What is functional food?

For hundreds of years, herbs have been used as a medicinal remedy. Many of our medicines today originate from natural remedies, with the best-known example probably being aspirin, derived from the white willow tree[1]. Functional food is consumed as part of the normal diet, with the aim of providing an optimal balance of nutrients to give the body its best chance at good health.

The increased interest in health and well-being we have seen in recent years has led to a better understanding of diet, with gut health being one of the most influential issues. This behaviour has been mirrored in a focus on nutritional, functional food for our animals.

Despite veterinary studies into the benefit of diet on health and wellbeing lagging behind human clinical studies, the demand for less processed foods for human consumption is already being mirrored in pet food products. Recent industry literature shows that millennials and GenZ have “made it their mission to be so well-informed, they understand that different ingredients promote different health needs essential to a diet”.

There’s been an explosion of alternative dietary options, including ancestral, vegan, raw meat and grain-free diets, and an increase in the number of functional foods such as probiotics making their way into commercial pet foods – and pet food labels![2]

Fad or fact?

A recent study (2022)[3] proposed a redefinition of functional foods as follows:

“Functional foods are novel foods that have been formulated so that they contain substances or live microorganisms that have a possible health-enhancing or disease-preventing value, and at a concentration that is both safe and sufficiently high to achieve the intended benefit. The added ingredients may include nutrients, dietary fibre, phytochemicals, other substances, or probiotics.”

So, are functional foods just a fad or are there real health benefits for dogs? Consumed on a regular basis as part of a varied diet[4], functional foods and nutraceuticals are ingredients like probiotics, fibre, vitamins and minerals, that offer health benefits over and above the nutritional value in essential nutrients as established by the Association of American Feed Control Officials (AAFCO).

The inclusion of functional ingredients such as dietary fibres, prebiotics, probiotics, and postbiotics in commercial pet foods has become a widespread practice[5]. One study demonstrated “…that feeding a diet containing a fibre–prebiotic–probiotic blend to adult dogs may provide many health benefits, including improved stool quality, beneficial shifts to faecal bacteria and metabolite profiles, reduced blood lipids, and enhanced gut immunity.”.

Functional foods for dogs

Logically, foods are identified as functional when they provide health benefits. Phytonutrients and nutraceuticals have been shown to provide medicinal and health benefits for humans and dogs alike. But since they haven’t (yet) been established as essential in the canine diet, there can be no deficiency[6] – and consequently no requirement.

But there is no denying that they are beneficial. As one study points out[7], the overall effects of any diet are more complex than can be predicted by essential nutrients alone.

Dietary intervention has been shown to improve gut function in dogs[8].  Functional foods modify gastrointestinal physiology, they can improve brain function and may reduce the risk of certain diseases: not in humans, in dogs[9]. (This study recommends further investigation of functional food for pets, to better understand use in disease prevention and treatment.)

Of all external factors, diet – above all – shapes the composition and activity of the gut microbiota, which play a role not just in gastrointestinal diseases in dogs[10] but also conditions like dermatitis, obesity and diabetes[11].

A list of studies investigating how food can be used to aid dog health is provided in a separate post. For instance, the study evidencing that an adequate diet may be crucial to a good oxidative balance in dogs; or the study showing that a diet enriched with antioxidants had a positive effect on fertility and thyroid activity, or evidence that antioxidant and botanical-enriched diets might be a valuable alternative to treat cognitive defects and behavioural disturbances.

For those looking to incorporate plant-based ingredients in home-prepared diets or home-made treats, this study[12] is also very useful. It looks at the potential benefits (nutrition and health) of plant-based ingredients as part of the canine diet.

Dogs can utilise energy from animal and plant-based sources, so my dog’s diet includes both, along with plant-based “non-essential” phytonutrients. From what I have read, this broader balance is more likely to offer a wider range of nutritional and health benefits. The main aim to ensure that everything my dog eats, insofar as I can control it, is functional. Her diet, based on a rotation of meat and plants, is as varied as possible and of course tasty, with the best palatability levels I can manage to create!

In a way, it seems as if we’re coming full circle, back to the days when dogs lived on table scraps, before Mr James Spratt was inspired to manufacture the first dried dog biscuits after seeing strays eat hardtack on a London quayside. Maybe those table scraps weren’t so bad after all….

 

 

References:

[1] Mahdi JG, Mahdi AJ, Mahdi AJ, Bowen ID. The historical analysis of aspirin discovery, its relation to the willow tree and antiproliferative and anticancer potential. Cell Prolif. 2006 Apr;39(2):147-55. doi: 10.1111/j.1365-2184.2006.00377.x. PMID: 16542349; PMCID: PMC6496865.
[2] Weese JS. Evaluation of deficiencies in labelling of commercial probiotics. Can Vet J. 2003 Dec;44(12):982-3. PMID: 14703084; PMCID: PMC340366.
[3] Temple NJ. A rational definition for functional foods: A perspective. Front Nutr. 2022 Sep 29; 9:957516. doi: 10.3389/fnut.2022.957516
[4] Functional foods in pet nutrition: Focus on dogs and cats, Research in Veterinary Science, Volume 112, 2017
[5] Lee AH, Lin CY, Do S, Oba PM, Belchik SE, Steelman AJ, Schauwecker A, Swanson KS. Dietary supplementation with fibre, “biotics,” and spray-dried plasma affects apparent total tract macronutrient digestibility and the faecal characteristics, faecal microbiota, and immune function of adult dogs. J Anim Sci. 2022 Mar 1;100(3):skac048. doi: 10.1093/jas/skac048. PMID: 35180312; PMCID: PMC8956131.
[6] Rahal, A., Verma, A. K., Kumar, A., Tiwari, R., Kapoor, S., Chakraborty, S., & Dhama, K. (2014). Phytonutrients and nutraceuticals in vegetables and their multi‐dimensional medicinal and health benefits for humans and their companion animals: a review. Journal of Biological Sciences, 14(1), 1–19. 10.3923/jbs.2014.1.19
[7] Tanprasertsuk J, Tate DE, Shmalberg J. Roles of plant-based ingredients and phytonutrients in canine nutrition and health. J Anim Physiol Anim Nutr (Berl). 2022 May;106(3):586-613. doi: 10.1111/jpn.13626. Epub 2021 Sep 8. PMID: 34495560; PMCID: PMC9291198.
[8] Fritsch et al. Microbiome function underpins the efficacy of a fibre‑supplemented dietary intervention in dogs with chronic large bowel diarrhoea. BMC Veterinary Research (2022) 18:245. https://doi.org/10.1186/s12917-022-03315-3
[9] Di Cerbo A, Morales-Medina JC, Palmieri B, Pezzuto F, Cocco R, Flores G, Iannitti T. Functional foods in pet nutrition: Focus on dogs and cats. Res Vet Sci. 2017 Jun;112:161-166. doi: 10.1016/j.rvsc.2017.03.020. Epub 2017 Apr 7. PMID: 28433933.
[10] Tanprasertsuk, J., Jha, A.R., Shmalberg, J. et al. The microbiota of healthy dogs demonstrates individualized responses to synbiotic supplementation in a randomized controlled trial. anim microbiome 3, 36 (2021). https://doi.org/10.1186/s42523-021-00098-0
[11] Amanda B. Blake, Jan S. Suchodolski, Importance of gut microbiota for the health and disease of dogs and cats, Animal Frontiers, Volume 6, Issue 3, July 2016, Pages 37–42, https://doi.org/10.2527/af.2016-0032
[12] Tanprasertsuk J, Tate DE, Shmalberg J. Roles of plant-based ingredients and phytonutrients in canine nutrition and health. J Anim Physiol Anim Nutr (Berl). 2022 May;106(3):586-613. doi: 10.1111/jpn.13626. Epub 2021 Sep 8. PMID: 34495560; PMCID: PMC9291198.

Important Considerations:

  • Always consult your veterinarian before making any significant dietary changes, particularly where there are pre-existing health conditions or dietary restrictions.
  • If you feed your dog a commercial food, check the label to see what ingredients it contains before giving more. Excessive intake of any foods can have adverse effects.
  • Ensure (where possible) that you use high-quality, organic products specifically formulated for pets (or better still, human grade ingredients) to avoid any potential adverse effects.
  • Introduce new foods gradually to avoid adverse effects such as gastrointestinal upset or diarrhoea.
  • I provide nutritional information purely as a helpful guide. Nutritional information on ingredients is obtained from the US Department of Agriculture’s FoodData Central site (https://fdc.nal.usda.gov/index.html) and any nutritional information provided in recipes is based on an online calculator: calories and other information will vary based on brands, ingredients and other factors.
  • Check nutrient levels and recommendations for your dog’s weight, age and activity. For example this nutritional guideline produced by FEDIAF.
  • I am not a professional nutritionist. I am sharing recipes that I have created and tested in my kitchen and that have been tasted and approved by our doggy friends.