Are you navigating the complex world of cancer treatment and wondering about dietary supplements? You're not alone. Many patients turn to supplements to manage side effects and boost their well-being. But with so much conflicting information out there, how do you know what's safe and effective? Let's dive into the key insights from the Society for Integrative Oncology (SIO) 2025 Annual Meeting, where Dr. Channing Paller shed light on this crucial topic.
The Growing Need for Guidance:
Oncologists are increasingly asked for advice on integrating conventional care with integrative approaches. The challenge? The safety and effectiveness of many supplements remain unclear. Dr. Paller from Johns Hopkins University addressed this need, reviewing the most relevant data on vitamins, minerals, and lifestyle interventions. Her goal? To help clinicians provide safe, evidence-based recommendations.
Vitamin D: The Superstar Supplement:
Dr. Paller kicked things off by highlighting vitamin D, which has the most substantial body of evidence. But here's where it gets controversial... Chronic vitamin D deficiency, found in over 50% of newly diagnosed cancer patients, can lead to serious issues like low calcium, muscle weakness, and increased fracture risk, especially in older adults. The NCCN guidelines recommend screening and supplementing all at-risk patients, particularly those undergoing hormone therapy or with bone metastases. Aim for serum 25-hydroxyvitamin D levels between 30–50 ng/mL. Remember, vitamin D₃ is more effective and should be taken with a meal containing fat for optimal absorption.
Vitamin B12 and Folate: Common Deficiencies, Simple Solutions:
Vitamin B12 deficiency affects up to 48% of cancer patients, particularly those with gastrointestinal issues, older adults, or those on certain medications. Symptoms like anemia, neuropathy, or fatigue can develop gradually. Replacement options include oral, sublingual, or intramuscular forms. Folate deficiency, though less common, can result from poor diet, alcohol use, chemotherapy, or oral contraceptives. Early warning signs include megaloblastic anemia and mucosal ulcerations. Dr. Paller recommended 1 mg of folic acid daily for correction and maintenance.
Vitamin C: A Dual Nature:
Vitamin C acts as an antioxidant at low doses but can become a pro-oxidant at high intravenous concentrations. Dr. Paller referenced recent studies examining its potential role in cancer therapy:
- A 2024 Phase II trial in metastatic pancreatic cancer showed promising results when high-dose intravenous vitamin C (HDIVC) was combined with standard chemotherapy, improving progression-free and overall survival.
- However, a randomized trial in metastatic castration-resistant prostate cancer (mCRPC) found no significant benefit, highlighting the need for careful patient selection in future trials.
Trace Elements: Zinc, Selenium, and the Fine Line:
Zinc deficiency can cause impaired taste, dermatitis, and reduced immunity. Mild deficiencies can be corrected with slightly higher-than-recommended doses. However, chronic intake exceeding 75 mg/day may increase the risk of aggressive prostate cancer. Similarly, selenium, essential in small doses (55 µg/day), may raise the risk of both prostate cancer and diabetes when consumed in excess, especially among men with specific genetic variants. Dr. Paller emphasized that "moderation is essential" and supplementation should only address true deficiencies.
Curcumin and Green Tea: Promising, But Not Without Risks:
Curcumin, the active compound in turmeric, has anti-inflammatory and potential anticancer properties. It's generally considered safe, even at doses of 4,000–8,000 mg/day. However, it can interact with certain chemotherapies and has been linked to liver toxicity in some formulations. Green tea extract (EGCG) also shows chemopreventive potential. Studies have shown that women consuming 3–5 cups of green tea daily had a lower breast cancer recurrence rate. And this is the part most people miss... Excessive intake (≥800 mg/day) has been linked to elevated liver enzymes and reduced efficacy of certain drugs.
Omega-3 Fatty Acids: Supporting Nutrition:
Fish-derived omega-3 fatty acids (EPA and DHA) are crucial for inflammation control and metabolic health. While not recommended for all patients, the ESPEN Clinical Nutrition Guidelines suggest considering omega-3 supplementation in weight-losing or malnourished patients undergoing chemotherapy. High-dose fish oil has antiplatelet properties, requiring caution in patients on anticoagulants or at risk of bleeding.
Exercise: The Proven Survival Advantage:
Shifting from supplements to lifestyle, Dr. Paller underscored the power of physical activity. A randomized controlled trial showed that structured exercise significantly improved disease-free survival in patients with stage I–II colon cancer. The ASCO and SIO recommend at least 150 minutes of moderate or 75 minutes of vigorous exercise per week, plus 2–3 strength sessions.
Conclusion: A Balanced Approach:
Dr. Paller's key takeaway? Focus on balance and evidence. Address true deficiencies like vitamin D, B12, and folate. However, over-supplementation can be harmful, with risks of liver toxicity, drug interactions, and reduced treatment effectiveness.
What are your thoughts on this information? Do you have any experiences with these supplements? Share your insights in the comments below!
