Gastric Acidity – What, How and Why?

Answers: Gastric Acidity – What, How and Why?

I am new to feeding raw diets. I keep reading that one of the things that makes cats different from many other mammals is their highly acidic digestive systems. Why is having an acidic stomach important for cats? How does it help them?
Cats need a highly acidic stomach in order to properly digest their food. But, the carbohydrates in many processed foods make the stomach less acidic. Meat protein stimulates stomach acidity by triggering the production of hydrochloric acid in acid-secreting cells within the stomach. A complex cascade takes place when a cat or dog ingests food. Put simply, 80% of the gastric juices secreted are a direct result of chemoreceptors in the stomach detecting the presence of meat-based proteins. This keeps the stomach at a very low pH of around 1-2. A low pH means high acidity. This low stomach pH is important because digestive enzymes work best in an acidic environment and the acidity in the stomach will sterilize ingested pathogens, bacterial or fungal.
When a cat or dog swallows a commercial pet food that is high in carbohydrate and plant protein and low in meat protein, acid-secreting cells in the stomach are not stimulated to produce much hydrochloric acid. The pH within the stomach rises to around 4-5 and a high pH means low acidity. The acidic chyme leaving the stomach is the trigger for the next stage of digestion in the small intestine. The acidity encourages the flow of bile and the flow of pancreatic enzymes necessary to continue the digestive process. If the stomach contents are not sitting at a pH of around 1-2, then digestion is impaired throughout the rest of the digestive tract as well.
What does this mean for cats and dogs? A diet high in carbohydrates inhibits stomach acidity. A raw meaty bones diet, either of whole meats or ground, requires a highly acidic stomach for digestion. Cats and dogs should not be fed a combination of processed and raw diets. If they are fed a combination, they can experience a range of problems:
  • They will struggle to properly digest their foods.
  • They may become constipated with undigested bone spicules impacted in the rectum, a very painful situation.
  • Raw meaty bones can sit for long periods in the stomach, which may lead to vomiting bone, or worse still, an obstruction.
  • They may experience a gastro-intestinal upset when the bacterial load of the ingested food runs riot in the alkaline stomach environment. Gastric acidity is needed to sterilise ingested pathogens. Processed pet foods can be contaminated with salmonella and mycotoxins. The gastric acidity is a first line of defence, so cats and dogs with reduced acidity are vulnerable.
If you are transitioning your cat to a raw meat diet, you may be feeding a combination for a short period of time. It is important to observe your cat carefully during this time and move as quickly as possible to a fully raw diet, to lessen the risk of any adverse effects.
Note: Feline Nutrition provides feline health and nutrition information as a public service. Diagnosis and treatment of specific conditions should always be in consultation with your own veterinarian. Feline Nutrition disclaims all warranties and liability related to the veterinary advice and information provided on this site.
Dr. Lyn Thomson trained at the University of Bristol in England and is studying with the Australasian College of Nutritional and Environmental Medicine. A dedicated and experienced advocate of bio-appropriate nutrition, Lyn practices in Auckland, New Zealand. Her Raw Essentials stores have grown to seven retail locations, providing a variety of raw diet products for cats and dogs.

Follow the Feline Nutrition Foundation