Eating with Two Yardsticks: The Nutrition Doc's Burden of Proof
Nutrition has a very important influence on health - and here I agree absolutely with Dr Matthias Riedl, the “Ernährungsdoc” and “poster boy” of German nutritional medicine (1). However, I have made experiences of my own that stand diametrically opposed to his statements and recommendations.
Sur-Praise
This time, though, I can at least begin with praise: episode 79 of the Ernährungsdocs podcast is about nutrition alongside treatment for multiple sclerosis (MS). In this episode I heard Dr Riedl make a statement that he has otherwise - as far as I have heard - always expressly denied:
Whenever giving up wheat has come up before, coeliac disease has invariably been named as the hard criterion: “anyone without coeliac disease has no reason to avoid wheat”. That is not the case here, for the first time I am aware of, and he explicitly addresses ATI(2) as a further reason to avoid wheat and other grains, or at least to regard them very critically.
Dis-Praise
That, however, is also where my praise ends, because on the other hand he once again spreads fear and dread about Metabolic state in which the body burns fat rather than glucose for fuel. Characterised by a measurable level of ketone bodies in the blood. → more nutrition, and talks up vegetable oils rich in Fatty acids with multiple double bonds in the molecule — chemically more reactive than saturated fatty acids. Typically (but not exclusively) plant oils. Omega-3 and omega-6 fall into this category. → more. On the subject of grain he goes only half the way, replacing one grain with another, exactly as if that category were indispensable and utterly impossible to imagine a diet without.
And yet the line of thought is heading in the “rightTM” direction. His intention is - by his own account - the same as mine. He simply stops halfway, so as not to disturb his apparently grain-centred world view.
In this episode we also see - very clearly and explicitly - the patient’s wish to contribute something to her own treatment herself. But more on that in a further article about this episode, which I am preparing separately and will publish.
Featured Article
Nutrition Doc: Cognitive Dissonance and Ignorance of Ketogenic Nutrition
In an episode of the Ernährungsdocs podcast, Germany’s most prominent nutritional physician demonstrates shocking ignorance of and attitude towards ketogenic nutrition
Read more →The Demand
Over the course of the episode (first at approx. 20 minutes) ketogenic nutrition comes into play. After the inevitable mention of treating epilepsy in children, it moves straight back to the reasons Dr Riedl has for not engaging more closely with ketosis:
If you look beyond that, at what evidence we have for a positive effect, you have to say that a great deal of research is being done, but nothing is entirely clear. … Sometimes a certain effect shows up in cancer, sometimes in neurological disorders, but on balance you have to say that at present no recommendation can be given to structure a strongly fat-focused diet. … The current state of things, in short, is: we don’t know.
So far nothing about this shocked me; this is exactly the Dr Riedl I know. Ketosis is not for him - to put it sarcastically: it would restrict his beloved oats. And if you rule it out as categorically as he does, then the statement “we don’t know” is of course true as well. For certain values of “we”.
But then comes a core part of his statement, the part that triggered me:
A ketogenic diet is a severe restriction of quality of life, and it is extremely difficult to carry out, and in the long run it also leads to deficiency symptoms(3). That is why you also have to have damned good evidence in the studies in order to recommend it. …
That would be a dietary recommendation with potential side effects. And so I demand really watertight studies, as good as the ones we have for medicines.
In other articles here we have already dealt with the very careless handling of statistics and relative risk in nutritional science. Imagine Dr Riedl’s patients making the same demands of him regarding his dietary recommendations: I know of no study that demonstrates to pharmacological standards that fibre, “the rainbow”, “the Mediterranean diet” or even his oats are beneficial, advisable or necessary.
But that is not necessary either, because he does not demand this standard universally - not by a long way…
Two Yardsticks
…and he does so twice over - both times within the same episode, only a few minutes apart.
Secondary Plant Compounds, Completely Natural Proteins
The first double standard stands in direct contradiction to other statements in the same podcast:
In the context of treating MS he describes it as advantageous not only to restrict carbohydrates but also to avoid ATI - a brief reminder: these are ordinary constituents of grains and cereals.
…in us … they can cause local inflammatory reactions in the gut. And these ATI-activated inflammatory cells and messenger substances can promote further inflammatory processes in organs via the blood.
I congratulate him on this insight. Unusually, though, at this point he does not use one of his favourite terms: “secondary plant compounds”. ATI belong in that category.
The unambiguous indication that two different measures are being applied here comes from him. Directly before the description of the effects of ATI on the body quoted above, he says
[Dr Riedl:] That is an abbreviation for amylase trypsin inhibitors. These are completely natural proteins, which occur not only in wheat but also in other cereals. And for the cereals they have a purpose in germination, for example, or also against predators.
“Completely natural proteins”? Every bit as natural as ricin, phytohaemagglutinin (both covered in the article “Superfood or Antinutrient”; ricin is a lethal natural protein), or as prions (the agents behind mad cow disease, which one or two readers may still remember).
Ah yes, and predators? That includes humans, of course.
ATI are therefore a defence mechanism of plants. The difference between a feeding deterrent and a poison is the dose - with ricin that dose is very small, whereas ATI are tolerated by many people at higher doses - though apparently not by MS patients.
So for once we are dealing with a “secondary plant compound” for which Dr Riedl does not use this normally positively loaded category. The term is too neutral for me anyway, and for many of the substances in that category I normally prefer the term “antinutrients” - ATI are not the only problematic substances, as we have already learned in other articles here.
Pharmacological Standards
Are there studies on the effect of ATI in MS? Yes - and Dr Riedl cites them himself: animal models, and human studies with 16 participants which examined, over three months, the difference between wheat-reduced food and “very wheat-rich nutrition” (his words).
These studies he considers (explicitly) sufficient to advise a wheat- and ATI-reduced diet. Congratulations.
The double standard comes back into play for complete wheat avoidance in the form of the ketogenic diet at approx. 24:30: here too there are promising reports and research topics, but of course ketogenic nutrition cannot (in his eyes) be an option. As a reminder:
That would be a dietary recommendation with potential side effects. And so I demand really watertight studies, as good as the ones we have for medicines.
Side effects? He does not name them - only obscure “deficiency symptoms”, which to my sarcastic mind sounds like “wholegrain deficiency” - not a recognised, billable clinical picture, and no symptoms(3).
Furthermore, the demand for studies “as for medicines” is an exclusion criterion. I read it as a declaration that he is absolutely not interested. At approx. 14:00 it goes:
For nutritional medicine we have a poor evidence base. That is simply because there are few incentives, because there is no industry supporting such research. And because these studies are also very, very difficult to carry out.
You cannot blind them, for example. A food is a food, I can see that. A pill I can give as a placebo, but I cannot give a food as a placebo. Everyone can see what it is.
That is the nuclear option: without a double-blind, placebo-controlled study there is no drug approval. He demands one for ketogenic nutrition, knowing full well that even simple blinding is impossible, and thereby excludes it entirely from any consideration whatsoever.
You cannot even accuse him of lacking knowledge, let alone of ignorance - because he knows exactly what he is talking about:
That is why we suffer from an acute shortage of good, large studies with many thousands of people. The difference with this small study is that if I were testing medicines there, if I were to test medicines on 16 patients, then you have to say that is nowhere near enough. But if I test a form of nutrition and I then swap the groups over again and see every time that when more wheat was eaten they got worse, and I can even demonstrate it in the blood. …
…forms of nutrition other than the ketogenic one, however, may illustrate their benefit with 16 people, unblinded and with anecdotes - and are considered on that basis:
Then for me as a nutritional physician the point has come where I have to recommend it, because it does not harm the patient. The recommendation I am making is not a medicine with possible side effects, but rather a recommendation that makes the diet healthier if anything.
By his own account, an ATI-poor diet appears to be healthier for MS patients. I would point out that the carbohydrate share in ketogenic nutrition is so small that grain - and with it the ATI it contains - is eliminated virtually completely.
To demonstrate that, you do not even need a study.
But as a matter of principle: you cannot apply pharmacological standards to a form of nutrition in one place, state clearly in another that such standards will never exist for nutrition in general, and then recommend as treatment the approach from a small study with 16 participants.
(╯°□°）╯︵ ┻━┻A Questionable Deficiency
Dr Riedl knows ketogenic nutrition as a treatment option in the context of epilepsy. I wonder what makes the “malnutrition” he refers to acceptable in that case.
Speaking of deficiency: what exactly is Dr Riedl(3,4) missing in ketogenic nutrition, and why does he not remedy it by the same means applied to vegan nutrition? Everyone knows that a healthy vegan diet is only possible at all with supplementation of certain micronutrients. Once the deficiencies are known, they can be remedied in a targeted way - exactly as he does himself.
From my own experience I can say: I doubt the deficiency, but out of genuine interest I would like to learn more about it.
And the Patient?
Up to this point it has been about constituents and about studies. But a further point of criticism from this podcast episode concerns not the burden of proof but the patient herself: what is expected of her, and what she wants for herself. That is the subject of the next article.
More comments for the same podcast episode
Asking a Lot, Trusting a Little: The Nutrition Doc and the Informed Patient
If something is hard, that is a sign it is worth doing👍. Or that it is not worth even considering👎. It depends.
Read more →