Using Supplements Incorrectly Can Sabotage Your Treatment Program

By Keith I. Block, MD

For many years now, my colleagues and I have studied the complex interactions between supplements and cancer, and supplements and conventional treatments.  Some of these interactions are therapeutically beneficial — as I discussed in my two preceding blog articles — while others can be unfavorable, interfering with treatment and/or resulting in adverse side effects.  Without a clear understanding of these diverse interactions, you may be inadvertently undermining your entire treatment program.

Many supplements may be used for a certain purpose yet have untoward effects in other areas.  For example, some agents may support your physical or mental health, but may also promote tumor growth, reduce the effectiveness of treatment, or even increase the risk of life-threatening complications such as internal hemorrhages.  Very few of the patients we see at the Block Center are aware that many supplements can be problematic and have a potential dark side when used improperly — either in the wrong combinations, at the wrong time, or in the wrong dose.

To give you some idea of the potential range of untoward effects, consider the following caveats concerning supplement use among people with cancer:

• High vitamin B6 levels reduced the treatment response to cisplatin chemotherapy in ovarian cancer patients.  Also some laboratory data suggest that vitamin B6 stimulates lung tumor growth.
• In theory, the high-dose use of selenium, N-acetylcysteine (NAC), and St. John’s wort may curb the effectiveness of certain chemotherapy drugs.  (I discuss the last of these agents in greater detail below.)
• Tangeretin, a flavonoid found in citrus fruits, was found to completely block the tumor-inhibitory effect of tamoxifen in animal models of breast cancer (In addition, grapefruit, too, has been found to weaken the effectiveness of tamoxifen).
• Vitamin E and various blood-thinning herbs may greatly raise the risk of hemorrhage for patients who have recently undergone intensive chemotherapy.
• Vitamin B12 and calcium have both been linked with more aggressive prostate cancers and could therefore undermine a conventional treatment protocol for that particular disease.

Here I will focus a bit more on St. John’s wort (SJW), an herb that is clearly effective against mild to moderate depression—a condition that’s fairly common among cancer patients.  Unfortunately, SJW may reduce the effectiveness of many drugs, including anesthetics, opioids, antidepressants, oral contraceptives, anticoagulants, protease inhibitors, and, yes, chemotherapy agents as well.

In the 21 August 2002 Journal of the National Cancer Institute, researchers from the Netherlands reported that SJW seemed to lower the effectiveness of the chemotherapy agent, irinotecan, as evidenced by a significant decrease in blood levels of the active drug metabolite.  Additionally, the degree of bone marrow suppression (which results in a drop in immune system functioning) was substantially worse in the presence of SJW.  These findings could have major implications for patients with colorectal cancer and certain other cancers.

In their conclusion, the researchers suggested that “irinotecan metabolism and toxicity are altered by SJW, and that the two agents cannot be given safely in combination without compromising overall antitumor activity.”  (In addition, two more recent clinical trials have investigated the effect of SJW on metabolism of the anticancer drug Gleevec; both studies found evidence that SJW may compromise the efficacy of this drug.)

As to how to use this information, much depends on your clinical context, on where you’re at in the recovery continuum.  Let’s say, for example, that you are experiencing depression and you’re not presently receiving chemotherapy.  Use of SJW could help you experience a marked improvement in your mood and overall well-being.  But again, this same agent may have multiple serious interactions with the chemotherapy drugs you’re receiving, once that treatment begins.  As a precautionary measure, it makes good sense to avoid SJW during chemotherapy, at least until more definitive studies are conducted that demonstrate whether or not the tumor-killing effects of chemotherapy can be compromised by SJW.

Fortunately, there are many alternatives to taking SJW, and I’m not just talking about pharmaceuticals.  In my advice to patients who report feeling depressed fairly often, I suggest avoiding all alcohol, caffeine, and sugar, as these substances tend to worsen depression.  Additionally, there is some evidence that both aerobic exercise, particularly short intervals of higher intensity aerobics, and acupuncture may aid in the treatment of depression.  Talk therapy, meditation, deep-breathing practices, and other relaxation techniques may also be helpful alternatives to drug-based therapies.

The take-home lesson should be clear.  When faced with a serious medical challenge like cancer, you should not assume that nutritional and herbal supplements are risk-free.  Safety (and, by extension, efficacy) issues should always come first.  Particularly if you have cancer, it’s important to seek out the expertise of someone who understands how supplementation strategies can be potentially problematic, and how their inappropriate use can hinder, rather than bolster, your plans for treatment and recovery.

Lastly, it is important for you to discuss any and all supplements you are taking with your healthcare provider.  Ideally, a supplement protocol will be individualized to your unique needs and regularly monitored and modified, as necessary.  This is usually best accomplished with a physician or clinical expert who has extensive experience with the use of these integrative strategies.

Comments

[Teresa]

I'm supposed to start Tamoxifen soon. Can I eat oranges or do I have to give them up?

[Buy Herbal Supplements]

Most of the money spent these days on supplements is wasted because most supplements are not worth what you pay for them. It is important to learn how to select supplements that are worth your money, but again, supplements are not a substitute for real food. Nothing can replace the nutrition provided.

[Laura Sutherland]

When I was going through chemo, I thought I should be straight-forward with my oncologist and shared what I was taking at the time. His response was that I should stop ALL supplements except Vitamin D. I had been taking COQ10 for years as part of my blood pressure control regime. After my treatment, I learned that patients who are taking Adriamycin should be taking COQ10 to protect their heart from the toxicity of the drug. Why don't oncologists know this stuff? My doctor did know about the dangers of St. John's Wort. This does not translate to all supplements being dangerous! By the way, I have found your book 'Life Over Cancer' very helpful during my recovery and return to health.

[Rhonda Wood]

Can high dose vitamin C (60 grams) have a detrimental effect on my kidneys? I have been tested and do have the enzyme necessary to break down the Vitamin C.