SAN DIEGO—Cancer patients at high risk for bone loss due to their disease or its management may want to cut down on the diet cola consumption. New data presented at the Endocrine Society’s 92nd annual meeting and expo suggest that drinking diet colas on a regular basis may be associated with a decrease in bone mineral density (BMD) and an increased fracture risk.
Previous studies have linked any type of cola drink with an increased risk for fracture. However, a new study by researchers at Walter Reed Army Medical Center has found drinking diet cola on a regular basis may have an adverse effect on overall bone health.
“Cola beverage consumption may increase the exit of calcium from the body, and cola beverages do not contain calcium and often replace calcium from other sources in the diet. So, overall in the big picture, it is probably not good for your bone density in the long term,” said lead study investigator Noelle Summers Larson, MD, a pediatric endocrinology fellow at Walter Reed Army Medical Center, Washington, DC.
Larson and her colleagues previously found that within 45 minutes after diet cola consumption, there is a brief dip in parathyroid hormone (PTH) followed by a surge in PTH. The increase in circulating PTH was accompanied by a parallel increase in alkaline phosphatase. The researchers theorized that urinary calcium excretion would increase after diet cola consumption. In the current study, they measured calcium and phosphate excretion in urine for 3 hours after ingestion of 24 ounces of diet cola or an equal volume of water.
The researchers recruited 20 healthy women aged 18 to 40 years to participate in the study. Exclusion criteria were recent fracture, known bone disease or vitamin D deficiency, or use of steroids or a diuretic. Women were also excluded from the study if they were breastfeeding or taking vitamin D supplementation above the current US recommended daily allowance.
The subjects were randomized to drink 24 ounces of water or diet cola on two different study days, and urine was collected for 3 hours after ingestion of the designated beverage. Data on 16 subjects were analyzed because four subjects were excluded due to laboratory error or nonadherence with the protocol. The researchers compared calcium and phosphorus excretion per 3 hours after water consumption with values after diet cola consumption.
Mean calcium excretion over 3 hours after diet cola ingestion was 6.85 mg higher than after water consumption, and mean phosphorus excretion was 41 mg higher among the diet cola group. They concluded that diet cola ingestion may result in a negative calcium balance acutely in young, otherwise healthy women. They theorize that this may help explain the clinically observed decrease in BMD and increased fracture rate in women who consume colas on a regular basis.
Larson said this study did not include cancer patients and so it is not possible to make any conclusions about diet cola consumption and BMD in patients being treated for cancer. However, she said because bone loss is a paramount issue with many oncology patients, these findings may be important. “This study doesn’t give any specific data that would help in those particular patients, although I would think that for anyone who is at increased risk for decreased bone mineral density and osteoporosis [drinking diet cola] wouldn’t be a helpful thing,” said Larson in an interview with The Oncology Pharmacist. “It would be best to consume more drinks that contain calcium and vitamin D.”