Are Supplements Safe? An Integrative Oncology Expert Weighs In. 

Learn about which supplements should be taken with caution, and which are safe to use.
Photo of a mushroom.

Turkey tail, green tea, magnesium – these are just a few of the supplements that factor into conversations around adjuvant therapies for cancer. Data around supplements is, generally, limited, yet patients want to know: which ones are safe, which are effective, and how should they be taken?

“There’s a lot of misinformation out there,” says Dr. Amy Littlefield, ND, MSOM, FABNO, a board-certified naturopathic physician and acupuncturist in Middlebury, VT, who specializes in integrative oncology, chronic disease, and lifestyle medicine. She notes that as supplement companies aren’t subject to FDA drug standards, few opt into third party testing because it increases their costs. Still, some take Quality Assurance (QA) seriously. “Patients interested in supplements for adjuvant therapy should consult a provider who can identify reputable brands and offer guidance based on their individual patient profile,” says Dr. Littlefield.

Conventional With Alternative

The way that a supplement is incorporated into a patient’s treatment plan matters greatly. “It’s not about ‘alternative’ vs. ‘conventional’ medicine, but ‘conventional with alternative,’” says Dr. Littlefield.

Within this framework, Dr. Littlefield evaluates supplements by asking the following questions:

  • Will it help? Is there science-backed evidence showing how this supplement improves outcomes and enhances quality of life? Does the supplement compliment the patient’s lifestyle and treatment goals?
  • Will it harm? Will this supplement put the patient at risk for physical damage or toxicity? Will it interfere with the metabolism and strength of conventional medicine? Will using this supplement cause financial harm, due to the costs of the treatment? Is it easily accessible, or does the patient have to drive far to receive treatment – and if so, what is the impact of that commute?

When it comes to lifestyle medicine – i.e., exercise, sleep quality, social connection, stress management, and nutrition – supplements play ‘second string.’ Take exercise, for example: studies show it’s an effective lifestyle medicine for combating cancer, but not all cancer patients have the energy to follow a fitness regime. For these patients, the right supplement can help them feel well enough to exercise, says Dr. Littlefield: “There's a role for supplements that improve quality of life enough for patients to be able to follow through on their treatments.”

Using Supplements with Caution 

Given the vast and largely unregulated vitamin and supplement market, Dr. Littlefield thinks of products as falling in one of two categories: ‘Generally Safe’ and ‘Needs Caution.’

‘Generally Safe’ 

The safest supplements tend to be compounds and vitamins that are intrinsic to the proper functioning of our bodies, with supplements simply augmenting the body’s natural supply. They can also be compounds that form an essential part of our diet (see “fish oil”). Dr. Littlefield strongly recommends finding food-based sources when possible.

Prebiotics and Probiotics 

Probiotics are any living microorganism considered to be “good bacteria” that we can consume or apply to the body. Prebiotics are plant-based fibers that feed good bacteria. Working in harmony, probiotics and prebiotics balance the microbiome (i.e., our gut), where they break down food into nutrients that are more readily absorbed by our body.

During the course of cancer treatment, a healthy gut microbiome is essential because it influences mood, energy level, immunity, and digestive symptoms – all of which promote a better quality of life. And when a patient’s quality of life is better, their compliance with that treatment plan tends to be better, too.

Both prebiotics and probiotics can be sourced in a variety of healthy foods. Prebiotics include vegetables such as garlic, leeks, oats, and bananas; and legumes such as chickpeas, lentils, and edamame. Probiotics are found in fermented food, like yogurt, kefir, sauerkraut, kimchi and injera.

Vitamin D 

Vitamin D is a popular, all-around supplement favored by people living in colder climates such as Vermont and Northern New York State. It's also a well-researched supplement for cancer therapies. A clinical trial out of Boston University found that taking vitamin D improved patients’ ability to survive cancers of the digestive tract, including colorectal cancer. Other studies have found that vitamin D plays a role in reducing metastatic disease progression; addressing bone density, which is relevant in hormone-modulated diseases such as breast and prostate cancers; and improving immune system regulation through treatment.

The recommended daily amount of vitamin D for an adult is 600 to 1000 units per day; and while sunshine provides some of that daily dose, Dr. Littlefield encourages her cancer patients to aim for 2000 units per day during the winter, when the sun’s intensity is lowest. This is especially important for patients who work indoors and are diligent with sunscreen, as they’re likely to get less vitamin D from sunlight.

Magnesium 

Generally considered a safe supplement, magnesium can be an inexpensive way to manage side effects of cancer treatment such as cramping, fatigue, constipation, and headaches. It’s found in plant-based foods, such as spinach, legumes, nuts, seeds, and whole grains; and is also available as a supplement, since diet sources can be low. “Given that supplementation of magnesium is safe and inexpensive, I augment what is in the diet with a supplement and observe for improvement – which can often be profound,” says Dr. Littlefield. Magnesium is also associated with mental health benefits: a 2017 clinical trial at UVM found magnesium to be an effective treatment for depression.

Coenzyme Q10

Also called CoQ10, or sometimes Ubiquinol, Coenzyme 10 is an antioxidant produced by the body and used by cells for growth and maintenance. Aging, stress, and illness deplete CoQ10 levels; and while trace amounts of this enzyme are found in meat, fish, and nuts, diet alone can't replenish the body’s supply. That’s where supplements can help – especially for cancer patients after they’ve undergone radiation treatment. “CoQ10 addresses quality of life issues related to fatigue, which can be beneficial for cancer patients after undergoing physically taxing treatments,” says Dr. Littlefield.

Fish Oil 

Fish oil has been featured in many medical studies, and its efficacy in treating a wide range of conditions is what makes it a valuable addition to integrative cancer treatment.

Take breast cancer: breast cancer survivors have an increased risk of heart disease – a condition fish oil has been shown to mitigate. A patient care plan that integrates fish oil will help address that comorbidity. Depression is another example. Several studies have found omega-3 polyunsaturated fatty acids to have a therapeutic effect on the improvement of depression. This is promising news for cancer patients, 25% of whom find themselves battling depression.

The benefits of fish oil across the field align with the goal of integrative medicine, says Dr. Littlefield. "We see patients as whole people rather than just a cancer diagnosis," she says. "As oncologists continue to cure cancer and enable patients to live longer, the value of treating the whole person in the context of survivorship becomes really important."

‘Needs Caution’

Supplements that are not derived from compounds produced naturally in the human body require caution, says Dr. Littlefield. “It's especially important to source these supplements from quality brands, which are less likely to carry contaminants,” she says.

Green Tea 

“There are phenomenal in-vitro studies of green tea that have produced good results,” says Dr. Littlefield. “However, in-vitro studies [i.e., studies not on people but taking place in a lab, with cells, tissues, and organs] are not what we base medical decision-making on.” The few clinical studies involving green tea and cancer patients have been promising, including one from the Mayo Clinic that found a positive impact on chronic lymphocytic leukemia (CLL) patients who were given EGCG, the active ingredient in green tea.

The biggest concern with green tea is toxicity from contamination. Aluminum and pesticides are prevalent in substandard green tea, and numerous studies have found toxins present in up to half of randomly tested samples. “Controlling for those risks is extremely important when adopting green tea preclinically for a patient who’s trying to prevent their CLL or Myelodysplastic syndromes (MDS) from progressing to a treatment stage,” says Dr. Littlefield. A high-performance liquid chromatography (HPLC) undertaken by the manufacturer is a reliable way to assess for contaminants. However, most manufacturers that do this level of quality assessment only sell to or through physicians, and at a higher price point than store-bought green tea.

Coriolus Versicolor (AKA "Turkey Tail" Mushroom) 

Although Coriolus Versicolor or Turkey Tail is relatively new to Western medicine practices, it’s been used for centuries in Chinese traditional medicine, where it’s known as Yun Zhi, a tonic that treats lung conditions and other ailments.

Research shows Polysaccharide K – or PSK, the active ingredient in Turkey Tail – to be compatible with conventional treatments. In fact, in Japan, PSK is an approved mushroom product for treating cancer. “There is robust, randomized clinical trial evidence around Turkey Tail that shows improved overall survival of breast, colon, lung, melanoma, and kidney cancer patients,” says Dr. Littlefield. However, patients with autoimmune diseases or who are on immunotherapy treatments should not use Turkey Tail, says Dr. Littlefield. 

Turkey Tail is usually taken as a hot water extract in tea or soup; and it’s also available in capsule form, which contains a concentrated amount of PSK. As with any capsule-based supplement, it’s critical to look for companies that use third-party QA to confirm the product’s purity and strength.

Integration is Key

With more and more studies and clinical trials looking into the efficacy of supplement use in adjuvant therapies, it’s important to remember that, when it comes to treating cancer, conventional medicine always outperforms alternative medicine.

2017 study out of Yale School of Medicine confirmed as much when it found that patients who chose alternative therapy over conventional treatments for curable cancers have a higher risk of death. That’s why it’s critical to integrate these two approaches within the right framework. “Lifestyle medicine and conventional medicine are givens,” says Dr. Littlefield. “The best way to harness the benefits of supplements is to integrate them – with guidance from a medical professional – into a comprehensive plan of care.”

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