Does anyone save these and still have this issue? There was an article in it entitled "Soy's Not Always Savvy". I'm wondering what it says and if it was written by Dr. Kellon (a contributor on his magazine) or John Lyons. I found a site where you can order back issues, but I could not get the site to work properly. Does anyone know of any reputable, recent things published online regarding soy intolerance in horses?
I believe John Lyons Perfect Horse and what used to be called Michael Plumb's Horse Journal (now just Horse Journal) are put out by the same publisher.
Believe it or not............after I typed the above, I went looking as I used to get Perfect Horse YEARS ago. I don't have anything after 1998 BUT in the November 1998 issue of Perfect Horse, there is an article on Soy plainly named......"Soy Intolerance."
Also in the February 2009 issue of Horse Journal, there is an article about colonic ulcers and Irritable Bowel Syndrome. Soy is named in that article as a trigger for hind gut issues.
The soy issue is near and dear to my heart as I have a pony with either colonic ulcers and/or IBS. It was that 2009 article in Horse Journal that the lightbulb FINALLY went on for me after dealing with bloated belly, wet, heavy manure and watery, gassy squirts for 7 YEARS! Vets were stumped. I took him off soy and within 24 hours he was 70% improved.
My 2 WB mares are also sensitive to it as I believe soy affected their heat cycles. Both mares (mother and daughter) used to have very "expressive" heats. Soy can suppress progesterone (found in human studies) and increase estrogen. Both mares tested low progesterone, so I took them off it as well and supplemented with chastetree berry for a few weeks to get progesterone back up and they have been fine since.
Soy can also suppress thyroid function as well. I wonder if this is why we seem to be seeing so many more horses with thyroid issues (Cushings) than we did say 20 -30 years ago - upon the advent of complete feeds.
This topic (soy is bad) has developed the patina of "proven" when it is anything but.
I meant pituitary (which does affect thyroid function as well).
No one is saying soy is bad but there are individuals out there that are allergic/sensitive to it. It is a cheap form of lysine which is why it is found in every complete feed and ration balancer out there. Whey is a far more superior form of protein, but it's cost makes it not as attractive.
There are multiple studies showing the effects of soy in humans. I know someone personally who went on a "health" kick and began eating a lot of tofu. She, at the time, was also trying to get pregnant. She began having all sorts of hormonal imbalances, mainly a spike in estrogen. She quit eating soy and within a few months her hormone imbalances leveled out.
Like anything, there are individuals that are sensitive to it. I have a pony that is--she can't even have soy hulls. My pony was overweight. We put her back in work and she lost weight, but when I removed all soy from her diet--including her handfuls of TC Senior--she dropped even more and her eyes immediately cleared (they would run).
Allergy and/or intolerance to soy is a hugely different issue than supposed hormonal imbalances from soy.
No doubt there are LOTS of people with lots of intolerances of lots of food products, and horses, too. This could just as readily be said about corn, wheat, alfalfa, I even know someone whose horse is completely intolerant of beet pulp. Doesn't mean any of those products is necessarily something to be avoided in all circumstances.
For every study suggesting possible negative effects, there are studies suggesting putative benefits for one population or another. Until there is compelling evidence one way or another, I'm keeping it in the category of "food product, use as needed".
Possible health benefits from soy. I think it's safe to assume that infants of any species should not be getting anything more than mama's milk if we want to be the SAFEST. But that's an entirely different concept than soy's potential risks vs. benefits in adults.