Calcium Carbonate and Magnesium Oxide in Soylent - Dangerous?


Hello all,

I just turned 21 and I have been dealing with chronic disease for about 3 years now including a very aggressive autoimmune disorder along with suspected chronic Lyme and coinfections. I have constantly done tons of research on all sorts of different aspects of health on both the allopathic and alternative sides in the quest to regain my health and understand what is going on. I recently came across Soylent and I really like the idea of it, yet I’m skeptical about a few ingredients in the official Soylent - especially calcium carbonate and magnesium oxide in particular. I already ordered a week’s supply regardless to give it a fair try and see if it helps me in any way. I haven’t come across any discussion about calcium carbonate and magnesium oxide on these forums so far, so I decided to make this thread.

Anyway, when I was searching for answers to my health issues (for which every doctor I have seen so far has been totally and utterly useless in solving) I came across a guy named Hveragerthi on who debunked a lot of bullshit that circulates around on curezone and I found him to be very intelligent and helpful. He was able to help massively reduce the severity of my autoimmune with his advice where all the doctors I have seen failed entirely, and as a result I have a lot of respect for him and his information.

Note: Skip this paragraph if you have no interest in learning about autoimmune. If anyone else is dealing with autoimmune or is just interested in this information he has a brilliant writeup on autoimmune disorders here: and the basic gist of it is this: “Autoimmune disorders result from immune suppression, not hyperactivity as is commonly believed. It is the suppression of the adrenal glands that leads to the over production of low affinity (nonspecific) antibodies that tag healthy tissues for destruction. The rest of the immune system does its job just as it is supposed to. This is also why immune suppressants, such as stress, stimulants and steroids actually make autoimmune conditions worse.”

Hveragerthi frequently warns against the use of calcium carbonate and magnesium oxide. Here are some related quotes from him:

“Calcium carbonate is frequently used as a cheap calcium source. Common sources include oyster shell, coral, some antacids and dolomite. The problem with carbonates is that they will neutralize stomach acid.

“Carbonates neutralize your stomach acid, thus leading to a host of problems. These include acid reflux, infections, reduced ability to digest proteins, reduced ability to absorb minerals and some B vitamins like B6, B2 and folate, and further reduction of stomach acid due to the lack of absorption of zinc and B vitamins needed to synthesize stomach acid.”

“The form of calcium is also important. Calcium carbonate, including coral and Tums, is garbage. It neutralizes the stomach acid decreasing the absorption of the calcium and other minerals, as well as some vitamins needed for bone strength. It is the cheapest form of calcium though, and so is found in many supplements.”

“Not all forms of magnesium are the same though. Magnesium oxide is the most common form sold because it is so cheap for manufacturers to use. But it also the least absorbed. When it comes in to contact with water it forms in to magnesium hydroxide, which is caustic to the tissues. It is frequently used as a laxative because it burns the intestinal wall leading to a release of fluid in to the intestines and increased peristalsis.”

"Magnesium oxide cannot absorb as magnesium oxide. Instead, as with most minerals, the magnesium has to react with an acid turning it in to an absorbable salt.

Problem is that many people lack sufficient levels of stomach acid as levels drop with age and there is a major over use of antacids, acid blockers (proton pump inhibitors), carbonates and oxides in supplements and alkaline waters all of which further reduce stomach acid reducing mineral absorption.

In the case of magnesium oxide, when this is combined with water it forms the highly alkaline and caustic magnesium hydroxide. This not only neutralizes stomach acid, inhibiting magnesium absorption, but it also burns the intestinal wall
due to its caustic nature.  This is why magnesium hydroxide is used as a laxative such as Milk of Magnesia.

Acidified forms of magnesium, such as magnesium citrate or malate, do contain less actual magnesium.  But these are better absorbed than magnesium oxide and the amounts in supplements are increased to still meet the body’s demands.

Another simple way to look at this is that more is not always better.  Pure magnesium metal has more magnesium than magnesium oxide, but I would not advocate ingesting magnesium metal."

"For those who incorrectly think that magnesium oxide ingestion is safe:…

[A case of the milk-alkali syndrome with a small amount of milk and magnesium oxide ingestion–the contribution of sustained metabolic alkalosis induced by hypertonic dehydration].

We described a patient with the milk-alkali syndrome induced by the ingestion of small amount of milk (200 ml/day) and ice cream (145 g/day) and the administration of small dose of absorbable alkali (magnesium
oxide 2.0 g/day) for the treatment of chronic constipation. The present case shows not only triads, i.e., hypercalcemia (s-Ca 14.3 mg/dl), metabolic alkalosis (s-HCO3- 37.4 mEq/L), and renal insufficiency (s-Cre
2.3 mg/dl) but also hypernatremia (s-Na 161 mEq/L) and hypertonic dehydration after the frequent episodes of elevated body temperature. The milk-alkali syndrome has been defined as the hypercalcemia with a metabolic alkalosis from a high amount of calcium intake and long term administration of absorbable alkali in any form, usually as calcium carbonate for the treatment of peptic ulcer. As the present case could be distinguished from any other cases previously reported with regard to the amount of calcium (0.4 g/day) and alkali (36 mEq/day) intake and the clinical situations that induced the syndrome, we compared the present case with the previous reports, calculating the amount of calcium and alkali intake from milk and absorbable alkali. After the introduction of the H2 blockers for peptic ulceration, the most cases with milk-alkali syndrome had provoked by the smaller amount of calcium than previously reported, which were associated with the treatment of relatively large amount of alkali (50-150 mEq/day), suggesting the role of sustained metabolic alkalosis for the development. In the present case the metabolic alkalosis induced by hypertonic dehydration and enhanced by absorbable alkali intake also could cause an increase of renal tubular reabsorption of calcium and a decrease of ionized calcium which might produce increased secretion of parathyroid hormone followed by vitamin D3 activation and increased Ca absorption from the gut. The metabolic alkalosis might be essential to the development of the milk-alkali syndrome without a high calcium and absorbable alkali intake."

More on the importance of stomach acid:

“Neutralizing stomach acid is a VERY BAD idea. Stomach acid is required to absorb minerals, to control pathogenic microbes, to absorb some vitamins like B6, B12, and folate, and to properly digest proteins since the protein digestive enzyme pepsin cannot work without sufficient stomach acid. Therefore neutralizing stomach acid can over time lead to vitamin and mineral deficiencies, infections, allergic reactions to undigested proteins, arthritis and osteoporosis, etc.”

“It should be noted that most of the nutrients needed to form stomach acid are acid dependant for absorption. Therefore the lack of stomach acid leads to further declines in stomach acid, leading to less absorption of stomach acid forming nutrients, leading to less stomach acid formation…   It is a vicious cycle downhill once started.  Therefore I recommend avoiding antacids, acid blockers also known as proton pump inhibitors, alkaline waters, calcium carbonate (coral, oyster shell, dolomite), calcium oxide/hydroxide (lime) and magnesium oxide/hydroxide.”

Functions of stomach acid:

"Stomach acid is present to:

  1. Help protect the body from pathogens that would otherwise enter through the digestive system.  Many pathogenic bacteria, such as E.  coli and H. pylori THRIVE in an alkaline environment.  This is why E. coli lives in the part of the intestines that is alkaline and H.  pylori secretes ammonia to neutralize stomach acid to protect itself.  Reducing stomach acid just makes it that much easier for these pathogens to set up shop in the body where they DO NOT belong.

  2. To allow for the absorption of minerals as non-chelated minerals are reacted with the acid to convert them in to absorbable salts.

  3. Reduction of acid reflux, which actually results from the lack of stomach acid.  A lack of stomach acid leads to fermentation by yeast overgrowth in the stomach and by fermentation of foods not being digested properly.  The resultant gas formation builds up in the stomach and is eventually rapidly released up the esophagus carrying traces of acid with it.

  4. To allow for the proper digestion of proteins. The digestive enzyme pepsin cannot work without sufficient levels of hydrochloric acid (stomach acid). When proteins are not broken down properly the intact proteins can enter the bloodstream forming antigens. This in turn can possibly lead to serious and even life threatening allergic reactions.

  5. Absorption of vitamins. The B vitamins B6, B12 and folate in particular are dependent on sufficient stomach acid for absorption. Stomach acid levels decline though with age naturally. This is why deficiencies of B6, B12 and folate are so common in the elderly.

  6. Conversion of silica to orthosilicic acid for use by the body. Silica is essential for the formation of collagen, elastin, and chondroitin. Without sufficient silica we develop numerous conditions including osteoporosis, osteoarthritis, heart disease, emphysema, diverticulitis, etc. Even wrinkles and cellulite can result from a loss of silica leading to a reduction of the structural proteins collagen and elastin. In order for silica to be absorbed and utilized it must first be converted in to orthosilicic acid. This occurs from a reaction between silica and water, but the process is greatly enhanced by the presence of an acid. The primary acid for this conversion is stomach acid.

As I mentioned before stomach acid DECLINES with age. This leads to a drop in the conversion of silica in to orthosilicic acid, and therefore a loss of collagen, elastin, and chondroitin production as we age. Now go back and look at the symptoms that develop from the loss of these structural proteins.  Notice how these are not seen in younger people but are common in the elderly? So why do we see this in the elderly? Because the lack of stomach acid interferes with the absorption of nutrients needed for the production of structural proteins.  These nutrients include silica, zinc, copper and amino acids."

“As we can see if you want to speed up the production of ‘age-related disorders’ a simple way is to do this is to neutralize your stomach acid.”


The Real Problems With Soylent Are Not Fixed In Version 1.1

See a doctor in real life. Self diagnosis and internet doctors can safely be dismissed out of hand, 100% of the time.

To address your concerns, the bloodwork from volunteers didn’t indicate any deficiencies, so Soylent’s formulation avoids the anti-nutrient effects you’re worried about. As to the rest, no matter how well informed or well intentioned, you cannot trust your sources on the internet. If you have real medical issues, see a real life doctor.

Magnesium in Soylent comes from the oat flour. Calcium carbonate is added individually to Soylent.

There is a vast gap in your friend’s knowledge of the digestive process. Anything stomach acid dissolves “neutralizes” the acid - and that’s what the acid is for. To react with the food and dissolve it into a chemical slime that your stomach and instestinal cilia can sweep into your system. 2.5g of calcium carbonate is easily dissolved by a minimal amount of stomach acid. You produce 700 ml of stomach acid per meal. A single 1000 mg tums tablet (according to a science fair project I vaguely remember helping a little brother with) neutralizes 60ml of stomach acid. Assuming a 1 to 1 correlation of the effects of a tums tablet with calcium carbonate mixed into Soylent, 60x2.5 = 150ml of stomach acid is neutralized. The correct way to look at it would be “it takes 150ml of stomach acid to digest the calcium carbonate content.” It’s not taking away from anything else.


By the way, I’m not trying to be mean or snide - I literally mean that self-diagnosis and internet doctors should be disregarded in favor of real doctors consulted in person. The forum matters - and internet forums are not the place for medical advice. Maybe there’s a forum out there that’s all doctors talking amongst themselves, and they discuss medical issues and seek advice, but only other doctors are qualified to interpret, in context, the information they share. Only 8+ years of school gives you the foundational trivia and experience needed to distill the right answers (advice, diagnoses, etcetera.) You may be plenty smart enough, you may even be a doctor, but unless you’re explaining something trivially limited in scope (which nutrition and metabolism is not, even a relatively mundane chemical reaction between calcium carbonate and stomach acid) then there is a very large opportunity for miscommunication and misinformation, however well intended the conveyance of information.


@jrowe47 He indicated real doctors were useless in solving which I can relate to. My wife had a chronic health problem and if it weren’t for her and I doing research and managing her own medical file she would probably still be sick or dead. Doctors see you for about 1/2 hour and try to understand the problem well enough to prescribe a pill and get you out of their office. So unless you have experience dealing with very complex health issues you probably have no clue how frustrating it is to get well using Doctors as your only hope.

BTW I recommend a documentary called “Under our Skin” to seen how lime disease is not properly being diagnosed or managed by doctors today. It my be an eye opener for how the medical establishment isn’t always right.


@jrowe47 I understand, thanks for your replies.

I wasn’t asking for any medical advice. This post was only intended as a discussion about calcium carbonate and magnesium oxide in soylent and whether they actually have any significant adverse effects or not. My mind is not made up on either side of this issue.

I agree about self-diagnosis and internet doctors. That can potentially be very dangerous. I have been going to real life doctors and continue to look for the right one, but they haven’t been helpful so far with my main health concerns.

Magnesium in Soylent does not only come from Oat Flour. According to this link, magnesium (as magnesium oxide) is also added:

Can we really say that every person on this planet produces 700 ml of stomach acid per meal? Why would this not vary as compared to say testosterone levels which one guy may have a testosterone level of 140 and another may have a testosterone level of 780 for example? I know hormones are a completely different realm than stomach acid, but what I’m trying to get at is can’t the amount of stomach acid produced also vary significantly from person to person? Sure a healthy person SHOULD produce 700 ml of stomach acid per meal, but does everybody really produce this much? What about people who produce say only 200 ml of stomach acid per meal (assuming they exist)? Then assuming the carbonate neutralizes 150 ml, there is only 50 ml left and that may be insufficient for optimal digestion. What is wrong with this example?

Thanks again!

Edit: I’m not sure how my name changed from NinjaKnight to compdude but I’m the OP :smiley:


@NoFlames thanks for that, I agree :slight_smile:

I’ll also check out that documentary, I haven’t seen it yet.


Good catch. It looks like the old micronutrient breakdown is outdated. Probably they changed the formula to reduce oat flour and had to compensate. @JulioMiles can you confirm this? And hopefully post an updated micronutrient breakdown?


@compdude, I know regular doctors aren’t often helpful; I went to three, plus a naturopath (she was an Doctor of Naturopathy, at least), plus a specialist in bones and fascia, and it took them FOREVER to figure out what was wrong with me.

If you have insurance (or live in a civilized country with socialized health care) I cannot recommend enough: get a referral to a rheumatologist. Mine asked SO MANY questions and spent so much time with me, and I am confident in his diagnosis and treatment plan. Even his medical assistant inspires confidence. It’s just a totally different experience.


While we can most all agree that neutralizing stomach acid will have negative impacts on nutrient uptake, the point above remains valid. It would take a very, very large amount of calcium carbonate to take the pH in your stomach to 7. As for the amount of stomach acid varying, sure it will vary on body size, but the error bar won’t be that vast. Using the 700 mL value is a good starting point.

Do a mass balance on whatever values you feel comfortable with, or better yet, build a spreadsheet and determine how much calcium carbonate is required to alter the pH of your stomach based on various volumes and the calcium carbonate content of Soylent and go from there. This is a crude way of doing this, as the gut is a dynamic system, but it should give you perspective on how hard it is to alter pH with the amounts we are talking about here.


Your stomach acid is intended to be neutralized. That’s what happens as it breaks down the nutrients. 700ish ml per meal is generated, and if the calcium carbonate neutralizes 50ml per meal, then you’re left with around 92% of your stomach acid left for the rest of the food. It’s not enough to be a problem.