Month on Vegan Diet Shifts Epigenetic Patterns Assoc with Aging and Inflammation
today.ucsd.edu28 points by littlexsparkee a day ago
28 points by littlexsparkee a day ago
So much science work and analysis - all likely ruined by poor dietary controls. I skimmed the actual linked paper to see any details about the vegan vs meat rich diets and didn’t see any discussion whatsoever on that crucial part of the whole thing.
I was very curious if they’d kept the protein, fat and carb proportions constant, or what even is the typical meat rich diet. Is it spam and sausage at every meal? Could be from all the paper mentioned.
The paper did say they instructed the two groups to eat the same calories but overall the vegan group stayed the same weight while the meat group average gained kilo. One meat person gained 5kg!!! The meat group clearly did not eat their normal amounts of calories, an assumption the paper seemed to rely on.
I’m not sure you can just make a direct comparison between protein amounts, so that control may not work as you intend. As I understand it, your body metabolises dietary protein into amino acids, which it then uses to synthesise the protein it needs (that’s why even if you eat meat, your body isn’t made up of cow protein it’s made up of human protein). Meat eaters get most of their protein from meat and dairy products which contain complete proteins in the sense that they contain all the amino acids humans need. There aren’t that many complete proteins that are vegan so vegan diets tend to include a mix of grains and pulses. These give all the amino acids your body needs to synthesise protein but have a different balance meaning that 100g of plant-based protein != 100g of meat-based protein, and keeping them exactly the same by weight might actually be unhealthy for the vegan group.
As I understand it, the way to achieve what you’re going for would be to calorie-control both groups and then set a percentage of calories from protein and specify for the vegans what the breakdown needed to be between grains and pulses. That would be a right royal pita to manage so might be more overhead that it’s worth idk. On the other hand it may make the study more definitive.
I’m always skeptical of studies like this because the group that shifts to a vegan diet might just be shifting to a healthier diet in general and therefore that might be the effect you’re seeing rather than an effect that shows veganism is better than meat eating per se. Like what if people in a third group kept eating meat but had some sort of controlled meat-eating diet. They may well see an improvement just because now they’re thinking about their diet to meet the restriction and so are making healthier choices as a side-effect.
Source: not an expert but have been vegetarian for nearly 40 years at this point and vegan for about 10ish of those. Veganism kind of crept up on me so I don’t know the actual day I started. I don’t have an opinion about whether anyone else should eat meat. My choice is just about what I eat.
The complaint is that if you strip the controls out, then you're no longer betting on diet. Because whoever maintains a fully plant-based diet is drawn from a population that 'probably' smokes less, drinks less, sees doctors, sleeps, blah blah. True.
But nobody constructs elaborate arguments about hypothetical Oreo-vegans because they're worried about hypothetical Oreo-vegans. The same person who wants a randomized control trial about how 'healthy' a plant-based diet is versus an omnivore diet will happily take creatine on the strength of a forum post.
A thought experiment: bet money on who you think will live longer. Someone vegan or someone who isn't. No whining about controls like "how well planned is the diet", how much they exercise, if they smoke, and so on. Just a deadpool bet at a dive bar.
Ultimately, I've never found any of this research showing that vegan diets are good for you to be worth the controversy. It's not that 'veganism' is intrinsically better than eating meat. Fiber up, saturated fats down, and so on, and a vegan diet is a very good implementation of it. I have a feeling the reason why it makes peoples throats so tight has nothing to do with health.
> I’m always skeptical of studies like this because the group that shifts to a vegan diet might just be shifting to a healthier diet in general and therefore that might be the effect you’re seeing rather than an effect that shows veganism is better than meat eating per se.
This happens with pretty much every dieting study. In fact the population of vegans is now less healthy on average as it's become more mainstream and more junk food products are aimed at vegans.
Yes, that's true.
Despite the fact that I happen to eat mostly vegan food myself, I am extremely skeptical about the claims of most such studies that claim positive results for vegan diets, because, as you say, they lack adequate dietary controls that would enable the interpretation of the results.
I looked in the paper at "Materials and Methods", but there was no useful information about the actual diets, because it sent the reader to some older papers, where supposedly the diets were described.
I went to one of the referred papers, and there the description was equally useless, because there had been no strict controls. The participants were given guidelines about what they should eat and an example recipes book and then they provided weekly reports about what they had eaten.
This is not good enough to know with any certainty which are the components of the diet that had the observed effects.
Typically, the so-called vegan diets are healthier diets than what most people eat, for other reasons than for not including substances of animal origin.
None of the dietary studies that I have seen has provided any conclusive evidence that meat per se is the harmful ingredient, and that the differences in outcomes are not caused by other factors, e.g. inappropriate proportions between protein, fat and carbohydrates, too many calories, too much animal fat, unhealthy methods of cooking, like frying, unnatural composition of the food ingredients of animal origin caused by industrial farming methods, e.g. excessive amounts of hormones, vitamins, antibiotics etc., and so on.
>None of the dietary studies that I have seen has provided any conclusive evidence that meat per se is the harmful ingredient
This is innacurate if not simply false; according to the WHO red meat is a class 2 carcinogenic and sausages are class 1 carcinogenic. This leaves only white meat as non cancerogenic
If you look at the data vegan (and vegetarian to a lesser extent) diets over various studies consitently perform better in cardiovascular health and cancer rate (colon in particular) compared to the omnivorous conterpart
Those mentioned by you are very specific kinds of meat, and there were doubts about how healthy they are long before the last century.
There is absolutely no evidence that any data about red meat or sausages also applies to other kinds of meat, e.g. those that have negligible content of myoglobin and saturated fat, like poultry breast or white fish.
I agree with what you said, that almost any study about vegan or vegetarian diets shows positive effects, but it is never clear which are the differences from the comparison diets that really mattered, because the compositional differences between diets were too many and too variable.
The OP is actually talking about the studies that the WHO was using to classify meat as a class 2 carginogen. For meat preserves the evidence is clear and known mechanistically, but for meat in general it's inconclusive at best and badly-designed at worst.
Click-bait junk science. The authors contradict themselves, admitting the study "does not demonstrate" cancer prevention or aging reversal. State-sponsored hype ignores proven killers like sugar, tobacco, and alcohol.
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