Friendly foods
Some nutrients perform better with the right partners. Choosing when they meet can enhance nutritional value.
Nutrition centres on the question of food compared with nutrients. Generally, a healthy diet is one that provides the right nutrients, in the right balance, with sufficient diversity.
In studying nutrition, one of the most valuable lines of inquiry in the context of gut health and the gut microbiome has been the theory of synergy, antagonisms and (ultimately) bioavailability. Food synergy is a concept that examines how nutrients interact and how those interactions influence absorption and bioavailability[1].
My problem with the idea of feeding only a single, fixed formulation like kibble is that it flies in the face of scientific research into nutrient synergies and antagonisms. Never mind the monotony, or even protein levels: how can one product provide all nutrients without any antagonisms? And what about bioavailability? That opens up its own can of worms (no novel protein pun intended!).
Nutrient relationships
Nutrients aren’t absorbed in isolation: when foods are paired well, nutrients enhance each other’s performance. And it’s not just a matter of them “rubbing along” with each other. Certain foods are more efficient when consumed together than when consumed alone. This is the principle of food synergy – where the nutritional effect of a whole meal is greater than the sum of its individual parts.
But when foods are mismatched, they interfere with each other. Excess fibre or phytate (naturally present in whole grains, legumes and seeds) can lock minerals away. A lack of dietary fat prevents absorption of fat-soluble vitamins. Calcium and zinc compete for the same transporters, so one can block the other. Antagonism can reduce health benefits of certain nutrients when they’re consumed together – or even in incorrect quantities and/or ratios[2].
Bioavailability
Vitamins and minerals are involved in almost every biological process: from oxygen transport to antioxidant defence. But how to provide food that delivers everything the body needs in a form it can actually use? That’s where bioavailability – the proportion of a nutrient that is absorbed into the bloodstream after digestion – comes in. I think of bioavailability as the scientific mechanism behind synergy.
Synergy is the “what”; bioavailability is the “why”.
Health is determined in dogs, as in humans, by what the body can actually absorb. As far as I can see, no single meal can work. Whatever the quality of ingredients, there will still be antagonisms. How can all the nutrients, if taken simultaneously, reach their targets and perform their functions? This issue is becoming clearer as the science discovers more about nutrient interactions.
Rotation
If I can’t feed all required nutrients effectively in a single day, how can I meet nutritional requirements? Calculating requirements spread over a week offers a realistic and reasonable timeframe to feed nutrients effectively. Scientific research supports that pairing foods strategically, altering food preparation and rotating meals can significantly improve nutrient bioavailability Official nutritional guidance also recognises the assessment of nutrient intake over an appropriate time period. And, importantly, this approach enables the right pairings: mixing and matching ingredients across multiple meals to create synergies and improve availability.
One study notes that the food synergy concept supports the idea of dietary variety and of selecting nutrient-rich foods to enhance nutritional impact. In practical terms, my solution is to achieve canine nutritional requirements (insofar as they’re available to home cooks) across a week rather than in a day or a single meal. This distributes complementary foods more evenly, with the ultimate aim of increasing bioavailability. Small, nutrient-focused building blocks (e.g. meat, seeds, grains or separate vegetables) can be added when required to make up shortfalls and avoid deficiencies.
We know that:
Absorption depends on partners
Most vitamins and minerals need co-factors for efficient uptake.
- Pair fish oil and fatty broths with ingredients that are rich in vitamins A, D, E and K
- Pair iron-rich foods with vitamin C sources
The food matrix controls release
Nutrients are bound into proteins, fibres and plant cell walls. Cooking methods can help release them from that matrix, increasing bioavailability.
- Slow cooking and steaming preserve nutrients
- Add linseed or salmon oil when cooking vegetables
- Sprouting can improve bioavailability
Competition affects outcomes
Some compounds block each other’s transport pathways. If a meal is heavy in inhibitors, availability drops even when total nutrient content looks adequate on paper.
- Avoid combining zinc with calcium
- Don’t combine iron and calcium.
Digestion happens in phases
The stomach, small intestine and microbiome each have different roles. Balanced meals support the full digestive process.
- Provide a blend of protein, fat, fermentable fibre and antioxidants
- Rotate ingredients to diversify substrates for the microbiome
Building the blocks
So one topping – for example beef with buckwheat and carrots – might be healthy but it won’t provide everything. A simple addition, such as a parsnip and celeriac duo, can broaden the fibre profile and add potassium and folate to support digestion and fluid balance.
Another topping, say chicken with rice and green beans, could be supplemented with a pumpkin and broccoli duo to provide carotenoids, vitamin K and additional minerals, support antioxidant defence, gut health and overall metabolic balance.
These are just examples. Building blocks can be added or rotated as needed, targeting potential gaps and ensuring that, viewed over a week, the full set of nutrients is available and more likely to be absorbed. Ingredients like grains, seeds, eggshells and mucilages can also be added singly and separately. Grains and seeds are added, for example, to rotate substrates for the microbiome and manage phytate load, preventing mineral lock-up in specific meals; ground eggshells can be added to achieve required calcium levels; and mucilages to adjust the overall fermentable fibre profile (supporting the microbiome) or to aid gut transit.
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The more we understand about our own biology and that of plants and animals, the better we will be able to discern the combinations of foods, rather than supplements, which best promote health[3]. For us and our dogs: because there’s a surprising similarity between the human and canine gut microbiome[4].
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References:
[1] Jacobs DR Jr, Gross MD, Tapsell LC. Food synergy: an operational concept for understanding nutrition. Am J Clin Nutr. 2009 May;89(5):1543S-1548S. doi: 10.3945/ajcn.2009.26736B. Epub 2009 Mar 11. PMID: 19279083; PMCID: PMC2731586.
[2] Townsend JR, Kirby TO, Sapp PA, Gonzalez AM, Marshall TM, Esposito R. Nutrient synergy: definition, evidence, and future directions. Front Nutr. 2023 Oct 12;10:1279925. doi: 10.3389/fnut.2023.1279925. PMID: 37899823; PMCID: PMC10600480.
[3] Jacobs DR Jr, Gross MD, Tapsell LC. Food synergy: an operational concept for understanding nutrition. Am J Clin Nutr. 2009 May;89(5):1543S-1548S. doi: 10.3945/ajcn.2009.26736B. Epub 2009 Mar 11. PMID: 19279083; PMCID: PMC2731586.
[4] Coelho LP, Kultima JR, Costea PI, Fournier C, Pan Y, Czarnecki-Maulden G, Hayward MR, Forslund SK, Schmidt TSB, Descombes P, Jackson JR, Li Q, Bork P. Similarity of the dog and human gut microbiomes in gene content and response to diet. Microbiome. 2018 Apr 19;6(1):72. doi: 10.1186/s40168-018-0450-3. PMID: 29669589; PMCID: PMC5907387.
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 are feeding commercial food, check the label for ingredients 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 canine nutritionist but supporting research is cited.
- The recipes shared were created by me and tested in my kitchen – and tasted and approved by our doggy friends!