The data supporting anticancer activity in natural supplements is extensive. Unfortunately, oncologists and patients are hampered by the paucity of high-quality clinical trials in deciding which supplements might improve clinical outcomes. Designing and conducting these studies is expensive and will take many years before we have answers (i.e. which supplements work for which cancers, what doses are effective, how do they interact with other therapies/compounds, etc.) These studies can be done and must be done, but what do we do in the meantime?
Most oncologists suggest to their patients that they simply consume a diet containing a wide-variety of phytonutrient compounds. Although this is certainly a safe (first do no harm) recommendation, it is very challenging for most individuals to consistently eat enough anticancer foods to load their blood and tissues with ‘effective’ concentrations of nutrients and anticancer compounds. This is where using a variety of natural supplements may be useful. As an analogy, oncologists prescribe the chemotherapy drug Taxol (derived from the bark of a Yew tree) as a high-dose, concentrated agent. To achieve a similar efficacy, one would need to consume pounds of Yew tree bark each day to potentially achieve any significant clinical efficacy…imagine the low level of compliance of following this regimen.
As one of my colleagues, Dr. Jeffery Blumberg (Director of the Antioxidants Research Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University) has been quoted: “The average diet is poor when it comes to meeting recommended intakes of vitamins and minerals. Only about 3% of Americans adhere to the dietary guidelines. How many Americans do you know who eat five to nine servings of fruits and vegetables a day and consume at least 50% of their grains as whole grains? If you are eating a perfectly healthful diet, then you don’t need supplements. But for the 97% who aren’t there yet, for goodness sake, take a multivitamin.”
The rationale for recommending a diet containing a variety of anticancer phytonutrient compounds is the same for why oncologists often prescribe a multi-drug regimen, enabling a multi-pronged attack on more than one critical function in the cancer cells at the same a time. This multi-drug approach has significantly improved clinical outcomes in cancer control. Almost every day, I read new studies that demonstrate promising anticancer activity from natural compounds (i.e. EGCG, curcumin, etc.). Unlike the majority of chemotherapeutic agents, many of these natural compounds affect cancer cells from multiple pathways. Important cancer-promoting mechanisms can lead to tumor growth progression when not tightly under control. Regulation of these mechanisms is controlled by numerous proteins and receptors, which can be influenced by natural dietary compounds.
Examples of nutrient compounds with anticancer activity on the regulatory proteins/receptors above:
- Inhibition of NF-kB: (resveratrol, curcumin, EGCG, isoflavones, omega-3 fatty acids, vitamin D3, pomegranate extract, ashwagandha, gingerol, milk thistle, lycopene)
- Reduction in 5-LOX: (omega-3 fatty acids, boswellia extract/AKBA, curcumin, lycopene)
- Inhibition of Ras: (curcumin, limonene, vitamin E, garlic extract/diallyl sulfide)
- Reduction in COX-2: (omega-3 fatty acids, berberine, feverfew, gingerol, EGCG, curcumin, resveratrol, milk thistle, gamma tocopherol)
- Inhibition of Caspases: (cucumin)
- Inhibition of PARP: (curcumin)
- Inhibition of AMPK: (curcumin)
- Inhibition of Galectin-3: (modified citrus pectin)
- Inhibition of E-selectin: (alpha-linolenic acid, omega-3 fatty acids)
Where do we go from here?
I am increasingly of the mindset that a rational approach to the use of various supplement compounds (each with different mechanisms of action) could provide benefit for our patients. A rational approach is one in which the selected supplements have the potential for benefit (based on preclinical and/or clinical data), have a low probability for harm and are taken with the knowledge of your oncologist. Consume as many of these natural anticancer compounds in their whole foods form, as there are often numerous anticancer compounds that are not present in isolated extracts. However, I suggest taking certain supplements in circumstances when it may not be realistic to consistently achieve therapeutic levels of specific anticancer compounds from consuming the whole food.
Which supplements should I take? What dosage? What are the safety concerns?
These are the multi-million dollar questions. As another one of my colleagues, Dr Keith Block (Director, The Block Center For Integrative Cancer Treatment) says: “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.
Attacking cancer with an evidence-based, multi-pronged, individually-tailored nutrient regimen can be safely implemented with the help of a knowledgeable integrative provider. While we await (years-decades) for scientists to study the anticancer efficacy in natural compounds, a rational approach can be implemented today. Conventional oncologic therapies (i.e. surgery, chemotherapy, radiation therapy) should not be dismissed in favor of an alternative approach (i.e. dietary-alone). Instead, combining various therapies (i.e. conventional therapies, dietary therapies, physical activity, stress reduction, etc.) should be the standard of care for everyone who has been diagnosed with cancer. This complex, but rational approach is best coordinated by a multi-disciplinary team who regularly communicate with each other regarding their mutual patients. This is the field of integrative oncology.