Over the course of winter, many horses end up gaining weight from a lack of work and getting fed a little more than they should. While some additional weight gain is not unusual during winter, it’s important not to end up with a horse that gets too fat or even obese by springtime.
While managing a hard keeper can be difficult, as we discussed in a previous blog, regulating an easy keeper’s weight might be an even bigger challenge. If you have a horse with weight issues, this is where omega-3s come in. According to a variety of research in humans and animals, omega-3 supplementation can promote healthy weight regulation and weight loss.
Understanding Leptin, Cytokines, Insulin, and Adiponectin
Now before we discuss the research on omega-3 and weight management, let’s first explain the primary actors involved in weight gain.
Body fat (aka, adipose tissue) actively secretes chemicals that can affect a person or an animal’s health. These chemicals include the hormones leptin and adiponectin, as well as inflammatory proteins called cytokines. These chemicals also interact with insulin, a hormone that helps the body store energy from food for future use.
These chemicals all impact and interact with each other. For instance, the pro-inflammatory cytokines can disrupt insulin action, causing the body to store more body fat. In horses, cytokines have been associated with higher body condition scores. In people, they have been shown to increase oxidative stress, damage tissues, and affect metabolism.
Cytokines can also impair the neurons in the brain that respond to leptin. Leptin is the chemical that sends a signal to the brain that the horse is full and can stop eating. This could be why there is a correlation between leptin and body condition scores in horses. Indeed, fatter horses often have a higher concentration of leptin, which then results in increased insulin levels in the blood. Elevated insulin tells the tissues to hold onto body fat, which then makes the horse fatter.
The last key hormone in this equation is adiponectin. The function of adiponectin is to improve insulin sensitivity, reduce inflammation, and decrease vascular tone. One study from Germany (1) showed that low adiponectin levels in a group of mature ponies correlated with a decrease in insulin sensitivity, which could contribute to health problems.
What Studies Say About Omega-3s
Current evidence in humans suggests a positive, dose-dependent relationship between omega-3 fatty acid intake and circulating levels of adiponectin. Since obesity results in less circulating adiponectin, providing omega-3s back to the horse may help combat this. In addition, omega-3s in obese human subjects have been shown to increase leptin levels, which helps the person feel satiated.
Studies on different animal species also show that omega-3 supplementation can have a direct impact on weight loss. In a study involving dogs, two groups of obese beagles were fed diets similar in calories but differing in the amount of omega-3 fatty acids by 2,000%. The group fed the greatest amount of omega-3s from fish oil lost significantly more weight than the group fed the lower dose of omega-3s. This was due to the fat-burning property of the fish oil’s omega-3s. In addition, research in rodent studies has shown that omega-3 supplementation has helped reduce weight gain and body fat in mice.
Evidence within human research shows a reduction in body weight and body fat in overweight and obese people with an increased intake by 0.3-3.0 grams/day of omega-3s. In addition, some studies have shown that omega-3 supplementation might also promote increases in lean tissue mass, which could possibly increase metabolism, indirectly helping with body fat reduction. Scientists also indicate that supplementing with 1.9-5.0 grams of omega-3s could promote nutrient disposal by muscle tissue, thus reducing the number of nutrients that can be turned into fat and stored as fat tissue (2).
In a review of the benefits of omega-3s for obesity management, authors summarized that omega-3s help to regulate inflammation, platelet adhesion, blood pressure, heart rhythm, and triglycerides. They also found that in the majority of studies assessing the effect of omega-3 fatty acids on adiponectin, omega-3 intake induced statistically significant increases in adiponectin levels in both animals and humans. This included studies with subjects of a normal weight range, along with overweight and obese study subjects (3).
While more research needs to be done specifically in horses, these results are promising.
Other Suggestions for Reducing Weight Gain
Based on the research results, and due to the inflammatory nature of cytokines, it’s important to reduce inflammation in the body of a fatter or obese horse. It’s well accepted that omega-3s reduce inflammation. Therefore, research indicates that omega-3 supplementation could indeed be beneficial for a variety of reasons.
In addition to omega-3s, providing additional antioxidants, such as vitamin E, C, beta carotene (or vitamin A), and lipoic acid, can help with inflammation. It would also be beneficial to reduce the easy keepers’ intake of oils high in omega-6 fatty acids, such as soybean, vegetable, safflower, and corn oils.
In addition to dietary adjustments, regular exercise is important when dealing with an easy keeper and should be tailored to the individual horse to reduce the risk of injury. Exercise will help to burn calories and keep all internal systems functioning more efficiently. Finally, it’s important to keep a close eye on your horse’s weight. It can often be hard to detect increases in weight when a horse is already overweight, but it’s important not to allow the horse to continue on a downward spiral.
If you have a horse with weight issues, we always advise that you consult with a veterinarian or an independent equine nutritionist to get help. Especially if you need to make changes in your horse’s diet, it’s important to contact a professional to get advice that’s specific to your horse.
1. Ungru et al. 2012. Effects of body weight reduction on blood adipokines and subcutaneous adipose tissue adipokine mRNA expression profiles in obese ponies. Vet Rec.; 171(21):528.
2. Buckley, JD, and P. Howe. 2010. Long-chain omega-3 polyunsaturated fatty acids may be beneficial for reducing obesity—A Review. Nutrients; 2(12): 1212. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257626/
3. B Gray, F Steyn, PSW Davies and L Vitetta. Omega-3 fatty acids: a review of the effects on adiponectin and leptin and potential implications for obesity management. European Journal of Clinical Nutrition (2013) 67, 1234-1242.