Diet and supplements: Eat plenty of fruit and vegetables if you want to live longer and have a lower risk of diseases such as cancer. There are no short-cuts, however - taking vitamins is no substitute for the real thing.
Why fruit and veg consumption is good for us came up for discussion yesterday at the BA meeting in Norwich. Eating more plant-derived foods ranked as the sixth most important factor in prolonging life, said University of East Anglia's Prof Susan Fairweather-Tait.
Large population studies provide the immediate answer. "Fruit and vegetables reduce your risk of chronic diseases when you look at it on a large scale."
Prof Fairweather-Tait said including these foods in your diet pulled down the risk of Alzheimer's disease, cardiovascular disease and stroke. There were also clear indications that cancer risk was also lowered, particularly of the digestive system.
She cited a range of studies to support this view. Cardiovascular disease was 30 per cent lower in men who managed the "five-a-day" recommendation to have five servings of fruit and veg each day compared to men who ate very little plant-derived foods.
One study showed that eating the "five-a-day" could lower blood pressure as effectively as drug interventions. These results were "really quite impressive", she said.
Another study found that increasing from three to four portions per day could lower cholesterol in some people.
However, she said people were very slow to grasp the benefits that fruit and veg provided. Only 25 per cent of the UK population consumed the five portions despite active government-sponsored campaigns. "The evidence is pretty clear. There are a lot of questions still to be answered, but the evidence is overwhelming."
It has also been proven that the benefits do not come specifically from the higher vitamin intake fruit and veg provide. There is much more to it, suggested Dr Lee Hooper from the University of East Anglia.
She discussed a range of studies where groups were given supplements including vitamins A, C and E and also beta-carotene. Beta-carotene is known to help reduce bad cholesterol and reduce the risk of hardening of the arteries.
One study where subjects ate vegetables rich in beta-carotene showed a 29 per cent reduced risk in cardiovascular-related death. Yet when the beta-carotene was given as a supplement in another trial it actually increased the risk of cardiovascular-related death.
She said other studies of vitamin C and E supplementation gave no improvement in avoiding disease. High-dose vitamin E actually increased risk. Taking supplements was, therefore, no substitute for maintaining a high consumption of fruit and vegetables.
