Question about Proposition 65 "warning" in FAQ


I have a question about the Proposition 65 section of the FAQ dealing with arsenic, cadmium, and lead levels in Soylent. One point that’s not mentioned in that FAQ page is whether Rosa Labs is actively working on reducing levels of these elements, perhaps by different sourcing?

I’m not that concerned about the arsenic and cadmium levels (especially relative to other common foods), but the lead levels cause me a bit of a pause. It’s not a huge issue, but it would be a plus if this was something that was being addressed proactively, or planned to be addressed.

Soylent alleged to contain unsafe levels of heavy metals
My Review of Soylent
Notice of legal action against Soylent. (Not from me! Just posting a link.)
:/ Lead & Cadmium
(post withdrawn by author, will be automatically deleted in 24 hours unless flagged)
Heavy Metals in Soylent
Heavy Metals in Soylent

I don’t think that anyone besides Rosa Labs can answer your question, but this made me wonder about the potential cardiovascular, kidney, and reproductive health (and possibly other) effects of consuming Soylent with its current lead content so I did a little bit of looking around to see if there was anything there. I’m surprised that I hadn’t seen that warning before and couldn’t find any existing topics on this forum about it.

Disclaimer: this isn’t anywhere near my field of expertise so it’s possible I’ve made errors in interpreting the EFSA’s report (below). I would also be happy to be corrected if there are any mistakes or there are things I didn’t consider. All of these calculations assume a 100% Soylent diet.

According to the European Food Safety Authority (EFSA), the BMDL dietary lead values in adults are 1.5 μg/kg/day and 0.63 μg/kg/day for cardiovascular and kidney effects, respectively. So for a 160 lb (~72.6 kg) adult, that equates to consuming ~108 μg/day for cardiovascular effects and ~45 μg/day for kidney effects. I didn’t see any values for mental or reproductive effects in adults but they might exist somewhere I haven’t looked. Assuming you’re getting 2000 kcal from Soylent every day, you’re only consuming around 28 μg/day (6.95 μg/serv * 4 serv/day = 27.8 μg/day) of lead which is under the BMDL for both cardiovascular and kidney issues.

For children the BMDL for neurodevelopmental effects is 0.5 μg/kg/day. If we cut the daily consumption of Soylent down to 1500 kcal (3 servings), weights below ~92 lb (~42 kg) are in the stated range for neurodevelopmental effects. If we want to make the unfounded but possibly not unreasonable assumption that the BMDL for mental effects in adults is the same as that for children, you’d have to weigh ~123 lb (~56 kg) or less before you’re in the area of 0.5 μg/kg/day or more (assuming a 2000 kcal diet).

TL;DR: Based on my rough calculations I’m not very concerned about this for myself (as an average adult male); though given the potential for harm from chronic low-level exposure it would be very nice if Rosa Labs were doing something to reduce the amount of lead in Soylent (through formula changes, changing suppliers, etc). If I were someone who weighed anywhere near 123 lb (~56 kg) I would (personally) make a rapid diet change away from Soylent. If I had children I also (personally) would not risk giving it to them with its current formula.


Does anyone know how this level compares with other foods?


Thank you LeerSpace for the detailed analysis – that’s helpful.


More info in spreadsheet linked in the FAQ.


@sylass94: Unless I’m misunderstanding something, Soylent is lower in arsenic than both of the example meals, and lower in cadmium than one of the example meals, but higher in lead than both of the example meals.

In the first example, Soylent contains roughly 1.9x the lead of the example meal, and in the second example, Soylent contains 4.7 times the lead of the example meal.

Both comparison meals are fish-based meals, which tend to be higher in heavy metals to begin with, as I understand it. Tuna in particular is a bioaccumulator of heavy metals.


Thanks! I can see how the fish would be bad with arsenic.

For others: here is the spreadsheet which shows where they got the numbers, and here are the results of the FDA study where they pulled the numbers from.
(It shows arsenic, cadmium, calcium, copper, iodine, iron, lead, magnesium, manganese, mercury, molybdenum, nickel, phosphorus, potassium, selenium, sodium, zinc)

I wonder if there is any measurable mercury in Soylent?


I’m sorry, I should have read your full post, I thought you were worried about all 3.

The lead content of Soylent is of negligeble concern. You are more likely to contract ill effects from the high lead in soil (in America) from the days that catalytic converters weren’t very effective, or from illegal lead piping in your home.

The CDC has been moving the goalpost of lead ‘toxicity’ for decades, which is good I suppose. Better to be careful than negligent. But the decisions are not backed by research so much as this growing ideology of a 'lead free America", which would actually cost tens of billions of dollars to conduct properly anyway. Personally, I wouldn’t worry about it. The triphasic excretion cycle and distro methods are effective enough on their own to keep you plenty safe from the lead content of Soylent.

Good point on the fish being used as an option though. I wonder if they did that intentionally. Seems… fishy (lol! oh, me…)


lol! But you are right - it feels like they chose some intentionally high-levels-biased meals to compare to…

Should compare to some other typical meals: meat & potatoes, salad, and a big mac. :wink:


Let’s not get into the meat and potatoes of the issue, it’s quite late and I’m fairly tired.

Joking aside, I think Soylent (once again) is geared for this type of problem. Measuring toxicity and driving out unwanted compounds would be far easier than traditional foodstuffs that have been cultivated in countries with, say, dirty water (take the arsenic-laden irrigation of Bangladesh) or other environmental contaminants. Growing the ingredients in a closed off system with limited chance of exposure would reduce the contaminants dramatically, if not completely. This incredible convenience must be why so many people cry “too good to be true” when they hear about the product.

I don’t want to try to downplay the issue of heavy metal poisoning, but the numbers today are far lower than in decades past. Emissions have plummeted and occupational exposures are even becoming rarities - which are currently the front runners for toxicity reports. It’s far better (but not ideal, of course) to be exposed to trace amounts in the diet. It may seem counter intuitive, because you’re directly ingesting the toxin, but you don’t absorb nearly 100% of it. In occupational cases, you’re exposed to far higher levels and not in places where your stomach acids and gastric pits can prevent absorption.


The FAQ page in question, for reference:


As a Californian, I apologize for this notice. I would suggest you do what we do and ignore that shit. Everything in excess is known to cause cancer given enough time and exposure, even dihydrogen-monoxide. The nanny state in it’s effort to protect us against litigation and against stupid has put that notification in so many places now that it’s basically irrelevant now.


These kinds of things are always more worrisome with Soylent for people who are consuming nothing but Soylent. With fish or something like that you might have it here and there, but when you’re consuming 2000 calories every day that’s 42.8 Cadmium every day. I tend not to get worked up about these kinds of things, but I definitely worry more with Soylent than normal foods.


I have nothing against California’s pro-active legislation on the matter, but the heavy metal content of Soylent is of negligible concern. A cup of spinach contains about 10 times the cadmium levels. 4 oz of sunflower seeds contains about 7 times as much.

One thing that does bother me is that the label requirement is more indiscriminate than it could be. By the same logic, you could label fuel cell cars with: “Contains chemicals known to the State of California to be used for hydrogen bombs”. It’s technically accurate, but not really worth warning people about.


But are people surviving on nothing but spinach or nothing but sunflower seeds? Because some people are quite literally surviving on nothing but Soylent. That’s where the difference comes in.


Surviving on nothing but Soylent is slightly irrelevant. I could easily see myself having a daily snack of 4oz of sunflower seeds (currently I have almonds and pistachios) and/or having a salad with a cup of spinach every day for lunch (a woman at work does this). This would be on top of whatever else I eat, which will also have some amount of heavy metals in it. So even if I was 100% Soylent I would be getting significantly less of these metals than if I was eating normal food.

Also are the amounts of heavy metals in Soylent anywhere near what is considered dangerous? Remember you body is well equipped to deal with heavy metals and other toxic substances in small enough doses.


But are people surviving on nothing but spinach or nothing but sunflower seeds?

Let me be clear. A cup of spinach has about 10 times as much cadmium as ONE serving (500 kcal) of Soylent. Whether or not someone is living entirely on it is a moot point. Even a healthy daily amount of spinach is going to contain more cadmium than Soylent several times over.

As for the arsenic levels, the Codex Alimentarius project has addressed this issue ad nauseam.

According to food safety toxicologists, the issue of arsenic levels in food is not a typical food safety issue in that there are no known instances of illness nor are there scientific studies that directly connect arsenic in food in general, or in rice specifically, to any adverse health effects in the U.S.
It is also important to know that foods contribute only 20% of dietary arsenic exposure and that fruit and vegetables as a group contribute a greater amount than rice and other grains. Water accounts for the remaining 80%.

Let’s recap:

Lead - negligible concern
Arsenic - negligible concern
Cadmium - negligible concern

(Source: Probabilistic Modeling of Dietary Arsenic Exposure and Dose and Evaluation with 2003-2004 NHANES Data, U.S. Environmental Protection Agency, March 2010, Xue et al.)


The point wasn’t really about surviving on one thing. The point I was trying to get at was that very few people have a daily snack of 4 oz of sunflower seeds every single day. Even with spinach, very few people will literally eat spinach every day. (To preempt the “it depends on the person” crowd, yeah, it depends on the person.) With Soylent users, many will consume a pouch a day every day.Sorry if I wasn’t clear at first.

Quite a few people consume 4 servings of a Soylent each day. Not a lot of people consume literally eat a cup of spinach every single day, and for those that do, this is probably something they should watch out for. On top of that, you are comparing Soylent to some of the worst offenders in each group, but you aren’t looking at all the groups together. Just because something else is worse doesn’t mean Soylent doesn’t have a concern.

I really hate this kind of rhetoric. It’s been talked about before, okay. That doesn’t mean everybody has seen it or even that there was a consensus.

I’ll just stop right there and say that Soylent is not your typical food. Most people eat a variety of foods as well, and on top of that, the absence of evidence is not the evidence of absence. I never said that Soylent had in issue in the positive form of the argument, I simply said it was worth watching out for and that there were added concerns.

Well simply saying “negligible concern” is subjective. On top of that, as I mentioned earlier, absence of evidence is not evidence of absence. If you want to make the positive claim that this is not an issue, you need proof of that. You can’t say that since there is no evidence to the contrary, there is no problem. It’s better to be on the safe side and be conservative with this kind of stuff rather than write it off as not a concern and later find out there were serious concerns.


I think you may be missing the point @sylass94 and I are trying to make. You can reasonably expect to be exposed to higher levels of various heavy metals on a diet of regular food than a diet of Soylent.


You can be, but typically the diversity of a person’s meals will help level things out. I know what you are trying to say, but I’m not sure you know what I’m trying to say. If you do, then we may simply be stuck at a point of disagreement.