Yes, I know, we can keep going down this rabbit hole. Turns out that a completely vegan diet, which has no DHA, is completely sufficient to sustain the body [1]. The human body is incredibly adaptive and increases its efficiency of converting ALA to DHA/EPA. This conversation I think will shake down how the heme iron/non-heme iron efficacy research. A study long ago showed that non-heme uptake was much poorer than heme iron and so the conclusion was something like "you need to eat 10x the non-heme iron" which has since become "conventional" wisdom. When you remove heme iron (stop eating meat), your body is able to absorb non-heme iron at the same rate. We call this a "smart drug" which changes uptake based on concentration levels. Basically, the study participants at the time ate so much meat that their iron levels were so high that non-heme iron is not processed.
Edit: The other thing I wanted to say is 1 tbsp of flaxseed has 2.4g of ALA and that the adequate intake of ALA is 1.6g and 0.3g of DHA/EPA. If we assume a 10% conversion rate for both (depends on many factors and a tad high), you get 0.24g of DHA/EPA. So, 2 tbsp of flaxseed and you're good. I put it in my smoothie in the morning.
The study linked by you has shown that the concentrations in blood of DHA and EPA for vegans were less than half of those for omnivores.
Therefore this study is also one of the many which have shown that the human body has only a limited capacity of converting ALA into DHA and EPA, so that the nutritional supplements with DHA and EPA are beneficial for vegans (e.g. from oil of Schizochytrium, a non-plant non-animal unicellular living being, which is falsely named as "algae" by vendors, to sound more like a vegetable to vegan ears, if the cheaper fish oil is deemed to be unacceptable).
This study certainly does not support your claim that "a completely vegan diet, which has no DHA, is completely sufficient to sustain the body".
Yes, it is enough to have ALA in your food to avoid a quick death, but ALA is not enough to ensure a good health and a long life.
>e.g. from oil of Schizochytrium, a non-plant non-animal unicellular living being, which is falsely named as "algae" by vendors, to sound more like a vegetable to vegan ears
You seem to be implying here that Schizochytrium is not a vegan product, even though "non-animal" is completely sufficient to meet that criterion.
I agree that, as you say, being non-animal is sufficient.
Nevertheless, I find it funny that the vendors have felt the need to use the word "algae" for marketing this product.
It is true however that while "algae" is incorrect, there is no appropriate word to name them that would be easily understood by the general public.
At most they might be called "protists", as in many biology manuals, which is a word that I strongly dislike as meaningless.
("Protists" means "the first", but among which and according to what ordering criterion? "Protist" is a word normally used with the meaning "unicellular eukaryote" a.k.a. "unicellular nucleate", but one should better use the words that are meant.)
They say this and then don't address the elephant in the room: the huge fall-out rate concerning vegans going ex-vegan.
Additionally, "completely sufficient to sustain the body" is about the lowest barrier to entry one can set. People aren't interested in sustenance alone, even if you take away cultural factors.
I have known a few vegans who developed weird health problems after a year or two of vegan diet, but I believe that this happened precisely because they had a careless attitude about the necessity of supplementing a vegan diet.
I have also transitioned to a vegan diet, but only after studying very carefully all the available information, so besides food made from vegetables I take 10 chemical substances about which there is reasonable certainty that they are either necessary or beneficial for vegans, because the plants either do not contain them or they contain them in too small quantities, and the human body either cannot make them or it can make them only in too small quantities.
Just curious, do you take creatine? It's typically a workout supplement but vegans tend to be deficient in it and can really notice measurable cognitive and physical improvements.
Just as you say, there is evidence that it is beneficial in certain circumstances, e.g. for increasing the capacity of anaerobic effort of the vegans who train for sports competitions, but it is not clear if it is beneficial unconditionally.
The evidence is very clear that it's beneficial if you have a dietary deficiency (which you almost certainly do). If not for the proven physical benefits, the cognitive benefits alone are likely worth it. Where the evidence is ambiguous is how beneficial it is for someone who meets minimum daily dietary intake to then supplement it.
I have no doubt about the effects of a creatine supplement on the muscles, as there the action mechanism is well understood, but I am more skeptical about the claimed cognitive effects, because the mechanism for such effects is not known yet.
Moreover, for substances like creatine, which can be produced in limited quantities by the human body, like also for DHA, EPA, choline or taurine, there may be large differences between individuals. Some people might not need supplements for one or more of these substances, at least when they are young, while for others supplements may be indispensable, at least when they become old.
In general, it is much more prudent to take a supplement, even when its necessity is not certain, than to not take it, because in the first case if your choice was wrong it just does not have any useful effect, while in the second case if your choice was wrong it could cause serious health problems.
I have already thought that I should try sometime in the future a creatine supplement, to see if I notice any change, but for now I cannot not see any cognitive differences between present and how I was before switching to an 100% vegan diet.
Yes it can, in very small amounts. You'd have to eat a ton of the synthesis precursors as a vegan to obtain anywhere near the optimal amount or to approach what a meat/fish-eater gets in their regular diet.
The complete list includes 4 mineral salts, sodium chloride (yes, the common salt belongs here, because salt may be not necessary for those who eat enough animal food, but an adequate amount, neither too low, nor too high, e.g. 4 to 5 g/day is mandatory for vegans), calcium citrate, potassium iodate (or iodide) and sodium selenate, then 3 fatty substances, DHA, EPA and cholecalciferol (a.k.a. vitamin D3), then finally 3 organic compounds of nitrogen, which happen to be abundant in liver, choline bitartrate, taurine and cobalamine (a.k.a. vitamin B12).
All these have been shown to have significantly lower levels in the body of the vegans who do not take the corresponding supplements.
Especially the need for a calcium supplementation is often overlooked, which leads to a higher risk of fractures.
if you really take care of your health, independent of eating meat or not, being vegan is about supplementing b12 and that is all, for the most cases.
animals on livestock are supplemented with nutrients (specially grain fed) just like you could supplement yourself
now about calcium intake, if you really take a look, most of the claims are hypothetical and require further studies to comprove, as well some findings like this;
https://pubmed.ncbi.nlm.nih.gov/19350341/
Thanks for the link, but even this study, which claims to have not found large differences between vegans and omnivores, still reports that e.g. the prevalence of osteoporosis in the femoral neck (which increases the risk of hip fracture) was 1/7 among omnivores, but more than 1/6 among vegans.
A vegan does not need a large amount per day of calcium supplementation, but all the studies, including this one, demonstrate that a small amount of additional calcium is necessary to reduce the risk of bone fractures to the same level as for omnivores.
what are you doing to worry about hip fracture? are you a rock climber?
despite all the advantages of a strictly vegetarian diet, like better stamina, endurance etc. worrying about calcium intake is a bit mislead. as there is a big difference of having a slight lower bone density than omnivores and getting worried about having your bones broke.
it is like the argument of omega-3 content of flaxseeds and chia being poor translated into useful chains of acid like DHA… all you have is to increase your intake on the ballpark of 160% rather than 100% from animal sources… which translate in having to eat the enormous amount of 3 tbsp of chia per day, so you can overcome the “inefficiency”
plus not even getting into who are the vegan people being researched on osteoporosis rate. there is vegans who survive out of pasta and soda (which contributes for osteoporosis) and those who eat a superb healthy varied diet; plus vegans who do not exercise (which contributes for osteoporosis) and those who do ETC.
Those numbers are ridiculously high when considering institutes are starting to push veganism but conveniently skip the fact veganism is difficult to maintain even for upper middle class people with almost everything available to them.
It's like the Scrum/Agile debate all over again, but in the form of diets. Yes, that means the diet itself may not be the problem, but good luck changing the environment.
You can get DHA from algea sources and still eat vegan.
There is also a sex-linked difference between ALA conversion to DHA/EPA, with women, and women who are pregnant or brestfeeding converting significantly more ALA to DHA than men. Men were converting far less than 10% while women were converting more than 10%.
>" Turns out that a completely vegan diet, which has no DHA, is completely sufficient to sustain the body [1]. "
Massive claim with only one little study for a source. You are behaving like the strawman vegan right now, making ludicrous claims on nitpicked data; you are not furthering your cause by spreading disinformation online.
At least they made an effort to support their statement. I don't see why you should go through the trouble of contradicting it without providing any sources yourself.
Edit: The other thing I wanted to say is 1 tbsp of flaxseed has 2.4g of ALA and that the adequate intake of ALA is 1.6g and 0.3g of DHA/EPA. If we assume a 10% conversion rate for both (depends on many factors and a tad high), you get 0.24g of DHA/EPA. So, 2 tbsp of flaxseed and you're good. I put it in my smoothie in the morning.
[1] - https://pubmed.ncbi.nlm.nih.gov/16087975/