Thursday, December 21, 2006

Cervical vaccine may help boys!

The benefits of Australian of the Year Ian Frazer's cervical cancer vaccine may extend far further than previously thought, research has found. A study of cancer incidence in kidney transplant patients suggests the vaccine, marketed in Australia as Gardasil, should be considered for boys as well as girls, Sydney researcher Claire Vajdic said. Dr Vajdic, of the University of NSW, and colleagues found kidney transplant recipients were three times more likely to develop cancer than the general population.

She said many of the cancers were known to be caused by the human papilloma virus (HPV), the target of Professor Frazer's vaccine. "Of the 18 specific cancers with greater than threefold increase in risk, five were at sites that are known to be caused by human papilloma virus (tongue, mouth, vulva, vagina, penis)," the researchers wrote in the latest edition of the Journal of the American Medical Association. "An additional four were at sites for which the evidence for human papilloma virus is limited or inconclusive (eye, salivary gland, oesophagus, nasal cavity)."

The researchers studied almost 29,000 Australians who had a kidney transplant between 1982 and 2003. Dr Vajdic said 1236 cancers were picked up during an average 8« years of follow-up after transplantation. The risk of lip cancer was 47 times higher than in the general population. "For lip cancer, exposure to UV radiation and tobacco products are thought to be important causal factors but the role of human papilloma virus is under study," the researchers wrote.

Dr Vajdic said scientists believed the increase in cancer risk among transplant patients was associated with having to take drugs to suppress the immune system, thereby avoiding organ rejection. Although she believes the research suggests a much broader role for Professor Frazer's vaccine, the benefits may not be felt for decades even if universal immunisation were achieved. Professor Frazer said the prerequisite for immunising boys with the vaccine was the need for proof that the vaccine was effective in males. [Got that right!]


Trans fat worries irrelevant to Australia anyhow

Some small amounts of trans fat occur naturally in red meat and dairy products, but it's the artificially concocted version that has health officials worrying most. Formed by bubbling hydrogen through polyunsaturated vegetable oil, trans fat is a more solid, stable fat than a regular oil. It has a longer shelf life, can be reused and reheated without spoiling, is ideal for deep frying and gives food a crunchy, crispy texture. Those are also the same characteristics that make trans fat particularly dangerous. The stiffer a fat is, the more likely it is to stick inside your artery walls and stay there. A review of trans fat published in the New England Journal of Medicine in April found that a 2 per cent increase in trans fat increased the risk of coronary heart disease by 23 per cent (2006;354:1601-1613).

New York's ban was the latest action in response to a wave of concern over the negative health effects over the fat. Earlier this year the US Food and Drug Administration began enforcing a requirement that food manufacturers include information about trans fat on labels there - a step other countries such as the UK are also considering.

Australia is also looking into ways to lower the amount of trans fat people are consuming - a joint effort by the National Heart Foundation of Australia, the Dietitians Association of Australia, the Australian Food and Grocery Council and Food Standards Australia New Zealand. These groups will meet early next year to discuss issues and make recommendations to the government.

Whether trans fat should be labelled is among the issues that will be discussed. Currently manufacturers only have to list trans fatty acids if they're making a health claim about the product, such as "no cholesterol'' or "low in saturated fat''. Also on the agenda of next year's meeting will be possible healthy replacements for the partially hydrogenated vegetable oils that are the main source of trans fats.

In the meantime, an increasing number of companies and food manufacturers are reformulating their products to remove trans fat in the face of mounting public concern. In November McDonald's announced it would reduce the trans fat found in the food in all 740 of its Australian franchises, by about 85 per cent, by switching to a healthier canola sunflower blend that has less than 1 per cent trans fat and is high in monounsaturated fat (a good fat).

Brands such as Nestle, Woolworth's Home Brand, Arnott's and others have made similar decisions to reformulate their products to reduce trans fat, or get rid of it completely where they can. But some people are pushing for a ban like that in New York. Last week the Greens announced they would be drafting a bill with a similar objective to put before the Senate, but it's a plan that has received little support from the groups on the collaborative, or from the Government itself.

For one thing, there's just not the same scale of problem here, says Lydia Buchtmann of Food Standards Australia New Zealand. "There's not a huge percentage of trans fat in the Australian diet. We've been carrying out a formal review with dietary modelling, and the preliminary findings have been that 0.6 per cent of our total kilojoules come from trans fat, which is well below the World Health Organisation's maximum limit of 1 per cent,'' she says. By contrast, Americans are consuming 2 to 3 per cent of their daily kilojoules from trans fat. One likely reason is that Australian manufacturers tend to use canola blends, which are more readily available here than the partially hydrogenated soy bean oil so prevalent in America, says Dave Roberts, technical director of the Australian Food and Grocery Council.

Experts say that focusing too much on trans fat could blow things out of proportion and misdirect our attention from saturated fat, which is actually the bigger culprit of heart disease in Australia because we consume so much more of it. "It's an issue if you're a fast food consumer and you're eating at one of the fast food establishments that still uses oil with trans fat in it - but there's not much of it is any more,'' says Peter Clifton, director of CSIRO's Nutrition Clinic which conducts nutritional research and trials on cholesterol, oils, fats and other topics. "Saturated fat is more of an issue. The average consumer would have 20g to 30g of saturated fat a day, compared with two to three grams of trans fat.''

It's a point echoed by the Heart Foundation, among others. "Trans fat is as harmful, if not more so, than other types of fat. However, Australians consume considerably more saturated fat,'' says the foundation's national nutrition program manager Barbara Eden. More than 13 per cent of our daily kilojoules are currently coming from saturated fat while the Heart Foundation recommends that no more than 8 per cent of our total kilojoules come from unhealthy fat - saturated and trans fat combined. "If the focus is on lowering trans fat, what could happen is companies will just swap to an oil that has no or very little trans fat - but could still be very high in saturated fat,'' Eden says.

Take KFC for example. The chain has been vocal about its use of a trans fat-free oil, but that turns out to be palm oil - which contains more than 50 per cent saturated fat. nutritionist Catherine Saxelby says there's one other problem with focusing too much on removing trans fat from food: "They occur in foods that we don't want people to eat too much of anyway,'' she says. "If people just ate basic staple foods they wouldn't have a problem.''



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].

Trans fats:

For one summary of the weak science behind the "trans-fat" hysteria, see here. Trans fats have only a temporary effect on blood chemistry and the evidence of lasting harm from them is dubious. By taking extreme groups in trans fats intake, some weak association with coronary heart disease has at times been shown in some sub-populations but extreme group studies are inherently at risk of confounding with other factors and are intrinsically of little interest to the average person.

The use of extreme quintiles to examine effects is in fact so common as to be almost universal but suggests to the experienced observer that the differences between the mean scores of the experimental and control groups were not statistically significant -- thus making the article concerned little more than an exercise in deception


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