January 19, 2023 – Cancer dietitian Lisa Cianciotta often sits across from a patient who suddenly fishes a bottle of antioxidant supplements out of his bag and says: “My friend told me it works really well,” or “I read on the Internet that it is very good against cancer.”
Although taking an antioxidant pill sounds harmless, Cianciotta, a clinical nutritionist who works with cancer patients at NewYork-Presbyterian Hospital in New York City, knows full well that this popular complement can interfere with a patient's radiation or chemotherapy treatments.
However, many cancer patients imagine that these over-the-counter vitamins, minerals or herbal remedies will help them. most use no less than one dietary complement alongside their cancer treatment.
And meaning Cianciotta is facing a difficult conversation.
Drug-supplement interactions are complex and infrequently vary depending on the complement, form of cancer, and form of treatment. They may cause more harm than good. For example, popular supplements can cancel out the results of cancer treatment, making it less effective, or increase serious unintended effects, similar to: Liver toxicityIn other cases, nonetheless, supplementation, similar to vitamin D in patients with vitamin deficiency, could also be helpful, says Cianciotta.
These drug-supplement interactions may be difficult to pinpoint because greater than two thirds of doctors have no idea whether their patients take dietary supplements.
Here's what patients have to know concerning the potential risks of taking supplements during treatment and the way oncologists can discuss this sensitive, often poorly understood topic with patients.
The complex landscape of pharmaceuticals and dietary supplements
The list of dietary supplements and how they can interact with different treatments and sorts of cancer is lengthy and complicated.
However, certain supplements appear to have an affect on cancer treatment independent of other aspects and will due to this fact be avoided. One example is supplements that significantly alter the degrees of the protein cytochrome P450 within the body. This group of enzymes plays a key role within the metabolism of medication, including chemotherapy and immunotherapy drugs.
Certain dietary supplements – especially St. John's wort extract – can decrease or increase the activity of cytochrome P450, which in turn can affect the concentration of cancer drugs within the blood, says William Figg, PharmD, deputy director of the Center for Cancer Research on the National Cancer Institute in Bethesda, MD. For example, studies show that this common herbal complement can increase the activity of cytochrome P450, which may result in lower levels of cancer drugs.
Outside of drug metabolism, patients with hormone-related cancers similar to breast and prostate cancer should avoid supplements that may alter testosterone or estrogen levels, Figg says. The evergreen shrub ashwagandha, for instance, is marketed as a method of reducing stress and fatigue, but it could actually also increase testosterone levels – a possible problem for patients with prostate cancer who’re receiving androgen deprivation therapy, which lowers testosterone levels.
Many oncologists advise patients against taking antioxidant-based supplements – especially turmeric and green tea extract – while receiving radiation therapy and certain chemotherapies. These therapies work by generating an abundance of highly reactive molecules called free radicals in tumor cells, which increase the stress in these cells and ultimately kill them. Antioxidants can theoretically neutralize this effect, says Skyler Johnson, MD, radiation oncologist on the University of Utah Huntsman Cancer Institute, Salt Lake City. Some studies suggest that antioxidant supplements can mitigate the effects of radiotherapy and chemotherapy, although the The evidence is mixed.
Some dietary supplements, including high-dose Green tea extract And Vitamin Amay cause kidney or liver toxicity, and “many cancer patients already have impaired kidney or liver function,” says Jun J. Mao, MD, chief of integrative medicine at Memorial Sloan Kettering Cancer Center in New York City. Even herbs that don’t interfere with the results of a cancer drug, like Steviamay increase treatment-related unintended effects similar to nausea and vomiting.
Another potential problem with dietary supplements: It is nearly unimaginable to know exactly what’s in them. Just last 12 months, for instance, the FDA sent almost 50 warnings to corporations that market dietary supplements. The problem is that federal manufacturing regulations for dietary supplements are less strict than for drugs, so some supplements contain ingredients that usually are not listed on the label.
One historical example was that Supplement PC-SPESa mix of eight herbs marketed for men with prostate cancer. The dietary complement was recalled in 2002 after traces of pharmaceuticals similar to diethylstilbestrol, ethinyl estradiol, warfarin and alprazolam were present in certain batches.
To complicate matters further, some dietary supplements may be helpful. Most cancer patients “are malnourished and lack nutrients that they could get from food,” says Cianciotta.
Patients are repeatedly tested for vitamin deficiencies and given supplements when needed, she says. Vitamin D and folic acid are two of essentially the most common deficiencies on this patient population. Vitamin D supplementation may improve outcomes in patients who’ve received a stem cell transplant by supporting the transplant and rebuilding the immune system, while folic acid supplementation may help reduce low red blood cell counts and hemoglobin levels.
Although she rarely observes vitamin poisoning, Cianciotta emphasizes that more shouldn’t be at all times higher and that taking supplements, even when it appears protected or is justified attributable to a deficiency, ought to be done under the supervision and careful monitoring of the patient's care team.
Bringing the usage of dietary supplements to light
Too often, providers have no idea whether a patient is taking dietary supplements.
A key reason: Supplements are sometimes touted as natural, which many patients equate with safety, says Samantha Heller, senior clinical nutritionist at New York University Langone Health in New York City.
This implies that patients might not be aware that a dietary complement can act like a drug and interfere with their cancer treatment, and due to this fact may not realize the importance of telling their doctor.
Still, the promise of herbs, vitamins and minerals may be tempting, and there are various the reason why patients decide to take them. One principal appeal: Supplements will help some patients feel more empowered.
“Cancer is a disease that takes away a lot of control from the sufferer. Taking supplements or herbs is one way to regain some sense of control,” says Mao.
The phenomenon can also be cultural, he says. Some people grow up taking herbs and supplements to remain healthy or combat health problems.
Pressure or advice from family or friends who think they’re helping a loved one with their dietary recommendations may play a job. Friends and family “can't prescribe chemotherapy, but they can buy herbs and supplements,” says Mao.
Patients who seek greater control over their health or that suffer from high levels of tension could also be more likely to just accept advice from family and friends or to imagine false or misleading claims concerning the effectiveness or safety of supplements, explains medical oncologist William Dahut, MD, chief scientific officer of the American Cancer Society.
In addition, social media often amplifies and normalizes this misinformation, Johnson notes. In a Study 2021 published in Journal of the National Cancer InstituteHe and his colleagues found that one-third of the most well-liked cancer treatment articles posted on social media in 2018 and 2019 contained false, inaccurate, or misleading information that was often harmful.
Some of the false claims, Johnson said, referred to unproven, potentially unsafe herbal remedies. These included “lung cancer can be cured with cannabis oil” and “goldberries cure and prevent cancer.”
Faced with exaggerated “cure promises,” some patients keep taking dietary supplements under the radar for fear of judgment or criticism.
“Doctors should avoid making patients feel judged or telling them not to go online to do their own research,” Johnson says.
Instead, you will help patients feel empowered by directing them to reliable online information sources, he says. Cancer.gov and the Memorial Sloan Kettering Cancer Center About the herbal database Providing accessible and accurate details about dietary supplements and cancer treatments to healthcare professionals and patients, he notes.
If a specific complement shouldn’t be protected during treatment, providers should find a way to elucidate why, says Cianciotta. In a Recent study80% of healthcare providers surveyed believed that herb-drug interactions might be problematic, but only 15% could explain why.
“If we can explain why we currently advise against a particular supplement, that tends to be better received than if we simply tell a patient not to take something because it's bad,” she says.
Another key’s to listen rigorously to patients to grasp why they’re taking a specific complement. Does the patient feel uncontrolled? Are they experiencing nausea?
“Ask patients why they are taking a particular supplement often uncovers unmet needs or psychosocial issues,” says Mao. This information can allow doctors to suggest an evidence-based alternative, similar to mindfulness meditation or acupuncture for stress management.
What if a patient has received a dietary complement from well-meaning friends and relatives?
“Simply telling a patient that a particular supplement is useless or harmful can cause tension in the family,” says Mao.
Instead, he recommends reformulating the issue.
“We want to better understand how patients tolerate chemotherapy or immunotherapy before we add other things to them. We want to make it clear to them that now may not be the right time to add a supplement to the mix,” says Mao.
The bottom line is: “Patients want to play an active role in their own care and we want to help them do that safely,” he says.