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What’s the Difference Between Plant and Animal Hormones? Part 2

All plants and animals produce hormones. Best Food Facts experts are helping us understand how hormones function and answering questions about hormones in our food in a three-part series.

Each hormone has a specific function in an organism, like a lock and key, the first article explained. Another article looks at why animals are given hormones. Best Food Facts expert Dr. Tim McAllister, principal research scientist with Agriculture and Agri-Food Canada, helps us understand the difference between hormones that occur in animals and plants.

What is the difference between plant-based and animal-based hormones?

Dr. McAllister: “The biggest difference between the two types of hormones is that they simply have different chemical structures. Plant-based hormones are called phytoestrogens and there is a large variety of different types of phytoestrogens in plants. With animal hormones, there is significantly less variety and number of types. Yes, they are structurally different, but they can have some components of their structure in common – this is why even though some hormones have different names they can still have similar biological effects.”

Do our bodies digest and breakdown plant-based and animal-based hormones differently?

Dr. McAllister: “Regardless of the type of hormones, our bodies break down the hormones we consume and use them as an energy source. All meat has hormones in it and all plants have hormones in them, so the rate of degradation will depend on the type of hormone you are referring to and its susceptibility to digestion from the enzymes in your body not the source of the hormone.”

If we were to digest an animal-based hormone and a plant-based hormone – would they affect our bodies differently?

Dr. McAllister: “Generally, animal-based hormones have a greater impact on our bodily function compared to plant-based hormones because we have evolved to produce these hormones that have regulatory effects in our system. Whereas plant-based hormones have evolved to have regulatory effects in the systems of plants. There can be cross-reactivity, where plant-based hormones can have effects on animal systems and vice versa.”

What is the difference between natural and synthetic hormones?

Dr. McAllister: “Natural hormones would be a hormone that is naturally produced in the animal’s body or the plant. A synthetic hormone is one that is synthesized in the lab which mimics the structure of any given natural hormone.”

So even though it is produced in the lab, it is a replicate of the natural hormones that our bodies produce already?

Dr. McAllister: “That’s right. There are key components in the structure of hormones that interact with receptors. If you duplicate these components synthetically, you can have similar outcomes as to what the natural hormone will have either from the plant or the animal. “

In Canada, the only animal that may be given added growth hormones are beef cattle. Do farmers give them natural or synthetic hormones?

Dr. McAllister: “Some farmers use either synthetic and natural hormones.”

How does a farmer choose when to implant natural or synthetic hormones?

Dr. McAllister: “The biggest factor when choosing a hormone to implant is based on the goal of the farmer and what they wish to achieve when using the hormone. The activity level of the hormone in the animal’s body is dependent on the structural component of the hormones itself. For example, if the animal is already mature, then you might want to choose a more active hormone because the goal is to increase their weight in a short amount of time.  If you have an animal that is out in the pasture maturing, you would choose a lower activity hormone as their will be further opportunity to increase growth during the finishing phase.”

Should we be concerned with consuming animal products when hormones may have been used through their growth process?

Dr. McAllister: “All meat and plant products have hormones of some type. There is no such thing as ‘hormone-free beef,’ ‘hormone-free pork’ or ‘hormone-free lettuce’ as hormones are essential for the function of both plants and animals. An important thing to note is that many of the hormones we consume from either ‘no-hormone added’ meat or ‘hormone added’ meat do not actually interact with the internal receptors in our body.

“When beef farmers choose to implant their cattle with hormones, the goal is to effectively use this hormone and have no trace of it left in the system before the animal goes to slaughter. Implants are designed to slowly release hormones into the animals’ system to increase the efficiency of their growth from the time of implant to when the hormone is completely used up. In most cases, the hormones in the implant are completely used up by the time the animal is ready to go to slaughter.”

All plants and animals naturally produce hormones. Synthetic hormones are produced in a laboratory and function similar to natural hormones. Most of the hormones that we consume in our food are digested and do not interact with receptions in our body.

Part 1 – Are There Hormones in My Food?

Part 3 – Why Are Animals Given Hormones?