Is rice protein complete?


The ingredients description says that Soylent uses rice protein. I recall that cereal proteins are incomplete because they lack or are too low for the essential amino acids lysine, tryptophane and threonine. Are there any other amino acid sources in the mix to balance it or is it a low quality protein?


To answer the title question - the rice protein used in Soylent is complete. Period. Cick below to read more detail, or look up Axiom’s product, Oryzatein.


Tryptophane is absent, lysine and threonine are low for rice.

From the Oryzatein website:

Oryzatein rice protein isolate is as beneficial as Whey Protein Isolate

If the protein is the same it is low quality. Whey protein is low quality protein because it is low in tryptophan (none), cysteine, and methionine. This is fine for babies but bad for children and adults.

I don’t think it is equivalent to Oryzatein because the amino acid profiles are different.

Good thing everyone here is supplementing their food sources.


Your link it unrelated… it has nothing to do with the rice protein in Soylent.
I believe this is a PDF of tests done on the rice protein that is actually used
But I do not know for sure… Tryptophan is not absent from what I could tell, and didn’t look into lysine… but I do recall previous talks about it, conclusion being there was enough because Soylent had slightly more protein per serving/day. But someone else will have to confirm this.


Are we really going to start another one of these?


Please do proper research before making ludicrous claims.


Tryptophane and Threonine still look low on both the Kalman mdpi source and the fao source (mg/g column A). The mdpi paper says that the protein composition is the same as cooked (parboiled) brown rice so it should match fao.

I also don’t understand how Kalman comes up that whey protein has more tryptophan than soy protein. This doesn’t match the accepted FAO at all and is very suspicious.


See, that’s what I’m talking about. Hammer agrees with fao that soy has more tryptophan than whey but Kalman doesn’t.


But do they say whey is deficient in any of the essential amino acids like you did?

Also that PDF you seem to be fond of is for buffalo and cow milk not whey protein concentrate or isolate. Similar but different products.


Threonine wasn’t listed and Hammer found whey also low in tryptophan (same as FAO).

I did two calculations, one for tryptophan and the other for glutamic acid. Soylent lists 38 g as a serving. For a 175 lb person three servings would give:

1333.8 mg Tryptophan (rda is 278 to 476 mg)

and for glutamic acid
7241 mg/serv vs 6300 mg RDA

So the glutamic acid (nonessential) is good but the Tryptophan is actually triple the RDA. That is over consumption.

Go figure. Remember when I said it is difficult to balance individual nutrients in one food? Case in point. The extra gets stored as fat and consumes cell cycles, aging you.

From paleohacks.

So, first let’s assume you digest your protein into the usable building blocks: amino acids. Excess dietary amino acids cannot be stored for future use, nor are they excreted unused. Instead, they are converted to common metabolic intermediates that can be either oxidized by the citric acid cycle or used to form glucose or fat. The excess nitrogen liberated by the metabolic degradation of amino acids is excreted in the form of urea via the urea cycle.

So according to the RDA the tryptophan is too high for the serving but they probably can’t lower it because that would make something else too low (like the glutamic acid though it’s nonessential). It’s a sacrifice.


So you agree that Soylent isn’t deficient in any essential amino acids?


Yes, he is.


Hopefully this thread will die more quickly than the last…


It looks ok for threonine and tryptophane but now I have a question about the extra aminos.

I did two more calculations. According to the RDI info on vitalhealthzone there is a maximum daily overdose limit of about 500 mg for both tryptophane and threonine for a 175 lb adult. Each serving of soylent gives 844 mg of threonine and 342 mg of tryptophane. This means that threonine exceeds the recommended toxicity limit by 166.7 mg/serving. trytpophane exceeds the limit by 341 mg/serving.

That’s a big overdose of aminos. Does anyone not finish it because they feel full?


@horsfield, Off-topic. A couple of days ago i saw a thread on which i saw somebody who i think was you who posted something about issues with calcium citrate. It was an old thread. Was it really you who posted that? because i cant remember exactly. If it was you, can you post that again or PM me that whenever you find the time?


Hah, you keep looking for something bad you can pin on Soylent… Though this time you may have struck gold if what your link says is true…

I must admit that I did not know too much of a specific protein could be overdosed. "gastrointestinal upsets
Since the first two have been reported by some Soylent users, then we can’t rule specific essential amino acids out as the contributing culprits.

Is it a serious problem? No. As most Soylent users do not actually experience any of these problems. (I did)


Interesting. I suspect that people with larger body weights are more tolerant due to having a higher RDI. Remember this is only two of the amino acids. There are more.

A good way of testing amino acid toxicity would be to determine your body weight in kilograms, calculate RDI and they supplement and see if it triggers the same symptoms. One could also do an elimination diet.


Sure, i welcome you to find more that are actually too high that could potentially cause problems.

But apparently 8-12g is actually the recommended range of it… Or of supplementing it. As maximum?


Tryptophane is the highest one on the list so let’s work on that one and see if we can eliminate those two symptoms.


I have definitely not had any of those symptoms (at least no more than before Soylent). I’m not a particularly big guy (about 5’9" and around 175 lbs last time I checked)