Analysis of Herbals, Dietary Supplements in Oncology

During a presentation at the 2019 Community Oncology Conference, researchers discussed the use and safety of herbals and dietary supplements in the oncology setting.

Herbal supplement sales have nearly doubled from 2000 ($4.2 billion) to 2017 ($8 billion). However, since they are considered food products, they do not have to adhere to the same regulations as conventional medicine.

In 1990 herbal supplements became part of the dietary supplements umbrella, and the Dietary Supplement Health and Education Act of 1994 (DSHEA) states that the manufacturer has a responsibility to make sure the product is safe prior to marketing. There are also guidelines on how the product is marketed—for instance, a supplement can say it “improves memory” but cannot claim it “prevents Alzheimer’s.” Disclaimers must also be included that statements on the product are not Food and Drug Administration (FDA)-approved, and that it is not intended to “diagnose, treat, cure or prevent any disease.” However, the FDA’s responsibility to take action if a supplement is deemed unsafe only kicks in after the product has already hit the market.

Herbal supplements are often marketed as natural, which leads patients to automatically believe they are safe—which may not be the case. They could also interact with other medications a patient is already taking. They may also contain undeclared active ingredients, and some have found to be contaminated with metal.

The presentation notes some supplements/treatments other than medication that have shown some promise in oncology:

  • Lactobacillus: possibly helpful with chemo-induced diarrhea and abdominal discomfort; may reduce hospital care and chemotherapy dose reductions due to gastrointestinal side effects
  • Barley, rice bran, and oats: a diet high in dietary fiber could reduce the risk of stomach cancer
  • Calcium: clinical trials show that taking calcium supplements 1.2-2 grams daily for up to 4 years can reduce the risk of colorectal adenoma recurrence by up to 29%
  • Beta-carotene: women at high risk for breast cancer may reduce their risk by up to 18% with beta-carotene
  • Caffeine (guarana): caffeine from any source could reduce non-melanoma skin cancer risk by 14%, and caffeinated coffee may reduce the risk by 18%
  • Marijuana (cannabis): patients with neuropathic pain due to chemotherapy and other conditions could reduce their pain intensity if they inhale marijuana tetrahydrocannabinol in doses of 1.6-96 mg daily for up to two weeks


Michael J. Schuh, Ginger Blackmon. Safety of Herbals, Dietary Supplements and Aromatherapy in Cancer Patients.