Recently I had a conversation with another member via PM about L-Lysine supplementation and how I was concerned. She can "out" herself, or not, if she wants since she knows I'm going to post in part my end of the conversation here.
So how often do you supplement L-Lysine and for how long? For what condition? Are you concerned about the below information if you don't "pulse" supplementing L-Lysine but give it on a long-term, continual basis? If not, why?
L-Lysine, since it's an amino acid should be used judiciously, and you have to be careful with it because it is part of a process in conjunction with other amino acids. L-Lysine will compete with arginine and deplete the arginine, so you don't want to exceed a maintenance dose of 250mg on a long-term basis. I've always done 500mg per day in the acute phase (divided in two doses), then 250mg per day (again divided between two doses) for a few days after symptoms have subsided, then I stop it.
A little excerpt from Pet Education about arginine:
"Arginine is also an amino acid. Most animals manufacture the amino acid ornithine through various processes, some of which require arginine. In cats, the only method to produce ornithine is to convert it from arginine. Ornithine is necessary because it binds ammonia produced from the breakdown of protein. If cats are deficient in arginine, there will not be enough ornithine to bind the ammonia, and severe signs such as salivation, vocalization, ataxia, and even death can result from the high ammonia levels. These signs often occur several hours after a meal, when most of the ammonia is produced. Although deficiencies are rare, they cat occur in cats who are not eating or have certain liver diseases such as hepatic lipidosis."
I was concerned about over-supplementation causing a depletion of arginine (and therefore ornithine) for kitties that are on it.
She posed a question regarding why kitties that have been on it long-term show none of the signs of depleted arginine. My thoughts were:
With regards to the long term maintenance dose of L-lysine, I wonder if 1) diet comes into play, and 2) the efficacy or purity of the brand of supplement could be in question? Regarding the purity of a specific product, maybe having access to consumer lab reports would be beneficial (if the product has been tested, that is)? Although some supplements have the USP designation on them, so that would be something to look for maybe?
My thoughts are that a raw diet would contain a higher amount of naturally occurring arginine, and therefore no clinical signs of deficiency even if the L-lysine is competing with the arginine (both 1 and 2 above)? And maybe that's why a high maintenance dose has to be given in the first place?
There are studies that show a diet with NO arginine clinical signs will exhibit within one hour of just one meal.
http://jn.nutrition.org/content/115/4/524.full.pdf (page 2/525, second column)
"However, within an hour of consuming a single meal of a purified diet containing all the essential nutrients with the exception of arginine, near adult cats exhibited sialorrhea (frothing at the mouth), ataxia, emesis and tetanic spasms with emprosthotonus. In severe cases the clinical signs included cyanosis and death from respiratory failure (15, 16). Arginine deficiency in the cat is the most rapidly induced nutrient deficiency observed in any mammal."
A fascinating (to me ) study: Arginine: An Essential Amino Acid for the Cat (a pdf). Part of this study is that kitties, when given a choice, chose the diet that contained arginine. (Fascinating except for the kitties that suffered.)
End of conversation and now bringing it public.
So what say you, fellow TCS members? Thanks!