Feline nutrition – a raw perspective

MANY pet owners would agree a key difference between the canine and feline ethos is that you can own a dog but merely feed a cat.

It seems the domestic cat is not in a hurry to relinquish its deity status since we began worshipping them back in ancient Egypt. While they continue to bestow upon us humble humans the honour of preparing their daily banquet, we are left with the responsibility to continually strive to find the answer to what constitutes nutrition for optimal health.

The notoriously fickle nature of cats has unmistakably impacted the UK pet food market, resulting in a comparably narrower range of products than for dogs, despite their equivalent population sizes of 8-9 million.1

Cats, however, are not spared from the obesity epidemic currently gripping both human and veterinary medicine, with as many as 40% of cats seen in practice currently overweight.2

Recent review and meta-analysis of human data has potentially shifted the culpability from energy-dense fat to carbohydrates, even casting doubt over widely publicised historical recommendations.3

The metabolic idiosyncrasies of the domestic cat, believed to be derived from their adaptation to a high protein/low carbohydrate diet of mainly animal tissue 4, are a key consideration in feline nutrition.

A reduced regulatory capacity to rising dietary carbohydrate 5,6,7,8 in addition to a restricted ability to maintain nitrogen balance across a range of protein intakes 9, demonstrates the cat’s limited metabolic flexibility in comparison to other species.

Consequently, it raises the question of whether to attempt to mimic this evolutionary profile, which sees feral cats derive just 2% of metabolisable energy (ME) from carbohydrates 10, in contrast to the 30-40% of ME from carbohydrates commonly offered in dry complete foods.

However, an inherent flaw in study design repeatedly hinders the deduction of the optimal dietary balance. This occurs when the variation of one macronutrient inevitably alters the balance of the others, thereby obscuring a clear cause and effect relationship.

Aside from this limitation, high dietary carbohydrate has been frequently implicated in many common feline health disorders, such as diabetes mellitus 11 and urinary disease.12 In the management of these conditions, dietary carbohydrate restriction has subsequently been seen to be beneficial, in addition to other factors such as higher moisture content.13

In contrast, high protein diets have shown most promise, and support the emerging popularity of raw diets for cats. For example, obesity management can be assisted by greater satiety 14, increased diet-induced thermogenesis (at least twice as much heat is lost relative to fat and carbohydrate 15) and conservation of lean body mass.16

Loss of lean body mass is often clinically significant, particularly in the management of geriatric cats whose loss of protein reserves can lead to a greater risk of morbidity and mortality.17 Furthermore, osteoarthritis is commonly underdiagnosed in cats 18, and these geriatrics could also benefit from raw diets containing ground bone, presenting a readily accepted natural source of minerals to support joints.

While raw diets have a huge potential to meet the unique needs of the domestic cat both in sickness and in health, they are not without their own challenges. A somewhat ironic poor palatability is occasionally reported, which is often actually due to matters of transition, suspicion and temperature.

Physiologically, a typical one-week transition period is usually sufficient, but in reality it may take several weeks to overcome the inherent suspicion, particularly for a cat accustomed to the flavours and texture of a dry food.

It is also well known that cats instinctively prefer their food closer to the body temperature of their natural prey. Therefore, the introduction of a frozen raw food must be done with due consideration and thorough defrosting to allow at least ambient temperature to be reached.

As with any raw product, microbiological and nutritional standards remain a key concern. However, proactive EU legislation and growing popularity are driving standards and awareness ever higher. The availability of cat-specific raw complete diets, balanced to EUrecognised FEDIAF guidelines, only acts to cement this option as a viable alternative within feline nutrition.

With a convenient nugget design offered by Natures Menu, portion control is simple, and practicality concerns of the past are outdated even for the busiest modern household.

Cats will undoubtedly always be fussy creatures with which we choose to share our lives, but we must respect their unique needs as obligate carnivores in order to fully satisfy their complex and interdependent nutritional requirements.

References

1. Pet Food Manufacturers Association (PFMA), Pet Population Report 2014, [online]. Available: www.pfma.org.uk/petpopulation-… [Accessed 4th March 2015].
2. Pet Food Manufacturers Association (PFMA), Pet Obesity: Five Years On, PFMA, London, 2014.
3. Z. Harcombe, J., Baker, S., Cooper, B. et al (2015) Evidence from randomised controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis. Open Heart 2 (1).
4. Morris, J. (2002) Idiosyncratic nutrient requirements of cats appear to be dietinduced evolutionary adaptations. Nutr Res Rev 15: 153-168.
5. MacDonald, M. and Rogers, Q. (1984) Nutrition of the domestic cat, a mammalian carnivore. Ann Rev Nutr 4,521- 4,562.
6. Kienzle, E. (1993) Carbohydrate metabolism of the cat. 1. Activity of amylase in the gastrointestinal tract of the cat. J Am Physio and An Nutr 69: 92-101.
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10. Plantinga, G., Bosch and Hendriks, W. (2011) Estimation of dietary nutrient profiles of free-roaming feral cats: possible implications for nutrition of domestic cats. Brit J Nutr 106: S35-S48.
11. Rand, J., Fleeman, L., Farrow, H., Appleton, D. and Lederer, R. (2004) Canine and Feline Diabetes Mellitus: Nature or Nurture? J Nutr 134 (8): 20,725-20,805.
12. Lek Charoensuk, C., Osbourne, C. et al (2001) Association betwen dietary factors and calcium oxalate and magnesium ammonium phosphate urolithiasis in cats. J Am Vet Med Assoc 219: 1,228-1,237.
13. Markwell, P., Buffington, C. and Smith, B. (1998) The Effect of Diet on Lower Urinary Tract Diseases in Cats. J Nutr 128 (12): 27,535-27,575.
14. Halton, T. and Hu, F. (2004) The Effects of High Protein Diets on Thermogenesis, Satiety and Weight Loss: A Critical Review. J Am Coll Nutr 23 (5): 373-385.
15. Westerterp, K. (2005) Diet induced thermogenesis. Nutr Metab 1: 1-5.
16. Laflamme, D. P. and Hannah, S. S. (2005) Increased dietary protein promotes fat loss and reduces lean body mass during weight loss in cats. International Journal of Applied Research in Veterinary Medicine 3: 62-68.
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18. Bennett, D., Ariffin, S. and Johnston, P. (2012) Osteoarthritis in the cat 2. How should it be managed and treated? Journal of Feline Medicine and Surgery 14 (1): 76-84.