Peanuts can be murderous for those with severe peanut allergies. Chugging gallons of otherwise-harmless water in minutes can become fatal. And, in those with a rare genetic disorder, taking in too much protein causes heightened levels of ammonia in the blood, which can contribute to everything from fatigue to death.
Such was the case for Meegan Hefford, a 25-year-old Australian woman who reportedly died following consumption of high levels of protein supplements in preparation for a bodybuilding competition in what many outlets have referred to as a “protein overdose.” However, doctors later determined that she had an undiagnosed urea cycle disorder, which affected the way her body processed all that protein. Unfortunately, they didn’t catch it until it was too late, according to PerthNow, a local news outlet that originally covered the case.
While the news is tragic, and Hefford’s family is understandably speaking out about the need for regulation of protein supplements (of course, it’s always wise to talk to your doctor before adding any kind of supplements to your routine), it’s also important to remember that protein consumption in itself is not dangerous for the vast majority of us—not any more than peanuts or water.
What are urea cycle disorders—and how common are they?
When you eat protein, enzymes in your digestive tract break the nutrient down into amino acids. These amino acids come attached to nitrogen, but cells within the liver remove that and convert it to urea, which the kidneys then process and allow you to excrete via urine, Donald K. Layman, Ph.D., professor emeritus of food science and human nutrition at the University of Illinois and leading protein researcher, tells. However, in those with a urea cycle disorder, the liver isn’t able to do its usual thing, allowing nitrogen to build up in the blood in the form of ammonia.
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“Most babies born with the genetic defect die within a few days of birth,” Clement Rose, M.D., an internist at Weiss Memorial Hospital in Chicago, tells. “It’s very rare, especially in adults.” According to the National Urea Cycle Disorders Foundation, one in every 8,500 babies is born with the disorder, and up to 20 percent of sudden infant death syndrome (SIDS) cases may be attributed to metabolic disorders, including urea cycle disorders. “You have a greater chance of being struck by lightning than having a urea cycle disorder,” he says.
So how could Hefford have gone 25 years with such a serious health condition without realizing it? According to Layman, urea cycle disorders range in severity depending on which liver enzymes a patient is deficient in and just how low their levels are. That means she may have been able to process enough protein without issue that the disorder went undiagnosed. But clearly that’s an exceptionally rare situation, and there’s really no way to know the specifics of Hefford’s case.
Can you really have a “protein overdose”?
We don’t know exactly how much protein Hefford was consuming in combination with her training, but Layman notes that it’s totally safe for healthy adults to take in up to 3 grams of protein per kilogram of body weight each day. For a 140-pound woman, that works out to 190 grams of protein per day. It might be safe to have even more, but researchers haven’t tested the theory because there’s no real reason to eat that much protein every day.
So what is the right amount? It’s probably more than you think. The current recommended daily allowance (RDA) for protein—which denotes the lowest requirement rather than the optimal amount—is set at 0.8 grams of protein per kilogram body mass. But most research from the past decade suggests that number is actually too low—especially among those who are highly active or are older than 30 because the body becomes less sensitive to protein intake as we age, Layman says. For instance, recent research published in The American Journal of Nutrition argues that the average American (who actually consumes slightly more than the RDA) still isn’t getting enough protein for optimum health.
As a conservative amount, Layman recommends that most people consume between 1.2 and 1.5 grams of protein per kilogram body weight—roughly 90 to 140 grams—of protein per day. However, body size actually makes a smaller difference here than you might expect. So it’s probably easier to let the total grams of protein be your guide rather than body-mass equations, he says.
For example, 2015 review in the journal Applied Physiology, Nutrition, and Metabolism concluded that consuming 25 to 35 grams of protein per meal or snack is ideal for overall health. Each gram of protein contains four calories and it’s recommended that healthy adults get between 10 and 35 percent of their calories from protein. So, if you’re getting around 2,000 calories per day and getting around 25 percent of those from protein, that works out to 125 grams of protein per day, which lands right in that 25-to-35 grams range.
Still, it’s wise to increase your protein intake gradually.
When pumping up your protein intake—or making any nutritional changes, for that matter—it’s important to be informed about your health and how that might affect your individual needs.
For instance, all urea disorders aside, many other existing conditions can lead to ammonia toxicity if left untreated, Rose says, including cirrhosis of the liver, kidney disease, and hepatitis. “Any physical that you’ve ever had should have looked at your levels of creatinine, ammonia, and liver enzymes,” Layman adds. “A physician should pick right up on any of these levels being abnormal, which would point to renal or liver issues.” That, in turn, could point to any potential problems with your ability to process protein. So, if you don’t already check in with your doctor regularly, there’s another reason to do so.
Interestingly enough, though, increased protein intake can actually improve liver and kidney function in people without existing issues, according to Layman. That’s because, when you eat more protein, your body gradually increases the levels of the enzymes necessary for protein breakdown—the key word here being “gradually.”
“If you go from eating 50 grams to 100 or 200 per day overnight, nitrogen levels in the blood will go up quickly,” he says. In his research, he finds that most female participants enter studies eating about 60 grams per day. So, if his team is trying to get them up to 120 grams (a typical target), they’ll take five or six days of gradually increasing protein to get there. And it’s best to take the same approach at home, increasing by roughly 20 or so grams per day.
For those who have trouble getting their protein intake at a recommended amount through whole foods alone, protein powders and shakes can be helpful additions, board-certified sports dietitian Kelly Pritchett, Ph.D., R.D., C.S.S.D., a spokesperson for the Academy of Nutrition and Dietetics, tells.
However, before supplementing, Pritchett recommends talking to your doctor or registered dietitian about your options and thoroughly reading all labels. Unfortunately, supplements including protein powders are not intensely regulated by the FDA, which means that it’s on you to ensure that your protein powder actually contains what it says it does—and nothing else. “Make sure the product has been tested for purity and quality control,” she says. The most common certification program for protein powders is NSF Certified for Sport, which screens ingredients and laboratories to guarantee the nutritional content of supplements and makes sure it doesn’t contain any banned substances. You can also search certified protein supplements at the program’s website.