Should You Avoid Giving Your Dog Legumes?

Are legumes really harming your dog’s fertility?

When preparing a bitch for breeding or supporting a stud for fertility, nutrition plays a pivotal role. A well-balanced, species-appropriate diet can have huge impacts, negative and positive - including improving conception rates, pregnancy outcomes, and litter viability.

One group of ingredients under increasing scrutiny is legumes – including peas, lentils, chickpeas, and beans – which are now common in many commercial dog foods and home-cooked diets. I'll walk you through the growing concerns around legumes for our breeding dogs and offer evidence-based, practical alternatives.

1. Phytoestrogens: Disrupting the Hormonal Balance

Legumes (particularly soy, peas, lentils, and chickpeas) contain phytoestrogens – naturally occurring compounds that can interact with oestrogen receptors in the body. While some argue that phytoestrogens block rather than mimic oestrogen, the truth is more nuanced.

For breeding bitches, small hormonal shifts at critical stages – like ovulation or embryo implantation – can mean the difference between a successful pregnancy and a missed one. Phytoestrogens may contribute to:

• Irregular or silent seasons
• Delayed ovulation
• Reduced conception rates
• Poor uterine receptivity

We simply don’t have enough species-specific research to determine a "safe" level of phytoestrogen exposure for dogs in this context. Until we do, removing them is a low-risk, high-reward decision.

2. Anti-Nutrients: Blocking Key Fertility Minerals

Legumes contain anti-nutrients like:

• Phytic acid – binds calcium, zinc, and magnesium (all crucial for reproduction)
• Lectins – can damage the gut lining and interfere with nutrient absorption
• Protease inhibitors – reduce protein digestion and amino acid availability

This matters for both male and female fertility. A bitch carrying a litter needs rapid access to bioavailable minerals, and a stud producing semen needs consistent protein and micronutrient intake. Legumes can work against both goals.

3. Taurine Absorption and Amino Acid Deficiencies

While not directly a fertility nutrient, taurine plays an important role in reproductive tissue function, cardiac health, and foetal development. Legume-heavy diets have been shown to reduce taurine levels in some dogs – not because legumes lack taurine (they do), but because they interfere with absorption and displace animal proteins that naturally supply it.

For breeds already prone to DCM or where nutrition is tightly linked to semen quality or pregnancy outcomes, this is a risk not worth taking.

4. Overuse in Kibble and Processed Diets

And honestly - this point is my biggest gripe. Although it isn't the most health concerning, it is laziness and epitomises a lot of our dog food industry. Many grain-free or budget commercial foods rely heavily on legumes to inflate protein percentages without using meat. Peas alone can appear multiple times on an ingredient list as:

• Pea protein
• Pea flour
• Pea fibre
• Green split peas
• Yellow peas

This concentrates phytoestrogens and anti-nutrients in unnatural ways, which is far more concerning than feeding the odd whole chickpea. Not to mention half of those are already ultra-processed before they even start as an ingredient in the dog food. Do you know the best, non-processed protein of all? Meat.... Shock? 

Meat is expensive, premium and costly for manufacturers to include. However ethical, honest and transparent food companies don't need to cut corners, they invest in quality ingredients and are often proud of their minimal ingredient list. I recommend you take a closer look at your food labels...

5. The Evidence May Be Limited, But the Patterns Are Clear

There is one blog on Google that frequently circulates to defend legumes and flax, which argues that phytoestrogens are misunderstood and that no canine studies prove harm.

Our view? Absence of evidence, is not evidence of absence.

The lack of long-term, reproductive-focused studies in dogs doesn’t mean these ingredients are harmless. Experienced breeders and reproduction-focused vets have noted improved results when legumes are removed:

• Bitches cycling more predictably
• Higher conception rates
• Larger litter sizes
• Reduced early pregnancy loss

This anecdotal data, across multiple breeds and feeding styles, can’t be dismissed.

6. Species Extrapolation is Valid

Critics argue most phytoestrogen studies are in mice, pigs, or sheep. But dogs are mammals too, with comparable reproductive hormone pathways. We already rely on livestock data for supplementation guidance on things like oxytocin, many veterinary medicines, Folic Acid, Selenium, and even Calcium. And do you know why? Because livestock are a vital part of our food chain - so there is a huge financial incentive to undertake research to improve their health, wellbeing and breeding outcomes.

However there is no such ulterior motive for the industry to invest in our our pet dogs. So species extrapolation is required. And if legumes cause reduced litter sizes, silent heats and uterine changes in livestock, and dog breeders are seeing similar issues - do you not think it’s biologically plausible, and logical to be looking for a link? I do.

Better, Safer Alternatives

Instead of legumes, find a dog food that has the following ingredients that actually support fertility:

• High-quality animal protein (turkey, beef, lamb, egg)
• Low-starch vegetables (pumpkin, courgette, leafy greens)
• Fertility-friendly fats like Organic Wheatgerm Oil

These provide the bioavailable protein, fats, vitamins, and minerals needed for healthy hormones, quality eggs and semen, and robust embryo development. And consider adding in fertility focussed Supplements such as Royal Jelly, Selenium, and natural Folic Acid to ensure your dog is getting everything required for a healthy breeding process.

This isn’t about fear-mongering or following fads. It’s about putting reproductive success first. Until peer-reviewed, long-term research in breeding dogs proves that legumes and phytoestrogens pose no risk, it’s wise to avoid them when preparing for pregnancy or supporting a stud.

Many breeders have reported better outcomes by making this change – and when you’re dealing with precious new life, every advantage counts.

If you’d like help reviewing your dog’s diet before breeding or would like support selecting the right supplements, join our Holistic Breeding Support Club for expert guidance every step of the way!

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