One of the saddest statements I hear from dog owners is, “My dog eats a prey model diet and doesn’t need fruits.”
I want to show you how this belief could shave months or even years off your dog’s life. Fruits, and especially blueberries, are the superheroes of the food world. Research says the benefits of blueberries for dogs is better health and longer lives.
Are Blueberries Good For Dogs?
Let’s get this question out of the way first …
Yes, dogs are carnivores. But being meat-eaters doesn’t mean dogs can’t digest blueberries and other fruits and veg. So, the answer to the question, can dogs eat blueberries? … is yes, dogs can eat blueberries, and they should.
In fact, berries account for 2/3 of the food eaten by adult wolves in Voyageurs National Park in late summer. And the bulk of this is blueberries. Now, you might scoff and say, “Just because wolves eat blueberries doesn’t mean they can digest them.” And you’d be right. Nobody has measured plant digestibility in the carnivorous wolf.
But they’ve measured it in the carnivorous polar bear.
In his book Ruined By Excess Perfected By Lack, Richard Patton PhD says his trials showed that … “polar bears are fully capable of digesting carbohydrates in a dry feed, at about 85 percent, the same as any omnivore.”
So wolves can digest blueberries. And they seek them out. But why?
It seems that, for a long time, wolves knew something about blueberries that humans didn’t.
How Blueberries Reached Superfood Status
Blueberries are a relatively new crop … they weren’t cultivated until 1911. This was when Frederick Coville discovered they needed acidic soil. But for decades afterward, blueberries were only found in Eggos and muffins. That is, until 1996 …
That’s when Tufts scientist James Joseph proposed that colorful fruits like blueberries carried health benefits. Joseph used an ORAC (oxygen-radical absorbance capacity) test on different fruits and vegetables to measure their antioxidant abilities.
And like that, the lowly blueberry was the newest superfood. No other fruit scored higher than the blueberry for its antioxidant properties. It even scored higher than açai.
Since then, the blueberry has been extensively studied … and not only for its antioxidant abilities. But for its anti-inflammatory activity and effects on the brain and nervous system.
And the blueberry finally claimed true superfood status.
The Antioxidant Power Of Blueberries
Oxidation is the common cause of cellular damage and aging. Over time, metabolic byproducts build up in your dog. These substances are called reactive oxygen species … or free radicals. Free radicals accumulate in your dog’s cells and organs. And free radicals damage your dog’s cells. In fact, they’re the main cause of aging and degenerative diseases.
The damage free radicals cause to the body is called oxidative stress. When free radicals build up in large amounts, they harm the cell membranes and even DNA. This leads to age-related diseases such as diabetes, arthritis and kidney disease.
And the damage to DNA leads to cell mutations and cancer.
Free radicals aren’t only a byproduct of metabolism. They can also build up when your dog is exposed to toxins, pollution, chemicals and drugs. The foods your dog eats can also generate free radicals. The main offenders include foods containing preservatives, starches and rancid fats.
‘The biggest problem with free radicals is that they’re thieves. They steal electrons from neighboring molecules. When an electron is stolen from a molecule, it’s called “oxidation.” And if the oxidized molecules don’t find a new electron, they become new free radicals.
The result is a cascade of free radicals. Billions of new free radicals can react every second. And if left unchecked, free radicals build up quickly in the body … like a toxic rust. This oxidative damage leads to severe diseases developing in dogs. This is especially true for older dogs … who are more vulnerable to the effects of oxidative stress.
To make matters worse, your dog’s immune system has no protection against free radicals. The only way to control them is through your dog’s diet.
Antioxidants are molecules from foods that can help stop free radical cascades … and the oxidative stress they cause. Antioxidants are only found in plants … they don’t come from animal sources. And the best source of antioxidants is fruits and especially berries.
But blueberries contain a large amount of a special antioxidant that’s not found in many other foods … and that’s why blueberries for dogs are so valuable.
The Benefits Of Blueberries For Dogs
Since the 90’s, blueberries have been extensively researched. Unlike many other superfoods, scientists have done studies in blueberries for dogs.
Researchers in Italy divided service dogs into two groups (1). Both groups ate kibble … but they gave one group of dogs blueberries and other berries. After 18 weeks the dogs eating blueberries had lower markers of oxidative stress. There was also a significant reduction of oxidative stress.
A second study compared the antioxidant levels in sled dogs (2). The scientists found that dogs eating blueberries were much better protected against oxidative damage than the control group.
Most of these benefits are due to blueberries’ polyphenol content. Polyphenols are naturally occurring phytochemicals that are powerful antioxidants. And blueberries are a more potent source of antioxidants than any other fruit. In fact, researchers are looking at blueberries to prevent the dangers of radiation exposure in astronauts.
And the benefits don’t end there …
Blueberries for dogs can also inhibit tumor growth, prevent mutations, lower blood sugar and decrease chronic inflammation. A study on older humans showed that eating 2 cups of blueberries a day improved mobility (3). In other trials, people who drank blueberry juice had lower blood sugar levels.
Blueberries are also nutritious. They’re rich in vitamins A, C, E and K, as well as trace minerals.
But these aren’t the only health benefits of blueberries for dogs – or for people. They have a very distinctive claim to fame …
How Blueberries Protect The Brain
The brain uses more oxygen than other body tissue. This makes the brain and nervous system extremely vulnerable to oxidative stress. If your dog suffers from senility or neurodegenerative disorders … it’s mainly caused by free radical damage.
The interesting thing about blueberries is this … they contain a special antioxidant that can cross the blood-brain barrier.
Researchers at Tufts University in Boston fed rats blueberries for two months (4). The rats eating blueberries performed better at memory and maze tests than the control group. When the researchers looked at the rats’ brains, they found blueberry pigments there. Spread throughout the brain were little antioxidants from blueberries called anthocyanins.
Anthocyanins are the phytochemicals that give blueberries their blue-red color. They also help give blueberries their potent antioxidant properties. Although they carry other health benefits … anthocyanins are the blueberry’s very best superpower. Blueberries contain more anthocyanins than any other food.
Research Into Blueberries And The Brain
This has driven a lot of blueberry research in the last 20 years. Human studies show children do better on cognitive tests after eating blueberries (5). They show “dietary blueberry” improves cognition in older humans (6). Another study showed that mice eating blueberries were less likely to develop Alzheimer’s disease. And one showed pro-inflammatory genes in aged rats were reduced to the levels of young rats.
There’s research in dogs too. A 2007 study at University of California looked at brain aging in dogs and concluded “antioxidant treatment can result in significant improvements” and that diets rich in antioxidants reduce cognitive dysfunction (7).
Blueberries for dogs aren’t your ordinary, run of the mill antioxidant … they’re a clinically proven dietary supplement. And if your dog doesn’t get this supplement in his diet, he’s missing out.
How Many Blueberries Can I Give My Dog?
There are two types of blueberries: wild and cultivated. Wild blueberries are much smaller than their cultivated counterparts. And they’re often darker in color.
That dark color means they contain more anthocyanins … more than twice the amount. Wild blueberries can be grown organically. This prevents harmful pesticides and herbicides from getting into your dog … where they produce more free radicals.
Blueberries are a food, so the amount you give your dog doesn’t need to be precise. Try adding fresh blueberries as 5% of a fresh diet. If your dog eats kibble, he’ll need a lot more antoxidants, so double the amount to 10%.
Most dogs don’t mind the taste of blueberries … but if your dog is on the picky side, you can give him freeze-dried blueberries. With the water removed, you’ll only need 1/10 the amount, so it will be easier to hide in his food. A 1/4 teaspoon for a medium or large sized dog should be enough.
- Sechi S et al. Oxidative stress and food supplementation with antioxidants in therapy dogs. Can J Vet Res. 2017;81(3):206-216.
- Dunlap KL, Reynolds AJ, Duffy LK. Total antioxidant power in sled dogs supplemented with blueberries and the comparison of blood parameters associated with exercise. Comp Biochem Physiol A Mol Integr Physiol. 2006 Apr;143(4):429-34.
- Schrager MA, Hilton J, Gould R, Kelly VE. Effects of blueberry supplementation on measures of functional mobility in older adults. Appl Physiol Nutr Metab. 2015 Jun;40(6):543-9.
- Shukitt-Hale B. The beneficial effects of berries on cognition, motor behaviour and neuronal function in ageing. Br J Nutr. 2015 Nov 28;114(10):1542-9.
- Whyte AR, Schafer G, Williams CM. Cognitive effects following acute wild blueberry supplementation in 7- to 10-year-old children. Eur J Nutr. 2016 Sep;55(6):2151-62
- Miller MG et al. Dietary blueberry improves cognition among older adults in a randomized, double-blind, placebo-controlled trial. Eur J Nutr. 2018 Apr;57(3):1169-1180.
- Cotman CW, Head E, et al. Brain aging in the canine: a diet enriched in antioxidants reduces cognitive dysfunction. Neurobiol Aging. 2002 Sep-Oct;23(5):809-18.