Have you asked yourself why upper limit of Manganese is 11mg/day?


Yes, in oxide or salt form it can pose problems. Oxide and salt forms are inorganic forms. They qualify as mineral forms, and they are not forms the body is equipped to deal with in large amounts (the amounts normally found in water are trace amounts). The manganese compounds in plants are not oxide or salt forms. They are more complex compounds that the human body has had to learn to deal with over thousands of years of plants being a major component of the human diet.

Look, I don’t want to be rude, but I don’t have time to have a discussion like this with someone who does not want to learn enough basic chemistry to understand that different compounds of a given element can act and react totally differently from each other. I have explained how this works in as much detail I have knowledge to do (without spending hours on Google to find all of the specific compounds and chemical reactions involved). If you don’t want to believe me, and if you are not willing to learn enough chemistry to understand what I am talking about, there is no way I can convince you, and I am not going to waste my time trying to teach you. It’s your choice. You can try to convince everyone that you are right by arguing your side, or you can actually become right, by learning what is true.


Deal with, in any amount? Humans havent evolved to eat a full vegan diet.

Edited: Although different compounds of an element can act differently, there are actions that are shared/similar by these compounds too.

Also you are the one who dug up this dead subject. I am not arguing for the sake of arguing.This issue is very important, as in the future millions will be consuming this product.


Ok, good point. The evidence indicates that humans can deal with it in larger amounts than in non-organic forms (20mg being the largest amount that we know humans have consumed regularly without observed side effects).

Unfortunately, I did not realize it was dead until I had already dug it up. My subscription email suggested it as a good topic. I apologize. I guess I cannot trust the emails to give me up-to-date information on what is going on in the forums.

You are totally right that this is an important topic. And it is true that different compounds of a given element tend to have some shared traits. I am going from a point of view here that we do have evidence supporting the conclusion that organic manganese compounds are less toxic than inorganic ones. (And there are known cases of other metals where this has been fairly well proven. Magnesium is one that is highly toxic in inorganic forms but no toxicity of organic forms has been ever observed, even when consumed in very large amounts.)

You did also ask what the difference is between consuming it in water and consuming it in food. The difference is that the compounds are dramatically different. One interesting thing about compounds is that more complex compounds tend to exhibit fewer traits of the elements they are composed of. Organic compounds are more complex than inorganic ones on a very extreme level (many common organic molecules are composes of millions or billions of atoms). I said that I don’t know the specific details for organic manganese compounds, but it is possible (even probable) that the other constituent elements totally overpower the manganese traits.

What it comes down to is that thus far, the evidence indicates that most people consuming large amounts of food with high amounts of manganese do not have adverse reactions. We have between 10 and 15 years during which these diets have been common enough to expect at least a few recorded instances of side effects. What this means is that diets containing up to 20mg of manganese from organic (in the chemical sense, not in the “organically grown” sense; I think this ambiguity is why “food source” is commonly used here) sources won’t cause any observable side effects, for at least 15 years. It is possible that 20mg over 20 years will start to cause problems, though the odds are very low.

Really though, there are too many unknowns. There are not many known compounds that cause problems that are only observed after 20+ years (ethanol is one, and high glycemic index foods are another). This means that the odds are low that manganese from organic sources is toxic at the 20mg/day level. Still, I agree that this does deserve attention. I would argue that amounts in soylent that are a little above 11mg/day is safe enough that we will probably know enough more about this before it is too late to avoid any bad consequences.

Anyhow, when it comes to organic compounds, we cannot assume that they will have any of the properties of the elements they are composed of. You are right though: This does not mean that we should automatically treat them as safe.


For the record, Soylent uses a sulfate bound form of manganese. Any studies pertaining to that form in particular would be welcome.


I am curious about that as well. As far as I have seen, most supplements use mineral forms of metal compounds. I know it is easy to overdose on iron supplements (while there are no known cases of iron poisoning from eating too much red meat). I think they generally try to use forms that require pretty high amounts to be toxic, but if they are using a mineral form in official Soylent, this is certainly a valid concern. (And, this is equally true for anyone making their own mix using supplements for a majority of the manganese.)


Specifically, Soylent 1.5 contains 2.19 mg of manganese from manganese sulfate, 9.9 mg from brown rice protein, and 1.8 mg from oat flour. I don’t think they’ve released a spreadsheet for 2.0 yet.


Just a side note; it is not “easy” to overdose on iron supplements. It’s not something likely to happen by accident. You’d have to intentionally swallow irrational large numbers of pills for no reason. It’s far easier to overdose on, for example, aspirin.

Iron overdose is more likely with children taking pediatric vitamins, because they may eat them like candy, popping one after another. The serious cases happen when a child gets their hands on adult supplements and starts popping them like candy - each adult iron supplement (which is typically designed to help an iron-anemic woman recover from the condition) has many days’ worth of iron for a child, and they’ll eat a whole bunch of them. They can consume weeks or months worth of iron in a couple of minutes.

This has absolutely nothing to do with the form of iron in meat nor its safety. You simply can’t eat enough meat in one day to get several weeks’ worth of iron.


Someone with short term memory issues could overdose on iron supplements by forgetting they already took them several times in the same day. Yes, it is not anywhere as likely to happen as with asprin or other drugs, but supplements in general are harder to OD on than drugs. You are totally right that the most common problem with iron poisoning is children though.

This is true of nearly all nutrients. There are very few nutrients that have high enough concentration in food to cause side effects. Many minerals have been observed to be more likely to cause side effects as non-organic compounds than as organic.

For iron specifically though, most modern supplements use an iron compound that is easier for the body to deal with in large amounts. The iron found in meat and in most modern supplements requires a certain threshold to be consumed before the body starts to absorb it. Further, these compounds are easier for the body to reject once it has as much as it needs. The forms of iron that were used in supplements before that were much easier for the body to absorb and much harder for it to reject, which made iron poisoning from supplements much easier. So, most modern supplements would probably not be toxic even if you did accidentally take a few extra once in a while, but this is because they are using more complex compounds designed specifically to be safer. Many modern supplements do this kind of thing with metals.

The fact, however, is that most nutrient compounds found in foods, even in relatively large concentrations, are impossible to eat in sufficient quantity to cause toxicity. This is part of the reason that many of the IoM upper limits are based on maximum observed intake or on poisoning from industrial or mineral sources. Toxicity for many minerals has not been observed from organic sources at all. Most nutrient toxicity has been observed from cases of consuming nutrients in forms that are rarely or never found in real foods.


I know this is an old thread but I want to point out that while 400 mcg of selenium in non organic form is toxic you can easily take many times that when consuming brazil nuts with no ill effects.