Friday, September 30, 2005


And if the NYT says it, it must be so!

The diet messages are everywhere: the National Cancer Institute has an "Eat 5 to 9 a Day for Better Health" program, the numbers referring to servings of fruits and vegetables, and the Prostate Cancer Foundation has a detailed anticancer diet. Yet despite the often adamant advice, scientists say they really do not know whether dietary changes will make a difference. And there lies a quandary for today's medicine. It is turning out to be much more difficult than anyone expected to discover if diet affects cancer risk. Hypotheses abound, but convincing evidence remains elusive....

Dr. Barnett Kramer, deputy director in the office of disease prevention at the National Institutes of Health, said: "Over time, the messages on diet and cancer have been ratcheted up until they are almost co-equal with the smoking messages. I think a lot of the public is completely unaware that the strength of the message is not matched by the strength of the evidence." .....

Dr. Tim E. Byers, a professor of preventive medicine at the University of Colorado Health Sciences Center in Denver, was convinced that up to 20 percent of cancers were being caused by diet and he wanted to be part of the exciting new research that would prove it. "I felt we were really on the cusp of important new discoveries about food and how the right choice of foods would improve cancer risk," Dr. Byers sad. That was 25 years ago, when the evidence was pointing to diet. For example, cross-country comparisons of cancer rates suggested a dietary influence.....

At the same time, some cancers were inexplicably becoming more common or, just as inexplicably, fading away in the United States. In 1930, for instance, stomach cancer was the second leading cause of cancer death in women and the leading cause in men. Now, Dr. Stampfer says, stomach cancer is not even listed in the American Cancer Society's 10 leading cancers. "So people think, 'What's happened in the past 70 years to make that change?' " he said. "Diet comes to mind."

The best studies are the hardest to conduct: prospective studies that that follow healthy people for years instead of looking backward and relying on memory. Even better - and harder and more expensive - are studies that randomly assign people to follow a particular diet or not. But those more difficult studies were well worth doing, researchers said. And as more studies started, scientists hoped for definitive evidence that diet affected cancer. But as the results from those studies have begun to roll in, many researchers say they are taken aback. The findings, they say, are not what they expected.

Fat in the diet, the studies found, made no difference for breast cancer. "For fat and breast cancer, almost all of the prospective studies were null," Dr. Schatzkin said. Fiber, in the form of fruits and vegetables, seemed to have a weak effect or no effect on colon cancer.

The more definitive randomized controlled trials were disappointing, too, with one exception. A study reported in May found that women with early stage breast cancer who followed a low-fat diet had a 20 percent lower risk of recurrence. Even so, the effects were just marginally statistically significant. The study's principal investigator, Dr. Rowan Chlebowski of the Harbor-U.C.L.A. Medical Center, said it needed to be repeated before scientists would be convinced.

Nonetheless, the study contrasted sharply with those preceding it. Several involved beta carotene and antioxidant vitamins like C and E, substances that scientists thought were the protective agent in fruits and vegetables. The idea was that antioxidants could mop up free radicals in the body, which left unchecked could damage DNA, causing cancer. Beta carotene was of special interest. People who ate lots of fruits and vegetables had more beta carotene in their blood, and the more beta carotene in the blood, the lower the cancer risk.

But a four-year study that asked whether beta carotene, with or without vitamins C and E, could protect against colon polyps, from which most colon cancers start, found no effect. People who took either beta carotene, vitamin C, vitamin E or all three had virtually identical rates of new polyps compared to participants taking dummy pills.

Another study, of 22,000 doctors randomly assigned to take beta carotene or a placebo, looked for an effect on any and all cancers. It found nothing. Two more, involving current and former smokers, found that those taking beta carotene actually had slightly higher lung cancer rates than those taking placebos.

Studies of fiber and colon cancer were similarly disappointing.

More here


While British educational standards are going down the plughole, the British government is obsessing about what the kids eat

Ruth Kelly declared war on tuck shops yesterday as part of her campaign to expel junk food from schools. The Education Secretary said that crisps, chocolate and fizzy drinks would be banned from sale in schools from September 2006. Schools will be required by law to empty vending machines of the products and remove them from tuck shops. A spokesman for Ms Kelly said that new legislation would cover “any way that food is served in schools, in tuck shops and vending machines”.

Processed burgers, sausages and other foods high in fat, salt and sugar content will also be outlawed as part of new nutritional standards for school canteens. Ms Kelly told delegates at the Labour Party conference in Brighton that it was time to act against the diet of junk food served to pupils at school. “I am absolutely clear: the scandal of junk food served every day in school canteens must end,” she said. “And because children need healthy options throughout the day, from next September no school will be able to have vending machines selling crisps, chocolates and sugary fizzy drinks.”

Head teachers’ leaders said that many parents send children to school with packed lunches containing crisps, chocolate and fizzy drinks. They also said that head teachers could not change what was sold in vending machines because they were controlled by outside contractors under the Government’s Private Finance Initiative.

Ms Kelly’s spokesman said that companies would have to amend their contracts to comply with the new law. Instead of sweets and crisps, vending machines will be expected to offer items such as milk, bottled water and fresh fruit. The Education Secretary said that she would publish a report next week by the Government’s school meals review panel setting out detailed proposals for tough nutritional standards. Her announcement followed government promises to improve school dinners after a television campaign by the celebrity chef Jamie Oliver highlighted appalling standards of nutrition.

John Dunford, general secretary of the Secondary Heads Association, said that a ban on unhealthy food in schools would be difficult to implement. “Children eat over a thousand meals a year, but less than 200 of these are in school,” he said. Mr Dunford said that plans to make Ofsted responsible for inspecting the quality of school meals was “just silly”. Mick Brookes, general secretary of the National Association of Head Teachers, said: “School leaders are heartily sick of having initiative after initiative foisted upon them. “We wholeheartedly support healthy schools programmes, but to expect schools to provide a quality meal for less than the price of the cheapest unhealthy burger does not stand up to serious scrutiny.”

More here


Two headlines this week will have left parents in despair. First was a claim by the Soil Association that 25 per cent more pesticides were found in samples of school fruit compared with fruit bought from shops; second was news from Canadian researchers who found that children who drink bottled water rather than fluoridated tap water may be missing out on tooth protection.

It's not fair, is it? There you are thinking that you are doing the right thing and someone tells you that you've got it wrong, yet again. Why is it, for example, that your children are toting a bottle of water in their lunch boxes? Because you thought getting them to drink water would be better for them than sending them in with cartons of tooth-rotting squash. Similarly with the schools fruit programme. You thought five a day was good and now someone is telling you that school fruit is full of pesticides.

Neither of these headlines gives the whole picture. Children today have better dental health than their parents and most are likely to reach adulthood without a single cavity. Most will also keep their teeth to old age, unlike their grandparents. This spectacular improvement is due to fluoride which, in those parts of the country that do not have fluoride either added to the water or present naturally, comes mainly from toothpaste. N ot so long ago there was a scare that children were having too much fluoride from toothpaste, hence the recommendation that under-sixes use only a pea- sized amount on their brush.

Is water better than squash or cola? You bet. And providing it in a form that's accessible and pleasant (unlike the school drinking fountain) is entirely sensible.

As for fruit and veg, it's taken us the best part of a decade to get people to understand that five portions a day is the way to go. How little acquaintance children have with green stuff was shown on Jamie Oliver's School Dinners programme. Several children didn't know what an onion looked like.

All but two of the pesticide residues identified in the Soil Association report were below government maximum residue levels, which are set with a wide safety margin and also assume that a substance is consumed at breakfast, lunch, tea and supper, every day, which is clearly not the case in real life. Thus a "maximum" residue is very tiny. The benefits of eating fruit and vegetables far outweigh any possible harm from pesticides, which at these levels has yet to be proved.

So ignore the headlines, and if you can get fruit, veg and water, of any type, into your child, take three house points, a gold star and go to the top of the class immediately.


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