Making Sense of Stress: The Gut-Brain Connection

The more we learn about the gut-brain connection, the better we can get at addressing equine health issues.  One of the most common issues in horses of all ages and lifestyles is stomach ulcers, also known as Equine Gastric Ulcer Syndrome (EGUS). Signs of EGUS include: weight loss, reduced appetite, decreased performance, poor body condition and hair coat, poor attitude (irritability, resistance, reluctance to go forward), increased spookiness, less focus, girthiness, back soreness, sensitivity to being groomed, and colic.

The root of gastric ulcers is stress.
This stress can come from a variety of sources: training stress, shipping stress, competition stress, large meals of processed feeds, limited hay, limited pasture, medications, and illness are among the most common. There is also the stress felt with a new turnout situation, a new pasture mate, being moved to a new barn or stall, the stress of the humans around the horse, of the rider and trainer, and of the other horses. Stress can also come from abrupt weather changes or long-term weather extremes like drought.

The equine extrovert, the equine internalizer
Like human extroverts, the equine extrovert generally makes it very clear to others that he or she does not feel good, and is stressed. This is the horse who overreacts to stimuli, who lets you know in no uncertain terms there is a boogeyman in the corner of the arena. These horses don’t hide the fact that their tummies hurt. The equine internalizer, on the other hand, is much more difficult to read. This is the horse that doesn’t display outward symptoms of stress. These are the stoic horses, the ones that are harder to read and whose symptoms are much more subtle.

Whichever personality type a horse has, however, equine stress is the same in terms of its causes, effects, and the ways we can seek to reduce it.

The cortisol connection
When a horse feels stress, the body ramps up the production of stress hormones from the brain and adrenal gland. Compounds like norepinephrine and cortisol communicate with the gut, sending news of stress and altering what it would normally do so that the mind and gut can fight off the active stressor.   This is a beneficial response to acute stress: the fight or flight reaction.

Chronic stress, however, causes the stress hormones like cortisol to be released frequently, causing the gut-brain axis to trigger low-grade inflammation, resulting in decreased nutrient absorption and less blood flow to the GI tract. Chronic stress disrupts the immune system, heightening the inflammatory response. Excess cortisol can increase blood sugar levels, decrease protein synthesis, lower immune function, and reduce production of prostaglandin—a substance in the GI tract that protects the mucosal lining from the acids of the stomach.

Chronic stress affects the brain
Neuroscientsts at the University of California, Berkeley, have found that chronic stress and elevated cortisol levels trigger changes in brain function and structure. Some of the effects of chronic stress on the brain include: reduced ability to learn or remember; shrinking of the hippocampus and prefrontal cortex areas critical for control of impulsive behavior; and reduced levels of serotonin, dopamine and other critical neurotransmitters which play an important role in mood, learning, concentration, appetite, and sleep.

Treatment, relapse, and getting to the root of the problem
The conventional approach to treating gastric ulcers is with omeprazole, sold as the equine formula Gastrogard. This proton pump inhibitor reduces gastric acid secretion, literally turning it off to give the mucosa time to heal. There is no question that omeprazole works, and most horses with gastric ulcers are healed within 4 to 6 weeks. Oftentimes, unfortunately, we see horses treated for gastric ulcers develop another gastric ulcer weeks or months after treatment. Back onto omeprazole these horses go, and the merry-go-round of medicine and relapse continues. Unless we eliminate all stress, or all that our horse perceives as stress, the merry-go-round will never stop.

Like the drug omeprazole, many equine calmers simply focus on the symptoms of stress—mainly the over-reactive, spooky, lack of concentration in horses. While these calming supplements do work, they are missing a vital component: they don’t deal directly with cortisol.  Which means they’re not taking the all-important gut-brain connection into account.

A New Formula

When I formulated BioStar’s Equilibrium many years ago, it was with my eye on the gut-brain connection, and specifically the role of stress. That’s why Equilibrium contains ashwagandha, the Ayurvedic plant that has been clinically tested for its ability to reduce
cortisol, and its contribution to increasing serotonin in the brain.

I started testing a small group of horses on a new formula, using Equilibrium ground into a powder, and the addition of another important Ayurvedic plant: holy basil (also known as Tulsi). Holy basil is one of the
sacred plants of Ayurvedic medicine. Like ashwagandha, it reduces cortisol and supports glandular, endocrine, and circulatory balance within the body system.

Update January, 2017: Thera Calm no longer contains Holy Basil.  Instead, we have added Haritaki as well as Organic Hemp Seeds.

Haritaki (Terminalia Chebula) is a large deciduous tree whose fruit and leaves have been used in Ayurvedic, Tibetan, and Traditional Chinese Medicine for thousands of years. In Tibetan Medicine it is known as “the King of Medicine”; nearly all the Tibetan herbal formulas contain this plant. It activates three medians of lung, large intestine, and stomach.

Terminalia Chebula is one of the tri-doshic plants in Ayurveda, balancing to the three different body/mind types, called doshas. Its traditional use has been for gastrointestinal disorders including ulcers, as well as respiratory disorders.

Published research  demonstrated the cytoprotective effects of Haritaki on the gastric mucosa. Recent studies highlight the antioxidant and free radical scavenging activity of Haritaki, capable of inhibiting lipid peroxide formation and scavenging hydoxyl and superoxide radicals. Free radicals and oxidative damage play a huge role in muscle and tissue degeneration, metabolic disease, and inflammation.

Haritaki supports the GI tract including the delicate mucosa, supports the lungs, and provides important antioxidant activity, and anti inflammatory effects.

For additional neurotransmitter support, particularly serotonin, I added a milk protein called casein.   This milk protein is also in BioStar’s Thera Calm K9: the only calming formula that was able to stop my dog Crockett’s car sickness, and put all four of my Australian Shepherds into a sound sleep for several hours.

A 2010 study published in Nutritional Neuroscience by Choi, et al compared the ability of different proteins to raise levels of brain neurotransmitters that influence mood. The study showed that in the cortex, serotonin levels were ten times higher after eating casein than after eating proteins from soy, wheat, barley, corn, and rye.

I added undenatured whey protein to the formula because a specific protein it contains called alpha-lactalbumin can reduce cortisol and raise brain serotonin activity (American Journal of Clinical Nutrition, Markus et al, 2000). An ever-growing body of studies has shown that whey proteins and their component peptides have a wide range of biological activities, including protection of gastric mucosa by endogenous prostaglandin synthesis. Several studies have indicated that quality whey protein may play an important role in protection against gastric ulcers. Considering the gut-brain connection, adding undenatured whey protein is important support for horses under stress.

The glutamine connection: Casein and undenatured whey protein provide high amounts glutamine, an amino acid that plays an important role in healing intestinal mucosa and nourishing the epithelial cells that line the small intestine.

Testing the new formula
We tested the new formula Thera Calm EQ on a number of different horses, from hunters and jumpers with a lot of blood, to layup horses, to dressage horses, and even a moody mare. The results in some cases were dramatic: owners seeing improvement within 24 hours. The higher the stress in the horse, the quicker the results became apparent. Horses with moderate to low chronic stress needed to take Thera Calm EQ for a longer period of time to show the benefits of reduced cortisol, a happy GI tract, and increased brain serotonin.

Thera Calm EQ
The combination of cortisol reduction, serotonin increase, and GI support make Thera Calm EQ an important nutritional, whole food solution for horses under stress. This unique blend of foods and plants that take the gut-brain connection seriously and provide real biological support for horses under stress will be available soon from BioStar.

Sources:
(Preventative effects of chebulic acid isolated from Terminalia chebula on advanced glycation-endproduct-induced endothelial cell dysfunction, 2010)