Q. People’s Pharmacy has gotten me into a problem with my dear wife. As a regular reader of your column, I always share stuff with her if I think it may help. Your comment about taking magnesium supplements to help alleviate persistent constipation is a case in point.

She started taking magnesium and it helped her bowel function immediately. I was happy to have her benefit from your column. So what’s the problem?

Her 90-year-old father, a long-time heavy user of milk of magnesia, is now having significant kidney malfunction issues. His medical advisors have identified the laxative as the cause.

My wife has abruptly stopped using her magnesium supplement because of what is occurring with her dad. Could you kindly comment on any kidney risks associated with magnesium?

A. Magnesium is essential for muscles, nerves and bones. This mineral helps regulate blood sugar, blood pressure and heart rhythm.

The daily RDA is 420 mg for men and 320 mg for women. American diets are frequently low in magnesium, and commonly prescribed blood pressure medicines containing diuretics may deplete this mineral.

People with kidney problems are unable to tolerate excess magnesium. They should avoid supplements, laxatives or antacids that contain this mineral. Overdosing on magnesium may overwhelm the system and result in magnesium toxicity. This may be what happened to your father-in-law because of his milk of magnesia habit.
If your wife’s kidney function is normal and her physician monitors her magnesium levels she should be able to tolerate up to 350 mg daily.

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  1. Freedom Run

    Well it is quite difficult to put a limit on that, on behalf of all mankind, isnt it? It varies from individual to individual and from situation to situation. Setting standards on behalf of all mankind is exactly one of modern medicines problems. It needs to be fixed in someway.

  2. Freedom Run

    Excellent advice. The problem described above is probably not the magnesium, but because it is an unbalanced use of the nutrient. When it comes to minerals (and much else in life really), finding a balance is what counts and solves problems. Using magnesium to treat acute health concerns, can often help, but in the long run you will need to rely on balancing your overall mineral intake.
    We could very often benefit from supplementing with minerals, but it has to be done right, sometimes monitored, at the right balance and taking in assorted health concerns of the specific individual. Again: as much else in life… Setting an upper limit on magnesium intake to just 350 mg/day, is in my opinion on the “too safe to work wonders” side of things. Healthy individuals, can tolerate very high amounts for quite some time, it is very non-toxic. I believe the advice on 350 mg is to avoid recommending something that potentially could be harmful to a seriously ill or health-challenged person. A typical doctors advice. Especially in the country of America, where insurance have penetrated and sadly distorted many ordinary activities unfortunately. Its alright with me, I understand it all, but as I said this limit is on the “too safe to work wonders” side of things. Reply if you like.
    PEOPLE’S PHARMACY RESPONSE: People without kidney disease can probably judge if they are getting too much magnesium based on whether they develop diarrhea. Diarrhea is an indicator that it’s time to cut back.
    We agree that balance in minerals and even vitamins is undoubtedly the best way to go. It isn’t always easy to get personalized advice on that, though.

  3. Freedom Run

    Because doctors advice are most often beyond diets and nutrition. Why? Because they are not educated in it. Because people should check up on the own diet BEFORE contacting a doctor. Because doctors are often called to solve problems immediately, which can often be difficult if you only rely on a diet- or habit-change. Your advice is excellent and simple.

  4. EM

    I added a magnesium supplement after reading your comments in above article & it did for me what no amount of flax, oat bran, Psyllium or other fiber has been able to do- help with regularity without bloating or gas.
    I take 200mg. twice a day with meals. I don’t want to cause any damage to my kidneys . Is this safe for long term use?

  5. LGF

    I would like to know about absorption through the skin, as I, too, use it as an antiperspirant/deodorant.

  6. Terry

    If you want to alleviate constipation, just eat a half-cup or more of 100% WHEAT BRAN every day. I buy a big bag of it for only $1.30. Now, even with Milk, it’s like eating sawdust!!! So, I cover it with Pancake Syrup, and it’s then more than edible.

  7. Connie

    We women are supposed to have about 1200 mg of calcium per day–and we’re supposed to have half as much magnesium. Well, that puts us well over the 350 mg that Joe and Terry say should be the top amount.

  8. Brent B.

    Whenever magnesium is taken, it should be balanced out with calcium. I’ve also heard that only a small percentage of the magnesium in magnesium oxide tablets is actually metabolized by the body. So you might want to use a form like magnesium glycinate or magnesium taurate, to get a greater benefit. I also use the epsom salts (magnesium sulfate) in my bath water, and it seems to make quite a difference in my health. And you can also use flax seed oil softgels for a great fiber / regularity solution. Moderation and balance are the right approaches — and be sure to listen to your body and discontinue anything that causes you trouble!

  9. EJ

    Why are you not suggesting using a daily scoop of ground flax seed either on breakfast cereals, or mixed in yogurt and/or or sliced fresh fruit in the morning? If that doesn’t ensure “regularity”, use psyllium husks or some comparable vegetable bulking agent [on a one-time basis] & then start using ground flax seed to keep functioning normally..

  10. Judith M.

    I have started taking 500 mg of magnesium a day and I feel so much better. I do however uses milk of magnesia as a deodorant. Could absorption through the skin, along with the daily dosage be too much magnesium and affect the kidneys?

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