Dietary Magnesium Replacement Prevents Chemotherapy-Related Hypomagnesemia

An education program about a magnesium-rich diet was effective at increasing dietary intake of magnesium among patients with ovarian cancer receiving carboplatin-containing chemotherapy. These findings, from a prospective feasibility study, were published in JCO Oncology Practice.

Hypomagnesemia, or a serum magnesium level of less than 1.8 mg/dL, occurs in the majority of platinum-based chemotherapy recipients.

To evaluate the effects of a dietary magnesium educational program, researchers recruited patients with untreated ovarian cancer who were scheduled to receive at least 6 consecutive cycles of carboplatin-containing chemotherapy at the MD Anderson Cancer Center. Twenty-one of 26 patients enrolled completed at least 5 cycles of chemotherapy and were included in the analysis.

The intervention comprised instruction about magnesium rich diets, a food reference list, weekly phone calls, online communication, and patient interview during chemotherapy visits. Feasibility was defined as patient adherence to at least 60% completion of dietary recalls and average daily dietary magnesium intake of 280 mg or more.

Patients were a mean 60 years old, 67% were White, and 95% had advanced disease.

The average dietary magnesium intake was 100.53 mg/day at baseline, and only 6% of patients achieved an intake of at least 280 mg. Patients increased their magnesium intake over the course of the study. 

Intake peaked at chemotherapy cycle 2 (mean, 437.37 mg) and the proportion of patients achieving intake goals peaked at chemotherapy cycle 5 (67%). Overall, 16 patients were adherent to the magnesium diet and 5 were not. 

Incidence of hypomagnesemia was higher (80% vs 19%; P =.025), need for intravenous magnesium was greater (60% vs 6%; P =.028), and serum magnesium levels were lower (mean, 1.78 vs 2.02 mg; P =.009) in the patients who were not adherent to the intervention diet, compared with those who adhered to the diet.

The major limitation of this study was the lack of a comparator cohort.

“Weekly education about magnesium-rich foods was effective and likely necessary in increasing dietary magnesium intake. Adequate dietary magnesium intake appeared to be protective against occurrence of hypomagnesemia and the need for medical intervention,” the study authors concluded.