Hacker Newsnew | past | comments | ask | show | jobs | submitlogin

Long-time swimmer here. Without extra magnesium, I will get spasms in my legs from time to time while exercising. With extra magnesium, I don't.


I used to be a competition bicyclist - daily training sessions of hours and hours. If you don't get enough magnesium, look at your diet. With normal healthy food you should get more than enough.


>With normal healthy food you should get more than enough.

No, I looked into it some years ago and it seems unfeasible. For instance you'd have to eat about 15 stalks/heads of broccoli daily to get the RDA of magnesium, and that amount is likely suboptimal.


I had a look at https://ods.od.nih.gov/factsheets/Magnesium-HealthProfession..., and I can definitely say that with the amount of food I was eating during my bicycling years I would have no trouble at all getting my RDA.. :) But the situation would look more grim if I were just sitting in a chair all day and eating small meals just because I didn't get hungry enough to eat more.


I'm working on a food delivery service that helps count macro- and micronutrients (in Shanghai).

RDA of magnesium is ~400mg, which is reachable with ~300g of cooked salmon or halibut (~600 kcal), or 350g cooked navy beans (~250 kcal).


An ounce of pumpkin seeds and a cup of black beans and you'd only have to eat 7 servings of broccoli.


I do eat quite a lot of broccoli but I still don't fancy eating 7 heads every day -- enough to cover two dinner plates.

So I take a magnesium tablet before bed. Less work to prepare and to digest.

The present moral aversion to supplements seems faddish to me. We've gone from one extreme in the 1960s where everyone looked forward to taking all food in pill form, like fictional astronauts, to another extreme where supplements of any kind are frowned upon by many including in the medical establishment. Some supplements don't absorb very well, it's true, and some consumers are irresponsible -- yet atoms are atoms and molecules are molecules regardless of the source.


The problem with that sort of suggestion is that by the time you're eating the food that high in this and the food that's high in that and the food that's high in the other, you've gotten to your ~2000 calories for the day and are still missing nutrients, plus your diet is infeasibly bland.

There are some things that if you can't get them from a normal diet are certainly most easily obtained from supplements. Vitamin D, depending on your location, is certainly one. There's reasonable evidence that magnesium is another. IIRC, there's a couple of others where even eating a normal healthy diet won't really get you to where you ought to be. There's also plenty of vitamins where unless you eat a really crazy diet, or you've got some sort of absorption disorder (I'm in that camp so I've had to learn more about this than I really would have cared to), you're never going to be deficient, because you get plenty. Vitamin C, for instance, is effectively impossible to be deficient in. There's a lot of ongoing debate about the virtues of doses higher than "not deficient", but you'd have to go out of your way to get scurvy in the modern world.


Then maybe the RDA is just wrong. If we can't eat enough healthy food to sustain us without becoming obese, then the numbers are wrong. I mean, how could we have possibly made it as long as we have as a species if we are only now realizing that we can't eat enough good foods to be healthy???


>how could we have possibly made it as long as we have as a species if we are only now realizing that we can't eat enough good foods to be healthy?

Partly due to agricultural soil depletion of certain elements like magnesium, zinc, iodine.

Btw our prehistoric ancestors weren't especially healthy either:

https://imgur.com/gallery/2G0BDwx


> Partly due to agricultural soil depletion of certain elements like magnesium, zinc, iodine.

Well, maybe yes or maybe no

https://www.sciencedirect.com/science/article/pii/S088915751...


It wasn't poor health killing people at 30. The leading cause of death at that age was hunting accidents. Besides that and the high infant mortality, people otherwise lived to ~70.


In addition to trukterious' point, which I agree with, I would echo that the idea that the RDA is just wrong is also a distinct possibility. Take a look at this: http://blogs.creighton.edu/heaney/2015/02/13/the-iom-miscalc... Ponder what it implies about the other RDA values. And look at the date. It wasn't that long ago.

I just pulled a fairly recent bottle of CostCo Vitamin D out here, and it's still using a value of 800IU as the RDA.


This seems like an example of the naturalistic fallacy.

Why assume that food with the optimally healthy composition of nutrients exists in nature? People can survive just fine without being maximally healthy.


I didn't say "maximally healthy". It is, however, rather obvious that we were healthy and able to last this long and THUS the foods we had to consume gave us what we needed without having to take supplements.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: