IT WAS ONCE thought that all MPs were hanging on to life and sanity by the tips of their fingers as they tried to cope with two homes, sometimes two jobs, long hours and no certain career structure. This was a myth. Research carried out in the late 1960s by two occupational physicians, one an MP himself, demonstrated that Members of Parliament were at greater risk of succumbing to stress-related diseases only in their first parliament, or every parliament if they were in a marginal seat. The health of the other MPs, and their longevity, compared favourably with that of their contemporaries.

This week a new group of MPs will join the House of Commons for the first time. They will all be in the higher-risk category until their next election is behind them.

Just when we should all be taking every opportunity to benefit from one simple measure to combat stress — eating oily fish at least twice a week and preferably more often — one London institution that could have helped has been forced to close.

Blagden’s, the Marylebone fish shop that been run by three generations of the same family, closed last week, its prosperity destroyed by congestion charges and traffic wardens just as the British fishing industry was destroyed largely by concessions made to the European Union by Edward Heath’s Government. David Blagden served his last customer on April 30; the final blow was the congestion charge that removed 20 per cent of his business overnight.

Oily fish is rich in omega 3, an essential fatty acid. omega 6 and omega 9 are also important, but an adequate supply of omega 3 — and the correct balance between omega 3 and 6 — provides a formulation that is beneficial to virtually every system of the body in every age group.

The advantages start in the womb. Pregnant women who have an adequate intake (ie, two or three portions a week) of oily fish have babies who are not only brighter and more alert but grow into toddlers who are more likely to be intellectual leaders in the kindergarten. This advantage has been shown to continue until at least primary school level.

It is not only omega 3’s ability to make the best of whatever education a child is having that gives those children an advantage. They are also, it emerges, better behaved. Oxford University has confirmed earlier work from Dundee University that giving children omega 3 enhanced their cognitive ability. The Oxford work also showed that it made the children less unruly and ill-behaved.

Nor is the effect on mood of an adequate supply of omega 3 to the brain confined to children. It also reduces tension and stress, and therefore anger, in all age groups. Research published in 2003 by scientists at Lausanne University and the regional hospital at Brest, in France, showed that people given 7.2g (¼oz) of fish oil daily for three weeks experienced a remarkable reduction in levels of the stress hormones, including adrenalin and cortisol, and of blood fat. It is these biochemical changes, produced as a result of stress, that decrease the life expectancy of newly elected MPs and legions of other people in stressed jobs.

Reducing stress through a balanced diet rich in omega 3 fish oil will also, as research correlated and published by the British Association of Anger Management has found, improve our ability to cope in stressful situations so that we become less likely to snap at colleagues, partners and fellow drivers (80 per cent of British drivers have been involved in a road rage incident). Nearly seven out of ten office workers have experienced office rage.

It is not only unborn babies, toddlers prone to temper tantrums and children starting primary school who benefit from fish oils in the diet, whether these come from oily fish, specially produced eggs (omega 3-rich eggs, marketed by Columbus eggs and Stonegate, are available in supermarkets), or fish oil supplements.

Middle-aged people who take fish-oil supplements have healthier arteries and less heart disease. Extensive research by Professor Philip Calder, of the University of Southampton, has shown that omega 3 fatty acids reduce heart attacks and strokes by stabilising atherosclerotic plaques. In old age, fish oil reduces hostility (as it does in other age groups) and also the likelihood of developing Alzheimer’s.

Pregnant women should avoid too much cod liver oil, however, because of its high levels of Vitamin A, and should ask their doctor before taking it.