Recent paper review – L-carnitine and betaine supplementation

Pet food manufacturers often supplement diets with various ingredients that target specific health conditions and help to differentiate their products from the competition. Some of these diets are very narrow in scope, such as veterinary diets, while others provide a broader supportive function such as over-the-counter diets marketed for hip and joint or cognitive support. These functional diets are rising in popularity among consumers and, in a recent survey, health and nutrition were ranked as the top priority in consumers’ purchasing decisions.¹ As such, many pet food manufacturers seek to highlight the benefits of existing ingredients in their diets or make small formula changes that allow them to make certain claims. Therefore, novel research into the functional benefits of ingredients and nutrients is of immense value to the industry.

An example of one of those nutrients is L-carnitine. L-carnitine is an amino acid derivative that is commonly supplemented to support cardiac health and promote energy metabolism in veterinary and over-the-counter diets. A recent study suggests that supplementation with a combination of L-carnitine and the amino acid derivative, betaine, can help to support the immune system in healthy adult dogs.² Adult beagles were supplemented with betaine, L-carnitine, or a combination of both over 90 days.

Furthermore, cytokines are small proteins that play an important role in cell signaling and immune function. Pro-inflammatory cytokines are associated with several diseases such as renal disease,³ obesity,⁴ and inflammatory bowel disease.⁵ As such, reduced cytokine release in unstimulated cells may be beneficial in preventing several disease states, especially in aging animals. In dogs supplemented with a combination of betaine and L-carnitine, cytokine release in the absence of stimulation was reduced in compared to the control. Additionally, supplementation with betaine and L-carnitine enhanced the cytokine response when cells underwent an immune challenge. Taken together, these results suggest that supplementing dogs with a combination of betaine and L-carnitine may be beneficial for the immune system. Specifically, these results suggest that they may reduce the immune response, under normal conditions, while enhancing its response to pathogens.

Several strategies currently exist to support immune function in dogs, including supplementation of carotenoids and antioxidants,^1-3 and various herbs.⁴ While several of these have scientific backing, the regulatory status of several herbs used to support immunity limits their use in complete and balanced dog food. For example, Echinacea purpurea has been shown to support immune health in dogs, though it is not the Association of Animal Feed and Control Officials (AAFCO)-defined ingredient. As a result, these options are typically only available for supplements, limiting the options that brands have to support an immune claim in pet food. Since betaine and L-carnitine are both approved for use in complete and balanced diets, this study provides promising evidence for additional immune-supporting ingredients in pet food.

References

1. Chew, BP, Park, JS, Wong, TS, Kim, HW, Weng, BBC, Bryne, KM, Hayek, MG, Reinhart, GA. 2000. Dietary β-Carotene Stimulates Cell-Mediated and Humoral Immune Response in Dogs. J. Nutr. 130(8):1910-1913.
2. Chew, BP, Mathison, BD, Hayek, MG, Massimino, S, Reinhart, GA, Park, JS. 2011. Dietary astaxanthin enhances immune response in dogs. Vet. Immunol. Immunopathol. 140(3):199-206.
3. Murai, T, Kawasumi, K, Tominaga, K, Okada, Y, Kobayashi, M, and T. Arai, T. 2019. Effects of astaxanthin supplementation in healthy and obese dogs. Vet. Med. 10:29-35.
4. Guan, Y, Chen, J, Zhou, S, Liu, C, Guo, S, Shi, D. 2018. A randomized and controlled study of the effect of Echinacea purpurea on canine parvovirus and distemper virus antibody levels in dogs. Am. J. Trad. Chinese Vet. Med. 13(2).

About the author: Chuck Zumbaugh, MS, Ph.D. works at BSM Partners as an Assistant Manager in Nutrition Services. He has experience in biochemistry, chemistry, software development, and animal nutrition. Outside of work, he enjoys spending time outdoors with his family in Kansas.

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