Thursday, 15 March 2012

Could Air Pollution Be Making Us Fat? - more "scientific" nonsense

Discovery News asks breathlessly (how appropriate!), and in all seriousness "Could Air Pollution Be Making Us Fat?" - read the original, it's hilarious.
A hypothesis proposes that rising levels of CO2 in the atmosphere may be contributing to obesity.
Breathing in extra carbon dioxide makes our blood more acidic.
Lowered pH in the brain makes appetite-related neurons fire more frequently.
Obesity is not as simple as many people think.
If you think that's enough for a chuckle, read this
Steadily rising levels of carbon dioxide in the atmosphere may be affecting brain chemistry, increasing appetite and contributing to the obesity epidemic, according to a new hypothesis, which still awaits rigorous testing and inevitable debate.
The idea proposes that breathing in extra CO2 makes blood more acidic, which in turn causes neurons that regulate appetite, sleep and metabolism to fire more frequently. As a result, we might be eating more, sleeping less and gaining more weight, partly as a result of the air we breathe.
So "breathing in extra CO2 makes blood more acidic" does it? How does blood become "more acidic" when it's alkaline, with a typical pH of 7.41 for arterial blood (7.0 is "neutral, lower values are "acidic")? That "extra CO2" is of course included in the 0.039% or 390 parts-per-million of CO2 that's in the air we breathe.

Reality check: an adult male's lung capacity is between 4 and 6 litres, the greater the bigger and fitter the individual is. When breathing normally, that is when sitting or standing still, the amount of air left in the lungs, and not exhaled is between 1.8 and 3.4 litres, roughly a third to half of lung capacity. That remaining air contains about 4% CO2, or 100 times the concentration breathed in. We're being asked to accept that the tiny annual increment in the 0.039% of atmospheric CO2 is going to make blood more acidic, when each intake of breath starts with residual air in the lungs containing 4%? I have a mental list of adjectives for this kind of "research", but I'll keep them to myself, and stick with the moderate "bullshit". The Discovery News author wonders (as she might well do) -
It's still far from clear whether the amount of CO2 we are currently exposed to is enough to make a difference, or whether exposure at specific times in development make more or less of a difference.
No, it's definitely not "far from clear" - simple maths, a scientific education (or an inquiring and sceptical mind), and Google is all you need to show that it can't "make a difference". It's as valid an hypothesis as claiming that wearing wet socks will increase your chance of drowning, due to the "additional water" increasing the level of water in the swimming pool (or the ocean - even more ridiculous).

I might be "eating more, sleeping less and gaining more weight", partly as a result of the utter and total crap I find daily on the 'net. I do find I'm reading Discovery News less, and drinking more though, so there is an upside. Can someone develop a "bullshit filter" for the 'net? They'd make more money than Bill Gates made in his lifetime. I don't know of an app. for that, though I may be wrong, which is an acknowledgement of possible error many scientists won't make.

I refuse to even begin to skewer the nonsense about higher blood acidity making people eat more. I have my standards, you know. I also have a question of my own - could "rising levels of CO2 in the atmosphere" be making some of us stupid? Please note, Dear Reader, I don't include you and I in that "us" of course, but you get the idea.

Must remember to add "CO2 makes you fat" to the list.

No comments:

Post a Comment