Oriental mushrooms have been valued by herbalists for centuries but new research thrusts the humble common A. bisporus into the limelight due to their potentially powerful health-giving properties. A. bisporus includes white mushrooms (button, closed cup, open cup, large flat) and brown mushrooms (chestnut, champignon marron, crimini or portobello).

Studies at Pennsylvania State University show these varieties to score highly in antioxidants, comparing well with vegetables such as spinach. They are also a prime source of the powerful antioxidant L-Ergothioneine.

Other research suggests that mushrooms are a good source of lovastatin, which has been found to suppress the activity of the main cholesterol synthesis enzyme, hence possibly helping reduce the risk of heart disease.

Similarly, recent research in California concluded that mushrooms, in particular large white ones, contain substances that are effective in reducing the activity of the enzyme aromatase, which increases oestrogen levels. High oestrogen levels have been implicated in the risk of breast cancer.

Mushrooms also have a high nutritional value. They are low in salt and fat, cholesterol-free and provide dietary fibre, some protein and significant quantities of B vitamins, including thiamine (B1), riboflavin (B2), niacin (B3), pyridoxine (B6) and folate - particularly important if you are pregnant. They are a good source of minerals, including iron, phosphorus, magnesium and copper (needed for a healthy immune system) and selenium which helps protect us from heart disease, premature ageing and some cancers. They also contain more potassium than most vegetables and fruits, which can help lower blood pressure.

An 80g serving - approximately 14 baby button or four large closed cup mushrooms - counts as one portion towards your 5-a-day target.