Naturally Curious

Are so-called natural health products beneficial for your health or just hard on your pocketbook?

The general public and cancer patients specifically have a huge interest in the use of so-called natural health products (NHPs). Of course we want to know if they’re helpful and when we should use them. Beyond that, we want to know which ones to use and how. There’s a lot of information available online, but it can be overwhelming and confusing trying to make sense of what’s what in a world where everyone is trying to make a profit.

The first thing we should figure out is what they are. NHPs are the most commonly used category of complementary therapies in cancer care, and include vitamins, minerals, food products, food derivatives and some hormones. They’ve been touted as curative and preventive, treating a variety of cancers and other conditions. But what’s the reality? I wanted to find out more, and as I began looking at the scientific evidence, I realized there was a lot of really good information out there. I didn’t have the time to find, read and digest it all. So I hired a student, Ngaire King (winner of the Alberta Cancer Foundation’s Linda Singleton Summer Studentship), who spent four months this past summer reviewing the scientific literature on NHPs and making summaries to help me and others get a handle on what the research was saying.

These products are not necessarily benign: natural does not always mean safe.

The results were encouraging, and staggering. King carefully reviewed almost 900 scientific studies that investigated 72 NHPs. Most of these studies were in the context of cancer prevention, but many patients used NHPs to treat symptoms and side effects of cancer treatments. Some studies investigated NHPs as providing potential survival advantages when combined with conventional therapy. The Top-10 list of most-studied therapies emerged, and some stood out for helping to reduce risk for getting a variety of cancers. These include green tea, garlic, calcium, lycopene (found in tomatoes), Vitamin A, Vitamin C, Vitamin D, soy, folic acid (folate) and beta-carotene (orange vegetables). These seemed to help most in reducing cancer risk when consumed in foods as part of a person’s diet, rather than as supplements.

Other NHPs have potential for improving treatment outcomes when combined with standard therapies. These include Coriolus versicolor mushrooms (also known as PSK and turkey tail), shiitake mushrooms, melatonin (a sleep hormone taken as a pill), and flax seed and oil. Others, such as ginseng root, may improve chemotherapy effectiveness, and the mineral strontium may help reduce cancer-related bone pain. The caveat for all of these products is that more research is necessary to pinpoint how much is helpful for which types of cancer, and when to introduce them to the treatment process.

These products aren’t necessarily benign: natural doesn’t always mean safe. There can be interactions with medications you are be taking, contraindications, and the potential for overdose. Check that products have a Health Canada label certifying their contents. Sometimes you may get a product that isn’t what it says, or is contaminated, or has fillers and different ingredients. Memorial-Sloan Kettering Cancer Centre has a great online database where you can look up products and see what the contraindications and drug interactions are, and to check dosage. Finally, let your doctor and pharmacist know which NHPs you are taking.


Memorial-Sloan Kettering Cancer Centre’s NHP database is worth a visit: And we provide seminars on complementary therapies at the Tom Baker Cancer Centre’s auditorium, usually on the third Wednesday afternoon of each month. Call 403-355-3207 to confirm dates and times.

Dr. Linda Carlson is the Enbridge Chair in Psychosocial Oncology at the University of Calgary and a clinical psychologist at the Tom Baker Cancer Centre.

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