However, many Americans use supplements without knowing their effects. Just because they are available without a prescription, it doesn’t necessarily mean they are safe.
Patients don’t always reveal to their physicians what supplements they are taking. Herein lies a paradox: the perception is that supplements do not have the adverse effects of medications, but we expect them to perform like medications.
All supplements should be discussed with your physician before taking them. There are crucial factors to consider, such as dosage, your disease state, and whether you have a deficiency or insufficiency. Let’s look at the evidence.
Multivitamins and Other Supplements
The conundrum of one study, published in the Archives of Internal Medicine in 2011, was that it showed multivitamins and some other supplements may actually increase the risk of mortality. Multivitamins are the most commonly taken supplement.
Before we all panic, let’s look at the study. Results from the Iowa Women’s Health Study showed varying increases in mortality for those who consume multivitamins, copper, iron, magnesium, vitamin B6, folic acid and zinc. However, these results are not what they seem.
When you take a multitude of factors into account, only the multivitamins and copper, with 6 percent and 45 percent increases, respectively, in mortality, remain statistically significant.
There is also good news: vitamin D showed a 9 percent reduction in risk of death, and calcium also showed a similar effect. Interestingly, calcium at the highest dose greater than 1300 mg, lost this benefit.
We don’t know if calcium was taken in multiple dosages, since the body cannot absorb more than 500 mg at a time.
Before we draw conclusions, we need to consider a few things, such as the population, the size of the effect, what makes up a multivitamin, and the supplement dosages. Firstly, the population involved post-menopausal women, so results may not be applicable across the board.
Secondly, not all multivitamins are equal in the substances and amounts they contain. It is not clear which the participants were taking. Thirdly, the copper dosage does not seem to be clearly defined in the study.
Note that, though iron didn’t show statistical significance throughout, iron increased mortality risk up to 60 percent over incremental intervals in the study. Post-menopausal women should not take iron.
What does this really mean?
This study doesn’t necessarily mean you are going to die prematurely by taking a multivitamin or copper if you are an older woman. However, it is a wake-up call: supplements may not prevent disease nor improve quality of life unilaterally.
The relationship between micronutrients (vitamin and minerals in this case) and health is a U-shaped relationship. In other words, there is an optimal level of micronutrients that you want to achieve; if you are deficient, it is potentially dangerous, and if you overdose on micronutrients from supplements, it can be equally dangerous.
Supplements are not meant to replace a diet high in nutrients, such as a Mediterranean-type diet that has lots of fruits and vegetables. Supplements are just that – supplemental to diet and intended to correct insufficiencies or deficiencies.
It is also important to remember that vitamins and minerals from diet may have vastly different effects than those in supplements.
The moral of the story is that if you don’t have an obvious deficiency or disease that requires supplements, you may not need them. You should always consult your physician before taking them. At the very least, you may be wasting your money, but you may also be harming your health.