Biotin deficiency is very rare. Symptoms of biotin deficiency include1:
There are a couple of ways that a person could develop a deficiency in biotin. First, a very small number of people are born with a mutation in biotinidase that results in them not being able to cleave biocytin for absorption1. Another way is through the consumption of raw eggs. Drinking raw eggs is not something that most people do. However, some people do it to imitate Sylvester Stallone's movie character Rocky, who consumed them as part of his boxing training regimen. If you are not familiar with this movie the link below shows you how Rocky consumed his raw eggs.
The potential problem with consuming raw eggs routinely is that raw egg whites contain a protein called avidin which binds biotin and prevents its absorption. However, it would take more than two dozen egg whites consumed daily over many months to cause a deficiency, making this an unlikely occurrence2. Cooking denatures avidin and prevents it from binding biotin, meaning that cooked eggs are not a concern.
No toxicity of biotin has been reported.
References & Links
- Byrd-Bredbenner C, Moe G, Beshgetoor D, Berning J. (2009) Wardlaw's perspectives in nutrition. New York, NY: McGraw-Hill.
- Whitney E, Rolfes SR. (2008) Understanding nutrition. Belmont, CA: Thomson Wadsworth.
Rocky Raw Eggs - http://www.youtube.com/watch?v=NhkdLHSKo9s