Tuesday, October 13, 2009

SAD vs Traditional Japanese diet (2)

OK, many thanks to Lynne who managed to get the pdf. Extra Brownie Points for guessing that this was the paper I wanted, despite to my copy paste accident on the link!

It's talking about Japanese-Americans. You have to bear in mind that the information is limited by dietary preference questionnaires and the vagarities of deciding if someone has really had a heart attack. The group over 55 years is not shown as nothing much seems to make any difference in this group. Marmot discusses all of this in his paper. This is the relevant graph.

Now, you have to read this carefully. The pattern is the same, so I'll go through the top graph only. Looking at the left hand pair of vertical bars, the white one is the people who had a traditional Japanese up bringing and had a traditional Japanese diet preference. They had 2.5 heart attacks per hundred people.

Move over to the right hand side of the chart. Again the white bar is those people with a traditional Japanese up bringing but these are the ones who are now eating to what was the SAD back in the 1950s and 1960s. They had 0.4 heart attacks per 100 people. That is a relative risk of about 0.20, ie an American diet preference, compared to a traditional diet preference, appears to be HUGELY protective against CHD. Both of these groups are of a traditional Japanese style up bringing.

An American up bringing essentially doubles your risk of CHD, irrespective of whether you have a traditional Japanese dietary preference or an American dietary preference. It's worth noting that the combination of an American diet preference with an American upbringing is pretty well indistinguishable (3.0 heart attacks per hundred) from a traditional Japanese diet with traditional Japanese upbringing (2.5 heart attacks per hundred).

The protective effect of a traditional Japanese upbringing allows you to question any "dietary" intervention if it also adds in stress management, relaxation and exercise while asking you to shovel 1500kcal of rice a day down your throat!

Here's what Marmot, who had the misfortune to base his PhD on these data, had to say:

As the shot messenger I'd like to limp away now.



ItsTheWooo said...

I'm curious how it is even possible to have an authentic japanese upbringing BUT eat american food. I would think that a lot more must be different between this group, and the "japanese upbringing + japanese food" group. I don't see why any group of people would stay true to their heritage except for the single difference of eating exactly like the natives.

I am also curious what the japanese lifestyle entails exactly. Why is an american lifestyle so toxic? Is our life really that stressful? I guess it is. I always assumed lifestyle (stress) was a big reason people developed metaboic illnesses, since all evidence suggests cortisol is integral for both appetite and fattening (they give progesterone derivative megestrol to cachexic patients, it actually works... and progesterone largely affects appetite via funking with the adrenals, and megestrol will cause adrenal suppresion therebywhich as it is telling the body there is a lot of adrenal gland function by simply being present... and that's just the effect of adrenals on appetite... we don't even need to discuss protein catabolism and gluconeogenesis do we?)

I suppose it is possible that obesity/heart disease/metabolic disorder in general is at root a stress disorder (or at least is triggered by stresses quite often) ... but man, I didn't think our lifestyle was really that bad. I guess it is.

But all the same, I do suspect how "traditional" the japanese diet group really ate anyway... and for the "non traditional diet" group, how did they manage to keep everything the same EXCEPT for diet?

I'm thinking maybe "authentic japanese - diet" might be some kind of marker for severe stress, because it might be true that not being able to eat their traditional diet was less a choice and more forced upon them by poor social support systems (so they continued to live japanese but were forced to eat like americans... and in this case it isn't the food causing sickness in as much as it is the stress of having a crappy social situation).

Bris said...

"I'm curious how it is even possible to have an authentic japanese upbringing BUT eat american food."

Very simple. Most of the traditional Japanese foods weren't readily available in the USA so Japanese-Americans ate what was available. That didn't prevent them from following other Japanese traditions.