The science is saying that soya is not the nutritional silver bullet we all thought it was.

As at 2013/14 when I first wrote the original version of this page, 91% of soya grown in the US alone was GM, with 80% of the GM crop sprayed with Roundup so crop production could be improved by killing the weeds.

Unlike the Asian culture, where people eat small amounts of non-GM fermented soya bean products, western food companies separate the un-fermented soya bean into two golden commodities - protein and oil. And here’s apparently where the problem lies. Studies show that consuming un-fermented soya is linked to digestive distress, immune-system breakdown, thyroid dysfunction, cognitive decline, reproductive disorders, infertility, cancer and heart disease (so says Dr. Kaayla Daniel, author of ‘The Whole Soya Story’).

Here’s another huge fact and related to our horses – a staggering 80% of the world’s soya is apparently grown for farm animal feed, which just for the record is also why soya production is contributing to deforestation - we've all seen the desperate travesty that is the orangutan natural habitat displacement, in order to clear continent-sized tracts of land to grow soya. Much of today's soya trade is also grown in S.America, where soya forests are burned, destroying the natural habitat, then shipped round half the world.

So, apart from soya being both GM and soaked in chemicals, while continuing to make thousands of orangutans homeless, and creating a carbon footprint bigger than the planet itself, here are some more facts as to why I’d rather not feed it to my horses.

• Soya bean amino acid protein is equine-inappropriate, leading to water in muscle tissue, not proteinated muscle. Soys bean starch is also not able to be digested by the horse so leads to an intestinal gas buildup.
  
  
• Soya oil is rich in long chain fatty acids (the unhealthy ones) and contains predominantly polyunsaturated fats (the inflammatory fats), making it prone to rancidity. Worse, the oil is chemically extracted and highly refined using toxic levels of aluminium and manganese, being processed by acid washing in aluminum tanks, which can leach high levels of aluminum into the final soya product.

• GM soya has been linked to an increase in allergies. The plants contain genes from a bacteria that produces a protein that has never been part of any food supply. Disturbingly, the only published human-feeding study on GM foods verified that the gene inserted into GM soya transfers into the DNA of our gut biome and continues to function there. This means that years after we stop eating GM soya, we may still have a potentially allergenic protein continuously being produced in our intestines. And if it’s happening to us, it's happening to our horses – if your horse presents with allergenic responses, it might be worth checking your feedbag to see if soya oil or protein is listed.

• It's also been linked to infertility. In one specific animal test, cheetahs who were fed soybean developed an infertility syndrome, which was irreversible when the soybeans were removed from their diet, thought to be due to the presence of phyto-oestrogens in soy.

• Soya contains a starch known as Stachyose, which can't be digested in the small intestine. Hence it enters the large intestine (hindgut) and is a perfect feed for the resident lactic-acid bacteria, which create lactic-acid as their waste, which makes the hindgut environment acidic, where it should always be at a neutral pH, so leading to the hindgut acidosis/dysbiosis/SIBO/leaky gut domino effect.

• Soya contains hemagglutinin, a clot-promoting substance that causes red blood cells to clump together. These clumped cells are unable to properly absorb and distribute oxygen to the body’s cells.

• Soya contains goitrogens, a chemical that inhibits the uptake of iodine by the thyroid gland, so interfering with iodine metabolism.

• Soya contains phytates which bind to metal ions, preventing the absorption of certain minerals including calcium, magnesium, iron and zinc, all of which are essential for our horses biochemistry.

• Horses that are fed soya can be low in certain minerals, i.e. iron, manganese, chromium, cobalt and selenium. All vital for the growth of connective tissue in tendons, ligaments, joint cartilage, hoof and hair.

So why do equine feed producers include soya in horse feed? One reason only - it's a cheap protein source. However ... soya contains natural toxins known as anti-nutrients, some of which interfere with the crucial protein-digesting enzymes. There are much better alternatives to adding protein into your horse's diet, i.e. hemp seed, linseed or sainfoin, but the best source? Hay. Pure and simple.

Sources:

https://depaoloequineconcepts.wordpress.com/2016/05/31/the-negative-effects-of-feeding-soy-to-horses/

https://equinechallengesupplements.com/soy-in-horse-feeds-the-silent-antinutrient/