6 ms·

Comparison of Postsurgical Scars Between Vegan and Omnivore Patients

115 points by shadykiller 6y ago

hirundo 6y ago
> This study suggests that a vegan diet may negatively influence the outcome of surgical scars. This is unusually damning to veganism-as-it-is-practiced if not to veganism itself. It would be interesting to see these results across a wide range of diets.
- rektide 6y ago
  Agreed that there are probably ways to remediate some of these effects. I definitely favor smaller less impactful scarring, but also, so what? Calling ths "unusually damning" seems like a significant overinflation of concern. For all we know, it may have far more significant pro-recovery characteristics associated with it. "Oh you built too much scar tissue? Your vegan diet also stitched your blood vessels back together really well."
  - arkitaip 6y ago
    dang really needs to get YC to develop an AI that can automatically add /s to ironic comment.
    - stelonix 6y ago
      I'd rather HN not allow such comments and we try to make debate here better than on the rest of the internet.
    - centimeter 6y ago
      Or people could work on their ability to identify normal human modes of speech.
      - ben_w 6y ago
        Given we’ve had the internet for over a generation with this issue being known that whole time, I don’t think that’s actually something we can do. Not in general, not from plain text.
        centimeter 6y ago
        I think only morons, autistics, etc have a habitually hard time identifying sarcasm. These are not the people we should optimize the web experience for.
        ben_w 6y ago
        Only when spoken, not when written: https://theconversation.com/why-is-sarcasm-so-difficult-to-detect-in-texts-and-emails-91892 https://theconversation.com/why-is-sarcasm-so-difficult-to-d...
        centimeter 6y ago
        No, I have zero problem detecting sarcasm or irony in text. If you think about it for 5 seconds it's usually pretty clear.
        ben_w 6y ago
        If you have zero problem, you are unusual. Please note who wrote this paper, considering what they are famous for, as well as the results: http://web-docs.stern.nyu.edu/pa/kruger_email_ego.pdf http://web-docs.stern.nyu.edu/pa/kruger_email_ego.pdf
      - yjftsjthsd-h 6y ago
        Text inherently makes it difficult if not impossible to distinguish sarcasm that would be apparent with verbal/visual context clues.
- centimeter 6y ago
  One of several motte-and-bailey tactics used by vegans is going from “Veganism is healthy” To “Veganism can be healthy if you exercise an impressive amount of restraint, discipline, and judgement in your vegan diet”
  - petertodd 6y ago
    _If_ you can get enough exercise, you can be healthy on pretty much any omnivore diet because it's so hard to not get enough nutrition, and extra calories don't matter if you burn them off. I personally lost lots of weight when I was cycling regularly to work and school (10km and 50km round trip respectively), as well as caving and climbing on weekends. Almost everything I ate was fast food, because I had hardly any spare time. But I was definitely healthy and felt great so long as I took enough days off (I was getting enough exercise that I simply couldn't do it every day). Meanwhile, I know lots of people who have given up on vegan diets because they felt like their health was declining, even with regular exercise. I'm sure with enough care and nutritional science they could have gotten it to work. But it's so much easier to just add some animal products to your diet.
    - jxramos 6y ago
      I remember hearing the question asked someplace about whether any professional athletes are vegans, especially for the intense sports that require a lot of muscle rebuilding and maybe even contact sport healing and what not. That might illuminate things a bit.
      - asoneth 6y ago
        There is an advocacy* movie called The Game Changers which highlights several vegan athletes and makes the case that their plant-based diet contributes to their success. https://gamechangersmovie.com/ https://gamechangersmovie.com/ * I would not consider it a documentary as it has a clear agenda, but I found it interesting nonetheless.
      - centimeter 6y ago
        https://www.lonesomelands.com/new-blog/2019/9/16/t2amoscp1u1ynq1ms3sk9shr5ewlvj https://www.lonesomelands.com/new-blog/2019/9/16/t2amoscp1u1...
- badRNG 6y ago
  > This is unusually damning to veganism-as-it-is-practiced if not to veganism itself. I don't think a sample size of 21 is especially damning. Nor do I think that the study's authors would come to that conclusion either.
  - tpoacher 6y ago
    Depends. Emotive language aside (i.e. "damning") the low sample size is actually "more evidence" in the presence of a convincingly low p value. It means that this particular sample of 21 people would have to be extremely atypical under the null hypothesis of no difference. Therefore, given its low sample size (and thus wide standard error), it is 'some' evidence that the effect size is also probably quite large.
    - majormajor 6y ago
      That doesn't sound right. The reason sample size is important is because the larger the group, the less likely the group is to be atypical. I don't think you can turn that around and then say "this group is small, which itself is evidence, because otherwise it would have to be extremely atypical to show a difference." That's completely circular. The p-value is still the important thing because the p-value is itself affected by the sample size.
      - stevenhuang 6y ago
        No, effect size very much informs all of that. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3444174/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3444174/
      - tpoacher 6y ago
        > the larger the group, the less likely the group is to be atypical. Not true (unless I misunderstood what you were trying too say). The probability that a sample will be atypical under the null is exactly the significance level, and does not depend on its size. What does change with size is that the distribution around the statistic gets more concentrated, meaning your threshold moves to the left, towards lower effect sizes. Which also means that for smaller sample sizes, it is harder to reach significance, unless you're dealing with a fairly large effect size.
- asoneth 6y ago
  I'm not sure any of the vegans I know would give up veganism in order to minimize their scars any more than the meat-eaters I know would give up meat based on studies that show it can be mildly unhealthy.
  - moistbar 6y ago
    Maybe I'm reading into it too much, but the outcome of this study seems to suggest there may be other healing-related issues attached to veganism.
    - asoneth 6y ago
      I wouldn't be surprised, though I would be similarly skeptical that other healing-related issues would sway people one way or the other either since (at least the vegans I know) don't adopt the lifestyle for health reasons. Very large effects are unlikely given the number of long-term vegans who seem to maintain sufficient health. Whereas small effects might be considered a worthwhile sacrifice.
      - spicymaki 6y ago
        Agreed as a vegetarian, this study being called damning is a joke. Veganism has a pretty good track record with respect to health outcomes. Committed vegans that I know would still do it if it lowered their lifespan, because they are doing it for a higher cause (environmental, moral, spiritual, etc.)
  - imwillofficial 6y ago
    I reject your premise that eating meat makes you “mildly unhealthy”
    - asoneth 6y ago
      Exactly. [To clarify: I am not qualified to judge the general healthiness of any particular diet -- any sufficiently popular diet seems to have conflicting studies showing it is "healthy" and others showing it is "unhealthy". The point I intended to make above was that most people either outright reject or remain unswayed by these kinds of studies.]
- colanderman 6y ago
  "Veganism" denotes an ethical stance, despite the plant-based health foods movement co-opting the label, or some activists (ab)using health claims to promote a vegan diet. A study about scar tissue is in no way "damning" of it.
hprotagonist 6y ago
is effect size mentioned in the full text?
Gys 6y ago
> Conclusion: This study suggests that a vegan diet may negatively influence the outcome of surgical scars. > Twenty-one omnivore and 21 vegan patients who underwent surgical excision of a nonmelanoma skin cancer Interesting, but its a small group and stats are on the low end?
- redis_mlc 6y ago
  n=21 is not necessarily a small population from a statistical standpoint. Anyway, would be interesting to get comments from doctors who trest vegans. I'm not surprised at the result (we are what we eat), so perhaps vegans really should be on vitamins.
1996 6y ago
Related: the surgical scars of fasting mouse heal better (various publications report the same results) The same seems to apply in human, with various individual anecdotal report: https://www.quora.com/Did-long-term-water-fasting-improve-any-scars?share=1 https://www.quora.com/Did-long-term-water-fasting-improve-an...
- walshemj 6y ago
  I was told that loading up on carbs helped with recovery and I have a load of stuff downstairs in case i get called in.
  - 1996 6y ago
    I notice the downvotes to my post, but what you was told is demonstrably wrong. As for how/why it works: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7069085/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7069085/ "Fasting before or after wound injury accelerates wound healing through the activation of pro-angiogenic SMOC1 and SCG2" There are various other publications on autophagy (removing old stem cells and making new ones) For those who are going to say "in mice", the effects of true (water only) fasting has been replicated in humans, in well done trials, in even harsher conditions than surgery: chemotherapy. Fasting improves various things such as the severity of symptoms during chemo and the efficiency of the treatment: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5921787/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5921787/ "Short term fasting during chemotherapy is well tolerated and appears to improve quality of life and fatigue during chemotherapy" It may be counter intuitive, but there's a large body of evidence that fasting promotes healing (check the various reference of this 2018 trial: "Fasting cycles retard growth of tumors and sensitize a range of cancer cell types to chemotherapy" https://pubmed.ncbi.nlm.nih.gov/22323820/ https://pubmed.ncbi.nlm.nih.gov/22323820/ etc
    - walshemj 6y ago
      That's not what the senior colorectal doctor at the royal free told me last year.
RcouF1uZ4gsC 6y ago
> Wound diastasis was more frequent in vegans (p = .008). To me this is the bad part. Wound diastasis means that your incision opens up again. That is IMO a bigger complication than a scar since it likely requires medical intervention and puts you at risk for infection.
antattack 6y ago
What's the point of having a better looking scar if you're more likely to get colon cancer? Also, given that study itself measured Iron and B12, supplementing Iron and B12 may help scar healing w/o the (red) meat eating downside.
- decebalus1 6y ago
  > What's the point of having a better looking scar if you're more likely to get colon cancer? I don't think it's worth going into the extremes with this. Omnivore doesn't mean a buttload of red meat.
- xvedejas 6y ago
  I'm curious here: I am under the impression, possibly due to outdated info, that the issue with red meat was specifically that cooking it at high temperatures creates carcinogens (this being why bacon is especially bad). Would it be possible to avoid carcinogens by slow cooking all red meat at lower temperatures?
- centimeter 6y ago
  Attributing colon cancer to meat is, it turns out, complete bullshit, just like most other nonsense anti-meat fear-mongering (uric acid, cholesterol, etc.).
  - jjtheblunt 6y ago
    I'm not familiar with the data either way, so am reading to learn; why do you say it's bullshit?
    - zepto 6y ago
      In context, I think it’s as fair to call it bullshit as to claim it as a truth. It was being claimed as a truth to rebut the implications a peer reviewed study, but without any data to support it.
    - centimeter 6y ago
      Every time I get concerned about one of these things and look it up, it turns out to have been false.
SeanFerree 6y ago
Very interesting. Thanks for sharing!
gamblor956 6y ago
Not a surprise. Collagen is important for healing skin wounds, and vegans get none from their diet. (Collagen is just a protein, so it can be generated by the body, but it's easier for the body to simply take collagen from dietary sources.)
- subungual 6y ago
  Do you have a source for this? As far as I know, there is no way for the body to uptake and employ collagen directly. It needs to be broken down into smaller peptides, absorbed, and rebuilt, just like any other protein.
  - gamblor956 6y ago
    Yes, I should have been more specific that collagen gets broken down into collagen peptides. I didn't think I needed to be that specific since it's like the difference between Calorie and calorie (i.e., the distinction is not relevant to the discussion on hand). We know that the body can use collagen without digesting it first because collagen masks are used to heal burn victims. See, for example: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6565829/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6565829/, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3081477/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3081477/ Collagen is a protein. It is made up of several "peptides" referred to as "collagen peptides." When it is first digested, collagen is broken down into collagen peptides in the gut. The type of collagen determines the ratios of these peptides. Most, but not all of these collagen peptides get further broken down into amino acids in the gut. (Contrast to whey, which gets entirely broken down into amino acids.) However, a significant portion of collagen peptides can survive digestion, or leave the gut before they are digested. (Up to 10%, depending on the original source of the collagen.) The body can utilize these peptides directly to repair skin, because skin is mostly made of...collagen. The presence of collagen peptides simply lets the body go straight to creating collagen without having to wait while peptides are created from amino acids. (The body will still do that, but it's like starting a construction project with supplies on hand vs having to wait for supplies to arrive or be built.)
    - 6y ago
odyssey7 6y ago
Animal protein seems to be good for wellbeing, and there's a lot of overlap between veganism, wellness awareness, and alternative food choices. Given that and the already-existing ability to create collagen/gelatin in a lab that's suitable for vegans, I've always wondered why nobody has managed to get it to market as a food. There's already a growing group of wellness-focused people who don't want typical non-gelatin jelling ingredients like carrageenan and various gums in their foods; these provide only the jelling property and none of the nutrition of actual gelatin, and they are associated with inflammation. Edit: Maybe all of the funding is going toward grail projects like synthetic beef patties that have an element of technical novelty, rather than the comparatively boring process of creating collagen at scale and getting FDA approval?
- jfim 6y ago
  > Given that and the already-existing ability to create collagen/gelatin in a lab that's suitable for vegans, I've always wondered why nobody has managed to get it to market as a food. Outside of some pastry applications (eg. mirror cake glazing), it's pretty much only used for Jell-O and aspic, neither of which are particularly trendy at the moment. There's gelatin and collagen in soups as part of making broth, but it's not really something that people see as an ingredient.
  - yawnr 6y ago
    Huge demand for collagen powder as a beverage additive lately though. Could definitely be a real opportunity.
    - bobby_bob 6y ago
      For example, Nestlé purchased "Vital Proteins" last year and are making their collagen products to their Nestlé Health Science portfolio. https://www.fooddive.com/news/nestle-to-acquire-majority-stake-in-collagen-maker-vital-proteins/579639/ https://www.fooddive.com/news/nestle-to-acquire-majority-sta...
  - ben_w 6y ago
mint2 6y ago
This journal isn’t open access is it? I wanted so see the effect sizes not just p values which are unhelpful. But if the vegans are all vitamin b12 deficient, it’s not a surprise their health has consequences. And my other question is, is there self selection going on. People who go to hospitals have worse outcomes than people who don’t, so the best thing to do is to avoid hospitals. P < 0.001. Right? No, wrong. Did they become vegans due to digestive problems or other health issue? I’d really like to read the article to see if they considered these things.
chaimanmeow 6y ago
I would like to see a comparison between the top 10% vegan and omnivores. Most vegans are clueless when it comes to making up deficiencies in typical vegan diets. Glycine is one of the relevant aminos that is very suboptimal or even scarce in vegetarian and vegan diets. It is also going to be one of the important (and likely most common) limiting factors in tissue repair. Proline is also needed for collagen production, but not as deficient in Glycine as far as vegetarian diets. Glycine is also highly water soluble and a small molecule; it is constantly lost in urine. The need for glycine goes way beyond collagen production. It is essential for so many biological functions. Glycine is not considered an "essential amino" because the body produces glycine itself, hence it is overlooked by many. It turns out the body produces only enough to usually barely scrape by. My guess is if another group of vegans were given Glycine (at around 4 to 5 grams/day) supplementation the disadvantage relative to omnivores would be erased.
- UncleOxidant 6y ago
  I was completely vegan for a couple of years. I went that way to avoid gallbladder surgery - it worked, I had no gallbladder pain on a vegan diet. I Supplemented with B12 and Vitamin D as those are typically low to non-existent in the vegan diet. But I started to have problems with my teeth chipping - hadn't had that before. I did some calculations and realized that there was no way I was getting anywhere close to the RDA for calcium. So I started supplementing some calcium. After some gut problems I came to the conclusion that beans weren't working for me. I needed to quit eating legumes for a while which is highly problematic on a vegan diet as they're the major source of protein. Now I eat a tin of sardines twice/week (and other fish occasionally) which means that technically I'm not vegan any longer. At least the addition of fish did not cause any gallbladder problems.
  - tpoacher 6y ago
    I can't remember the exact reference here, but I remember a research paper which showed that veganism is associated with an increased risk of cholecystitis. This is despite the fact that a typical vegan diet is low in fat (which is the typical reason a vegan diet is promoted for gallbladder control). In fact, if I remember correctly, the 'lack' of fat was also the main risk; in that the occasional fact prompted a more violent reaction, thus increasing the risk for an impaction. I can try and find the article for you if you're interested, though I remember last time I tried to find it it was no easy task trying to sift through the myriad of google results containing vegan blogs recommending vegan diets for cholecystitis... But in any case, if you're going vegan for fear of cholecystitis, be aware it may actually have the reverse outcome!
sto_hristo 6y ago
Strange way to word the two patient types: vegans as opposed to omnivores. Vegans are still omnivores, they just stopped eating animal products because of beliefs. I also smelled once a vegan cake. It's a medical miracle they can survive on such a diet.
- DanBC 6y ago
  > Vegans are still omnivores, No they aren't. From New Oxford English Dictionary: > omnivorous > adjective (of an animal or person) feeding on a variety of food of both plant and animal origin.
  - sto_hristo 6y ago
    Herbivores are reciprocal to omnivores. Vegans are not comparable to either. Vegans don't eat animals not because they can't, but because of their beliefs. The word vegan describes a belief, contrary to omnivore and herbivore that describe physiology. A human may choose to walk on all fours because they're insane, but they will still be a biped.
    - deleted 6y ago
      [deleted]
    - DanBC 6y ago
      That's not how language works.
chmod600 6y ago
I'm curious if there are good, informative studies about mental health and veganism. Arguably mental health is more important when considering a choice like veganism.
- subsubzero 6y ago
  I found this: https://academic.oup.com/nutritionreviews/advance-article-abstract/doi/10.1093/nutrit/nuaa030/5850123?redirectedFrom=fulltext https://academic.oup.com/nutritionreviews/advance-article-ab... also: https://www.psychologytoday.com/us/blog/animals-and-us/201812/the-baffling-connection-between-vegetarianism-and-depression https://www.psychologytoday.com/us/blog/animals-and-us/20181... then there is the question: do people with mental health issues tend to gravitate towards veganism or is the diet itself is causing the issues. I would like to see a study with a large number of participants from diverse backgrounds who are meat eaters and then go vegan and see if that affects their mental health. However a meat eater who is then forced to eat soy products/meat substitutes they dislike may be unhappy for that very reason. Its a difficult test condition to say the least.
  - chmod600 6y ago
    You could have seven groups with varying levels of choice: group 1 is forced to be vegan, group 4 is the control group, and group 7 is forced to consume meat. Groups 2-3 would be nudged vegan, 5-6 would be nudged to eat meat. Measure them all and get happiness and health curves after 5, 10, 15 years. It would be expensive, but probably a better use of money than a lot of other stuff.
tpoacher 6y ago
I've actually noticed this effect on myself too. It's very pronounced in fact. I have a bad habit of biting my cuticles. I also happen to observe lent, effectively going vegan for 50 days every year. Typically my cuticles heal the next day, or two at most. But every single time I enter lent, suddenly my cuticles take more than a week to heal the same amount. The difference is very obvious, to me at least.
- hawk_ 6y ago
  curious what kind of lent you observe that's for 50 days not 40.
  - beervirus 6y ago
    If you count Sundays, it’s closer to 50 than 40.
    - hawk_ 6y ago
      i see, so apparenly different traditions count it differently. i had always heard of it as 40 days of lent or cuaresma etc... didn't know it could go upto 46 days.
  - deleted 6y ago
    [deleted]
  - 8fGTBjZxBcHq 6y ago
    Gonna be orthodox christian for sure. They do the vegan diet for lent and have a few extra weeks at the beginning. The extra weeks have slightly different rules and technically aren't part of lent but it amounts to about the same thing. Grew up in a family that did this and still do it because I like the structure and changes through the year.
bane 6y ago
When I was younger and training very heavily in some sports, I experimented a bit with different diets. Bottom-line the more meat heavy my diet, the faster I would heal from injuries -- radically so. For a while I went on a low-carb diet and ate a very heavy animal protein diet. I shed pounds, had absolutely unstoppable stamina, had far fewer injuries, stretching improved, basically never bruised, and healed from sports injuries that would have taken weeks in days. I felt like Wolverine. I also felt like a grease grenade all the time and got tired of the diet which is why I stopped, but it was definitely superhuman for me. I felt the worst in this sports context was when I experimented with a vegan/vegetarian diets. The effects were virtually the exact opposite. I'm sure with a nutritionist and more dedication I could have overcome many of these issues, but I found building a decent diet harder and required more effort.
- asoneth 6y ago
  I found similar results when I tried a vegan diet. Like you, I suspect that I could have made it work if I spent the effort to figure out what was missing. If I actually lived my life according to my personal ethics that's what I'd do. For now I've found vegetarianism significantly easier and a satisfactory compromise between ethics, health, and nutritional laziness.
- dempseye 6y ago
  What do you mean when you say you felt like a grease grenade?
  - bane 6y ago
    Just very very greasy out of my pores. Oily all the time, 2 or 3 showers a day to keep the grease out of my hair. That sort of thing.
- lupire 6y ago
  Did you ensure that you maintained protein level when you went vegan/vegetarian? It's easy to eat much less protein if you aren't careful.
kiwiandroiddev 6y ago
As much as the results of this study confirm what I would expect, keep in mind it was an observational study and not a controlled experiment. There might be some other factor at play in the vegan group, say, other than just their diet. Unfortunately I imagine an experiment to further investigate this would be hard to get past an ethics board. I.e. wounding the participants to see the effect on scar formation...
andrekandre 6y ago
it would be interesting to see what the potential causality would be for this (vitamins/minerals? hormones from the meat? fats?)
yesenadam 6y ago
Has anyone managed to actually get hold of the paper?
spicymaki 6y ago
I am not giving up my vegetarian diet due to one study (n = 21) of a potential negative affect (surgical scars). Meat-based standard American diet has negatives as well. Given that the iron and B12 levels were low for the vegans in the study it would be interesting if they supplemented that and check for an improvement. edit: corrected study participants number
chaddattilio 6y ago
Take an iron and B12 supplement. Done.
- mikkelam 6y ago
  Most vegans should be supplementing iron and all vegans should be supplementing B12 anyway..

115 points by shadykiller 6y ago

> This study suggests that a vegan diet may negatively influence the outcome of surgical scars. This is unusually damning to veganism-as-it-is-practiced if not to veganism itself. It would be interesting to see these results across a wide range of diets.

rektide 6y ago
Agreed that there are probably ways to remediate some of these effects. I definitely favor smaller less impactful scarring, but also, so what? Calling ths "unusually damning" seems like a significant overinflation of concern. For all we know, it may have far more significant pro-recovery characteristics associated with it. "Oh you built too much scar tissue? Your vegan diet also stitched your blood vessels back together really well."
- arkitaip 6y ago
  dang really needs to get YC to develop an AI that can automatically add /s to ironic comment.
  - stelonix 6y ago
    I'd rather HN not allow such comments and we try to make debate here better than on the rest of the internet.
  - centimeter 6y ago
    Or people could work on their ability to identify normal human modes of speech.
    - ben_w 6y ago
      Given we’ve had the internet for over a generation with this issue being known that whole time, I don’t think that’s actually something we can do. Not in general, not from plain text.
      - centimeter 6y ago
        I think only morons, autistics, etc have a habitually hard time identifying sarcasm. These are not the people we should optimize the web experience for.
        ben_w 6y ago
        Only when spoken, not when written: https://theconversation.com/why-is-sarcasm-so-difficult-to-detect-in-texts-and-emails-91892 https://theconversation.com/why-is-sarcasm-so-difficult-to-d...
        centimeter 6y ago
        No, I have zero problem detecting sarcasm or irony in text. If you think about it for 5 seconds it's usually pretty clear.
        ben_w 6y ago
        If you have zero problem, you are unusual. Please note who wrote this paper, considering what they are famous for, as well as the results: http://web-docs.stern.nyu.edu/pa/kruger_email_ego.pdf http://web-docs.stern.nyu.edu/pa/kruger_email_ego.pdf
    - yjftsjthsd-h 6y ago
      Text inherently makes it difficult if not impossible to distinguish sarcasm that would be apparent with verbal/visual context clues.
centimeter 6y ago
One of several motte-and-bailey tactics used by vegans is going from “Veganism is healthy” To “Veganism can be healthy if you exercise an impressive amount of restraint, discipline, and judgement in your vegan diet”
- petertodd 6y ago
  _If_ you can get enough exercise, you can be healthy on pretty much any omnivore diet because it's so hard to not get enough nutrition, and extra calories don't matter if you burn them off. I personally lost lots of weight when I was cycling regularly to work and school (10km and 50km round trip respectively), as well as caving and climbing on weekends. Almost everything I ate was fast food, because I had hardly any spare time. But I was definitely healthy and felt great so long as I took enough days off (I was getting enough exercise that I simply couldn't do it every day). Meanwhile, I know lots of people who have given up on vegan diets because they felt like their health was declining, even with regular exercise. I'm sure with enough care and nutritional science they could have gotten it to work. But it's so much easier to just add some animal products to your diet.
  - jxramos 6y ago
    I remember hearing the question asked someplace about whether any professional athletes are vegans, especially for the intense sports that require a lot of muscle rebuilding and maybe even contact sport healing and what not. That might illuminate things a bit.
    - asoneth 6y ago
      There is an advocacy* movie called The Game Changers which highlights several vegan athletes and makes the case that their plant-based diet contributes to their success. https://gamechangersmovie.com/ https://gamechangersmovie.com/ * I would not consider it a documentary as it has a clear agenda, but I found it interesting nonetheless.
    - centimeter 6y ago
      https://www.lonesomelands.com/new-blog/2019/9/16/t2amoscp1u1ynq1ms3sk9shr5ewlvj https://www.lonesomelands.com/new-blog/2019/9/16/t2amoscp1u1...
badRNG 6y ago
> This is unusually damning to veganism-as-it-is-practiced if not to veganism itself. I don't think a sample size of 21 is especially damning. Nor do I think that the study's authors would come to that conclusion either.
- tpoacher 6y ago
  Depends. Emotive language aside (i.e. "damning") the low sample size is actually "more evidence" in the presence of a convincingly low p value. It means that this particular sample of 21 people would have to be extremely atypical under the null hypothesis of no difference. Therefore, given its low sample size (and thus wide standard error), it is 'some' evidence that the effect size is also probably quite large.
  - majormajor 6y ago
    That doesn't sound right. The reason sample size is important is because the larger the group, the less likely the group is to be atypical. I don't think you can turn that around and then say "this group is small, which itself is evidence, because otherwise it would have to be extremely atypical to show a difference." That's completely circular. The p-value is still the important thing because the p-value is itself affected by the sample size.
    - stevenhuang 6y ago
      No, effect size very much informs all of that. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3444174/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3444174/
    - tpoacher 6y ago
      > the larger the group, the less likely the group is to be atypical. Not true (unless I misunderstood what you were trying too say). The probability that a sample will be atypical under the null is exactly the significance level, and does not depend on its size. What does change with size is that the distribution around the statistic gets more concentrated, meaning your threshold moves to the left, towards lower effect sizes. Which also means that for smaller sample sizes, it is harder to reach significance, unless you're dealing with a fairly large effect size.
asoneth 6y ago
I'm not sure any of the vegans I know would give up veganism in order to minimize their scars any more than the meat-eaters I know would give up meat based on studies that show it can be mildly unhealthy.
- moistbar 6y ago
  Maybe I'm reading into it too much, but the outcome of this study seems to suggest there may be other healing-related issues attached to veganism.
  - asoneth 6y ago
    I wouldn't be surprised, though I would be similarly skeptical that other healing-related issues would sway people one way or the other either since (at least the vegans I know) don't adopt the lifestyle for health reasons. Very large effects are unlikely given the number of long-term vegans who seem to maintain sufficient health. Whereas small effects might be considered a worthwhile sacrifice.
    - spicymaki 6y ago
      Agreed as a vegetarian, this study being called damning is a joke. Veganism has a pretty good track record with respect to health outcomes. Committed vegans that I know would still do it if it lowered their lifespan, because they are doing it for a higher cause (environmental, moral, spiritual, etc.)
- imwillofficial 6y ago
  I reject your premise that eating meat makes you “mildly unhealthy”
  - asoneth 6y ago
    Exactly. [To clarify: I am not qualified to judge the general healthiness of any particular diet -- any sufficiently popular diet seems to have conflicting studies showing it is "healthy" and others showing it is "unhealthy". The point I intended to make above was that most people either outright reject or remain unswayed by these kinds of studies.]
colanderman 6y ago
"Veganism" denotes an ethical stance, despite the plant-based health foods movement co-opting the label, or some activists (ab)using health claims to promote a vegan diet. A study about scar tissue is in no way "damning" of it.

hprotagonist 6y ago

is effect size mentioned in the full text?

Gys 6y ago

> Conclusion: This study suggests that a vegan diet may negatively influence the outcome of surgical scars. > Twenty-one omnivore and 21 vegan patients who underwent surgical excision of a nonmelanoma skin cancer Interesting, but its a small group and stats are on the low end?

redis_mlc 6y ago
n=21 is not necessarily a small population from a statistical standpoint. Anyway, would be interesting to get comments from doctors who trest vegans. I'm not surprised at the result (we are what we eat), so perhaps vegans really should be on vitamins.

1996 6y ago

Related: the surgical scars of fasting mouse heal better (various publications report the same results) The same seems to apply in human, with various individual anecdotal report: https://www.quora.com/Did-long-term-water-fasting-improve-any-scars?share=1 https://www.quora.com/Did-long-term-water-fasting-improve-an...

walshemj 6y ago
I was told that loading up on carbs helped with recovery and I have a load of stuff downstairs in case i get called in.
- 1996 6y ago
  I notice the downvotes to my post, but what you was told is demonstrably wrong. As for how/why it works: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7069085/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7069085/ "Fasting before or after wound injury accelerates wound healing through the activation of pro-angiogenic SMOC1 and SCG2" There are various other publications on autophagy (removing old stem cells and making new ones) For those who are going to say "in mice", the effects of true (water only) fasting has been replicated in humans, in well done trials, in even harsher conditions than surgery: chemotherapy. Fasting improves various things such as the severity of symptoms during chemo and the efficiency of the treatment: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5921787/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5921787/ "Short term fasting during chemotherapy is well tolerated and appears to improve quality of life and fatigue during chemotherapy" It may be counter intuitive, but there's a large body of evidence that fasting promotes healing (check the various reference of this 2018 trial: "Fasting cycles retard growth of tumors and sensitize a range of cancer cell types to chemotherapy" https://pubmed.ncbi.nlm.nih.gov/22323820/ https://pubmed.ncbi.nlm.nih.gov/22323820/ etc
  - walshemj 6y ago
    That's not what the senior colorectal doctor at the royal free told me last year.

RcouF1uZ4gsC 6y ago

> Wound diastasis was more frequent in vegans (p = .008). To me this is the bad part. Wound diastasis means that your incision opens up again. That is IMO a bigger complication than a scar since it likely requires medical intervention and puts you at risk for infection.

antattack 6y ago

What's the point of having a better looking scar if you're more likely to get colon cancer? Also, given that study itself measured Iron and B12, supplementing Iron and B12 may help scar healing w/o the (red) meat eating downside.

decebalus1 6y ago
> What's the point of having a better looking scar if you're more likely to get colon cancer? I don't think it's worth going into the extremes with this. Omnivore doesn't mean a buttload of red meat.
xvedejas 6y ago
I'm curious here: I am under the impression, possibly due to outdated info, that the issue with red meat was specifically that cooking it at high temperatures creates carcinogens (this being why bacon is especially bad). Would it be possible to avoid carcinogens by slow cooking all red meat at lower temperatures?
centimeter 6y ago
Attributing colon cancer to meat is, it turns out, complete bullshit, just like most other nonsense anti-meat fear-mongering (uric acid, cholesterol, etc.).
- jjtheblunt 6y ago
  I'm not familiar with the data either way, so am reading to learn; why do you say it's bullshit?
  - zepto 6y ago
    In context, I think it’s as fair to call it bullshit as to claim it as a truth. It was being claimed as a truth to rebut the implications a peer reviewed study, but without any data to support it.
  - centimeter 6y ago
    Every time I get concerned about one of these things and look it up, it turns out to have been false.

SeanFerree 6y ago

Very interesting. Thanks for sharing!

gamblor956 6y ago

Not a surprise. Collagen is important for healing skin wounds, and vegans get none from their diet. (Collagen is just a protein, so it can be generated by the body, but it's easier for the body to simply take collagen from dietary sources.)

subungual 6y ago
Do you have a source for this? As far as I know, there is no way for the body to uptake and employ collagen directly. It needs to be broken down into smaller peptides, absorbed, and rebuilt, just like any other protein.
- gamblor956 6y ago
  Yes, I should have been more specific that collagen gets broken down into collagen peptides. I didn't think I needed to be that specific since it's like the difference between Calorie and calorie (i.e., the distinction is not relevant to the discussion on hand). We know that the body can use collagen without digesting it first because collagen masks are used to heal burn victims. See, for example: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6565829/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6565829/, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3081477/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3081477/ Collagen is a protein. It is made up of several "peptides" referred to as "collagen peptides." When it is first digested, collagen is broken down into collagen peptides in the gut. The type of collagen determines the ratios of these peptides. Most, but not all of these collagen peptides get further broken down into amino acids in the gut. (Contrast to whey, which gets entirely broken down into amino acids.) However, a significant portion of collagen peptides can survive digestion, or leave the gut before they are digested. (Up to 10%, depending on the original source of the collagen.) The body can utilize these peptides directly to repair skin, because skin is mostly made of...collagen. The presence of collagen peptides simply lets the body go straight to creating collagen without having to wait while peptides are created from amino acids. (The body will still do that, but it's like starting a construction project with supplies on hand vs having to wait for supplies to arrive or be built.)
  - 6y ago

odyssey7 6y ago

Animal protein seems to be good for wellbeing, and there's a lot of overlap between veganism, wellness awareness, and alternative food choices. Given that and the already-existing ability to create collagen/gelatin in a lab that's suitable for vegans, I've always wondered why nobody has managed to get it to market as a food. There's already a growing group of wellness-focused people who don't want typical non-gelatin jelling ingredients like carrageenan and various gums in their foods; these provide only the jelling property and none of the nutrition of actual gelatin, and they are associated with inflammation. Edit: Maybe all of the funding is going toward grail projects like synthetic beef patties that have an element of technical novelty, rather than the comparatively boring process of creating collagen at scale and getting FDA approval?

jfim 6y ago
> Given that and the already-existing ability to create collagen/gelatin in a lab that's suitable for vegans, I've always wondered why nobody has managed to get it to market as a food. Outside of some pastry applications (eg. mirror cake glazing), it's pretty much only used for Jell-O and aspic, neither of which are particularly trendy at the moment. There's gelatin and collagen in soups as part of making broth, but it's not really something that people see as an ingredient.
- yawnr 6y ago
  Huge demand for collagen powder as a beverage additive lately though. Could definitely be a real opportunity.
  - bobby_bob 6y ago
    For example, Nestlé purchased "Vital Proteins" last year and are making their collagen products to their Nestlé Health Science portfolio. https://www.fooddive.com/news/nestle-to-acquire-majority-stake-in-collagen-maker-vital-proteins/579639/ https://www.fooddive.com/news/nestle-to-acquire-majority-sta...
- ben_w 6y ago

mint2 6y ago

This journal isn’t open access is it? I wanted so see the effect sizes not just p values which are unhelpful. But if the vegans are all vitamin b12 deficient, it’s not a surprise their health has consequences. And my other question is, is there self selection going on. People who go to hospitals have worse outcomes than people who don’t, so the best thing to do is to avoid hospitals. P < 0.001. Right? No, wrong. Did they become vegans due to digestive problems or other health issue? I’d really like to read the article to see if they considered these things.

chaimanmeow 6y ago

I would like to see a comparison between the top 10% vegan and omnivores. Most vegans are clueless when it comes to making up deficiencies in typical vegan diets. Glycine is one of the relevant aminos that is very suboptimal or even scarce in vegetarian and vegan diets. It is also going to be one of the important (and likely most common) limiting factors in tissue repair. Proline is also needed for collagen production, but not as deficient in Glycine as far as vegetarian diets. Glycine is also highly water soluble and a small molecule; it is constantly lost in urine. The need for glycine goes way beyond collagen production. It is essential for so many biological functions. Glycine is not considered an "essential amino" because the body produces glycine itself, hence it is overlooked by many. It turns out the body produces only enough to usually barely scrape by. My guess is if another group of vegans were given Glycine (at around 4 to 5 grams/day) supplementation the disadvantage relative to omnivores would be erased.

UncleOxidant 6y ago
I was completely vegan for a couple of years. I went that way to avoid gallbladder surgery - it worked, I had no gallbladder pain on a vegan diet. I Supplemented with B12 and Vitamin D as those are typically low to non-existent in the vegan diet. But I started to have problems with my teeth chipping - hadn't had that before. I did some calculations and realized that there was no way I was getting anywhere close to the RDA for calcium. So I started supplementing some calcium. After some gut problems I came to the conclusion that beans weren't working for me. I needed to quit eating legumes for a while which is highly problematic on a vegan diet as they're the major source of protein. Now I eat a tin of sardines twice/week (and other fish occasionally) which means that technically I'm not vegan any longer. At least the addition of fish did not cause any gallbladder problems.
- tpoacher 6y ago
  I can't remember the exact reference here, but I remember a research paper which showed that veganism is associated with an increased risk of cholecystitis. This is despite the fact that a typical vegan diet is low in fat (which is the typical reason a vegan diet is promoted for gallbladder control). In fact, if I remember correctly, the 'lack' of fat was also the main risk; in that the occasional fact prompted a more violent reaction, thus increasing the risk for an impaction. I can try and find the article for you if you're interested, though I remember last time I tried to find it it was no easy task trying to sift through the myriad of google results containing vegan blogs recommending vegan diets for cholecystitis... But in any case, if you're going vegan for fear of cholecystitis, be aware it may actually have the reverse outcome!

sto_hristo 6y ago

Strange way to word the two patient types: vegans as opposed to omnivores. Vegans are still omnivores, they just stopped eating animal products because of beliefs. I also smelled once a vegan cake. It's a medical miracle they can survive on such a diet.

DanBC 6y ago
> Vegans are still omnivores, No they aren't. From New Oxford English Dictionary: > omnivorous > adjective (of an animal or person) feeding on a variety of food of both plant and animal origin.
- sto_hristo 6y ago
  Herbivores are reciprocal to omnivores. Vegans are not comparable to either. Vegans don't eat animals not because they can't, but because of their beliefs. The word vegan describes a belief, contrary to omnivore and herbivore that describe physiology. A human may choose to walk on all fours because they're insane, but they will still be a biped.
  - deleted 6y ago
    [deleted]
  - DanBC 6y ago
    That's not how language works.

chmod600 6y ago

I'm curious if there are good, informative studies about mental health and veganism. Arguably mental health is more important when considering a choice like veganism.

subsubzero 6y ago
I found this: https://academic.oup.com/nutritionreviews/advance-article-abstract/doi/10.1093/nutrit/nuaa030/5850123?redirectedFrom=fulltext https://academic.oup.com/nutritionreviews/advance-article-ab... also: https://www.psychologytoday.com/us/blog/animals-and-us/201812/the-baffling-connection-between-vegetarianism-and-depression https://www.psychologytoday.com/us/blog/animals-and-us/20181... then there is the question: do people with mental health issues tend to gravitate towards veganism or is the diet itself is causing the issues. I would like to see a study with a large number of participants from diverse backgrounds who are meat eaters and then go vegan and see if that affects their mental health. However a meat eater who is then forced to eat soy products/meat substitutes they dislike may be unhappy for that very reason. Its a difficult test condition to say the least.
- chmod600 6y ago
  You could have seven groups with varying levels of choice: group 1 is forced to be vegan, group 4 is the control group, and group 7 is forced to consume meat. Groups 2-3 would be nudged vegan, 5-6 would be nudged to eat meat. Measure them all and get happiness and health curves after 5, 10, 15 years. It would be expensive, but probably a better use of money than a lot of other stuff.

tpoacher 6y ago

I've actually noticed this effect on myself too. It's very pronounced in fact. I have a bad habit of biting my cuticles. I also happen to observe lent, effectively going vegan for 50 days every year. Typically my cuticles heal the next day, or two at most. But every single time I enter lent, suddenly my cuticles take more than a week to heal the same amount. The difference is very obvious, to me at least.

hawk_ 6y ago
curious what kind of lent you observe that's for 50 days not 40.
- beervirus 6y ago
  If you count Sundays, it’s closer to 50 than 40.
  - hawk_ 6y ago
    i see, so apparenly different traditions count it differently. i had always heard of it as 40 days of lent or cuaresma etc... didn't know it could go upto 46 days.
- deleted 6y ago
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- 8fGTBjZxBcHq 6y ago
  Gonna be orthodox christian for sure. They do the vegan diet for lent and have a few extra weeks at the beginning. The extra weeks have slightly different rules and technically aren't part of lent but it amounts to about the same thing. Grew up in a family that did this and still do it because I like the structure and changes through the year.

bane 6y ago

When I was younger and training very heavily in some sports, I experimented a bit with different diets. Bottom-line the more meat heavy my diet, the faster I would heal from injuries -- radically so. For a while I went on a low-carb diet and ate a very heavy animal protein diet. I shed pounds, had absolutely unstoppable stamina, had far fewer injuries, stretching improved, basically never bruised, and healed from sports injuries that would have taken weeks in days. I felt like Wolverine. I also felt like a grease grenade all the time and got tired of the diet which is why I stopped, but it was definitely superhuman for me. I felt the worst in this sports context was when I experimented with a vegan/vegetarian diets. The effects were virtually the exact opposite. I'm sure with a nutritionist and more dedication I could have overcome many of these issues, but I found building a decent diet harder and required more effort.

asoneth 6y ago
I found similar results when I tried a vegan diet. Like you, I suspect that I could have made it work if I spent the effort to figure out what was missing. If I actually lived my life according to my personal ethics that's what I'd do. For now I've found vegetarianism significantly easier and a satisfactory compromise between ethics, health, and nutritional laziness.
dempseye 6y ago
What do you mean when you say you felt like a grease grenade?
- bane 6y ago
  Just very very greasy out of my pores. Oily all the time, 2 or 3 showers a day to keep the grease out of my hair. That sort of thing.
lupire 6y ago
Did you ensure that you maintained protein level when you went vegan/vegetarian? It's easy to eat much less protein if you aren't careful.

kiwiandroiddev 6y ago

As much as the results of this study confirm what I would expect, keep in mind it was an observational study and not a controlled experiment. There might be some other factor at play in the vegan group, say, other than just their diet. Unfortunately I imagine an experiment to further investigate this would be hard to get past an ethics board. I.e. wounding the participants to see the effect on scar formation...

andrekandre 6y ago

it would be interesting to see what the potential causality would be for this (vitamins/minerals? hormones from the meat? fats?)

yesenadam 6y ago

Has anyone managed to actually get hold of the paper?

spicymaki 6y ago

I am not giving up my vegetarian diet due to one study (n = 21) of a potential negative affect (surgical scars). Meat-based standard American diet has negatives as well. Given that the iron and B12 levels were low for the vegans in the study it would be interesting if they supplemented that and check for an improvement. edit: corrected study participants number

chaddattilio 6y ago

Take an iron and B12 supplement. Done.

mikkelam 6y ago
Most vegans should be supplementing iron and all vegans should be supplementing B12 anyway..