Are Supplements, and the Nutrients Found in Supplements, Studied Scientifically?

YES. There are thousands of studies that have been done on a variety of nutrients found in supplements, including studies on vitamins, minerals, herbs, herbal compounds, amino acids, and many others substances. Sometimes, researchers also study the finished supplement product itself—a few supplement products have scientific backing from many controlled clinical trials. While nutritional studies are published in many different journals, it is not uncommon to see clinical trials on nutrients or supplements, from leading research institutions, published in prestigious journals. When the studies are published in a journal, they go through a peer-review process, as in other scientific fields. This means the authors submit a study for publication, but before it is published, other researchers review the proposed study for methodology and clarity. The study’s authors then revise the paper based on the feedback before resubmitting it. The peer-review process is designed to minimise the publication of flawed science.

What Types of Studies Do Researchers Use to Investigate Supplements and Nutrients?

Researchers use a wide range of study types to investigate supplements and nutrients. These studies include research on cell cultures, animals, and, of course, humans. When it comes to human studies, there are two main types—observational studies and randomised controlled trials (RCTs).

Observational studies track participant behaviour, sometimes over decades, to look for correlations between what nutrients or foods participants consume and what diseases or symptoms they develop. While there are many kinds of observational studies, each with their own strengths and weaknesses, one of the advantages of an observational study is the ability to look at a large number of people (often thousands or tens of thousands) over long periods of time. However, the primary weakness of such a study is that it is only capable of showing an association between a nutrient and a disease or symptom, and cannot prove a cause-and-effect relationship between them.

This is where the RCT comes in. RCTs randomly divide participants into a treatment (supplement) group and a control (placebo) group. This generally gives researchers a higher degree of confidence that the observed effects are actually due to the treatment, and not to some other contributing factor. RCTs are considered the “gold standard” for all types of medical research. And, in fact, while RCTs make up only part of the available evidence on supplements, RCTs on supplements and nutrients in supplements likely number in the thousands.

Why Do Some People Claim That There Is No Evidence to Support Supplement Use?

People who claim there is no evidence behind supplements are most likely misinformed. There are many well-conducted studies on supplements that have found positive health benefits, and these studies follow the same methodological protocols and peer-review process as in other areas of medicine; it is not accurate to say generally that supplements are not supported by science. It is true that there may be a lack of studies on specific supplement products, and on some particular nutrients, but this only means that more research needs to be done on these products and nutrients; it does not change the fact that large amounts of evidence exist in support of some other nutrients.

Is the Research Behind Supplements All Positive?

The research behind supplements is just like the research on drugs and other medical treatments; some studies support the use of certain nutrients for particular conditions; other studies may conclude that the nutrient is not effective; some studies may confirm that certain nutrients help in particular conditions but may not help in others; and some studies may reveal adverse effects. The goal of nutritional research should be to sift through all the data and come to an overall conclusion about the usefulness of a particular nutrient. It is important to note that the existence of “negative” studies—ones that find no effect or possibly even adverse effects—is a normal part of medical science. Negative studies do exist when it comes to supplements; but they also exist for drugs. This does not mean, however, that there is no science behind supplements, or that supplement research is not evidence-based, especially considering the hundreds, if not thousands, of studies that clearly demonstrate health benefits.

How Do I Know Whether Science Supports the Use of My Supplement?

The first step is always to check with a doctor, and it is essential that the practitioner is knowledgeable about the science behind supplements. Many doctors receive surprisingly little training on supplement use; therefore, their opinion is likely less useful compared to other doctors who have received such training. When in doubt, talk to your doctor about his or her views on supplements, what training he or she has received, and how often he or she uses supplements to help patients. To start doing your homework, you can look up the supplement or health condition in which you are interested.