Laura Schoenfeld: Magnesium is one of those supplements that we would put in the constant supplementation recommendations, and there aren’t many that Chris suggests that people use indefinitely. Magnesium is one of those, and basically the reason for that is because a lot of our food supply is much lower in magnesium now than it used to be. Our soils have been depleted of magnesium. We’re also just not eating as much volume of plant foods as we used to, so our magnesium intake through food is a little bit lower than what we really need. Even if you’re eating a very healthy whole-foods, Paleo diet, the magnesium content is probably not going to be as high as it should be, based on, like I said, poor soil quality.
As far as what is long-term magnesium supplementation, this question is a little bit tricky to answer because is that forever? Is that for a year? Is that for six months? What is high dose? Maybe 1,000 milligrams of magnesium for six months would be considered too much long term, but if you’re taking 100 to 200 milligrams for the rest of your life, that might not be considered a problem.
As far as the dose I would consider safe for long-term maintenance, I don’t usually put anyone above, I’d say, max 400 milligrams per day, and I usually stick to closer to maybe 200 to 300 milligrams per day. A lot of my clients—and I will include myself in this—are not necessarily super-consistent with taking it every single day, which is actually not a bad thing. If you’re taking a maintenance supplement and you don’t take it every single day, it’s really OK. But there are some patients I’ve worked with, especially those that have chronic constipation, that they’ve been on really high doses for a very long time, like 600 or 800 milligrams a day, maybe even higher if they suffer from really severe constipation. I don’t like my patients being on that high of a dose for that long term. If we’re just looking at constipation, there’s really no reason that someone should need magnesium to have a bowel movement, and I’d rather fix the reason for them not having a bowel movement than let them be on high-dose magnesium for a really long time. Then as far as magnesium being a required mineral, it is, but you want to make sure it’s balanced with other things like calcium and some of the smaller minerals like zinc and copper and all that stuff. You don’t want to be taking huge doses of one mineral and not getting enough of the other one.
Long story short, I think 200 to 400 milligrams per day for most people is fine for a long-term, potentially indefinite dosage, with the understanding that people will probably take some time off from regular supplementation.
As far as the contraindications are concerned, I think that might be a better question for Chris, as far as what can be the downside of long-term magnesium dosage. The only reason why I’m saying that is because I have actually never had a client have any negative reactions to long-term magnesium use, so I’m not 100 percent sure, other than that hypotension issue, what the problems could be. I mean, we think about things about maybe calcium balance could get out of whack if you’re taking a lot of magnesium for a very long time. I don’t know if there’s a lot of data necessarily showing what the downsides of long-term high-dose magnesium supplementation is, but generally for most supplements, I don’t like to do anything that’s physiologically abnormal. If it would basically be impossible to get that much magnesium from your food, I don’t think it’s something you should be taking forever. I basically apply that logic to every supplement. If you can’t get that much from food, then I don’t want somebody on it for very long.