Walnuts and Phytic Acid

[Cireeric]

Recently I became quite interested in nutrition. I first read Dave Aspreys HeadStrong which I found very exciting to read. I implemented some of it and it made some difference for me. Now I read his next book, where he talks about "AntiNutrients" and specifically phytic acid. Before the book I thought Walnuts are a no brainer in terms of positive benefits for brain-health and bought them regularly, feeling good about it. Now Dave says they contain phytic acid which will suck the minerals out of me. I searched on the internet and couldnt really find consensus on the topic. This is a struggle since they were a stable in my diet, which I felt good about and now they are seemingly bad for me.

How seriosly should I take this topic of "anti-nutrients", especially related to walnuts and is eating a hand of walnuts a day now a net positive or negative for me?

Would love to hear the thoughts of some of the nutritional guys here on the forum

 

Edited July 17 by Cireeric

[Michael569]

Its one of those topics in nutrition that unfortunately gets way more attention than it should, mainly because of people like Dave (but also others), who despite their immense following fails to grasp some of the most basic ideas in nutritional sciences such as the hierarchy of evidence, the failure of mechanisms to translate in human outcome data and in general the risk of following fad trends for the sake of social media attention...

Anyways...

Back to antinutrients.

The way to look at this is to ask yourself: "if indeed phytonutrients were such an issue, how would we know"? 

The obvious answer to that question would be that "people who consume the most of them would run into severe health problems".  Right? 

Like, for example if the concern with phytic acid is that it , say, blocks the absorption of iron, zinc  and calcium, would we expect to see that people who consume the most nuts and seeds have...what? the most osteoporosis? the most iron deficiency anaemia? The most immunosuppression due to severe zinc deficiency? General malnutrition issues? 

Yet when we take a step back from mechanisms (e.g. phytic acid blocks iron absorbtion) and look at the large population data (meaning what happens when we look at human studies in real living people, not in petri dish)  we don't see any of that.

In fact, people who tend to eat more of these foods that are rich in antinutrients (vegetables, fruits, seeds, nuts, legumes, greens) tend to have less osteoporosis and less osteopenia and, in general a better health, be it from the position of chronic disease (heart, cancer, diabetes etc) or be it from the position of nutrient status (deficiencies, malnutrition etc). 

This is a major critic of reductionist approach to nutrition in general that overfocussing on mechanisms and then inferring recommendations to public based on that is not just stupid but dangerous. 

Take an example of soy: 

Soy contains a bunch of phytochemicals like Genistein, Daidzenin or Formononetin. Someone like Dave Asprey or Mark Hyman would find a mechanistic study that sees that when you drop genistein on a testicle cell from a rat, something happens. And they would proclaim "aha! soy is bad because it gives you testicular cancer"

But at the same time, these guys don't care that when we look at human outcome data (meaning mostly epidemiology) what we see is that people who regularly consume soy have - less prostate cancer, less bowel cancer, less lung cancer, better cardiovascular health and just tons of other improvements. 

This is why we have the hierarchy of evidence, because mechanisms are just so meaningless most of the time. 

And while sometimes mechanisms are interesting because they may incentivise new area of research in areas where evidence quality is poor, in topics where we already have robust human data, (such as benefits of nuts and seeds)  mechanisms just aren't relevant anymore and all they do is confuse the hell out of everybody. 

So what Dave is doing in this case is propagating quackery, muddying water for people who don't need to be concerned about this and generally making money on creating confusion...which isn't very nice

TLDNR
Walnuts are fine, don't worry about phytic acid, it is looking at functional nutrition from the wrong end. 

Edited July 17 by Michael569

[Cireeric]

Wow, thx for your detailed answer and reasoning! Will also think about the hierarchy of evidence concept. Finally I can enjoy my walnuts again  

I still pretty much enjoyed his book: HeadStrong and found some stuff in it quite useful and had the feeling that it had an positive impact on my wellbeing and cognition, mainly adding more good fats and doing IF or some other fasting irregularly + giing some more praise to some of my already implemented practices like cold-showers and meditation. Do you read it and what is your opinion on this book?

[Yimpa]

9 minutes ago, Cireeric said:

Wow, thx for your detailed answer and reasoning!

Much more sophisticated than ChatGPT 

[MarkKol]

Anti-nutrients and phytic acid are of no concern in nutrition, you'll still absorb the majority of the nutrients in your food.

What if I told you that phytic acid actually has anti-cancer properties? Lame carnivore meatheads