For a long time, scientists have known that adequate fruits and vegetables reduce the risk of heart disease, stroke and some cancers, quite possibly through their antioxidant capabilities.

Antioxidants are natural compounds in food that help neutralise the free radicals produced by the body. Free radicals are also quite natural, but tend to cause damage to all parts of the body over time, hence speeding up the ageing process. One example is the damage that can happen to DNA in the nucleus of all cells. If it becomes damaged, then chemicals within the body work to correct the damage before it becomes a cancerous cell. If the antioxidants within the body get overwhelmed then compounds in food give a helping hand.

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 5 highest antioxidant levels when compared to vegetables.

In 2005 it was found that mushrooms are very high in the powerful antioxidant ergothioneine, in amounts many times more than found in wheat germ or chicken liver, previously thought to be the highest sources. As ergothioneine is not produced by the body, dietary sources are important. Ergothioneine levels do not decrease with cooking, so you get your ergothioneine through both raw and cooked mushrooms.

That same year, scientists were surprised to find an ergothioneine transporter protein in the blood. 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 suggests that humans have long evolved as mushroom eaters.

Mushrooms are particularly high in phenolic compounds that have been long recognised for their antioxidant capabilities. A serve of mushrooms also 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.

Mushroom, prawn & asparagus stir-fry
Serves 4

1/3 cup oyster sauce
2 tbs soy sauce
1 tbs brown sugar
600g green medium-king prawns*, peeled and deveined
300g cup mushrooms, thickly sliced
2 tbs olive oil
1 small red onion, peeled and cut into wedges
1 bunch choy sum, trimmed, leaves separated and stems chopped
1 bunch asparagus, trimmed and cut into 3cm lengths
rice or noodles, to serve.

1. Combine oyster sauce, soy sauce and brown sugar in a small jug. Place prawns and mushrooms into separate bowls. Pour 1/2 the soy mixture over prawns and remaining soy mixture over mushrooms. Toss well to coat. Cover and place in the fridge to marinate for 15 minutes.
2. Heat a wok over high heat until hot. Add 1 tbs oil and prawns and stir-fry for 1-2 minutes or until pink. Remove and set aside.
3. Add remaining oil and onion to wok and stir-fry for 1 minute. Add choy sum stems and asparagus and stir-fry for 1 minute. Add mushrooms and stir-fry for 2 minutes or until mushrooms are almost tender.
4. Add prawns and choy sum leaves and stir-fry for 1 minute or until leaves just wilt. Serve immediately with rice or noodles.

* Note: Prawns can be replaced with sliced chicken, beef or pork fillet.