Saturday, July 30, 2011

Don't come round 'ere with yer facts and evidence

Nice story I first came across in the Listener. The Cochrane Collaboration has done an evidence-based medicine review of whether reducing your salt intake really does reduce your chance of heart attack or stroke, and found no evidence it does. If anything, it might actually increase your risk if you're already suffering some kind of heart disease.

For those unfamiliar with Cochrane reviews, they get researchers to look at what the evidence actually is for particular medical interventions. The researchers find all the studies they can that provide evidence one way or the other on the subject, then they strip out the poor-quality studies until they only have indisputably high-quality studies left, then they go through them with a fine-tooth comb to figure out exactly what the study really does provide evidence for. They're respected around the world for the quality of their work. Their latest effort, on reducing salt in your diet, is here: Reduced dietary salt for the prevention of cardiovascular disease. Their plain language summary:

Cutting down on the amount of salt has no clear benefits in terms of likelihood of dying or experiencing cardiovascular disease

Good news, huh? Apparently not. Experts reject the findings. Reuters has this to say:

Most experts are agreed that consuming too much salt is not good for you and that cutting salt intake can reduce hypertension in people with normal and high blood pressure.

Well, yes. But the question is, what evidence is that consensus based on? Apparently the answer is "Nothing reliable."

But you can always rely on nutritionists not to let inconvenient facts stand in the way of dogma. A Heart Foundation nutritionist is quoted on the Science Media blog:

Other types of research have conclusively linked moderate salt reduction with reduced risk. The Heart Foundation maintains its position of advocating salt reduction for all New Zealanders...

"Other types of research?" "Conclusively?" Seems that the Cochrane group could have saved themselves the effort of studying the evidence for themselves - all they needed to do was contact the Heart Foundation and ask a nutritionist. How silly of them.


Andrei said...

I tell you Milt the life expectancy in the West has nearly doubled over the past century and its due to clean water, efficient management of sewerage and processed food which doesn't fucking kill you because it is infested with nasty bugs.

And the food police go for this every time and call safe food "junk food" and claim it's not nutritious. When in fact it is highly nutritious.

Salt of course was an early preservative, and is a vital component of our diet, which of course is why it enhances the flavour of most foods, its our bodies telling us this is good for us.

To be sure everything we eat or do does contribute to the wear and tear of our bodies, which like it or not wear out - we are after all born to die.

T'aint nothing the pointy heads can do to prevent this.

The engineers who build and maintain the infrastructure and the people who figure out how to maximize food production, storage and delivery have done far more to improve the quality of life and extend it than the ninny public health types

JC said...

The pointy heads could save a great many lives, knock diabetes for six, massively reduce obesity if they would advise us to cut out bread, eat plenty of boiled meat with puha cooked in the (salty) water. (OK, I had to get salt in there somehow).


Anonymous said...

PHUCK! all these years depriving myself of flavour, and for nowt!
At least now I can add that sprinkle of salt and tell the pointy heads to stick the salt shaker where it fits (after I finished of course)

Anonymous said...

I hadn't cooked with salt (except in soup) or added it to food for years.

Then I had a blood test which showed I was low in sodium and was advised to start adding salt to meals.

That isn't proof either way for the ills or otherwise of salt but is a reminder that moderation is often very good medicine.

Psycho Milt said...

That isn't proof either way for the ills or otherwise of salt but is a reminder that moderation is often very good medicine.

I always figure your body has mechanisms for getting rid of excess sodium but none for making up a shortfall, so better too much than too little.

Andrei: I didn't comment on it but enjoyed your post about Tanya Tagaq - the Inuit are living, breathing demonstrations of why the "healthy food" bullshit is bullshit. These are people who spent thousands of years on a diet almost exclusively of meat and fat, and were at least as healthy as anyone else on the planet. I agree - "healthy" food is food that won't damage your health via toxins, bacteria etc, and processed food fits that bill quite nicely.

Also agree the "likelihood of death" remains 100% no matter what - a fact that can't be disputed but is often strangely absent from the literature.

Andrei said...

I always figure your body has mechanisms for getting rid of excess sodium

That's why the Good Lord gave you kidneys

Linda Reid said...

This blog (sadly it has been inactive for some time now) has some great analysis of various studies that show the opposite result to what their headline is.

For example, being overweight is not a death sentence - in fact overweight and even obese people live longer than thin people. There is no evidence that supports this international campaign to make people eat 'healthier' and be thin.