Manganese Warning in Oat Powder


Head’s up everyone. One of the other forum members got information form Bob’s Red Mill on their Oat Flour:

Now @rob mentioned he was using enough to get 40g of fiber a day, which, according to that nutrition info, would put your Manganese intake at 15mg a day, which is toxic.

Please be careful.


According to my calculations using that PDF, obtaining 40g of fiber from that source alone would mean you would be intaking 18.7mg of Manganese, which is 7.7mg above the UL according to this source.

Is that a toxic amount? I’ve learned that there’s a difference in some cases between breaching the UL and achieving toxicity. I can’t seem to find any sources that aren’t talking about ambient air toxicity … can anyone else provide hard resources?

Thanks for bringing this to our attention, @dualhammers!


Thank you for this! I was already skeptical about oat powder as an ingredient in soylent, because of the high levels of phytic acid. Assuming that Bob’s oat powder is representative of oat powders in general, this gives another reason to worry.


Don’t use it as a reason to worry. Any concentrated food source is bound to contain high levels of things we probably need to look out for - this isn’t something exclusive to foodstuffs you find paleo taboo.

Here is more information, particularly the safety section is of note.


I decided to look at this to see if this was something peculiar to Bob’s oat powder, and it appears that it is not.

Any concentrated food source is bound to contain high levels of things we probably need to look out for - this isn’t something exclusive to foodstuffs you find paleo taboo.

I actually agree with you on this point. The conclusion that I drew from it was that it’s probably not a good idea to include relatively unprocessed (as opposed to chemically pure) ingredients in soylent. For example, if you use oat starch instead of oat powder, that should not contain any of the nasties (like phytic acid and manganese) in significant amounts. I understand that oat powder was put in in order to include some slower carbs, so that should fulfill the purpose just as well.

As a further example, I experimented with making a soylent which used soymilk and oat powder as the carb and protein sources. The immediate show-stopper was that drinking all that soymilk produced unacceptable levels of gas. (I also gave up on it due to learning about phytic acid.) But note that if I had used soy protein isolate instead of soy, there would have been no gas. The gas-causing substances in soy are certain indigestible carbohydrates; they get removed in the protein extraction.


Just make sure you confirm that. I am not able to find any nutritional info on Oat Starch as an isolate that contains details on Manganese levels.


Phytic acid reduces manganese absorption from soy by 2.3 fold ( The phytic acid from the oats may reduce manganese absorption to within the UL.

New keto recipe... and it's yummy :)

@chrismatteri: Thanks for that piece of info! That may change the picture substantially.


I suspect this is much ado about nothing. From that pdf linked above…

The UL for magnesium represents intake from a pharmacological agent
only and does not include intake from food and water.


magnesium ≠ manganese


Read the PDF again, @Kasper, there is 4.9mg Maganese in 100g. You need 600g to reach 40 fiber.


Oh that was a reaction to captbunzo:

The UL for magnesium represents intake from a pharmacological agent
only and does not include intake from food and water.


My error. All these mags… My mind got mixed up, apologies…

That said, my recipe seems to have accidentally skirted around this issue by sourcing fiber from a combination of oat and psyllium husk powder.


Yes, but the phytic acid also reduces absorption of other essential minerals / nutrients.


Sort of a non-issue, isn’t it? I mean, who in his right mind would seriously consider putting HALF A KILO of oat powder into a single day’s ration of Soylent? It wouldn’t be practical! I’m formulating (just for my own use, from materials I already have in store) a real-food analogue of Soylent; For my carbs and fibre I’m using oat powder, buckwheat powder (abundant phytase to deal with the phytic acid of the oats), and spelt powder, but I’m only using like half a cup of oatmeal ground up, two tablespoons of ground buckwheat and the same of ground spelt, and that’s for a couple days’ worth (well, 2000 calories – I’ll be using it mostly to get through the calorie-restricted days on an IF regimen). Carbs also from a couple overripe bananas and additional fibre from a couple tablespoons of ground flaxseed. I can’t conceive of trying to drink something containing 500g of oat powder in a single day. BTW I’ll be COOKING the grain ingredients, again on phytate considerations. I would think that kind of sh!tload of raw oat powder would probably give the user one big bellyache, assuming he could get outside of it all in the first place. Once you get AFK and start mixing some non-virtual real ingredients you may view several things quite differently… :wink:


The only reason I brought it up, @J_Jeffrey_Bragg, is because @rob said his new formulation gets 40g of fiber. If he is only using Oat Powder that is half a kilo of oat powder.


Yes, @dualhammers after I reviewed the thread I realised that it was Rob’s own formulation you referred to, and that gives me some concern. I hadn’t realised – because Rob was not in the habit of posting details like quantity – that he proposed to use so much oat powder. Although personally I am quite fond of oats in almost any form, I’m painfully aware of the phytate problems and I was not happy when the formula changed to include oat powder; I thought it was a step backward at the time and I’m even more uneasy now. I wish Rob were more available for feedback; I understand how busy he must be, but we hardly even see John here and this is supposed to be his bailiwick. It creates a feeling of unresponsiveness. The “campaign” is, if anything, gathering momentum, $423K just now when I checked and it only turned over $400K this morning after backsliding last night – I guess some of those double-billings got ironed out then. But this is getting big, and I think it is attracting quite a few people with medical problems and touchy digestions who hope Soylent will solve digestive issues. Hence my worries about oat powder – raw oat powder at that. When I make my personal Soylent “realfoods analogue” here, I soak the starches and then cook them into a thin gruel before combining with other ingredients, all on account of phytate and digestibility issues.

Also it has occurred to me that with almost 7,000 weeks’ worth of Soylent presold to people who have never had a chance to taste it – IT HAD BETTER TASTE GOOD or there’ll be all kinds of complaints and bad press! I can’t imagine how the current formula must taste with half a kilo of raw oat powder as the major ingredient, not to mention the Alive vitamins which people say is foul tasting. Sigh… of course it’s no business of mine (and I have to admit I’m relieved to have no personal responsibility for any of this), but I would love to see it succeed and I can only speculate whether and to what extent Rob and his team are or aren’t attending to any specific issue discussed here on the forum, as there’s an almost total lack of feedback from them. Well, they have two months to iron it all out. I should think that half a million to a million bucks’ worth of preorders ought to create quite a bit of pressure to perform. We shall see, in due time.