Wednesday, March 25, 2009

BBQs in the gun again

It pays to look at the journal abstract (see following the article below). For a start, it says nothing about BBQs. It is concerned with meat consumption overall. Tiny differences were found and then only by comparing extreme groups. The study did have enough sophistication to control for education but education has only some relationship with occupation. If there is anything at all in the findings, the people in the big meat-eating group were probably manual workers in the main and the low meat-eating group were probably faddy middle class vegetarians and such like. And class differences are well known as an influence on morbidity and mortality. Any inferences from the findings are purely speculative

THROWING a steak on the barbecue is in the gun, after a major study found people who eat red meat are more likely to die from cancer or heart attack. Barbecuing red meat was also the cooking method that caused the most cancer causing "carcinogens", experts have warned.

The US study looked at the diets of more than 500,000 people and a follow-up 10 years later found those who ate the most red, or processed, meat had a higher incidence of death. Eating white meat - poultry or fish - did not have the same effect and was associated with a slightly decreased risk.

Cancer Council Australia chief executive Professor Ian Olver said that while the study could not be said to show that red meat caused cancer, the apparent link warranted further research. "Such population studies demonstrate these relationships between red meat and cancer deaths but are not able to prove that one causes the other," he said. "With red meat, for example, the method of cooking is important. "For example, more carcinogens would be expected to be produced from barbecue than by slow cooking (while) the other factor predisposing to cancer is the fat content of the meat."

The research, produced as part of the National Institutes of Health-AARP Diet and Health Study, is published in the journal Archives of Internal Medicine.

The study raised the question of what role meat should play in the diet, says Mark Wahlqvist, Director of the Asia Pacific Health and Nutrition Centre at Victoria's Monash University. He said that red meat in small amounts - even about an ounce or 30 grams daily - could make a significant difference to the risk of micronutrient (vitamins and minerals) deficiency. "(But) the corollary is that a plant-based diet is a preferred orientation for food intake in the human species and many studies support this conclusion," Professor Wahlqvist said.


Meat Intake and Mortality: A Prospective Study of Over Half a Million People

By Rashmi Sinha et al.

Background: High intakes of red or processed meat may increase the risk of mortality. Our objective was to determine the relations of red, white, and processed meat intakes to risk for total and cause-specific mortality.

Methods: The study population included the National Institutes of Health–AARP (formerly known as the American Association of Retired Persons) Diet and Health Study cohort of half a million people aged 50 to 71 years at baseline. Meat intake was estimated from a food frequency questionnaire administered at baseline. Cox proportional hazards regression models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) within quintiles of meat intake. The covariates included in the models were age, education, marital status, family history of cancer (yes/no) (cancer mortality only), race, body mass index, 31-level smoking history, physical activity, energy intake, alcohol intake, vitamin supplement use, fruit consumption, vegetable consumption, and menopausal hormone therapy among women. Main outcome measures included total mortality and deaths due to cancer, cardiovascular disease, injuries and sudden deaths, and all other causes.

Results: There were 47 976 male deaths and 23 276 female deaths during 10 years of follow-up. Men and women in the highest vs lowest quintile of red (HR, 1.31 [95% CI, 1.27-1.35], and HR, 1.36 [95% CI, 1.30-1.43], respectively) and processed meat (HR, 1.16 [95% CI, 1.12-1.20], and HR, 1.25 [95% CI, 1.20-1.31], respectively) intakes had elevated risks for overall mortality. Regarding cause-specific mortality, men and women had elevated risks for cancer mortality for red (HR, 1.22 [95% CI, 1.16-1.29], and HR, 1.20 [95% CI, 1.12-1.30], respectively) and processed meat (HR, 1.12 [95% CI, 1.06-1.19], and HR, 1.11 [95% CI 1.04-1.19], respectively) intakes. Furthermore, cardiovascular disease risk was elevated for men and women in the highest quintile of red (HR, 1.27 [95% CI, 1.20-1.35], and HR, 1.50 [95% CI, 1.37-1.65], respectively) and processed meat (HR, 1.09 [95% CI, 1.03-1.15], and HR, 1.38 [95% CI, 1.26-1.51], respectively) intakes. When comparing the highest with the lowest quintile of white meat intake, there was an inverse association for total mortality and cancer mortality, as well as all other deaths for both men and women.

Conclusion: Red and processed meat intakes were associated with modest increases in total mortality, cancer mortality, and cardiovascular disease mortality.

Arch Intern Med. 2009;169(6):562-571.

Should schools tell you what to put in your child's lunchbox?

There seems to have been a lot of backpedalling since this story first broke -- judging from the commenter below. Note that the one thing that is most heavily hated seems to be chocolate but there have been plenty of findings suggesting that chocolate is good for you. I don't assert that it is. I just want to point out the arrogance of people claiming to know what is best in a field beset by controversy and ever-evolving knowledge -- particularly when much conventional thinking does not stand up under objective test

You have to feel for headteacher Deborah Metcalf. Accused by the Daily Mail of running a sandwich box Stasi and the Daily Telegraph of presiding over a mealtime Gestapo, the head of Danegrove Primary School in Barnet, Greater London, is somewhat bemused. "Everyone had been very supportive," she told School Gate today. "At least until one parent went to the papers."

The story is to do with packed lunches, and the drive towards healthy eating. Having worked on healthy school lunches for the last few years, Ms Metcalf felt that it was time to make some suggestions to pupils' packed lunches too. A third of pupils at the school (which is 605 strong) bring packed lunches every day, and Ms Metcalf and her staff were not too thrilled to see that some lunchboxes were filled with fizzy drinks and crisps.

"We wanted the children who bring packed lunches in to try and make them healthy, like the school lunches. We suggested a pot of pasta or rice, sandwiches or pitta pockets, fruit or yoghurt." Plain or fruit cake is also acceptable at Danegrove, although not chocolate cake (which the canteen doesn't serve to the children taking school lunches either), fizzy drinks or "full-fat crisps". The new policy began in September and parents have been told about it repeatedly "It's in our newsletter every week," says Ms Metcalf.

But while the head and her staff thought the whole policy was going well, it seems that some parents were not as thrilled (although it has to be said that only one family went to the press, and they chose not to speak to the head first...). Those who flout the new policy receive a little note in their child's lunchbox, reminding them of the healthy eating policy, and very occasionally (Ms Metcalf can remember just one, yep, one occasion when the mealtime supervisor took away a packet of chocolate biscuits), offending items are removed.

Some parents will complain, in Daily Mail voice about this, but, I'm going to stick my head above the parapet: I think this is a good idea. There, I said it! The school is not being overly prescriptive (it doesn't recommend jam sandwiches, for example, but it hasn't banned them either), is trying to educate adults a little and by doing this, is helping children learn about healthy eating. Many of them won't pick this up at home, but eating more healthily will help them throughout their lives. However, I do have to say that I'm not convinced about the letter-in-the-lunchbox. That does seem a little over-the-top.

I'm sure many of you will disagree with my (generally) positive thoughts about this, and argue that you, as parents, should be allowed to give your child whatever you want to eat. Feel free - at least out of school time. But I do feel that there is an obesity problem in this country, and that suggesting a child doesn't have a can of Coke for lunch can only be a good thing. And the headteacher of this school says that the children's behaviour and concentration in the afternoons is far, far better now, which has to be a good thing... [But she would say that, wouldn't she? Have any objective observations or tests been done?]


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