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Acorns as food or supplement


mccoy

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Hi all,

I did a search on the forums engine and on google, but it yielded no significant results, hence I consider this a novel topic.

 

Acorns, or oak nuts as a food or a source of phytochemicals. In my garden I have a huge, probably bi-centenarian or older oak (Quercus robur), which of course yields an immense quantity of acorns.

 

I saw the various videos on youtube showing how the abundant tannins in acorns can be leached by cold water (extremely lenghty process) or hot water (boiling acorns successively a few times).

 

As a food, though, they don't seem particularly rich, so the tradeoff between time required to prepare it and benefits wouldn't seem attractive, except from the fact that it constitutes an unpolluted, wild source of nutrients.

 

  • Fats=24% (oleic acid mainly)
  • Carbs = 41%
  • Protein= 6%
  • Vitamins and mineral contens: not particularly attractive

So I wonder whether it is worth to eat acorns raw, in very small amounts (1 or 2 per day) to get advantage of its phytochemicals, mainly specific derivatives of the gallic acid. Or if it is just worth to crack them and boil them 5 times and eat'em as a main course. So far I just eat single acorns raw, they taste extremely astringent but by small nibbles I can eat one or two acorns. 

 

My question: has anyone already reasoned about this or is anyone already eating acorns? Details?

 

References:

 

https://en.wikipedia.org/wiki/Acorn  on macronutrients

 

Phenolic Compounds and Fatty Acids from Acorns (Quercus spp.), the Main Dietary Constituent of Free-Ranged Iberian Pigs

 

On lipid profile and micronutrients

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This is a more recent publication

 

A New Age for Quercus spp. Fruits: Review on Nutritional and Phytochemical Composition and Related Biological Activities of Acorns

 

It reports a pretty rich content of various phytochemicals, although not every specific one verified in all specieses

 

  • Diversified phenolic compounds, with specific molecules like salicilic acid from quercus salicina
  • beta-sitosterols
  • aliphatic alcohols

 

Also, toxicity of raw acorns due to the high content in hydrolizable tannins is discussed (emphasys mine).

 

 

 

The sensitivity to acorn toxicity appears to vary between species and individuals. Herbivores may be more susceptible than other mammalian species. However, acorn exposure has been well described as a cause of pathology in some mammalian species, causing ulceration of the mouth, esophagus, and rumen, with anorexia and progression to hemorrhagic diarrhea. In ruminants, for example, gastroenteritis and nephrotoxicity caused by acorns is well-reported. On the other hand, pigs appear to develop protection when exposed to oak leaves or acorns in the diet, by increasing the production of tannin-binding salivary proteins (Smith and others 2015). Despite the importance of the topic, there is no published study that has reported acorn toxicity in humans.

 

 

 

Despite the phylogenetic variability, phenolic acids (particularly gallic and ellagic acids and their derivative compounds), flavonoids (particularly flavan-3-ols), and tannins are somehow ubiquitous in all Quercus species (Table 1), as verified in Q. acutaQ. acutissimaQ. albaQ. cerrisQ. fagineaQ. glaucaQ. ilexQ. macrocarpaQ. marilandicaQ. muhlenbergiiQ. myrsinaefoliaQ. palustrisQ. petraeaQ. phylliraeoidesQ. pyrenaicaQ. roburQ. rubraQ. rotundifoliaQ. salicinaQ. suber, and Q. virginiana (Saffarzadeh and others 1999; Cadahía and others 2001; Cantos and others 2003; Ferreira-Dias and others 2003; Andrenšek and others 2004; Rakić and others 2006; Marquart and others 2007; Vanhessche and others 2007; Brossa 2009; Rocha-Guzmán and others 2009; Tejerina and others 2011; Kim and others 2012; Popović and others 2013).
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Always from teh article above cited.

Its seems that cooking preserves the phytochemicals (sometimes increasing their activity) and at the same time decreases the tannins concentration

 

 

 

Another obvious conclusion from Table 1 is the high number of tannin compounds. This is an important issue, because the high contents in tannins provide acrid aroma and astringent taste. These compounds are produced as part of the defense mechanism against parasites and they have been extensively reported as providing benefits to human health, specifically for their anticarcinogenic and antimutagenic properties; however, their antinutritional activity must always be taken into consideration, despite that dose which causes this negative effect is far beyond the level that one person would ingest during normal food intake (Chung and others 1998). In addition, the high contents of tannins might be decreased by submitting acorns to a cooking procedure, therefore also reducing their astringent properties. Furthermore, Rakić and others (2006) studied the influence of thermal treatment on physical and nutritive characteristics of acorn samples, as in their contents of total polyphenols, gallic acid, nitrogen compounds, and macro- and microelements, concluding that all the components were maintained upon treatment. In fact, in some cases, the functional properties of acorns were improved.
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At the end of the article, another added benefit which comes up is the presence of resistant fiber.

 

All in all, I'm pretty much convinced that the investment in time would be repaid. Most probably, it's better off to boil the acorn  to get rid of the excess of tannins and keep the other phytochemicals.

 

It seems that these are conserved and enhanced by thermal treatment. Raw acorns though ensure us that no beneficial compound is leached out.

 

Now the practical considerations so far would be:

 

  • How many raw acorns is possible to eat to stay into the hormesis region and not get across the border into the toxicity domain
  • How to optimize thermal treatments like boiling (what's the minimum or optimal boiling cycles) or roasting (not often cited)
  • Attractive recipes for boiled acorns, i.e.: how to include cooked acorns in the daily, or weekly diet.
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I've never had acorns but a friend said he used to eat them all the time when he was growing up. He said they were pretty disgusting.  Long boiling times supposedly improve the flavor dramatically.  I want to try them, maybe I'll go to the woods and get some today...

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I've had my first taste of cooked acorn, I'd say it was pretty satisfactory, the texture especially, and the taste which  at first is not too bland nor too strong (it becomes strongish though after chewing a couple of'em). I just boiled the shelled acorns 5 times. The acorns are pretty good as they are but now I'll have to devise some specific recipes. After eating a mouthful I felt the remaining tannins which have not been leached. I just ate 5 or 6 acorns the first time, out of precaution. The rest is now in a jar in the fridge, ready to be consumed during the week.  

I don't know why but my thought goes to the Iberic pig, who is freely pastured in the oak groves of southern Spain...

 

 

Acorns, shelled acorns and shells, today's work:

post-7347-0-63502000-1507750341_thumb.jpg

 

Plate of acorns after boiling and rinsing 5 times, ready to eat:

post-7347-0-36007100-1507750607_thumb.jpg

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I went out to the woods and gathered a handful of them.  I shelled them and just boiled them in a cup of water in the microwave for 4 minutes.  It was definitely one of the most bitter things I've ever eaten.  I have read you are supposed to boil them for 2 hours.  I found 2 other species of nut out there at the same time I was looking for acorns, I'm not sure what they are and haven't tried them yet, one is probably hickory.  I've got walnuts out there too but for some reason never gather them (kind of a pain to process, I need a big nutcracker).

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Gordo, I boiled those acorns 5 times for a few minutes, throwing away the water every time. The way you cooked them, I bet they are unedible, the acrid aroma and acid taste belies the huge content in tannins.

 

I compared the taste of leached acorns to that of the fresh, recently harvested walnuts and it was not much different. So tannins were surely decreased that way, to an hopefully hormetic amount. . So far though I only ate few of them at a time. I'll use them as an hormetic food to complement walnuts, and will develop some way to increase their quantity across time.

 

RE. walnuts: I would be patient and process just a few of them, wild walnuts must be exceptionally rich in beneficial phytochemicals. You just need 2 or 3 a day, I reckon, to boost all the immune functions, anticarcinogenic, antinflammatory gene expressions they are known to boost.

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  • 2 weeks later...

I prepared another batch of acorns. Boiled them briefly 6 times. This time the taste seems better, they are almost delicious and some of'em even taste chocolatey or nutsy. Apparently, acorns from different specieses have a widely different taste and astringency, I may venture to say that's true for different trees within the same species and different harvesting times.

 

What I found though is that the body at a certain point refuses them, that is nausea intervenes. I'm crossing the border from the hormesis region to the toxicity region. So no big acorn meals for me presently, just a few of them per day attentively listening to the body intelligence (a seemingly pretty unscientific concept which referes though to self defense systemic mechanisms).

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