The Essentials: Magnesium during chemotherapy

Magnesium Foods

A deficiency in magnesium occurs in 20%-100% of cancer patients undergoing chemotherapy. Magnesium is the second most abundant intracellular cation after potassium, and it is involved in more than 600 enzymatic reactions in the body.
Low levels of magnesium induce fatigue, mitochondropathy (compromised production of ATP) and risk for neuropathy, nephropathy as well as abnormal cardiovascular function (arrhythmia, hypertension) immune dysfunction, headache and altered bone and vitamin D metabolism.
Low level of magnesium is also associated with nausea, vomiting, headache, myalgia, constipation, anxiety, insomnia and depression, all common complaints of cancer patients. Long term deficiency of this important mineral can contribute to hypertension, migraine headaches and is associated with chronic inflammation and oxidative stress. All our patients are monitored for serum RBC magnesium to assess their status every 3-6 months long-term, and monthly during cancer treatments. Measuring the level of magnesium in the blood test (serum magnesium) is a not a reliable indicator of magnesium deficiency.
All our patients receive a therapeutic amount of highly bioavailable magnesium spread out over 3-4 doses per day to achieve repletion without the risk of loose stool, however extreme low level of magnesium  can be quickly repleted by intravenous infusion.
The chemotherapeutic agents that induce low level of magnesium are:

• Platinum Chemotherapy Agents: Oxaliplatin, Cisplatin, Carboplatin and
• Taxanes: paclitaxel (Taxol) nab-paclitaxel (Abraxane), docetaxel (Taxotere), Cabazitaxel (Jevtana).
• Vinca alkaloids vinblastine, vincristine, vindesine, and vinorelbine
• Aminoglycosides (gentamicin, streptomycin)
• Bleomycin
• Cetuxumab (Erbitux)
• Panitumumab (Vectibix)
• Cyclosporine
• Lenolidamide
• Tacrolimus
• Etoposide
• Bortezomib (Velcade)

Dietary sources of magnesium include: almonds, cashews, brazil nuts, pumpkin seeds, flaxseeds, cocoa, avocados, dark leafy greens, seaweed

References:
Hodgkinson E, Neville-Webbe HL, Coleman RE. Magnesium depletion in patients receiving cisplatin-based chemotherapy. Clin Oncol (R Coll Radiol). 2006 Nov;18(9):710-8. doi: 10.1016/j.clon.2006.06.011. PMID: 17100159.