Episode 4: Nutrition – Does heat-processing adversely affect nutrition? - a podcast by Dr. Robert Gaston, DVM - OneVetMed Podcast Host and Veterinarian

Episode 4: Nutrition – Does heat-processing adversely affect nutrition?


Continuing to examine the big concepts in pet nutritionEffects of heat-processing in commercial foods-

Manufacturing affects  nutrient quality and bioavailabilityExtruded 320ºF
Canned 500ºFHeating effects: Alterations in protein structure

Maillard reactionsBonding of sugar (glucose, fructose, lactose, maltose) with free amino group (such as lysine)
Digestive enzymes do not cleave the peptide bond adjacent to the amino acid with attached sugar moleculeMay increase microbial degradation of taurine in colon
Affected proteins are of no nutritional valueAllergenic?






Other “unusual crosslinking” of amino acids and peptides which result in compounds “not found in nature”“These compounds are not well-used by animals”
“Processing EFA in pet foods may affect their biological activity”{Small Animal Clinical Nutrition 4th Ed pp.55, 61}

Heating effects: Alteration of fatty acidsTrans configuration
Metabolized for energy and incorporated into lipid storageCannot function as EFA’s because they are not further metabolized to eicasanoids

C18:1 trans isomers inhibit hepatic carnitine and lead to increased liver triacyglycerol by lowering hepatic oxidation of fatty acids{Giudetti AM, Beynen AC, et. al. Hepatic fatty acid metabolism in rats fed diets with different contents of C18:0, C18:1 cis, and C18:1 trans isomers. Br J Nutr. 2003 Nov;90(5):887-93}

More pieces to the puzzle of heat processing effects:Carprofen half-life in cats

Recent study showed variation 17 hours to 44 hoursDifference in liver enzyme activities attributed to diet
Fresh, whole foods enhanced liver detoxificationCommercial diets detrimental effect




Propranolol half-life in catsStudy done ~20 years ago showed variation from 1-2 hours to>12 hours
Diet effects as seen with carprofenMajor pet food manufacturer had no interest in investigating why the variation in metabolism



{Dr. William Muir, lecture delivered at Veterinary Chiropractic Convention April 2003, and personal conversation.}Study of food allergy in dogs

After successful elimination diet, introduced commercial canned or kibble ‘equivalent’ diet25% recurrence of clinical signs (pruritus)
“With every treatment diet tried, some percentage of dogs redeveloped pruritus.”Explanations/Speculations

3-D protein structure altered with heating?Decreased digestibility?
Loss of important co-factors?{Rosser, EJ. Diagnosis of food allergy in dogs. JAVMA, Vol. 203, No. 2, July 15,1993 pp.259-262

Pottenger’s CatsNutritional study completed 1932-1942
Multigenerational studyNine hundred cats
Four basic feeding groupsOptimum diet groups

2/3 raw meat, 1/3 raw milk, Cod Liver Oil2/3 raw milk, 1/3 raw meat, Cod Liver Oil
Deficient diet groups2/3 cooked meat
2/3 cooked milk (pasteurized, sweetened condensed, evaporated, metabolized vitamin D)Effects observed with deficient diet

Dental diseaseReproductive abnormalities
AllergiesImmune disorders
Skeletal disease and osteoarthritisCardiac abnormalities
Renal diseaseRespiratory abnormalities
Gastrointestinal abnormalitiesHepatic abnormalities
Behavioral abnormalitiesEndocrine abnormalities
Ocular abnormalities{http://www.amazon.com/Pottengers-Cats-A-Study-Nutrition/dp/0916764060 }

{http://ppnf.org/ }Multigenerational effects – demonstrated “epigenetics” prior to understanding of gene structure or tools to examine
Studies in epigenetics reveals that food affects more than just calories and deficiencies…it alters the essence of genetic expression…in the individual…and for subsequent generationsUnderstanding nutrition is critical to longevity and health

{ NOVA | scienceNOW | Epigenetics | PBS }

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