I’m a big believer in targeted, but not indiscriminate, supplementation. Many supplements offer either a benefit next to impossible to obtain from diet (e.g. theanine) or give much higher quantities (e.g. resveratrol, vitamin D). (You can check out these and more on my supplements buying guide.) But there are a number of supplements that are associated with ill effects, yet are widely recommended either by doctors or mainstream health advice. Here are three supplements you should avoid.
Calcium is widely prescribed for its alleged effect on osteoporosis, the thinning of bones with age. The first problem here is that it doesn’t work. A meta-analysis of studies on calcium intake and risk of hip or other bone fracture concluded that there was no benefit and possibly even increased risk:
Pooled results from randomized controlled trials show no reduction in hip fracture risk with calcium supplementation, and an increased risk is possible.(1)
Lack of calcium is not the cause of osteoporosis or hip fractures, it’s lack of weight-bearing exercise, dietary protein, and vitamins D and K.
Calcium is, however, implicated in coronary artery disease, since calcification of arteries is strongly involved. Calcium in the coronary arteries strongly predicts cardiovascular events, and in those without other known risk factors, it is in fact the strongest predictor.(2)
Calcium supplementation is associated with an increased risk of heart attack: a meta-analysis in the BMJ found that people allocated to a calcium supplement had about a 30% increased risk of heart attack compared to placebo.(3)
Calcium supplements (without coadministered vitamin D) are associated with an increased risk of myocardial infarction. As calcium supplements are widely used these modest increases in risk of cardiovascular disease might translate into a large burden of disease in the population. A reassessment of the role of calcium supplements in the management of osteoporosis is warranted.
Another study found more than double the risk of heart attack in users of calcium supplements.(4)
Use of calcium supplements along with dietary calcium intake > 1400 mg a day was associated with a 2.5-fold increased risk of death.(5)
For the love of God, don’t take calcium supplements.
An irony here is that increased consumption of dairy products, which contain lots of calcium, is associated with much lower death rates.(6) The reason, in my opinion, is that it’s not the calcium that’s protective, but something else, probably both protein and fat, or conceivably vitamin K.(7) Dairy products also inhibit iron absorption, which probably has a lot to do with their health benefits.
Clearly, the problem isn’t whether someone is getting enough calcium, but ensuring that the calcium goes to the right places: bones and not arteries. Vitamin K helps to ensure that calcium goes where it belongs, and higher intake is associated with greater bone mineral density.(8) Vitamin D is also much more helpful for bone density than calcium.
The tragedy here is that doctors routinely prescribe calcium supplements to older people, especially women, who are at greater risk of osteoporosis. Another reason why you have to educate yourself and not blindly follow doctors’ orders.
I’ve written about iron extensively, the upshot being that keeping iron levels in the low normal range is important for keeping yourself free of disease.
Some knowledgeable observers of iron and health believe that much of the problem of iron overload in the American population is driven by iron supplements, rather than diet.(9) Most multivitamins contain iron, and doctors widely prescribe iron to women, even when they’re post-menopause. Older people also get them for anemia, even when the cause is unlikely to be iron deficiency.
Iron overload from multiple blood transfusions is associated with much higher risk of death in sickle cell patients, on the order of 12 times higher.(10)
Iron overload is dangerous and begins at a level much lower than most doctors believe.
Don’t take iron supplements unless you have a demonstrated need and they are prescribed by a doctor.
Be aware of multivitamins that contain iron. For men over 20 years of age, and women over 50 who want to take a multivitamin, a “mature” multivitamin is a better bet, since these don’t contain iron.
Beware of iron-fortified foods, as this is equivalent to taking an iron supplement. Some breakfast cereals contain 100% of the daily requirement of iron, this being added to it – besides the fact that they’re made with iron-fortified flour or corn meal to begin with. (Anyway, you don’t eat breakfast cereal, right? that stuff isn’t even food, will spike your blood glucose and insulin, and make you fat.)
Don’t eat breakfast cereal, is my advice. Instead, fast, or eat some eggs.
Copper is a somewhat overlooked but required mineral. Not too many people knowingly take copper supplements, although it is found in multivitamins.
High levels of copper are associated with large increases in death from cancer, more than double the rate of people with low levels.(11)
Copper is also associated with increased risk of Alzheimer’s disease, atherosclerosis, and diabetes.(12) People in at the highest quintile of copper levels probably got there through taking copper supplements, either directly or inadvertently.
Copper, like iron, is a reactive metal, so it’s not surprising that high levels will do this. One of the few times that copper supplements may be needed is when high doses of zinc are taken, since zinc blocks copper absorption. In fact treatment for Wilson’s disease, or an overload of copper, is high-dose zinc. But for most people this isn’t necessary, as high-dose zinc for long periods of time isn’t a good idea.
Watch for copper in multivitamins. Again, mature multivitamins – some of them anyway – may be formulated without copper.
Calcium, iron, and copper supplements are associated with health risks and should be avoided except under doctor’s orders. And even then, I’d be careful.
Is it any coincidence that all three of these are metals? I think it isn’t. Iron as a driver of aging may possibly be generalized to a metal overload theory – although we need them and can become deficient in them, too much is a bad thing. Of course, too much of anything can harm us, but we seem to be particularly susceptible to metal overload, since we have no regulated way of eliminating them from our bodies.
Since some of these supplements are added to things like multivitamins and foods like cereals, you should be aware of what you’re taking.
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