Monday, 21 July 2014

Ancel B. Keys' critique of "Diet and coronary thrombosis. Hypothesis and fact, by John Yudkin. The Lancet, 1957."

Ancel B. Keys has come in for a lot of flak recently over alleged "cherry-picking" of data for his 6/7 Countries studies. Here's Keys' critique:- "SUCROSE IN THE DIET AND CORONARY HEART DISEASE" of Dr. John Yudkin's "15 Countries" article.

Keys accuses Yudkin of bias, cherry-picking countries that fit his own hypothesis.

Here are some plots from Keys' 11 Countries article.
5-Year CHD cases/1,000 men vs Sucrose %E.

5-Year CHD cases/1,000 men vs Sat Fats %E.

Sucrose %E vs Sat Fats %E.

So there you have it.


Michael Trumper said...

From what I have read, Yudkin places a lot less emphasis on the epidemiological surveys that Keys did, but I could be wrong. Whereas, because epidemiological data was key to Keys hypothesis (and therefore criticisms of his famous charts struck a bit deeper, this was less of an issue of Yudkin.

In Pure, White, and Deadly Yudkin states several times that "the epidemiological evidence cannot by itself prove that sugar or any other factor is a cause of coronary disease."p. 98 He relies heavily on experimental results to bolster his hypothesis regarding how replacing fat or starch in the diet's of both animal and human subjects very quickly produces signs of what we now call metabolic syndrome. Keys on the other hand seems to have had much more faith int the epidemiological approach which lends itself to more criticism. Keys from what I can see was unable to prove the causal chain between saturated fat and CVD, whereas Yudkin had much stronger experimental data linking sugar to changes in metabolism and CVD. On a side note, Yudkin does not seem to have bought into the all starch = sugar argument.

Nigel Kinbrum said...

Although liver derangement (and hence Met Syn & T2DM) can be brought on quite quickly in humans by over-feeding carbs then fats (akin to making pate de fois gras), CA/CAD/CHD/whatever takes many years for plaque to develop.

∴ Experiments linking sugar to CA must be animal studies.

∴ Experiments linking fats to CA must be animal studies.

I'm currently reading Whew!

Michael Trumper said...

From what I have read overfeeding either or both causes metabolic issues. What Yudkin says is that replacing calories of glucose (starch) or fats with sugar (not overfeeding) quickly causes metabolic issues. It is an interesting read and he does mention both animal and human studies. Touching on a topic of recent interest, he also seems to have identified fructose as the main driver behind the changes, but have more reading to do..

I think I have the same PDF that Sheldon has. I feel your pain.

Nigel Kinbrum said...

RE Fructose: See Read the comments! Then see

Bazinga! ;-)

Michael Trumper said...

Read his stuff, don't find it all that compelling.

Nigel Kinbrum said...

AA is all about the evidence. The evidence doesn't support Lustig.

Sure, too much fructose is bad. Too much of anything is bad, one way or another.

Michael Trumper said...

We will have to agree to disagree, I think the emerging evidence does support the view that the current levels of fructose consumption is an issue.

While I am in agreement with some of AA's views, I think he is looking at it the wrong way, through the lens of a personal trainer who works with athletes/fitness enthusiasts who can handle large loads of fructose.

Saying too much of anything is bad doesn't really add anything to this. I think CICO is an extremely poor model of metabolism.

Nigel Kinbrum said...

Regarding overfeeding: I know that ~100% of dietary fructose ends up in the liver, due to Glu-T5 & fructokinase. The liver is depleted by HGP.

If Fructose input > HGP over a long period of time, the liver becomes full and excess fructose goes down lipogenesis pathway, raising liver fat content & fasting TG's a lot.

Excess dietary fructose is bad for the liver. See and

Excess dietary starch is bad for the liver, but more is needed, as <<100% of dietary glucose ends up in the liver.

Excess dietary fat is bad for cholesterol.

In conclusion, too much of anything is bad, in different ways.

Michael Trumper said...

Saying too much of anything is bad is true, but adds nothing to this.. I would argue that question is, does fructose have some unique characteristics that when consumed at current levels is a main contributor to the rise in metabolic/chronic diseases. My view is yes.

People can do quite well on diets either high in starches or fats. The threshold is fairly high for starch, fat, or protein before you start to see the unhealthy effects. I don't think we can say the same about sugar. The threshold is much lower and from what I see on a daily basis a lot of people have crossed it.

Nigel Kinbrum said...

I can agree with that. The $64,000 question is this: Why do a lot of people cross the safe fructose threshold on a daily basis?

Government healthy eating guidelines don't encourage high sugar consumption.

I say that it's the food manufacturers who are to blame, churning out 1,000's of different types of sugary crap & bombarding people with advertising. Organisations like the British Sugar Bureau vilified John Yudkin and churn out pro-sugar propaganda.

Whole fruits are a bit higher in sugar content than they used to be, but it's still nowhere near the sugar content of sweets, chocolate, cakes, biscuits, breakfast cereals, sauces etc i.e. manufactured foods. SSB's produce minimal satiety, so are another significant source of sugar.

As HFCS-55 is somewhat sweeter than sucrose, and SSB's have to have just the right amount of sweetness for maximum sales, I don't think that HFCS has worsened the problem.