Thursday, September 27, 2007


Groan! Surely the defenders of the Omega 3 religion can come up with better than this! The study reports the usual crappy "association" (i.e. cause intrinsically unknown) and it not even based on actual Omega 3 intake -- only on REPORTED intake! I don't think I really need to say more but I could mention tiny study, weak effect, indirect criterion and non-normal "sample" etc.

There are many big studies showing Omega 3 to have no beneficial effects on cancer etc. but the belief in fish seems to be deep-seated so SOMETHING that it is good for must be found. Since most people enjoy eating fish, however, no harm is done

A diet rich in fish and other sources of omega-3 fatty acids helped cut the risk that children with a family history of diabetes would develop the disease, US researchers said. "It is a relatively large effect," said Jill Norris, whose study appears in the Journal of the American Medical Association. "It is exciting because it suggests we might be able to develop nutritional interventions to prevent diabetes."

Type 1 diabetes, formerly called juvenile diabetes, is the most common form of diabetes in children. It occurs when the immune system goes haywire and starts attacking insulin producing cells in the pancreas. No one knows exactly what triggers this process, but heredity and environmental factors such as diet are thought to play a role. Several studies in animals have suggested that omega-3 fatty acids - which are found in fish, flaxseed oil, walnuts, soybeans and other foods - may help.

To test whether omega-3 fatty acids offer a potential protective effect, Jill Norris and colleagues at the University of Colorado at Denver studied 1,770 children between 1994 and 2006 who were deemed at high risk for diabetes because of genetic tests or because they had a sibling or parent with type 1 diabetes.

Data about their dietary intake were collected in food frequency surveys. Fifty-eight children in the study developed antibodies for the disease. The researchers found at-risk children who ate a lot of foods rich in omega-3 were less likely to develop islet auto-immunity - antibodies against the cells in the pancreas that precede full-blown diabetes. "This is the first study to show this," Norris said in a telephone interview. "This is all omega-3 fatty acids, not just the kind that are found in fish. "It is certainly not time to make any recommendations until we can see this in other populations," she said, adding that it is a very promising result.

Omega-3 fatty acids interfere with enzymes that play a role in inflammation, a potential trigger for type 1 diabetes. Omega-3 fatty acids have been shown to reduce the risk of heart disease, and researchers are studying whether they can slow the progression of Alzheimer's disease, some cancers and macular degeneration, a leading cause of blindness.

At least 194 million people in the world have diabetes, and the World Health Organisation expects that number to rise to more than 300 million by 2025. Most of these people have type 2 diabetes, which is linked with poor diet and lack of exercise. People with type 1 diabetes often must take insulin injections to control blood sugar levels.


Abstract follows:

Omega-3 Polyunsaturated Fatty Acid Intake and Islet Autoimmunity in Children at Increased Risk for Type 1 Diabetes

By Jill M. Norris et al.

Context Cod liver oil supplements in infancy have been associated with a decreased risk of type 1 diabetes mellitus in a retrospective study.

Objective To examine whether intakes of omega-3 and omega-6 fatty acids are associated with the development of islet autoimmunity (IA) in children.

Design, Setting, and Participants A longitudinal, observational study, the Diabetes Autoimmunity Study in the Young (DAISY), conducted in Denver, Colorado, between January 1994 and November 2006, of 1770 children at increased risk for type 1 diabetes, defined as either possession of a high diabetes risk HLA genotype or having a sibling or parent with type 1 diabetes. The mean age at follow-up was 6.2 years. Islet autoimmunity was assessed in association with reported dietary intake of polyunsaturated fatty acids starting at age 1 year. A case-cohort study (N = 244) was also conducted in which risk of IA by polyunsaturated fatty acid content of erythrocyte membranes (as a percentage of total lipids) was examined.

Main Outcome Measure Risk of IA, defined as being positive for insulin, glutamic acid decarboxylase, or insulinoma-associated antigen-2 autoantibodies on 2 consecutive visits and still autoantibody positive or having diabetes at last follow-up visit.

Results Fifty-eight children developed IA. Adjusting for HLA genotype, family history of type 1 diabetes, caloric intake, and omega-6 fatty acid intake, omega-3 fatty acid intake was inversely associated with risk of IA (hazard ratio [HR], 0.45; 95% confidence interval [CI], 0.21-0.96; P = .04). The association was strengthened when the definition of the outcome was limited to those positive for 2 or more autoantibodies (HR, 0.23; 95% CI, 0.09-0.58; P = .002). In the case-cohort study, omega-3 fatty acid content of erythrocyte membranes was also inversely associated with IA risk (HR, 0.63; 95% CI, 0.41-0.96; P = .03).

Conclusion Dietary intake of omega-3 fatty acids is associated with reduced risk of IA in children at increased genetic risk for type 1 diabetes.

JAMA. 2007;298:1420-1428.

Germs taken into space return more dangerous

Worrisome if replicated

It sounds like the plot for a scary B-movie: Germs go into space on a rocket and come back stronger and deadlier than ever. Except, it really happened. The germ: Salmonella, best known as a culprit of food poisoning. The trip: Space Shuttle STS-115, September 2006. The reason: Scientists wanted to see how space travel affects germs, so they took some along - carefully wrapped - for the ride. The result: Mice fed the space germs were three times more likely to get sick and died quicker than others fed identical germs that had remained behind on Earth.

"Wherever humans go, microbes go, you can't sterilize humans. Wherever we go, under the oceans or orbiting the earth, the microbes go with us, and it's important that we understand ... how they're going to change," explained Cheryl Nickerson, an associate professor at the Center for Infectious Diseases and Vaccinology at Arizona State University. Nickerson added, in a telephone interview, that learning more about changes in germs has the potential to lead to novel new countermeasures for infectious disease.

She reports the results of the salmonella study in Tuesday's edition of Proceedings of the National Academy of Sciences. The researchers placed identical strains of salmonella in containers and sent one into space aboard the shuttle, while the second was kept on Earth, under similar temperature conditions to the one in space.

After the shuttle returned, mice were given varying oral doses of the salmonella and then were watched. After 25 days, 40% of the mice given the Earth-bound salmonella were still alive, compared with just 10% of those dosed with the germs from space. And the researchers found it took about one-third as much of the space germs to kill half the mice, compared with the germs that had been on Earth. The researchers found 167 genes had changed in the salmonella that went to space.

Why? "That's the 64 million dollar question," Nickerson said. "We do not know with 100% certainty what the mechanism is of space flight that's inducing these changes." However, they think it's a force called fluid shear. "Being cultured in microgravity means the force of the liquid passing over the cells is low." The cells "are responding not to microgravity, but indirectly to microgravity in the low fluid shear effects." "There are areas in the body which are low shear, such as the gastrointestinal tract, where, obviously, salmonella finds itself," she went on. "So, it's clear this is an environment not just relevant to space flight, but to conditions here on Earth, including in the infected host."

She said it is an example of a response to a changed environment. "These bugs can sense where they are by changes in their environment. The minute they sense a different environment, they change their genetic machinery so they can survive," she said.



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 and margarine? They are just about pure fat. Surely they 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.


No comments: