Monday Pharmaceutical Mystery: July 29

Why is this healthy young man getting severe brain fog?

AJ, a man age 27 years, comes to your pharmacy counter inquiring about protein drinks. He is thin and athletic looking. He takes no medications, not even OTC products. He was wondering if you can recommend a brand of protein drinks or protein bars that taste good and does not have any allergens. He suspects he might be allergic to the ingredients in some because they often give him headaches, nausea, and sometimes severe "brain fog."

He has been a vegetarian most his life and just started weight lifting and body building. He knows he needs to eat more protein, but has a hard time forcing himself to consume protein drinks and meat.

Mystery: Why does he have an aversion to protein, and why does he get headaches, nausea and sometime severe "brain fog" when he consumes protein drinks? Is there a product you should recommend?

Solution: This person has a urea cycle disorder and lacks the enzymes to properly metabolize proteins. In this situation, the severe brain fog (aka altered mental status) is caused from buildup of ammonia levels in the brain and blood. Hyperammonemia can lead to cerebral edema, coma, and death. It is estimated that 1 in 8,200 people have this condition in the United States. Most people are diagnosed as infants, however, less severe defects go unnoticed until adulthood.

No products are recommended in the situation. People should be instructed to always listen to their bodies, and tell their doctors when something is not quite right so that further testing can take place. What is considered healthy for 1 person, could be lethal to another. Our bodies and health is very individualized.


Lien J, Nyhan WL, Barshop BA. Fatal Initial Adult-Onset Presentation of Urea Cycle Defect. Arch Neurol.2007;64(12):1777—1779. doi:10.1001/archneur.64.12.1777