Plants & Plausibility

Are plants protective for cancer? The evidence has been mixed, to say the least. Evidence, that is, in the form of specific human interventions. And it's fairly ambiguous observationally. Recently yet another result from EPIC was published, looking at correlation between fruit and vegetable intake and cancer. Basically there was no difference. The best-case hazard ratio was only down to 0.97 (compared with a more encouraging HR of 0.72 for, um, eating lots of cheese ... oops!). Given uncertainty in figuring out what people actually ate over the period, and given uncertainty around "correcting" for variables (these corrections are built upon pyramids of observational studies, it's not an exact science, although it pretends to be), this is probably meaningless. The biggest worry for the pro-plant brigade should be that even with the flaws, we could expect a more dramatic difference in hazard ratio simply (or solely) from healthy user bias. So it's possible plants are causing cancer. Who knows. If you're choking down foliage by the bucket in the belief you're saving yourself from cancer, there's not much evidence for that. Eat them if you like them. Or maybe to foster a diverse ecology of gut flora, or to poop a lot.

In any case, lots of smart people are absolutely convinced that plants have magical health benefits. I think this stems from a problem that Pauling succumbed to -- the plausibility peril. In the lab, we can see specific interplay at the molecular level, and this builds up a promising avenue of research. The plausibility peril: once we come up with a plausible explanation for how something could or might work, the plausibility itself acts as evidence in support of the theory. Not even deliberately or intentionally, but nonetheless it becomes a bit of a trap. E.g. you sneak up on some cancer cells in a beaker, minding their own business, and hose them down with tocotrienols. They stop growing. Well, that's certainly promising. Tocotrienols are in plants, thus eating plants might slow or stop cancer growth. And freebasing vitamin C might cause immortality (sorry, Linus). But when you try it out in humans it actually has to work. And often it doesn't, no matter how plausible the story.

High Confusion & Heart Disease in Women

A recent study came out observing a higher risk of heart disease within a 30k+ sample of Italian women who consumed higher carbs, or higher GI foods, or higher GL foods. What fascinates me is not the study itself, but the description of the results by both the press and the study authors themselves. More on that in a bit, first the study.

It was a cohort study. Take it with a grain of salt. A big one. The analysis for the women in the study concluded the following, ordered by relative risk:

1. women with highest GL [glycemic load] diets had a relative risk of heart disease of 2.24
2. women with highest total carbohydrate intake had a relative risk of heart disease of 2.00
3. women with highest GI [glycemic index] diets had a relative risk of heart disease of 1.68

Even though this study would seem to confirm my own biases, I think it's mostly worthless. It's an observational study that assesses diets based on questionnaires, so the data should be treated as highly unreliable. Given that, relative risks should be very high before we get too worked up. Relative risks around 2 in a study like this are pretty boring. (And fewer than 1 in 200 women developed heart disease over the course of the study, compared with greater than 1 in 50 men.) Useful only to generate funding for further studies. Not at all useful for guiding public health policy. So this isn't really worth so much attention in the press.

That said, I'm fascinated by how it was described, even by its own authors. There seems to be a real disconnect between the data and the editorializing. Let's review from a few lines above: total carb intake showed a greater risk than just GI. High GL, which is essentially a combination of the two, showed the highest risk. The risks of total carbs and high GL were close to each other, with high GI trailing in third farther behind. Naturally, the press coverage focused on GI.

The headline from the BBC explicitly and only mentioned "High GI". The Independent says "Sugary". The BBC article even rolls out these head-scratchers:

"high GI foods, rather than carbohydrates per se, appear to pose a risk"

and

"Low GI carbohydrates, such as pasta, which release energy and raise blood sugar far slower, showed no such link with heart disease."

Maybe I'm losing my reading comprehension skills. Let me look at the study again.... As I remembered, carbohydrates per se not only appear to pose a risk, but they appear to do so to a greater extent than high GI foods. Both of those statements are demonstrably false if you take the very study they claim to be about at face value. How's that for spin?

Worse, the actual authors of the study are being dishonest, saying,

"Thus, a high consumption of carbohydrates from high-glycaemic index foods, rather than the overall quantity of carbohydrates consumed, appears to influence the risk of developing coronary heart disease."

So the reporters are uncritically regurgitating how the study was described, rather than reporting on the study itself [likely the reporters never bothered to read the study], and the authors are misinterpreting their own results ["lying" is a strong word]. The study actually did in fact observe that "the overall quantity of carbohydrates consumed" influences the risk to a greater extent than high-GI foods does, yet the authors claim the opposite. Well, I'm baffled.

The only explanation I can come up with is that they've already decided carbs are good. Since most people keep protein intake within a fairly narrow range, the higher carb diet is the same as a lower fat diet, and vice versa. So in part what was observed was women eating more fat had lower risk of heart disease. This causes so much cognitive dissonance in the researchers they have to figure out a way to not say it. You already know the punchline, right?

"They could try broadening the types of bread and cereals they eat...."

That's right! Conclusion = Eat More Carbs!


____________________
bbc article
independent article

P.S. The only thing missing from the coverage was a recommendation for women to take statins.

Quiet Skies Over London

Speaking of air travel, there's been none of it here since Iceland has launched its Dr. Evil volcanic assault on the rest of europe. Once the blank skies were pointed out to me, I can't stop noticing. It's been beautiful and sunny and clear. The complete lack of anything in the sky is almost shocking. Odd and fascinating. And it's gone literally quiet as well. We're less than 5 miles from London City, which is a protected habitat and breeding ground for the endangered jumbolina, which makes a distinctive pitch-dropping sound on approach. We're also 15 miles from Stansted and about 18, as the heron flies, from Heathrow (a fact I try not to dwell on when I'm 90 minutes into an attempt to get there). There's never not metal criss-crossing the sky. Except now.

Domestic Air Travel in USA

or
"when did United become a discount airline?"
or
"you're doing it wrong!"

Flew United Airlines domestically for the first time in many years. I remember United as being one of the "premium" airlines, but from the moment I booked I was assaulted by piecemeal pricing and upgrades. Relentless pitches to upgrade my seat, my check-in, my luggage options, etc. The implied message, delivered repeatedly, was "our default service SUCKS! please pay more to make this journey bearable". At the airport, more weirdness. Upon check-in, I was given a "departure management card", rather than a boarding pass, that got me through security but I still had to check in again at the gate to get an actual seat. This didn't happen on the return trip, so I'm not sure what the deal was. The per-bag fee caused the predictable chaos. On the plane, united had put diagrams on the overheads as to how to align max-size carryons most efficiently in the bins. And the bins were full. Everyone had large roll-on carryons. Getting everyone on and off the plane took a loooong time. How is this helping anyone? How does this help the airline? I have no idea.

How and why did United decide to become a discount airline? Southwest Airlines is a true "cheap and cheerful" play. United's attempt is neither cheap nor cheerful.

First Dentist Visit Since The 90s

Been a while. Maybe 12 years. No cavities, no problems. I attribute my overall cavity-free streak to my gum-chewing habit. I have no evidence for that. The hygienist put a big hurt on me. Have to go back for a followup scraping session, too. Ouch. I will be upgrading my toothbrush to a sonicare. Yes, yes, and flossing.

Overall I'm having a hard time buying the every 6-12 month schedule the dentist recommends given the observed success of my once-a-decade scheme.

London Is Really Freaking Cold

London cold is a dense, damp thing. Seeps into homes & bones... seeps, settles, won't be sloughed.

London is (subjectively) the coldest place I've ever been. I've enjoyed January after January in Chicago (standing on an el platform in the dark of a subzero-F morning with a face full of windchill), brittle and bitter midwestern nights, razor-sharp snowy gusts in the alps... nothing makes me feel colder than a sunless & drizzly London spring day with the temp just above freezing.