The Nutrition Diva's Quick and Dirty Tips for Eating Well and Feeling Fabulous

Stop trying to micromanage your nutrients

Episode Summary

Nutrition Diva wades in to settle a marital squabble about how to take your calcium.

Episode Notes

Nutrition Diva wades in to settle a marital squabble about how to take your calcium.

Nutrition Diva is hosted by Monica Reinagel. A transcript is available at Simplecast.

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Episode Transcription

Hello and welcome to the Nutrition Diva podcast. I’m your host Monica Reinagel and today I’ve got a question from Caryn about calcium supplementation. 

I always love the opportunity to settle a marital squabble (you can think of me as the Judge John Hodgman of Nutrition), so the opening of Caryn’s email hooked me right away. 

“My husband is always hounding me to take my calcium supplement with a food source of vitamin C. This is not always possible, especially since I follow my DOCTOR’S recommendation to take calcium and magnesium supplements separately. My calcium supplement already contains vitamin C, so is taking it with additional C really necessary?”

Before I render my ruling in this case, a quick sidebar to address a couple of issues that Caryn’s question introduces. 

To tell you the truth, I was a bit confused by the doctor’s recommendation to take magnesium and calcium separately. Calcium and magnesium are both important for bone health—and foods that are high in one are often high in the other as well. This does not appear to be a problem in terms of absorption or metabolism. In fact, consuming them together may actually provide some benefit. These two minerals are often combined into a single product, affectionately referred to as a Cal-Mag supplement.  

But of course, supplements often provide nutrients in amounts far (far!) beyond what you’d get from foods. And high doses of a single nutrient can create imbalances or other issues (such as inhibited absorption) that would be very unlikely to occur if you were getting your nutrients from food sources.

Calcium over-supplementation is a real problem, in my opinion. Middle-aged women have been terrorized by the calcium-industrial complex into taking huge doses of supplemental calcium (with or without magnesium), in an effort to fend off osteoporosis. It’s not that osteoporosis is not a real threat. The problem is that most women don’t take this threat seriously until they get into their 40s and 50s, which is 20-30 years after their prime bone-building years. In an effort to make up for lost time, they start taking fistfuls of calcium every day. 

Not only is this not a very effective bone-building strategy, but high doses of calcium in midlife can lead to calcium build-up in the arteries, which (aside from your kidneys) is the last place you want extra calcium to be hanging out. 

Calcium is not the only nutrient involved in maintaining bone health, of course. And calcium-containing foods, including dairy products, cruciferous vegetables, fish, and tofu, conveniently provide many of those other important nutrients as well. If you’re worried about bone health, my advice is to get as much calcium as you can from your diet—and supplement only as much as you need to close the gap between what your diet provides and the recommended intake. For most women, this is likely to be 500 mg or less a day.  

But back to the issue at hand: I have no idea what dose of calcium and magnesium Caryn’s doctor has recommended, or what issues the doctor is trying to address with that supplementation. So I’m not in a position to have an opinion on whether it makes sense to take them separately. Hopefully, Caryn has a good enough relationship with her doctor that she feels she could ask for clarification—or even research to support—the recommendations that the doctor is making.

Of course, I feel no such compunction about wading into the marital dispute over calcium and vitamin C. 

What exactly is the advantage of taking calcium with vitamin C? The truth is, I am not at all sure. I poked around a little to see if there was research on vitamin C enhancing calcium absorption that I might have missed. I couldn’t find any. In fact, the one study I found which addressed the question directly found that vitamin C had no effect on calcium absorption one way or the other.

Perhaps there’s some other rationale behind the husband’s hounding (which, I’m sure, is totally well-meaning). For example, I notice that he seems unsatisfied by the fact that Caryn’s calcium supplement already contains vitamin C and specifically wants her to be taking her calcium pill with a “food source” of vitamin C.

But for me, most conversations of this sort eventually come down to this: The ways in which individual nutrients interact are so numerous and so complex that it’s virtually impossible to document them all—much less micromanage them. 

Which certainly doesn’t keep us from trying. You’ll find no shortage of articles online warning about the dangers of combining (or failing to combine) certain nutrients in the same meal (or dose of supplements). Some of this advice even has research to back it up—studies demonstrating that one nutrient inhibits or enhances the absorption of another—at least, in carefully controlled conditions that are rarely replicated in real life. 

But if you zoom out just a little, you quickly see that our understanding of the ways in which nutrients in foods interact with each other and with the incredibly complex, unique, and ever-shifting system that is our body is partial, at best. Which is why I don’t spend a lot of time worrying about trying to precisely time or combine specific nutrients or foods. 

Barring some sort of specific condition that increases your requirements or affects your ability to absorb nutrients, if you’re eating a reasonably varied and nutritious diet, your body will usually work it out. In fact, attempts to micromanage these things often backfire. 

For example, some have sounded the alarm that phytates—naturally occurring compounds found in beans and whole grains—block the absorption of calcium from foods. As a result, many are now worried that eating healthy foods that happen to be high in phytic acid will weaken their bones. 

But people who eat lots of beans and grains do not have a higher risk of osteoporosis. In fact, women who have the most phytates circulating through their bodies actually have less bone loss and fewer fractures over time. So, far from increasing your risk, a phytate-rich diet may actually help protect against osteoporosis.

How is this possible? For one thing, it appears that when your diet is high in phytates, your body adjusts by decreasing the amount of calcium that gets excreted in the urine. In other words, your body conserves calcium to make up for reduced absorption from foods.

Listen: A healthy diet, one that contains a variety of nutritious whole foods, is going to be chock-full of nutritional factors that compete with, enhance, and inhibit one another. Trying to control for all of this would be a full-time job—and a largely futile one, at that. Fortunately, your body has ways of working these things out on its own.

But I almost forgot to issue my ruling on the matter at hand! Does Caryn really need to consume her calcium supplement with additional vitamin C-containing foods? 

I’m siding with Caryn on this one—mostly on the grounds that grown adults with access to advice from actual medical professionals (not to mention the Judge John Hodgman of Nutrition™) should get to decide what they eat and when, without heckling (even of the well-intentioned variety) from the other adults they live with.

You can send your nutrition squabbles to me at, or leave me a voicemail at 443-961-6206.  

I’d also like to invite you to check out my other podcast. It’s called the Change Academy, where Brock Armstrong and I squabble about the art and science of behavior change. You can find it on all the major podcast platforms, so whatever app you’re using right now to listen to me, just head to the search bar and type in “Change Academy.”

Nutrition Diva is a Quick and Dirty Tips podcast. It's audio-engineered by Nathan Semmes with script editing by Adam Cecil. Our Podcast and Advertising Operations Specialist is Morgan Christianson. Our Digital Operations Specialist is Holly Hutchings. Our marketing and publicity assistant is Davina Tomlin, and our intern is Brendan Picha