Is high dose vitamin C (Vit C), selenium (Se), and sodium bicarbonate (NaHCO3) effective and safe for cancer treatment?

High-Dose Vitamin C, Selenium, and Sodium Bicarbonate Are Not Recommended for Cancer Treatment

High-dose vitamin C, selenium, and sodium bicarbonate are not recommended for cancer treatment as there is insufficient evidence supporting their efficacy and potential safety concerns exist with high-dose supplementation. 1

Evidence Against High-Dose Supplementation

Vitamin C

• The use of very large doses of vitamins and minerals is not recommended for cancer treatment due to lack of evidence and potential risks 1
• While vitamin C plays a role in maintaining health during cancer treatment, it should be obtained primarily through diet or standard multivitamin supplements containing approximately 100% of the Daily Value 1
• The few studies in which vitamin C has been given as a supplement have not shown a reduced risk of cancer 1
• Despite some promising preclinical studies showing cytotoxic effects of high-dose vitamin C on cancer cells, these positive effects have not been consistently demonstrated in human studies with advanced-stage cancer patients 2

Selenium

• Dietary supplementation of selenium is not recommended to reduce the incidence of future keratinocyte cancers in those with a history of skin cancer 1
• There is a narrow margin between safe and toxic doses of selenium, with the maximum dose in a supplement not exceeding 200 mcg per day 1
• As the kidney excretes selenium, doses in excess of the Dietary Reference Intake should be avoided in case of renal failure 1
• While some studies suggest selenium may have anti-cancer properties, high-dose selenium monotherapy has been shown to be inefficient in reducing mortality 1

Sodium Bicarbonate

• No evidence from major cancer guidelines supports the use of sodium bicarbonate as a cancer treatment 1

Appropriate Nutritional Approach for Cancer Patients

Recommended Nutritional Support

• During cancer treatment, a standard multiple vitamin and mineral supplement containing approximately 100% of the Daily Value may be beneficial as it can be difficult to maintain adequate nutrition 1
• Vitamins and minerals should be supplied in amounts approximately equal to the recommended daily allowance 1
• Food is the best source of vitamins and minerals, not supplements 1

Specific Indications for Supplementation

Supplementation may be appropriate in specific circumstances:

• Biochemically demonstrated nutrient deficiency (e.g., low plasma vitamin D levels, B12 deficiency) where dietary approaches have been inadequate 1
• Nutrient intakes persistently below recommended intake levels 1
• To meet public health recommended levels of intake (e.g., calcium or vitamin D for bone health) if not contraindicated due to cancer therapy 1
• Known health sequelae related to cancer therapy (e.g., bone loss requiring calcium and/or vitamin D supplementation) 1

Potential Risks of High-Dose Supplementation

Documented Risks

• High-dose beta-carotene supplements have been shown to increase the rate of lung cancer in clinical trials, despite observational studies suggesting dietary beta-carotene was associated with lower risk 1
• Antioxidants as high-dose monotherapy should not be administered without proven deficiency 1
• Doses exceeding ten times the Dietary Reference Intake should not be used in clinical settings without proven severe deficiency 1

Communication with Healthcare Providers

• Open dialogue between patients and healthcare providers should occur regarding dietary supplementation to ensure there is no contraindication in relation to prescribed cancer therapy or longer-term health effects 1
• Multidisciplinary consultation and management is recommended for patients with advanced cancer 1

Quality of Life Considerations

• In palliative care, high-dose intravenous vitamin C might be considered as a therapy improving quality of life and reducing cancer-related symptoms such as fatigue and pain, though the placebo effect cannot be excluded due to absence of placebo-controlled randomized trials 2
• Patients should be provided with or referred for best supportive and palliative care to optimize symptom management and maximize quality of life 1

Dietary Recommendations for Cancer Patients

• A diet rich in vegetables and fruits is associated with lower cancer risk, but there is little evidence that dietary supplements can reproduce these benefits 1
• In weight-losing cancer patients with insulin resistance, increasing the ratio of energy from fat to energy from carbohydrates may be beneficial to increase energy density and reduce glycemic load 1
• Nutritional intervention to increase oral intake in cancer patients who are malnourished or at risk of malnutrition is recommended, including dietary advice, treatment of symptoms affecting food intake, and offering oral nutritional supplements when needed 1

The evidence clearly shows that while proper nutrition is important during cancer treatment, high-dose supplementation with vitamin C, selenium, or sodium bicarbonate is not supported by current clinical guidelines and may potentially cause harm.