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Grain Free Dog Food UK & DCM:
The Evidence Explained
Written by Glenn Bell | Last updated June 2026 | 12 min read
Key Summary
- The FDA investigated a potential link between grain-free dog food and DCM from 2018 to 2022 — and closed the investigation without establishing any causal link
- The concern was tied to high-legume US formulas (30–40% peas/lentils as the primary carbohydrate), not grain-free food as a category
- UK brands were not implicated — UK vets did not see a comparable spike in DCM cases
- A June 2025 UK clinical review by Improve International concluded: "There's no conclusive evidence that grain-free diets cause DCM"
- Sweet potato is not a legume. It is a root vegetable that does not carry the same amino acid bioavailability concerns associated with peas and lentils
- Across our 25 grain-free recipes, every single one uses sweet potato as its primary carbohydrate. Only 2 contain peas — at 9%, as a vegetable ingredient, not a carbohydrate source
- Our Ultimate Plus Hydrolysed range is completely pea-free across all 5 recipes, using hydrolysed salmon, hydrolysed white fish, and hydrolysed turkey — all naturally rich in taurine — for maximum bioavailability
Contents
- What is DCM?
- The 2018 FDA Report: What It Actually Said
- What the 2025 Evidence Shows
- Why UK Brands Are a Different Conversation
- Sweet Potato vs Peas and Lentils: Why the Carbohydrate Source Matters
- How Our Grain-Free Range Is Formulated
- Taurine and Our Recipes
- The Ultimate Plus Hydrolysed Range: Grain-Free With No Peas
- Why Do Some Vets Still Recommend Against Grain-Free?
- Frequently Asked Questions
If you've been researching grain-free dog food, you've almost certainly come across some version of this warning: "vets say grain-free causes heart disease." It's repeated so often it sounds settled. It isn't.
This page explains what DCM actually is, where the concern came from, what the evidence really shows, and — crucially — why the specific carbohydrate source in grain-free food matters enormously. Because a grain-free recipe built around sweet potato is a fundamentally different product to the US foods at the centre of the original investigation.
What is DCM?
Dilated cardiomyopathy (DCM) is a disease of the heart muscle in which the heart becomes enlarged and weakened, reducing its ability to pump blood effectively. It is a leading cause of heart failure in dogs.
DCM has two distinct forms:
Hereditary (Genetic) DCM
- Linked to genetic predisposition
- Affects Dobermanns, Great Danes, Irish Wolfhounds, Boxers
- Considered irreversible
- Completely unrelated to diet
Non-Hereditary (Acquired) DCM
- Can develop without genetic predisposition
- Subject of the 2018 FDA investigation
- Some cases reversed when diet was changed
- Linked to specific US formulations — not grain-free as a category
The 2018 FDA Report: What It Actually Said
In July 2018, the FDA announced it was investigating a potential link between certain grain-free dog foods and an apparent spike in non-hereditary DCM cases. The reports attracted enormous media coverage — and the headline "grain-free dog food causes heart disease" spread widely, even though that was never what the FDA claimed.
"The FDA has not identified a mechanism, has not established causality, has not issued any recalls or dietary prohibitions, and has no sufficient scientific basis to take regulatory action."
— FDA, December 2022, formally closing the investigationOn 23 December 2022, the FDA formally ended routine public updates. The investigation did not conclude that grain-free food causes DCM. It concluded the opposite: that no causal link could be established.
What the 2025 Evidence Shows
Since 2018, multiple studies have looked at whether grain-free diets cause DCM. The picture is more nuanced than the original headlines suggested.
"There's no conclusive evidence that grain-free diets cause DCM."
— Dr Joanna Woodnutt BVM BVS MRCVS, Improve International UK Clinical Review, June 2025Other findings from peer-reviewed research:
- A metabolomic study identified 111 statistically significant differences between DCM-implicated diets and non-implicated diets, with the strongest associations pointing to peas and lentils — not the absence of grains
- A separate 28-day feeding trial found measurable changes in cardiac function in dogs fed pea flour specifically, but not in dogs fed lentil flour, rice flour, or a standard commercial diet
- In another short trial, dogs fed a high-legume grain-free diet showed changes consistent with DCM profiles — but blood taurine levels remained within normal ranges, suggesting the mechanism is not straightforward taurine deficiency
The emerging picture, where any link exists at all, points to high-legume formulations — specifically those where peas, lentils or other pulses are the primary carbohydrate — rather than grain-free diets as a category.
Why UK Brands Are a Different Conversation
The DCM cases reported to the FDA were almost exclusively a US phenomenon. UK veterinary bodies did not see a comparable spike. Improve International's 2025 review confirms this: vets in other countries did not report large numbers of additional cases.
There is a simple structural reason for this. The US grain-free formulas under investigation used peas and lentils as the primary carbohydrate — sometimes making up 30–40% of the recipe — because they were cheap, available, and provided good protein numbers on the label.
UK grain-free formulas took a different approach. The more established UK brands built their grain-free recipes around root vegetables, particularly sweet potato, rather than legumes. These are not equivalent products. They share a "grain-free" label while having very different ingredient profiles.
Sweet Potato vs Peas & Lentils: Why the Carbohydrate Source Matters
This is the distinction that the "grain-free causes DCM" narrative consistently fails to make.
Peas & Lentils (US Formulas)
- Protein-rich pulses (legumes)
- Used at 30–40% in implicated US diets
- Listed first or second in ingredient list
- May reduce bioavailability of taurine precursors
- Contain anti-nutritional factors
- Associated with DCM profiles in research
Sweet Potato (Ultimate Pet Foods)
- Starchy root vegetable — not a legume
- Used at 24% as primary carbohydrate
- Does not carry the same bioavailability concerns
- Rich in B vitamins, fibre, slow-release energy
- No association with DCM in research
- Used in every single one of our 25 recipes
Across our full range, sweet potato is the primary carbohydrate in every recipe. Two of our grain-free adult recipes include peas at 9% as a minor vegetable ingredient — roughly the same role broccoli or asparagus plays in other recipes. The majority of our recipes contain no peas at all.
How Our Grain-Free Range Is Formulated
That principle — sweet potato as the carbohydrate, not legumes — runs through our entire grain-free range of 25 recipes.
Every single one uses sweet potato as its primary carbohydrate source. The full range covers every life stage and breed size: puppy, adult, small breed, large breed, senior, and our Pure Superfood Blends for dogs that benefit from higher protein.
Out of 25 recipes, only two include peas — and in those two, peas appear as a vegetable ingredient, not a carbohydrate source. They are listed after sweet potato in the ingredient declaration at 9%. The role they play is comparable to broccoli or asparagus in other recipes: a vegetable contributing fibre, vitamins and variety. They are not there to replace the grain or bulk up the carbohydrate fraction.
This is a meaningful distinction. The US formulas implicated in DCM reports listed peas or lentils first or second in the ingredient list — meaning they were the dominant ingredient by weight. In our two recipes, sweet potato remains the primary carbohydrate at 24%, with peas as a minor supporting vegetable at 9%.
This is not a marketing position — it is a formulation decision we made from the start, and it reflects a deliberate choice to avoid the ingredient profile associated with the DCM reports.
Explore Our Full Grain-Free Range →Taurine and Our Recipes
Taurine is an amino acid involved in heart function. Significant deficiency can cause DCM. This is well established — but as the FDA investigation found, the implicated diets were not typically low in taurine itself. The concern was whether certain ingredients reduced taurine bioavailability or synthesis.
Our recipes address this from both ends.
Protein source: Our adult recipes use fresh fish as the foundation — Salmon & Trout (50% total fish, including 36% freshly prepared) and Tuna & Salmon (50% total fish, including 26% freshly prepared tuna). Fish — particularly oily fish such as salmon, trout and tuna — are among the richest natural dietary sources of taurine available. Unlike plant proteins, fish protein delivers complete amino acid profiles with naturally occurring taurine.
Omega-3 levels: The Salmon & Trout recipe provides 3% omega-3 fatty acids; the Tuna recipe provides 2.6%. These are high levels that support cardiovascular, skin and coat health.
No grain substitution with legume-heavy filler: Because sweet potato is the primary carbohydrate, we are not relying on peas or lentils to bulk out the formula or boost protein numbers. What you see on the label reflects the actual nutritional intent.
The Ultimate Plus Hydrolysed Range: Grain-Free With No Peas
For owners who want complete certainty on the legume question, our Ultimate Plus Hydrolysed range goes a step further. All five recipes are grain-free and contain no peas, lentils or other legumes in any form.
The protein sources across the five recipes are:
Higher Bioavailability
Pre-digested into small peptides, making amino acids — including taurine precursors — significantly easier for the body to absorb.
Naturally Taurine-Rich
Salmon and white fish are among the highest natural sources of taurine in pet food. Turkey is a strong source of taurine and its precursors methionine and cystine.
No Legumes Required
With hydrolysis, there is no need to use pulses to hit protein targets. Carbohydrates come from sweet potato only.
No Prescription Needed
Available to buy direct online. No vet referral or prescription required for any recipe in this range.
Five recipes. Five distinct health goals:
Why Do Some Vets Still Recommend Against Grain-Free?
This is a fair question, and it deserves an honest answer. Some vets continue to advise caution around grain-free diets, primarily because:
1. The headlines outlasted the investigation. The DCM investigation was high-profile and its conclusions were nuanced — but the headlines were simple, and those spread further.
2. WSAVA guidelines favour large manufacturers. WSAVA guidelines generally favour foods from large, established manufacturers with dedicated nutritional research teams. Grain-free brands were often smaller, newer, or "boutique" — which raised separate concerns about formulation rigour.
3. Some practitioners prefer to avoid uncertainty. Some practitioners, reasonably, prefer to avoid uncertainty where there is no clear nutritional benefit to grain-free feeding. This is precautionary, not evidence-based.
These are not unreasonable positions. But they apply most strongly to low-quality grain-free foods that substitute legumes for grains without careful formulation. A well-formulated, fish-based, sweet-potato recipe from a reputable UK manufacturer sits in a very different risk category.
If your vet has concerns, we'd encourage you to share the ingredient breakdown and protein source of your dog's food. The conversation is worth having with specifics in hand.
Frequently Asked Questions
Does grain-free dog food cause heart disease?
Should I be worried about DCM if I feed grain-free?
Was the DCM concern a UK problem?
Why do some UK vets still advise against grain-free?
Do any of your recipes contain peas?
What is taurine and why does it matter?
How do I know your food is properly formulated?
The Science Doesn't Support Blanket Avoidance of Grain-Free
It supports paying close attention to what replaces the grain. Our answer has always been sweet potato — across every recipe, every life stage, every formulation.
For owners who want to remove legumes from the equation entirely, our Ultimate Plus Hydrolysed range is grain-free, pea-free, and built on hydrolysed salmon, white fish and turkey — the most bioavailable option outside a veterinary prescription diet.
Explore Grain-Free Range Explore Hydrolysed Range
Sources & Further Reading
- FDA Investigation into Potential Link between Certain Diets and Canine Dilated Cardiomyopathy — fda.gov
- Woodnutt, J. (2025). Grain-free diets in pets: where are we at with the evidence? Improve International UK
- Bakke et al. (2022). Responses in healthy adult Labradors fed grain-free diets with high legume inclusion — PMC
