The claim is backed by a report from nutritionist Jane Clarke and Professor Robert Beelman from Pennsylvania State University, which claims that mushrooms are the source of the powerful antioxidant L-ergothioneine.
Cultivated mushrooms were found to outstrip wild varieties such as shiitake and oyster in content of some essential vitamins and minerals.
And the humble white mushroom and chestnut mushroom - which between them account for 95% of UK sales - were found to contain biologically active compounds that may help fight cancer and heart disease.
The campaign has won voluntary support from not just the major UK growers and marketing organisations, but also many of their counterparts in Holland, Belgium, Ireland and Poland. Bureau chairman Andrew Middlebrook said that some 30 companies were involved. "We believe we will be able to build on this support in the future."
The key aim is to raise the proportion of households buying mushrooms every month, which stands at just above half, according to TNS. UK consumers eat 170,000 tonnes of mushrooms a year, two thirds through retail at an annual value of £292m.
The need for action by British growers, who account for 30% of sales, was identified last year by a Warwick University report stressing the importance of improved marketing and closer industry liaison.
The campaign has grown out of that, following a failed attempt to secure an EU grant for promotion.
The bureau is also considering a generic branding exercise, which would seek to establish a mark similar to the Lion mark for eggs.
Middlebrook said: "We have had a lot of support from retailers, but we are not in a position to do anything yet."