Tuesday, May 03, 2011

Salt May Not be Unhealthy

Gary Taubes wrote What if It's All Been a Big Fat Lie? back in 2002 for the New York Times Magazine, which reinvigorated the Atkins/Southbeach/Paleo diets. He argues carbohydrates put us on an insulin treadmill, whereas proteins and fats satiate us. It seems the key effect is on your appetite via insulin regulation and the stability of going into fat burning mode, as opposed to some calories having different effects on your weight.

But he's a pretty interesting guy in general. His Blogginheads interview on last weekend's Science Saturday was pretty neat. He also wrote back in 1998 that the conventional wisdom on salt could be wrong too, with correlation not equaling causation. Indeed, there are a lot of bad correlations purported to be causations in medicine and biology, and it makes me skeptical of statins. Anyway, here's good news for salt lovers from a New York Times article on a study that included 3,681 middle-aged Europeans who did not have high blood pressure or cardiovascular disease and followed them for an average of 7.9 years.

A new study found that low-salt diets increase the risk of death from heart attacks and strokes and do not prevent high blood pressure, but the research’s limitations mean the debate over the effects of salt in the diet is far from over. In fact, officials at the Centers for Disease Control and Prevention felt so strongly that the study was flawed that they criticized it in an interview, something they normally do not do.

The investigators found that the less salt people ate, the more likely they were to die of heart disease – 50 people in the lowest third of salt consumption (2.5 grams of sodium per day) died during the study as compared with 24 in the medium group (3.9 grams of sodium per day) and 10 in the highest salt consumption group (6.0 grams of sodium per day). And while those eating the most salt had, on average, a slight increase in systolic blood pressure — a 1.71-millimeter increase in pressure for each 2.5-gram increase in sodium per day — they were no more likely to develop hypertension.


Glen said...

The obvious way to run a long-term controlled study is to vary the sodium level in institutional cafeterias. Pick a few high-security prisons or K-12 school districts that serve similar populations and set different sodium standards for their menus, then follow up on a random sample of the longer-term inmates/students.

Anonymous said...

With the medical profession and its associated propaganda arm in the media, the fervour with which they push their claims lasts about 5 to 10 years. A few years ago it was the scare over cholesterol, which led to to some fools switching from butter to margarine. Before that it was fears over lauric oils. Now it turns out that coconut oil is a healthier oil most others.


David Merkel said...

This could be nonlinear, where too much or too little salt could be bad for you. For average people, who are not trying to avoid salt, it is hard to get too little salt.

PS -- just thinking about KFC makes me want to get a glass of water.

AHWest said...

I told you that you would like Taubes. Both of you expose naked emporers in different territories. And find that the evidence simply doesn't support conventional wisdom, and then provide better frameworks for understanding what's really going on.
I place Ayn Rand in this category as well, in the realm of philosophy.

Dave said...

I'm on Atkins again now (lost 35lbs doing it last year, but gained 25 of them back since). It does work well for weight loss, but it's tough to stick with indefinitely if you like to eat a variety of foods. I found that I could maintain my weight without dieting by running about 15 miles per week, but I slacked off for a bit and kept eating.

One thing I'm curious about is the optimal amount of aerobic exercise for weight loss. I think with some of this diet & exercise stuff, you're better off experimenting on yourself a little bit and seeing what works for you. I have a hunch, for example, that I'll be better off running closer to ~9 miles per week while dieting. That way, I can lift some weights and get in and out of the gym in less than hour, and maybe not be as hungry as I am usually after running 5 miles and then lifting.

peterxyz said...

I'm with David - I'd love to know the reason why the people with the lowest sodium diets had such low sodium diets.

e.g. the health outcomes of people ceasing smoking aren't that great - a group of them have been told to cease by their doctors for very good reasons.

Eric Falkenstein said...

I did Atkins earlier this year and lost 14 pounds (in part because AHWest noted it worked great for him!) ...It's not easy, but easier than alternatives, and I do feel more full all day