The Dukan Diet & Vitamin A Deficiency

This is an old news story but I like to investigate what goes wrong on low carb diets.  So many people think extreme low carb diets are infallible and everyone should be able to do them.

A UK newspaper, the Telegraph, reported in 2012 the case of a man who almost died while on the Dukan diet, a low carb diet created by French MD Pierre Dukan. (

After two days on the “Attack” phase of the diet, which consists of only protein, Ashley Harrison was in the hospital in a coma with encephalopathy (brain dysfunction).  In the article, the encephalopathy is attributed to ammonia poisoning.  Ammonia is the by-product of protein metabolism in the body and can cause brain swelling.

It happened that Mr. Harrison had a genetic mutation resulting in a deficiency of ornithine transcarbamoylase (OTC)

Ammonia and OTC are part of the urea cycle.  While genetics may play a part, it is possible this man had a Vitamin A deficiency and that this either contributed to or was the real cause of his ornithine transcarbamoylase deficiency.

According to researchers, “Activities of hepatic carbamoylphosphate synthase-1 (CPS-1) and ornithine transcarbamoylase (OTC) were significantly lower in vitamin A – deficient animals than in control rats at the end of 13 weeks of feeding.  While the liver levels of ornithine and polyamines were significantly greater, that of glutamine was lower in vitamin A-deficient rats than in pair-fed controls.  The results suggest that vitamin A deficiency leads to a reduced efficiency of urea synthesis pathway, thus accounting for the increased ammonium nitrogen (Am-N) excretion seen in vitamin-A deficiency.” J. Nutr. 1989 Jan. 119 (1) 29-35.

Did his doctors know that vitamin A deficiency can cause OTC deficiency?  I bet my next paycheck they don’t have a clue.  Did they even check his serum vitamin A level?  No way Jose.  Did this man have a vitamin A deficiency that lead to his OTC deficiency?  This was a lost scientific opportunity and now the world will never know.

Part II: Did biotin deficiency lead to this man’s ornithine transcarbamoylase deficiency?  It certainly could…