Dispelling nutrition myths, ranting, and occasionally, raving


What you need to know about magnesium


Photo “nuts!” by Adam Wyles on Flickr, used under a Creative Commons Licence.

I recently read an article about magnesium that someone shared on facebook. Shockingly, for FB, it wasn’t nearly as inaccurate as I had expected. However, there were a couple of things in it that I wanted to address. The premise of the article was that most of us are magnesium deficient. This is untrue. Most of us don’t consume enough magnesium but there’s a world of difference between that, and being truly deficient. Magnesium deficiency manifests as an irregular heartbeat which may be accompanied by weakness, muscle spasms, disorientation, nausea, vomiting, and seizures. People who are at greatest risk of magnesium deficiency include: users of some diuretics, those with diabetes, people with alcoholism, as well as those who live in climates where they experience frequent heavy perspiration or those who have long bouts of vomiting or diarrhea.

So, how much magnesium should you be consuming? If you’re a man between 19 and 30 years of age, you should be consuming about 400 mg a day. Women in this age group should be consuming about 310 mg a day. Needs increase beyond this age by about 20 mg/d for men and 10 mg/d for women, and for those experiencing the conditions listed above. For more information of magnesium recommendations, click here. According to one of my old nutrition textbooks (Perspectives in Nutrition by Wardlaw and Hampl), assuming things haven’t changed that much in the past eight years, men consume 325 mg, women 225 mg, on average each day.

It’s not that terribly difficult to reach the recommended intakes of magnesium. One cup of spinach contains 157 mg, one cup of squash `105 mg, 1/4 cup of wheat germ 90 mg, 1/2 cup of navy beans 54 mg, 1 cup of plain yoghurt 43 mg… Nuts and seeds are also good sources of magnesium; as is dark chocolate and raw cacao (nibs, powder). Other leafy greens, beans, and legumes are also good sources of magnesium.

If you do decide to take a magnesium supplement, you should be aware that they are not all the same. Magnesium oxide tends to be the most common and inexpensive form of supplemental magnesium. However, it is also the most poorly absorbed form of magnesium. Liquid magnesium supplements will be best absorbed; the quantity of magnesium listed on the label is not as important as the form. As far as tablets and capsules go, Magnesium lactate, magnesium gluconate, and magnesium citrate are the most absorbable. However, magnesium citrate may have laxative effects, and magnesium hydroxide and magnesium sulfate are forms commonly used as laxatives. Zinc supplementation may interfere with magnesium absorption, while vitamin D supplementation may enhance magnesium absorption. Some medications may also affect magnesium absorption. As with any supplement, you should always check with your pharmacist to ensure that there will be no interactions with any other medications you’re taking. As with any nutrient, it’s best to try to get it from your food rather than from a supplement.


What to do if you’re tired

My recent decision to start following Dr Oz on twitter for blog fodder is now paying off. Yesterday I saw a tweet from him suggesting that if you were feeling tired that you might be suffering from a magnesium deficiency. While this is plausible (most North Americans don’t get enough magnesium – the above photo shows some good sources of magnesium), it’s certainly not the first avenue I would explore when someone complains of being tired. It’s funny how many of us seem to have forgotten about sleep as the most important contributor to preventing and alleviating fatigue. I’ve had people complain to me about feeling tired and then ask me things like “should I eliminate wheat?” Good nutrition definitely plays a role in how you feel and your energy levels but if you’re feeling fatigued and lethargic there are probably other avenues you should explore before nutrition, and definitely other nutrients you should explore before magnesium.

Here’s the line of questioning I would employ when feeling tired: How much sleep did I get last night? If I got less than eight hours I would attribute much of my fatigue to that. If you’re not getting enough sleep try quitting all electronics an hour before bed. Try getting into bed with a book at least half an hour before you actually want to fall asleep. Make sure that your room is as dark as possible. You may need to employ ear plugs and/or an eye mask to block out distractions, sexy no? There are lots of other tips for getting a good nights sleep. I googled some for you here. If duration or quality of sleep are not the culprits I would next ask how much exercise you’re getting? I know it sounds kind of counter intuitive but exercise can actually boost your energy, it can also help improve your sleep. Nutritionally, I would next ask if you’re getting enough water. I always keep a water bottle at my desk and when I get the post-lunch-sleepies I make sure to turn to the water before getting another coffee or tea. Nutrient-wise, I would first wonder if you’re getting enough iron, vitamin B12, and protein. Failing all that then I might explore magnesium, among other nutrients.

If you’re always feeling tired and this is a concern to you then you should probably see your doctor to determine the cause. While many of us don’t get enough magnesium this is rarely the primary cause of fatigue. Don’t diagnose yourself from a television personality.