It's "natural" so it's good for me, right?

Ever have one of those days where everyone seems to ask you the same question? All of my patients had questions about supplements that well meaning family and friends had recommended to them. I work with cancer patients, most of whom are receiving chemotherapy or radiation. One of my main concerns is making sure patients are not taking products that could interfere with their treatment or prescription medications or are otherwise harmful.

I also spend a significant amount of time educating patients about supplements in general. I think there is a common assumption that products over the counter or found on the internet are safe for general use. Unfortunately, this is not the case. Also, the term "natural" is grossly abused and overused. A frequent comment, "It's natural, so it couldn't hurt, right?". Absolutely not.

Let me count the reasons and explain why you need to talk to a health care provider before taking supplements recommended by well-meaning family and friends, especially if you are undergoing cancer treatment, are taking multiple prescription drugs, or have medical conditions or diseases.


  • The term "natural" is not regulated, it does not have significant meaning when it comes to supplements and does not mean it's healthy or good for us. Sunlight, arsenic, water, and botulism toxin are all natural; a vitamin or herb produced or extracted in a lab is not natural. When we take something like echinacea or valerian root in a capsule or tincture, this has been altered from its original form and our intention is to have a specific effect on the body.
  • Supplements can interfere with prescription medications. There are multiple herbs and vitamins that may thin the blood so people on blood thinners need to be especially cautious. Many herbs and some vitamins can affect blood pressure and blood sugar levels which is good if that is the intended effect, but if you are not being monitored by a provider this could cause problems. If your blood pressure is lowered too much, this can lead to lightheadedness. Some blood pressure medications affect nutrients that are reabsorbed by the kidneys and could cause levels in the blood to become too high. Some herbs affect the immune system which could be problematic for those with autoimmune diseases or cancer; sometimes we want to stimulate the immune system and other times we need to calm it down. Herbs have very complex interactions with our bodies.
  • I am concerned about people who are not medically educated recommending products to others as this may cause unintentional harm. A working knowledge of physiology, pharmacology, and biochemistry is necessary to understand interactions between supplements and drugs. I have spent nine years learning how to use drugs and supplements and still look up information to make sure patients are not taking pills that may interact with each other. Part of the problem is that we do not have an extensive body of research about supplement-drug interactions.

What can you do to make sure you're not unintentionally causing harm? Obviously, consulting a healthcare provider is the first step if you want to make sure it's ok to take a supplement. Unfortunately, many doctors haven't been trained in how to use herbs and some supplemental nutrients. A couple of web resources that are reliable: WebMDMayo ClinicNatural Standard (requires a subscription). You can schedule a supplement consult with me - see the consultations page for more information.

Originally published on October 18, 2014