For Some People, Too Much Protein Can Be Deadly—Here’s What You Need to Know About the Death of a Bodybuilding Mom

An Australian woman has died after consuming large amounts of protein from food and dietary supplements, her family says. The mom of two had increased her protein intake while preparing for a bodybuilding competition, but doctors discovered too late that she had a rare disorder that prevented her body from properly metabolizing the nutrient.

Meegan Hefford’s death certificate lists the previously undiagnosed condition, called urea cycle disorder, as a cause of death, Perth Nowreported Saturday, along with “intake of bodybuilding supplements.”

According to news reports, Hefford’s mother said the healthy and fit 25-year-old had “ramped up her gym sessions and gone on a strict diet earlier this year.” While attending college and working part-time at a hospital, Hefford would sometimes go to the gym twice a day.

Her mother also said she found “half a dozen containers” of protein supplements in Hefford’s kitchen, along with a detailed diet plan including protein-rich foods like lean meat and egg whites.

Hefford was found unconscious and rushed to the hospital on June 19, and was reported brain dead on June 22. It took two days for doctors to discover she had a urea cycle disorder, but she had reportedly complained about feeling lethargic and “weird” earlier in the month. Her mother said she’d worried about Hefford “doing too much at the gym,” and had warned her to slow down.

Urea cycle disorder is an umbrella term for a family of rare genetic disorders that affect about one in 35,000 people in the United States, says Nicholas Ah Mew, MD, director of the Inherited Metabolic Disorders Program at Children’s National Health System’s Rare Disease Institute. (Dr. Ah Mew was not involved in Hefford’s case.) 

People with a urea cycle disorder are deficient in one of six enzymes that help remove ammonia—a toxic byproduct that’s created when protein is metabolized—from the bloodstream. Normally, ammonia is converted to a compound called urea and is removed from the body via urine. But for people with urea cycle disorders, ammonia can build up in the bloodstream. When ammonia in the blood reaches the brain, it can cause irreversible brain damage or death.

According to the National Urea Cycle Disorders Foundation, this condition can occur in both children and adults, and cases can vary from mild to severe. Infants with severe forms of the disorder become seriously ill or die soon after birth, but it’s possible for children with milder cases to go undiagnosed.

Adults can also develop (or live for years with) mild cases, without knowing they have the disorder. “These people may have enough urea cycle function to get by on a day to day basis, until they hit some kind of perfect storm of events,” says Dr. Ah Mew. “Maybe it's a combination of illness or injury along with a large boost in protein intake, and it overcomes their ability to get rid of the ammonia in their system.