Veg out, live longer

Vegetarians have always claimed their lifestyle is healthier. Now new research appears to confirm that they do live longer. The reasons could be very simple, says Roger Dobson

When a vegetarian, Marie-Louise Meilleur, was named as the world's oldest person at 122, the usual hunt for the secret of her longevity ensued. Was it hard work, religion, having a lot of friends, a good man, a life of abstinence, being a non-smoker?

For the French-Canadian woman who took up fencing at 85, smoked till she was 95, still rode a bicycle at 100 and made a rap CD at 121, the reason for living so long was put down to a vegetarian diet, supplemented by modest amounts of olive oil, port wine and chocolate.

Mme Meilleur, who died six years ago, was the latest in a long line of holders of the title as the world's oldest person whose diets have been exclusively or largely vegetarian. Every now and then remarkably old people such as her emerge, although usually they are found among geographically isolated agrarian peoples whose diets are primarily vegetarian, such as the Hunzakuts of Pakistan and the mountain-dwellers of Turkey.

The notion that vegetarian diets lead to a healthier and longer life has been given further support from research based on the Second World War experiences of people in Scandinavia, where dietary restrictions virtually wiped meat off the menu. It is now known that the loss of meat led to a drop in the mortality rate, and that when diets returned to normal after the war, so too did the death rate.

In spite of these observations, there has never been any definitive proof of just how much extra time on earth a vegetarian can expect to get. Not, that is, until now. New research shows that being a vegetarian for 20 years or more adds almost four years to the average lifespan. Dr Pramil Singh, who led the research, says: "We are the first to come up with a life-expectancy figure showing a very important increase in life expectancy for those who follow a vegetarian diet for a long period of time.''

In the research, he and other epidemiologists analysed long-term data from a group of Adventists who have been monitored for more than 40 years. They also reviewed data from six other studies, including two in the United Kingdom and one in Germany. One of the two UK studies showed a 20 per cent drop in mortality among vegetarians, while the German study suggested an even greater reduction.

Although the British and German data supported the principle of reduced mortality in non-meat-eaters, it was the 7,100 people in the Adventist study who were the key to obtaining long-term accurate information from men and women who had been vegetarians for a considerable length of time.

"The Adventists gave us a unique opportunity," says Dr Singh, of Loma Linda University in California. "When you study populations and try to look at the effects of zero or low meat consumption, you get situations where some people follow it and other don't. What we have in the Adventists is a group of people who follow the recommendations of their church and who wind up being vegetarian for a long time. That is enough people with which to make mortality comparisons.''

Not only were the researchers able to follow the lives of the Adventist vegetarians; they were also able to distinguish between those who had been vegetarian for more than 20 years, those who had lapsed, and those who were eating little or no meat for a shorter period of time.

When the researchers analysed the data, they found considerable differences in the lifespans of the different groups. "Survival data indicate that long-term vegetarians do experience a significant 3.6-year survival advantage over short-term vegetarians,'' says a report based on the research. The life expectancy of the average 20-years-or-more vegetarian in the study was 86.5 years, compared to 82.9 for the short-term vegetarians. The figures were averaged for men and women.

The next big question facing researchers is why vegetarians live so much longer. Is it because they are exposed to fewer of any negative health effects that may be associated with meat eating? Is it because they benefit from the positive health effects of eating more vegetables? Or is it simply that people who choose to be vegetarians have lifestyles that differ in other ways which favour a longer lifespan?

"We simply don't know," says Dr Susan Jebb, the head of nutrition research at the Medical Research Council's Human Nutrition Research Unit in Cambridge. "There are all kind of things that could be going on. Vegetarians may be exposed to more of the beneficial effects of fruit and vegetables simply because they eat more, or the lifestyle package that often goes with being a vegetarian could play a role too. It may well be a little bit of each.''

In California, Dr Singh says that more work is needed to discover what could be important, but he points out that positive effects for plant foods have been found. "Among Adventists, one of the things we found was that consumption of legumes, nuts and salads seemed, in separate analyses, to show independent decreases in risk. We have additional work which suggests that use of legumes reduces risk of death. Green salad or green vegetable also seem to decrease overall risk.''

Other research suggests that the range of antioxidants that are found in the pigments of fruit and vegetables are among the most effective health-enhancing compounds in vegetables. Antioxidants help to prevent the cellular damage caused by free radicals in the body.

Researchers at Glasgow University found that some fruits and vegetables have more of one type of antioxidants - flavonols - than other crops. They have also found differences between different types of similar fruit and vegetables. Tiny cherry tomatoes, for example, have many more of the chemicals than bigger tomatoes. Red onions are full of flavonols, while the white version has almost none.

Colour is important, too. Researchers from a number of countries who have been taking part in an international study say that the more vibrant the colour of the vegetable, the higher its antioxidant level. Dr Luke Howard of Arkansas University says: "There are literally thousands of compounds in vegetables that may be health-protective, and we need to eat a wide variety. We also need to look at breeding fruits and vegetables that contain higher levels of health-protective substances."

As is the way with these things, of course, not all the evidence supports enhanced lifespan. One British study into longevity and diet based on 4,600 people found no difference.

Another difficulty is that not all those people who show great longevity are vegetarians. When Mme Meilleur died, her title passed to a 117-year-old American woman who hated vegetables. Relatives said that she had eaten chocolate, crisps, pretzels and sweets while avoiding anything remotely resembling a vegetable.

And then there's the strange case of Yukichi Chuganji, who inherited the mantle of the world's oldest person in January last year, at the age of 112. He bucked the apparent trend in a major way. It isn't just that the retired silkworm breeder from the island of Kyushu, in Japan, hated vegetables. The real blow is that one of his passions was eating meat.