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Comment by electrondood | Hacker News Reader

This is in line with what I've heard about sodium in the diet, which is that it's not bad in itself, but in proportion to your potassium intake.

I'd guess most Americans are deficient in magnesium and potassium, especially anyone who exercises regularly. If you're a male athlete, your actual magnesium need for example is about 800mg, which is twice the RDA of 400mg, which you're probably also not meeting.

I've helped people cure their chronic anxiety by noticing that they ran for an hour most days, and were taking zero supplemental magnesium.

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Not medical advice, but for folks looking to supplement with Mg, it's best to avoid Magnesium oxide, as it is very poorly absorbed. Magnesium chloride and Magnesium bisglycinate are much better absorbed.

There are charts out there showing the bioavailability of different compounds. As a rule of thumb, the oxide versions of a mineral (e.g. magnesium oxide, zinc oxide) are often the cheapest and least bioavailable versions.

I’ve had the best luck with magnesium threonate.

Where do you get 800mg of magnesium from? I just checked my multi-vitamin and it has 0 potassium and only 120mg of magnesium - my guess is to limit how much you end up just pissing out the first few hours after taking it.

I buy magnesium glycinate by the kilogram and just scoop the powder, aiming for a gram (2200mg of magnesium) by the kilo it costs 30-35 dollars, it's practically free as far as supplements go so I don't really care if I'm pissing most of it out, although it doesn't seem like I am. I am hesitant to mention the place I buy from because this doesn't seem like the place that looks kindly on promoting supplement companies. The only thing I ever ran into supplementing magnesium was disaster pants from choosing the wrong one (i.e. magnesium citrate, but I am sure others cause disaster pants at low doses too)

My working assumption about multivitamins is that they contain enough of a given vitamin/mineral to _say_ it's in there, but not enough to cause problems caused by an excess of that nutrient. Which makes them not very useful for nutrients which are commonly quite low in the common diet (like magnesium).

Magnesium, for example, is a laxative in higher doses. If you're selling a multivitamin, you don't want to be giving your customers diarrhea, so you run the numbers and put in just enough magnesium so that your customers will get the benefits of your product without tipping the scales into diarrhea-ville.

On a side note, if your multivitamin is using magnesium oxide, it's barely getting absorbed by the body anyway.

The better magnesium forms (like citrate) tend to be very voluminous. They might not want to make multivitamin pills large because people tend not to like that. That's my personal hypothesis. (People who have decided that they want magnesium specifically and are informed about the better forms will just (have to) accept the bigger pills.) Also, price probably plays a role.

arcanemachiner says >" if your multivitamin is using magnesium oxide, it's barely getting absorbed by the body anyway."<

Magnesium oxide works fine.

Suffered repeated bouts of cramps after hard swim workouts for 15 years (Masters' swimming). One day driving home a guy on the radio explained that you need as much magnesium as calcium. I began taking magnesium oxide. Results: no more cramps, breathholding ability way up and enjoyed a far more relaxed swim stroke.

Did you take MO as part of a multi or just as a standalone supplement?

I was taking a calcium pill (eating bananas too for K) and wondering why my cramps persisted. I added MgO and (poof) the cramps vanished and other good side-effects appeared immediately.

Though Ca and Mg are often combined, some combinations may be marketed differently. For example "Rolaids" is sold primarily as an antacid but is little more than calcium:magnesium oxides in the ratio 1:5. It tastes better than most CaMg supplements so, if someone wants to merely try a supplement, I recommend Rolaids!

Most Ca+Mg supplements have a ratio 1:2 of the oxides.

Nuts: walnuts, cashews, almonds, sunflower seeds

coincidentally i spent much of monday investigating the answers to that question

supposedly magnesium costs about 25¢/kg as caustic-burned magnesia https://pubs.usgs.gov/myb/vol1/2018/myb1-2018-magnesium-comp..., but that includes lots of impurities, probably including lead; you wouldn't want to eat it

the cheapest reasonably food-grade source i've found is probably food-grade magnesium chloride for supplements; it's hard to tell how much you're getting because magnesium chloride exists in various hydration states

here in argentina it costs 3.6 dollars per kilogram, which works out to somewhere between 11 and 36 dollars per kilogram of magnesium

the carbonate, the dead-burned oxide, and the hydroxide are also sold by the kilogram as food supplements; they don't have the hydration problem, and the prices i came up with were respectively

- 20 dollars per kg of carbonate and thus 70 dollars per kg of magnesium

- 15 dollars per kg of dead-burned food-grade oxide and thus 24 dollars per kg of magnesium

- 23 dollars per kg of hydroxide and thus 54 dollars per kg of magnesium

other non-food-grade sources i found in my search included galvanic protection anodes for hot-water heaters (35–44 dollars per kg); magnesium sulfate for bath salts, laxative, or fertilizer (17 dollars per kg of magnesium for the fertilizer, 24 for the bath salts); dolomite as fertilizer (20 dollars per kg of magnesium); and magnesium carbonate chalk as exercise equipment (91 dollars per kg of magnesium)

(my reason for this search was for formulating carbon-neutral cements, not supplementing my dietary magnesium, so i'd be delighted to find a non-food-grade source that was closer to 24¢ than 24 dollars)

24 dollars per kg of the oxide is 2.4¢ per gram

the chloride is highly water-soluble (you have to store it in a hermetically sealed container to prevent deliquescence; i bought a kilogram hermetically sealing jar from the health food store) so it's very easy to add to food. unfortunately it makes the food taste like horse shit, or more precisely like chewing on rubber bands, because those magnesium ions are extremely bitter

the oxide and hydroxide are almost perfectly insoluble in water, and the carbonate nearly so, and consequently they will not make your food taste like an accident in a quinine factory. they're just a little chalky. stomach acid converts them to the chloride, which is why mylanta is largely magnesium hydroxide

the other thing to keep in mind, aside from disturbing your stomach acid homeostasis, is that magnesium is a laxative. mixing it with food instead of taking it by iteslf helps with this. however, you don't want to mix it with food which is a good source of phosphate, such as coca-cola or high-phytate plants like flaxseed or beans, because the magnesium phosphate thus produced in your stomach has basically zero bioavailability. it doesn't matter if the phytate gets broken down by cooking because what it gets broken down to is phosphate

the oxide brand is a local argentine thing called 'natural whey', so you won't be able to find it abroad https://articulo.mercadolibre.com.ar/MLA-1165077489-oxido-de...

I take potassium and magnesium supplements in order to compensate for some preparation methods that I use to remove some undesirable substances from some vegetables, e.g. starch and phytic acid, but which end with a washing that will also remove some water-soluble substances like potassium and magnesium.

I have experimented with many variants, but I have eventually settled to use potassium citrate powder and magnesium bisglycinate powder.

I add these powders to the food together with the table salt. The daily intake costs me about 30 cents for both of them. It could be cheaper if I would buy them in greater amounts, but it does not make much sense, because even a box with 200 g to 400 g of powder would be enough for many months and if I would buy e.g. 1 kg I would need more than a year to consume it and there might be some degradation after all that time. I prefer pure powder because it is not only cheaper, but it also does not contain useless or maybe even harmful excipients, like pills or capsules.

I have also tried magnesium citrate, which is cheaper, but I have switched to bisglycinate because the latter is soluble in water (so like the common salt and the potassium citrate it disperses easily to attain a uniform concentration in the entire food) and it is also unlikely to form insoluble precipitates with any component of food (magnesium chloride will form insoluble precipitates with phosphate and with some organic acids from food), so it has the best chances for intestinal absorption.

Neither magnesium citrate nor bisglycinate modify the taste of the food, because the citrate is almost insoluble, while in the soluble bisglycinate the magnesium ions are not free, but chelated (i.e. surrounded) by glycine molecules. With magnesium citrate sometimes there was a mild laxative effect, because the stomach acid dissolves it and free magnesium ions reach the intestine. With bisglycinate I have not noticed anything, because it is not decomposed prior to absorption.

You can also put these powders directly in (hot) water as a tea-like drink. On their own they’re a little bitter (but IMO not unpleasantly so), but you can combine them with an actual tea (or something by sweet like squash) at which point the taste modification is quite mild

I would expect extremely poor bioavailability for dead-burned magnesium oxide. It's called "dead" burned because it has very low chemical reactivity when it's been heated that intensely.

don't eat the not-dead-burned version; the most common kind is as caustic as lye and will cripple you for life by burning your esophagus

'very low chemical reactivity' turns out, in context, not to mean that it resists being digested by stomach acid, so the bioavailability of the dead-burned type is just fine; this experiment came up with a figure of 43% https://pubmed.ncbi.nlm.nih.gov/2407766/

if it were 4% or 0.4% i would agree

That's higher than I expected. Thanks for the citation!

Furthermore, magnesium levels in soils are typically fairly depleted, so the FDA labeling for fruits and vegetables is often incorrect (having been measured a long time ago).

Most endurance athletes I knew equated bananas with potassium and carbs, but they're not a bad source of magnesium either.

Bananas are okay, nothing magical, speaking as a pretty good badminton player. Genetics is a big deal in athletics. You have to supplement whatever your parents didn't pass on to you.

Bananas are a passable source of potassium only when ripe. That quickly converts to sugar in a day or two. By the time light brown spots appear, most potassium is gone. Sunflower seeds and avocados are far better sources.

Are you thinking of fiber? Potassium is a metallic element. It can't be turned into sugar.

I think I am, yeah. The potassium benefit vs sugar content lessens as they ripen. They never actually LOSE the potassium as I stated.

I thought 300mg supplementation was the max your body could absorb each day.

If you do a lot of sport, you should take more than that?

I don't know about magnesium specifically but I know there were experiments with calcium showing that supplementation both a) didn't absorb 100% of whatever you took, and b) had an upper limit for what could be absorbed over N hours. At a certain point you just have to eat food with calcium in it. I wouldn't be remotely surprised to find that's true for most/all micronutrients.

Supplementation can help, sometimes, but will always be a fraction as impactful as a healthy, well-rounded diet.

Calcium and magnesium share some pathways for absorption and compete with each other. Not only is there a limit to how much calcium or magnesium you can absorb, but if you have a high-calcium diet, your body will absorb less magnesium.

There are other minerals which have this kind of competition, so supplementing with one mineral can cause problems with absorption of another.

IIRC, calcium uptake from the intestines is boosted by the presence of fatty acids. Different types of magnesium supplements have different absorption rates (e.g., magnesium oxide vs magnesium glycinate).

You can also take vitamin D3 to increase your calcium absorption.

Even to the extent that that may be true, it is going to be an average: different people's bodies will be different in what they can absorb, and the same body at different times will be different. Sometimes dramatically, particularly if you have a deficiency.

What doesnt make sense is the role the kidneys are not playing in a high sodium diet.

Sure there is the sodium potassium pump in cells, but what are the kidneys doing as they should be clearing the sodium, maintaining the balance.

Thank you! Probably sodium makes blood heavier and the heart has to work harder to pump it. I've had the same thinking about higher haemoglobin numbers (which I do, i am at too high HB for men) and I do suffer from borderline higher blood pressure since my adolescence (not to mention anxiety). Probably I should start taking more Magnesium to balance the minerals. Read somewhere on the internet that we need to balance the metals in our blood. Sodium, Potassium, Magnesium, Iron and Calcium lead to a healthy CVS system.

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