushrooms were rich in ergothioneine and that the levels did not diminish during cooking (Dubost 2006). The ergothioneine in mushrooms is bioavailable meaning that it can be easily absorbed by the body (Weigand-Heller 2011). 

Ergothioneine appears to protect blood cells, especially monocytes and red blood cells that transport nutrients and oxygen to body cells (Martin 2010). It also protects your artery lining from atherosclerosis (fatty deposits).

Is ergothioneine a new vitamin?

Low levels of ergothioneine in the body trigger the oxidation (damage) of DNA and proteins. For this reason it has been suggested that ergothioneine should really be classified as a vitamin because it is essential to our health (Paul 2010). Ergothioneine levels do not decrease with cooking, so you can get ergothioneine through both raw and cooked mushrooms, nor does it decrease with sunlight or UV light exposure so the levels are retained with high vitamin D mushrooms (Sapozhnikova 2014).

Ergothioneine has its own blood transporter

Scientists were surprised to find an ergothioneine transporter protein in the blood (Gründemann 2005). Transporter proteins only exist in the blood if they have a specific role. For example, haemoglobin is a transporter protein for carrying oxygen to cells. To find one for ergothioneine gives further support of the importance of ergothioniene for human health.

Mushrooms are also particularly high in phenolic compounds that have been long recognised for their antioxidant capabilities. A serve of mushrooms provides about a quarter of an adult’s requirements of selenium, an antioxidant mineral.

Put all the news together and it makes mushrooms one of the highest antioxidant foods on the market. It is good sense that mushrooms should regularly feature on your healthy eating menu. Please view the other fact sheets for a more detailed understanding of the health benefits of mushrooms.