Thursday, November 16, 2006

Meat bad for you (maybe)

The vegos will like this finding -- but since humans evolved as a meat-eating species, the conclusion is a highly improbable one

Women who eat red meat more than once a day double the risk of getting the most common form of breast cancer, doctors have found. A study of pre-menopausal women examined the effect of diet on different types of breast cancer and found that those who ate the most meat - especially in processed forms such as hamburgers and sausages - were at the greatest risk of hormone-sensitive breast cancers. The natural female hormones oestrogen and progesterone are essential for a range of bodily functions but are also responsible for stimulating growth in 70 per cent of breast cancers - those known as hormone receptor positive.

Eunyoung Cho, associate professor of medicine at Harvard Medical School, who led the study, said there were several reasons red meat triggered this type of breast cancer. They included the treatment of American beef cattle with hormones to speed up growth, carcinogens created when meat was cooked at high temperatures and the presence of a certain form of iron in meat.

More than 90,600 pre-menopausal American nurses aged 26 to 46 filled in questionnaires about their diets between 1991 and 1999, according to Archives of Internal Medicine, which published the research. Twelve years after the start of the study researchers identified 1021 cases of breast cancer in the group. Women who ate more than 1« servings of red meat a day (where a serving is defined as the main part of a dish) were 97 per cent more likely to have a hormone receptor positive breast cancer than those who ate three or fewer servings a week. The increased risk for those who said they had between three and five servings a week was 42 per cent.

Women who had meat in processed form such as sausages, salami and mortadella more than three times a week were 2.3 times more likely to get a hormone receptor positive cancer than those who ate them less than once a month. Those who ate hamburgers between one and three times a week were 71 per cent more likely than those who did so less than once a month.

There was little difference in the risk of hormone receptor positive breast cancer between those was ate unprocessed beef, pork or lamb between one and three times a week and those who did so less than once a month.

Dr Cho checked to ensure that causes of breast cancer such as obesity, smoking, alcohol and family medical history were not the real causes of the increased risks.


But did he check for confounding from that powerful health predictor, social class? NO. Journal abstract follows. Note that the results as reported imply that red meat eating lifts your probability of getting cancer from about 1% to 2% -- a very small effect, the sort of effect that is often not replicable. Although the large sample size makes the results statistically significant, that does not exclude other sources of random error:

Red Meat Intake and Risk of Breast Cancer Among Premenopausal Women

By: Eunyoung Cho et al.

Background The association between red meat intake and breast cancer is unclear, but most studies have assessed diet in midlife or later. Although breast tumors differ clinically and biologically by hormone receptor status, few epidemiologic studies of diet have made this distinction.

Methods Red meat intake and breast cancer risk were assessed among premenopausal women aged 26 to 46 years in the Nurses' Health Study II. Red meat intake was assessed with a food frequency questionnaire administered in 1991, 1995, and 1999, with respondents followed up through 2003. Breast cancers were self-reported and confirmed by review of pathologic reports.

Results During 12 years of follow-up of 90 659 premenopausal women, we documented 1021 cases of invasive breast carcinoma. Greater red meat intake was strongly related to elevated risk of breast cancers that were estrogen and progesterone receptor positive (ER+/PR+; n = 512) but not to those that were estrogen and progesterone receptor negative (ER-/PR-; n = 167). Compared with those eating 3 or fewer servings per week of red meat, the multivariate relative risks (95% confidence intervals) for ER+/PR+ breast cancer with increasing servings of red meat intake were 1.14 (0.90-1.45) for more than 3 to 5 or fewer servings per week, 1.42 (1.06-1.90) for more than 5 per week to 1 or fewer servings per day, 1.20 (0.89-1.63) for more than 1 to 1.5 or fewer servings per day, and 1.97 (1.35-2.88) for more than 1.5 servings per day (test for trend, P = .001). The corresponding relative risks for ER-/PR- breast cancer were 1.34 (0.89-2.00), 1.21 (0.73-2.00), 0.69 (0.39-1.23), and 0.89 (0.43-1.84) (test for trend, P = .28). Higher intakes of several individual red meat items were also strongly related to elevated risk of ER+/PR+ breast cancer.

Conclusion Higher red meat intake may be a risk factor for ER+/PR+ breast cancer among premenopausal women.

Trans fats antidote

The unmentionable alternative

We have heard angst, outrage and political rhetoric about traces of much-maligned trans fats (TFAs) in our diet -- and about the growing problem of obesity and the health problems it spawns. There is one overlooked proposal that could address both issues, leaving our foods free of TFAs and allowing us to eat french fries, ice cream and doughnuts with less risk of getting fat. The secret weapon not even considered: the fat substitute olestra.

The food cops prefer to talk about proposals that would (a) make it illegal to use oils and spreads with trans fats in restaurants and (b) require that most restaurants prominently feature calorie counts on all menu items. These two plans actually address two very different issues:

The first -- trying to reduce heart disease rates by banning trans fats in eateries -- is based only on speculative data and unusual level of exposure. True, high levels of dietary trans fats -- derived primarily from partially hydrogenated vegetable oils and frequently used in frying and preparing foods such as doughnuts and spreads -- can raise levels of LDL, the so-called "bad cholesterol." But TFAs are only one of several dietary factors that affect cholesterol levels (saturated fats are more important) and, more importantly, serum cholesterol is only one of several factors that may influence the risk of heart disease.

Cigarette smoking and high blood pressure, as well as diabetes and obesity, contribute far more to heart disease than any specific dietary factor. Even the strictest low-fat diet often modestly cuts cholesterol. So how could we expect significant effects on LDL cholesterol from banishing levels of just one type of fat -- one that on average represents less than 3 percent of our total daily calorie intake?

The second proposal would ineffectively confront a real problem, our life-threatening obesity epidemic. Including caloric information on every menu would likely do little to curb our waistlines. Most so-called "fast food" restaurants already display the calories on wall posters, food wrappers and placemats. Providing information on calories will not help if consumers do not fully understand what a desirable caloric intake actually is. A display of numbers will only confuse.

There is an obvious solution, though, that will address the perceived problems of trans fats and the real problem of obesity: invite restaurants to use olestra as a substitute for fats and oils in frying, baking and roasting. Olestra, the first noncaloric fat replacer, could be used in many ways. Not only is olestra stable in frozen products -- making it suitable for foods like ice cream -- it is stable at high temperatures, making it available for deep-frying, unlike other fat replacers. Olestra could replace a good portion of the 34 percent of fat calories we take in daily. In addition to protecting us from the (speculative) threat of TFAs, olestra would protect our hearts from the real deleterious effects of saturated fat.

Why aren't nutrition advocates petitioning the Food and Drug Administration to approve a whole slew of new applications for olestra? (It is now only FDA-approved for savory snacks and microwave popcorn.) The olestra solution is not even being considered by, for instance, those who held anti-trans-fat rallies outside the New York City Department of Health recently, nor by the Center for Science in the Public Interest. CSPI is trying to exorcise trans fats and regularly decries obesity as the work of "greedy" food companies -- but it drove many potential low-calorie and trans-fat-free products from the market with hyperbole about alleged side effects of eating olestra.

For the record, there is no scientific evidence ingestion of foods made with olestra has serious gastrointestinal effects. In large quantities, it can have some minor effects -- in the same way any other high-fiber diet (lots of beans, for example) would. But people can easily adjust their diets. Using olestra would give consumers a wider selection of foods --and permit them to enjoy foods they might otherwise shun. What's not to like about that?


Another reason why you have to be your own doctor as far as possible

General practitioners need to improve their knowledge of heart disease, according to an alarming report that found only 1 per cent of doctors could name the medications that reduced the chance of dying following heart failure. A survey of 803 GPs also found that only 15 per cent of GPs always asked their patients what over-the-counter medicines they were taking. When reviewing medication, only 12 per cent always asked whether the patient was using any complementary medicines. Australian Divisions of General Practice chairman Tony Hobbs said GPs tended "to prescribe the drugs that they are used to prescribing".



Just some problems with the "Obesity" war:

1). It tries to impose behavior change on everybody -- when most of those targeted are not obese and hence have no reason to change their behaviour. It is a form of punishing the innocent and the guilty alike. (It is also typical of Leftist thinking: Scorning the individual and capable of dealing with large groups only).

2). The longevity research all leads to the conclusion that it is people of MIDDLING weight who live longest -- not slim people. So the "epidemic" of obesity is in fact largely an "epidemic" of living longer.

3). It is total calorie intake that makes you fat -- not where you get your calories. Policies that attack only the source of the calories (e.g. "junk food") without addressing total calorie intake are hence pissing into the wind. People involuntarily deprived of their preferred calorie intake from one source are highly likely to seek and find their calories elsewhere.

4). So-called junk food is perfectly nutritious. A big Mac meal comprises meat, bread, salad and potatoes -- which is a mainstream Western diet. If that is bad then we are all in big trouble.

5). Food warriors demonize salt and fat. But we need a daily salt intake to counter salt-loss through perspiration and the research shows that people on salt-restricted diets die SOONER. And Eskimos eat huge amounts of fat with no apparent ill-effects. And the average home-cooked roast dinner has LOTS of fat. Will we ban roast dinners?

6). The foods restricted are often no more calorific than those permitted -- such as milk and fruit-juice drinks.

7). Tendency to weight is mostly genetic and is therefore not readily susceptible to voluntary behaviour change.

8). And when are we going to ban cheese? Cheese is a concentrated calorie bomb and has lots of that wicked animal fat in it too. Wouldn't we all be better off without it? And what about butter? It is just about pure fat. Surely it should be treated as contraband in kids' lunchboxes! [/sarcasm].

9). For a summary of the weak science behind the "trans-fat" hysteria, see here. Trans fats have only a temporary effect on blood chemistry and no lasting harm from them has ever been shown.


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