Meegan Hefford had an undiagnosed genetic condition called urea cycle disorder. Learn how common this scary condition really is, and the sneaky signs to watch for.


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 Now reported 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.” 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, 2017, 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.”

However, Dr. Ah Mew adds, people with undiagnosed urea cycle disorders usually have some symptoms. “Typically, there’s some combination of nausea, vomiting, and inability to think clearly, particularly after a large protein meal,” he says. “It’s very rare for someone to feel completely healthy and suddenly fall unconscious.”

And while Hefford’s case is very rare, it does raise concerns about the potentially harmful effects of dietary supplements—which are largely unregulated in Australia as well as the U.S. Hefford’s mother hopes her death will serve as a warning to others not to overdo it with bodybuilding shakes, pills, and powders.

Medical and nutrition experts told Perth Now that protein supplements aren’t necessary for most healthy people, and that it’s better to get the nutrient from whole foods rather than trying to “trick your body” into building muscle. “This case is obviously tragic and illustrates that you may not know you have a health issue that alters the way you metabolise,” Australian Medical Association WA president Omar Khorshid, MBBS, told the news organization.

Most people eating a balanced diet will easily hit the Recommended Dietary Allowance (RDA) for protein, which is 0.8 grams per kilogram (0.36 grams per pound) of body weight per day. But people who are very active, in middle age, or are trying to build muscle or lose weight are often encouraged to get more than that.

Dr. Ah Mew says that anyone looking to optimize their protein intake in order to increase muscle mass should consult with an exercise physiologist or sports nutritionist about the healthiest way to do so. But he says for most people, an occasional protein shake after a workout—with protein powder or without—should not be cause for concern.

“It’s important for the bodybuilding community to know that anyone who has repeated nausea, vomiting, headache, after eating lots of protein should get their ammonia levels checked,” he says. “But if you feel fine, it’s very unlikely that you’re going to have an undiagnosed disorder like this.”

Hefford's mom, Michelle White, recently told The Mirror about how her daughter's fitness habits ended up killing her, warning others about the condition that killed her child. "We had no idea her obsession with health would end up killing her," she wrote.

White also said that she found protein supplements in Hefford's kitchen cupboards after her death, in an essay cautioning others about the dangers of protein for people with urea cycle disorders. "It made me feel so angry and desperately sad," White wrote.