A Second Look at The Safety of Soy in Horse Feed

Are you consuming more than one glass of soy a day or eating the equivalent in soy protein? How about your horses' soy consumption?

Recent research has pointed to some potential deleterious effects from the consumption of soy products for both humans and other animals. There is not enough evidence for this to be definitive yet, but it is still worth examining.

Soy Online Service provides a variety of information about what soy does inside the mammalian body. The agricultural soy industry has not promoted this information.

Soy Safety: Depends on the Source, Nutritionists Say by Lisa Kemp of <a href="http://www.thehorse.com</a> says, <blockquote>Soy has long been considered a reliable source of protein for horses. But is it really safe?</blockquote> According to Jack Grogan, CN, Vice President of research and development at Uckle Health & Nutrition, <blockquote>Soy protein by itself can directly interfere with hormonal balance and be pro-inflammatory, increasing the metabolic stress load and affecting immune function. We feel feed enhancers that use soy protein are not in the horse's best interest.</blockquote> However, an equine nutritionist from Lexington, Ky. named Amy M. Gill, PhD has a different perspective. She says horses need vegetable sources of protein to supply amino acids. As far as nutritionists know, soy protein provides the closest match to equine amino acid requirements. She warns, <blockquote>Many of the human soy-related problems reported in the news are coming from women who overconsume soy protein, affecting their reproductive hormones, or from people who are truly allergic to soy products. Because horses are strict herbivores, they can have completely different metabolic responses to digesting individual ingredients than omnivorous humans do, so the effect of these ingredients could be different. No data currently exists, that I'm aware of, that shows soy protein has a negative effect on horses when it's fed in reasonable amounts, such as those included in nutritionally balanced horse feeds.</blockquote> Two things Gill has not addressed in this article are the facts that, in nature, horses do not eat soybeans as humans do, and that most soy is genetically modified and then solvent extracted to remove the soy bean oil, which is the primary product, leaving the meal, which is sold as animal feed. Grogan cautions owners not to throw the soy baby out with the bathwater. The jury is still out on soy oil, which has a different chemical makeup and fewer hormone-altering components. We need to be clear on the difference between soy protein and soy oil. The Horse.com warns that If your horse exhibits physiological or behavioral changes and you suspect a dietary cause, test before leaping to any conclusions. At </a><a href=" _cke_saved_href="http://www.thehorse.com</a> says, <blockquote>Soy has long been considered a reliable source of protein for horses. But is it really safe?</blockquote> According to Jack Grogan, CN, Vice President of research and development at Uckle Health & Nutrition, <blockquote>Soy protein by itself can directly interfere with hormonal balance and be pro-inflammatory, increasing the metabolic stress load and affecting immune function. We feel feed enhancers that use soy protein are not in the horse's best interest.</blockquote> However, an equine nutritionist from Lexington, Ky. named Amy M. Gill, PhD has a different perspective. She says horses need vegetable sources of protein to supply amino acids. As far as nutritionists know, soy protein provides the closest match to equine amino acid requirements. She warns, <blockquote>Many of the human soy-related problems reported in the news are coming from women who overconsume soy protein, affecting their reproductive hormones, or from people who are truly allergic to soy products. Because horses are strict herbivores, they can have completely different metabolic responses to digesting individual ingredients than omnivorous humans do, so the effect of these ingredients could be different. No data currently exists, that I'm aware of, that shows soy protein has a negative effect on horses when it's fed in reasonable amounts, such as those included in nutritionally balanced horse feeds.</blockquote> Two things Gill has not addressed in this article are the facts that, in nature, horses do not eat soybeans as humans do, and that most soy is genetically modified and then solvent extracted to remove the soy bean oil, which is the primary product, leaving the meal, which is sold as animal feed. Grogan cautions owners not to throw the soy baby out with the bathwater. The jury is still out on soy oil, which has a different chemical makeup and fewer hormone-altering components. We need to be clear on the difference between soy protein and soy oil. The Horse.com warns that If your horse exhibits physiological or behavioral changes and you suspect a dietary cause, test before leaping to any conclusions. At </a><a href=" http:="" www.dailydoseequine.com="" aboutyourhorse="" soybeanmeal.html"="">Dailydoseequine.com</a>, there is a list of 9 things to think about when feeding soy to horses. <blockquote>1. Soybeans contain excellent quality proteins, as amino acids, fairly well-balanced for performance. However, raw soybeans contain two toxic enzymes: Urease and lipoxdase which many horses react to. This makes it very important to roast them before using them in horse feeds. The flame-roasting process eliminates these "anti-nutrients" and turns the soybeans into an efficient source of the particular amino acids useful to the horse, as well as concentrated energy. 2. Many horses are allergic to the soy that is in the horse feeds today. Soy can be present as soybean meal (a byproduct of the soybean oil industry), raw beans, or roasted beans. Certain specific types of protein in soybeans have been shown to cause an inflammatory response in the intestine when exceptionally high levels of soybean meal are included in diets for early-weaned pigs (similar to horses). This allergic response seems to be greater if pigs are exposed to soybean meal (for example, in the sow's feed) before they are weaned. The processing that soybeans undergo in the production of soy protein concentrate seems to reduce the amount of these antigenic proteins. It is difficult to tell how the soybeans were processed when reading a label on a bag of feed and for the normal consumer it is near impossible to determine if their animal will have a reaction. 3. The anti-nutrients in soy are potent enzyme inhibitors that block the action of trypsin, erypsin, and other enzymes needed for protein digestion. These inhibitors are large, tightly folded proteins that are not completely deactivated during ordinary cooking. They can produce serious gastric distress, reduced protein digestion and chronic deficiencies in amino acid uptake. In test animals, diets high in trypsin inhibitors cause enlargement and pathological conditions of the pancreas, including cancer. These anti-nutrients can be destroyed by heating during processing, but not all soybeans are heat treated to create soybean oil and processing does not remove all of them. Most soybean meal is made through a solvent extraction process. 4. Soy and soybean meal contain goitrogens - substances that depress thyroid function. The thyroid is the regulator of metabolism. When thyroid function is depressed the horse gains weight and exhibits the classical signs of "metabolic shutdown." Some of the literature claims that these goitrogens are destroyed with heat treatment, but there is little scientific evidence to prove this information. 5. Additionally, a very large percentage of soy is genetically modified and it also has one of the highest percentages contamination by pesticides of any of our foods. 6. Soybeans are high in phytic acid (phytate), present in the bran or hulls of all seeds. It's a substance that can block the uptake of essential minerals - calcium, magnesium, copper, iron and especially zinc - in the intestinal tract. Although not a household word, phytic acid has been extensively studied; there are literally hundreds of articles on the effects of phytic acid in the current scientificliterature. Scientists are in general agreement that grain- and legume-based diets high in phytates contribute to widespread mineral deficiencies. Diets high in phytates result in waste material high in phosphorous and hence pollution. Genetically-modified soy is lower in phytic acid than non-genetically modified soy. 7. Another concern with soy is that it contains a natural chemical that powerfully mimics estrogen, the female hormone. Some studies in animals show that this chemical can alter sexual development. And in fact, 2 glasses of soy milk/day, over the course of one month, contain enough of the chemical to change the timing of a normal menstrual cycle. 8. Soy and soybean meal have their benefits. The use of soy in food originated in the orient and to this day, the asian diet incorporates a small amount of this product almost as a spice. This makes sense from the stand point of moderation. However the processed food diets for horses and humans in the US contain excessive amount of this ingredient which is resulting in insulin resistance, metabolic shutdown, foal health problems, premature puberty, allergies and more. 9. Soybean meal is made by extraction with a solvent. When extraction occurs unless there is a high quality solvent used (i.e. 99% pure) there are chemical residues left behind. Originally soybeans were extracted using trichloroethylene (dry-cleaning solvent) whose resides proved toxic to animals. Other solvents include hexane and pentane which are quite flammable and evaporate into the atmosphere adding to pollution of the earth.</blockquote> <a href="http://www.uckeleequine.com/news/15/" _cke_saved_href="http://www.uckeleequine.com/news/15/">For more information</a> <a href="http://www.chronofhorse.com/forum/showthread.php?p=4760681" _cke_saved_href="http://www.chronofhorse.com/forum/showthread.php?p=4760681">Discussions on the subject at the Chronicle of the Horse Forums</a>