Food Intolerances in Humans and Dogs
In our first blog, we looked at what can happen to dogs when they react to food. We saw three types of reaction; allergy, sensitivity and intolerance. Allergy is an immediate response like a bee sting. Sensitivity is a delayed response like bloating or diarrhoea after 24-48 hours. Intolerance can look similar to a delayed response but doesn’t involve the immune system as much. All three affect either the skin (and/or ears, rears and feet) or the gut or both. All involve disruption of the gut bugs, the intestinal microbiome.
Food Intolerances in Humans and Animals
I used to think food intolerances were the poor cousin in the allergy-sensitivity-intolerance trio of food issues, but lately, I’m thinking the research in this field is pulling its weight.
I now discover there are layers and layers of intolerance! Here’s a list to keep things simple:
1. Non-allergic food intolerances, including FODMAP*, wheat, lactose, histamine, food additives and bioactive chemical sensitivities.
2. Genetic food intolerances, in people, these include intolerance of sugar and starch because of digestive enzyme deficiencies.
1. Non-allergic Food Intolerances
To hit the nail on the head, these issues don’t involve the immune system, like classic chicken or beef sensitivity/hypersensitivities, where the body’s reaction to food is the problem. But the physical results are similar.
I see it as food entering the gut and then disrupting the happy bug equilibrium. The changed microbiome then has less ability to cope with the sugars and fibre going through the gut.
Wheat protein reactions go in the ‘sensitivity’ bracket (in my other article) because they are immune-mediated. Fermentation and maldigestion of wheat go in the ‘microbiome disruptor’ category. This is the same for lactose, milk sugar; it ferments, upsets bugs, creating bloating, pain and wind.
Histamine laden foods like dried meats and fish (!), all cheeses, avocado, sauerkraut, spinach, tomatoes and vinegars (including apple cider vinegar, I’m afraid) can overwhelm the gut with inflammatory signals, causing chronic IBS and itchy skin diseases in humans and dogs.
Food additives are some of the antioxidants, colours, nitrates and sulphites we add to human and animal foods, unfortunately. Raw complete foods usually contain none of these.
Bioactive chemicals are molecules in food that exert and effect on the eater. They disrupt the microbiome. Mundane items like cheese, banana, ham and fish, tomatoes and apples are full of them. Biochemists have identified some as amines (Cheese and chocolate), glutamates (tomatoes) and salicylates (apples and tomatoes).
2. Genetic issues Leading to Food Intolerances
Simply put, these are where you’re born without the gene for a digestive enzyme, so you can’t eat certain foods. They are well studied in people, but less so in vet med.
In people, the most common is called a sucrase-isomaltase deficiency. These are two enzymes that digest sugars in humans, and if you’ve not got them, you get uncomfortable when you eat certain foods. You’ll hear people say “Oh, I can’t eat watermelon, but mangoes are fine”, for example.
Summary
Don’t get bogged down in detail. If your dog can ‘eat everything’, you can disregard all of the above. If your dog has got food issues unresponsive to a simple elimination diet, then it’s worth printing this article out and taking it to the vets to discuss food intolerances.
Alternatively, you can start systematically eliminating non-protein food items from the diet, one week at a time, sequentially. It’s laborious, but it’s worth it!
*FODMAP defined as ‘Fermentable oligo-,di-,mono-saccharides and polyols’. Simply speaking, they’re types of sugars that cause over-fermentation and gas, or draw moisture into the gut by osmosis, causing ‘osmotic diarrhoea’.
