'She was clear that picking up a spade and plunging it into the ground enabled her to channel some of the anger she had felt the previous week at work.'

With trepidation I sunk my hands into the sack of cold earth, held as much as I could in my fingers then spread it over the ground. I carefully pushed seeds into the cushioned earth, watered it and returned to my front room for a beer. I had a new pastime. I was growing food. I awaited the arrival of carrots, beans and peas.

Friends and family all thought that the prospect was comical. They remained convinced I would only ever buy fruit and vegetables from supermarkets and my beloved Walthamstow market.

The next day, I told colleagues. I expected high praise. But such activities are not uncommon.

I was keen to share my earthy credentials with Joan, a gloriously healthy colleague who spends much of her time outdoors. The bending, stretching and lifting keeps her fit and supple. For her, being outside is the best thing about gardening. The British weather keeps her skin glowing. She is the picture of health.

And she was clear that picking up a spade and plunging it into the ground enabled her to channel some of the anger she had felt the previous week at work. 'I'd like to say it's about being at one with nature,' she said, 'but, in reality, it's a way of reducing my stress.' Memories of difficult meetings dissolved as she tore apart the earth.

For a close colleague, going to the allotment had become a regular and much-enjoyed activity for her and her husband. A nervous breakdown the year before had left him listless and withdrawn, his creativity stifled and his energy levels low. It had been a slow process, but digging and tilling had built his confidence and given him a reason to get out of the house. It was something they did together.

There was a lad in my class at school who often found himself in trouble and struggled to make friends. As a result, he became isolated. His worsening behaviour was of concern. Gardening was a distraction that held his attention (although buckets of soil had been thrown in temper and cheese sandwiches he disliked had been buried). And his plants flourished. It was the first time he had something to look after and he was proud of what he had created.

John, a dear friend, retired recently. He lived in a flat with no garden and the prospect of an allotment seemed too great a commitment. A local regeneration scheme had created a community garden and he was keen to get involved. The activity kept him fit and friendships developed, sometimes with people he would never usually meet. They could keep what they grew and his vegetables were better than any he could buy. They were tasty and healthy.

In the current climate, it would be foolish to suggest that the NHS should provide allotments or offer horticultural advice. But with a little creativity, gardening could be integrated into our work to increase physical activity, improve the nation's diet and help us consume five a day. It would make a small but important contribution to reducing heart disease.

There are additional benefits. For some it will help recovery from mental illness or manage stress. For others it will help create networks of friends, very important in maintaining health.

In primary care, we see local schemes to encourage residents to grow their own food. Others develop 'gardening on prescription' projects. And five-a-day projects work with schools. But seldom is the impact of schemes measured. Medical costs continue to escalate; it is time to calculate the health effects, in the widest sense, of growing our own.