The walnuts thread (they're the weird nut)

[Alex K Chen]

One source says they're the healthiest nut

https://www.lifeextension.com/magazine/2022/4/walnuts-extend-your-life

But I just ate a bag of walnuts today and noticed the HUGE difference between unexpired nuts and expired nuts. The expired nuts do not taste terrible - you have to compare them side by side to see the difference and it is huge

They are heavy in PUFAs, which makes them unusually prone to oxidation (of all the fatty acids, PUFAs have the highest benefits *and* highest harms)

https://photos.app.goo.gl/G8KUvDyTLfWJPbpv6

 

Quote

 

WHERE TO STORE WALNUTS

When you bring walnuts (shelled or in-shell) home from the store, the best place to store them is in your refrigerator or freezer, depending on when you’re going to use them. If you’re going to use the walnuts right away, place them in your refrigerator. If you’ll be storing them for a month or longer, store them in your freezer.

HOW TO STORE WALNUTS

If you buy walnuts in sealed packaging, you can store the walnuts in their original packaging in the refrigerator or freezer. Once you open the bag, transfer the walnuts to an airtight container to maintain freshness and then place them back in the refrigerator or freezer. If you buy bulk walnuts, either in-shell or shelled, place the walnuts in an airtight container for long-term cold storage.

 

Quote

Several nuts are among the dietary plants with the highest content of total antioxidants. Of the tree nuts, walnuts, pecans and chestnuts have the highest contents of antioxidants. Walnuts contain more than 20 mmol antioxidants per 100 g, mostly in the walnut pellicles. Peanuts (a legume) also contribute significantly to dietary intake of antioxidants. These data are in accordance with our present extended analysis of an earlier report on nut intake and death attributed to various diseases in the Iowa Women's Health Study. We observed that the hazard ratio for total death rates showed a U-shaped association with nut/peanut butter consumption. Hazard ratio was 0.89 (CI = 0.81-0.97) and 0.81 (CI = 0.75-0.88) for nut/peanut butter intake once per week and 1-4 times per week, respectively

The quality between walnuts seems to vary A LOT, it's crazy...

Edited September 5, 2023 by InquilineKea

[mccoy]

Very interesting topic. As a matter of fact, recently I've been mulling over my improved metabolic condition, whose cause I cannot really pinpoint.

Better lipids, better blood glucose and invariably optimal blood pressure levels, even if my sleep is erratic.

I would not have ventured to say it myself, but over the last two years, I've been eating consistently copious amount of walnuts, as a part of a carbs lowering scheme.

Every day, instead of bread, I'll eat walnuts, often together with fragments of parmesan cheese, an ideal combination.

The daily amount is often in the region of 2-3 ounces. 

But there may be other reasons, it may be lower bodyweight, more moderate physical activity, or else.

After about 6-8 months from the crop (if unshelled) walnuts start becoming rancid (oxidated), slightly at first, then more markedly until at a certain point I won't buy them any longer, waiting for the following:

1. Next crop in october-november (northern hemisphere)
2. Next crop in april-may (southern hemisphere). This is harder to find, but I'm on the lookout.

Of course, reading the article, there are so many objections rising, mainly about the observational nature and the precise number of 1.3 years extra life based on very imprecise and uncertain data.

 

[Alex K Chen]

Dark vs light walnuts:https://www.jstage.jst.go.jp/article/jos/70/5/70_ess20266/_article

[mccoy]

5 hours ago, InquilineKea said:

Dark vs light walnuts:https://www.jstage.jst.go.jp/article/jos/70/5/70_ess20266/_article

The above article relates in a way to the other thread where you were asking about old fruit and vegetables. Time almost invariably tends to bring about a degradation in the beneficial chemical compounds of plant-based food.

In the case of walnuts, fats oxidation and the increase in peroxide after months from picking is clearly felt by the sense of taste. It is felt even in other nuts, but almonds for example exhibit a slower chemical degradation. 

[IgorF]

Hm, for those who cares about pufa oxidation perhaps a general advice to keep the nuts supply in cold makes sense, the ratio according to ununavailable study from chatgpt's answer is 3 times approx:

The study published in the journal Food Chemistry in 2012 found that the oxidation rate of walnuts stored at room temperature for four days was approximately 0.089 mg of malondialdehyde per gram of walnut. The oxidation rate of walnuts stored at lower temperatures was approximately 0.028 mg of malondialdehyde per gram of walnut.

 

Another study

https://www.sciencedirect.com/science/article/abs/pii/S0956713508002582

Quote

Several studies have focused on the influence of storage conditions on pistachio, almond, peanut, and walnut at high temperatures such as 30, 36, and 40 °C. Results showed nuts to be dramatically more rancid as compared to those stored at 8, 10, 20 or 25 °C for the same period of time (Braddock et al., 1995, Crowe and White, 2003, Garcia-Pascual et al., 2003, Maskan and Karatas, 1999, Nepote et al., 2006).

but as for me the more interesting in this study - material permeability - there are fishy chances to know it at home and also an open question - are unshelled walnuts more protected during longterm storing against oxidation comparing to the best artificial packaging (especially in combo with low oxigen atmosphere).

 

So far I am not much concerned, I eat 26g of walnuts daily from 1kg packs, cheapest available and sometimes with insect concurents traces, a practice probably comparable to ancestors way for them, but I am doing it because of lazyness, not because of any ideological influence. When in a very rare cases I face unpleasant taste of a particular nut I am just throwing it away, but I am also not buying packs that looks too bad visually.

 

I also feel intuitively that oxidation in solid fractions is not a concern at all for anybody who consums comparable amounts of liquid fractions, just because I know from my past how different is chemistry in solid and liquid phases. But I could be wrong offcourse, this requires a longer investigation.

 

Br,

Igor

 

Edited April 21, 2023 by IgorF

[IgorF]

Also water activity is important for walnuts, seems J shaped

https://www.researchgate.net/publication/332527569_Water_Activity_Influence_on_Walnuts_Juglans_Regia_L_Microbiological_and_Oxidative_Stability

 

Quote

Thus, at water activities of 0.08 - 0.28 and 0.48 - 1.00 the oxida-

tion processes know a maximum intensity, water molecules form

multiple layers around the product, or are generally lacking, thus

opening oxygen access to the lipid substrate.

In the range of water activities of 0.28 - 0.48 oxidation processes

are characterized as slow, only one layer of water molecules is

formed around the product, so it cannot exhibit its solvent prop-

erties for conducting chemical reactions, as well it acts as a barrier

to oxygen access.

In a "Lipid oxidation" book by "Woodhead Publishing in Food Science, Technology and Nutrition" a value 0.3 as the most stable for walnuts is provided.

Here is also interesting https://journals.ashs.org/downloadpdf/journals/hortsci/56/10/article-p1244.pdf many nuanses like secondary+ oxydations mentioned.

 

In sum - for those who wants least issues - bio, vacuum packed, store in dry cool places for less than 3 months, very generic advice. The only problem - how to control the production and storage before the shelf, no idea if there are already available "enhancing" technologies to tackle rancid look and feel.

 

Br,

Igor

 

 

Edited April 21, 2023 by IgorF

[IgorF]

Some links about nuts and oxidation

in a book "Improving the safety and quality of nuts" - the part "Oxidative rancidity in nuts" F. Shahidi and J. A. John , Memorial University of
Newfoundland, Canada

is an article itself, DOI: 10.1533/9780857097484.2.19

it mentions "Oxidative rancidity in foods and food quality"

J. Velasco, C. Dobarganes and G. Márquez-Ruiz, Consejo Superior de
Investigaciones Científi cas (CSIC), Spain

doi.org/10.1533/9781845699260.1.3

as an example of potential health issues with oxidized fats e.g.

Dietary lipid peroxidation products and DNA damage in colon carcinogenesis
Ayako Kanazawaa, Tomohiro Sawab, Takaaki Akaikeb, Hiroshi Maedab

doi.org/10.1002/1438-9312(200207)104:7<439::AID-EJLT439>3.0.CO;2-K

 

All stuff is available via scihub, generally nice to know. I came to conclusion years ago that it is better to go without oils at all, especially a combo of oil and heat. But occasionally I am doing "controversial" things like eating a wok vegetables in a fastfood if I have no other option or buying roasted nuts (sometimes from dispenser). I hope this is a minuscule thing in comparison to amounts of unhealthy things I did in the past.

 

Br,

Igor

[mccoy]

16 hours ago, IgorF said:

I came to conclusion years ago that it is better to go without oils at all, especially a combo of oil and heat. But occasionally I am doing "controversial" things like eating a wok vegetables in a fastfood if I have no other option or buying roasted nuts (sometimes from dispenser). I hope this is a minuscule thing in comparison to amounts of unhealthy things I did in the past.

Igor, that seems an excessive caution to me.

After all, we have been endowed with sensors (taste buds and smell receptors) that are able to discern, admittedly after adequate training, the presence of inadmissible oxidation or rancidity of fats.

The sensors are also able to detect qualitatively variations in the level of oxidation. My brain elaborates immediately the signals coming from the taste (mainly) and smell when I'm eating a nut, analyzes the signals basing on prior knowledge and produces a function of the digestibility of the nut, which prompts my decision to swallow or to reject the nut.

In a few words, I always notice if the nut, especially the walnut, is freshly or well conserved or if it is oldish or kept in unfavourable environments. Also, everyone has noticed how some walnuts in the same stock are inedible, for some reasons I do not know. If the taste is working, then we have a reliable neurological system to avoid to ingest deleterious peroxide and oxidation products.

Bottom line: there are healthy fats like EVOO and all the group of nuts, why to abstain from them if we have the ability to discard the flawed products?

Edited April 23, 2023 by mccoy

[mccoy]

Interesting recent article on the above natural detection system.

 

Flavor Chemistry of Virgin Olive Oil: An Overview

by 

Alessandro Genovese

 ^1,*,

Nicola Caporaso

 ^1,2 and

Raffaele Sacchi

 ¹

 

ppl. Sci. 2021, 11(4), 1639; https://doi.org/10.3390/app11041639

Received: 30 December 2020 / Revised: 6 February 2021 / Accepted: 8 February 2021 / Published: 11 February 2021

(This article belongs to the Special Issue Advances in Food Flavor Analysis)

[IgorF]

Mccoy, I am not meaning I eat those nuts that looks really bad and tastes the same, I just don't care to the levels "close to obsession" on this topic. The reason - I think about these things quantitatively (chemical perspective) as well as intuitively counting the risks probabilities. I also tried to find any research that these not "ideally supplied" nuts could contain levels of chemicals that are known to be risky (not about contamination by "external" things) and failed in a brief search. Maybe I will come back to it but the topic is really a low prio for me and it is definitely time consuming. An example when I quickly found a thing that toggled me into a diet change - smoked paprika. I used it to make a morning salad more tasty without oils and quickly came to 40-60 grams of it daily because it was delicious for me. When I became curious if it is ok I quickly discovered that at such doses it is a concern for a long term so I switched to unsmoked version (it was a bit sad for a few weeks to adapt, the smoked one is much tastier). With oils - my TC was a bit higher even with EVOO so I decided to get rid of it completely, despite I like it.

A significant part of my personal diet strategy - to minimize the overhead of managing the things - I can play with micromanagement of components for weeks, even months but in a long term I prefer to stick with something simple and "no liquid oils policy" makes me sure I don't have a thing in the diet that already is covered with tens of thousands pages of written text and no answer if it is ok or not to have it as a substantial part of the diet (e.g. 25-40g daily, otherwise I will not taste it at all in a 1kg salad). For those who do have 5-7g of EVOO per salad 1-2 times a day and no TC increase I assume no problem to go with cold liquid oils, their higher oxidation rates will not be riskier enough I think.

I also do have good status of GSH/GSSG, good known as antioxidants vits statuses, etc but I don't believe in too simplistic ox-antiox theories, no intuitive perception if all these things are really protective as well as about oxidated lipids risks from normal (non-engineered) foods like nuts and so on, all together can't be assembled to something human brain (at least mine) can assemble to some good model, so I am almost sure my understanding of the things is wrong, but I don't care about this also))

 

Br,

Igor

ps. It would be really interesting to see some real world studies for nuts, not a constructed studies with separate known to be bad substances in artificially created models but I don't think somebody will ever get funding for such a research. I doubt also that all these already published papers on how good nuts are were done with "health-marketed" nuts (organic, vacuum sealed, fully controlled supply chain, 10x price comparing to usually available on the shelf), perhaps the nuts were just average quality available to the researchers.

Edited April 23, 2023 by IgorF

[mccoy]

13 hours ago, IgorF said:

For those who do have 5-7g of EVOO per salad 1-2 times a day and no TC increase I assume no problem to go with cold liquid oils, their higher oxidation rates will not be riskier enough I think.

I think I've been eating about 30-40 g of EVOO per day latest months and TC, as well as LDL-C values have decreased. Of course the decrease may be temporary so the analyses must be repeated. You and Ron are two guys who observed a deleterious effect of EVOO on TC, apparently there is a high difference of response across individuals.

Personally, I wouldn't be able to eat so many vegetables without an abundance of EVOO dressing.

[IgorF]

6 hours ago, mccoy said:

You and Ron are two guys who observed a deleterious effect of EVOO on TC

Well, there is an idea that it could depend on the source of the oil, I never experimented with a diverse set of them and they also weren't on the best part of the group (according to the comparison lists I saw in different places), so it is easy could be the case that I could react on other brand differently.

But I decided just to eat some olives instead of oil, I like them also)

Br,

Igor

 

[IgorF]

Some overview on walnuts chems:

Interaction of Phytochemicals from Walnut on Health: An Updated Comprehensive Review of Reported Bioactivities and Medicinal Properties of Walnut
Zheng Feei Ma, Jamil Ahmad, Imran Khan, Chee Woon Wang, Peiyuan Jiang & Yutong Zhang
doi.org/10.1080/22311866.2019.1709900

(available via scihub)

section on CVD mentions some benefits on lipid profile (e.g. a bit lower apoB - 7mg/dl https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5691297/) but a nice thing that seems independent from lipids - flow-mediated dilation. It could be the case (IMHO) that a significant part of long term benefit of walnuts comes from more elastic and dynamically adjustable vessels, especially for those who have higher pressure - ability to spread the hydraulic hit that could bring unwanted lipid carriers too close to the anchoring places on the vessel wall could make a difference when figures are big.

 

Some info on packaging and oxidation:

RELATION BETWEEN TYPES OF PACKAGING AND LIPID OXIDATION IN WALNUT (CARYA CATHAYENSIS SARG.)
Fei Tao, Haiyan Gao, Hangjun Chen, Wenxuan Chen, Lili Song, Linmei Ge
doi.org/10.17660/ActaHortic.2008.804.77

(available via scihub)

they conclude that ldpe+aluminium and vacuum packaging could preserve the good guality (good to be tasted) for up to six months.

 

Br,

Igor

Edited April 24, 2023 by IgorF

[mccoy]

3 hours ago, IgorF said:

section on CVD mentions some benefits on lipid profile (e.g. a bit lower apoB - 7mg/dl https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5691297/) but a nice thing that seems independent from lipids - flow-mediated dilation. It could be the case (IMHO) that a significant part of long term benefit of walnuts comes from more elastic and dynamically adjustable vessels, especially for those who have higher pressure - ability to spread the hydraulic hit that could bring unwanted lipid carriers too close to the anchoring places on the vessel wall could make a difference when figures are big.

Maybe the absolute abundance of walnuts I've been ingesting for the latest 2 years made a difference on my lipid profiles and my blood pressure, both at optimal quantities presently.

[drewab]

To me, the most mind boggling part of this thread is that you can get organic walnuts at Costco - I wish!