The complete guide to AMAZINGLY HEALTHY BLUEBERRIES in your dog’s diet, as an anti-oxidant, anti-cancer, anti-inflammatory etc
I have to tell you that I love blueberries, but my dog doesn’t. Yet Blueberries are THE MOST important non-meat healthy ‘supplement’ you can give your dog! And no, we don’t sell a blueberry dog treat !
In fact, Blueberries and blackberries, apart from Shark Cartilage and Green Lipped Mussels (for joints) and Omega 3 in wild roo and fish treats, are probably one of the greatest natural health boost you can give your dog.
Raising Archie spoodle mostly on a carnivore diet/ ancestral diet, high nutrition diet (adequate bio-available protein), high Omega 3, Shark cartilage for joint support etc .. has seen him show a strong preference to eating animal products. This means that he will eat around and leave any vegetable matter in his bowl. This is the only caveat to this article. Blueberries are GREAT for anti-oxidants with a host of amazing benefits, but you will need to find if you can get them into your dog!
The reason I researched this phenomenon for you, is recently I have read a large number of blogs extoling the virtues of the superfood blueberry and why you MUST include them in your dog’s diet, particularly as they age.
And I have to tell you this is a TRULY worthwhile ‘rabbit hole’ event.
SO many articles I read on popular sites were so narrow focused and pushing their own agendas. Often quoting the same quotes over and over, without any substantial background. But nothing that totally encompasses the SPECIFIC tech reasons (chemical data) of why blueberries over all other plant anti-oxidants, and SOME berries in particular, should be fed to your dog, UNTIL NOW.
Spoiler, it’s about their ACN profile and content!
The fact is that blueberries do show remarkable (TESTED) health benefits for humans and dogs, and yes much of it is anti-oxidant related. But in this article, I will answer:
1 What is an antioxidant, why use berry anti-oxidants.
2 Why Blueberries specifically are one of the best antioxidants for your dogs health, and what other benefits do they provide.
3 How much blueberries they actually need in their diet (and what type). . Is their a safe range you can feed? What high anti-oxidant berries are poisonous to your dog.
1 What is an anti-oxidant in regards to dog’s health
“An antioxidant is any compound, whether vitamin, mineral, nutraceutical, or herb that protects against cellular damage from reactive oxygen species, including free radicals, single oxygen atoms and hydrogen peroxide. Some of the more well-known antioxidants include ascorbic acid (Vitamin C), alpha-tocopherol (Vitamin E), beta-carotene, and enzymes such as catalase, superoxide dismutase and glutathione peroxidase.” Ref 9
What you should know about commercial dog food. The minimum requirements for a ‘complete and balanced” dog food is based on a voluntary dog food standard: aafco voluntary nutrition tables. They have woefully low protein requirements, NO carb requirements, but at least an over-abundance of vitamins and minerals.
While they don’t specify a SOURCE of any of these foods (ie, plant mineral or vegetable), the very high levels of vitamins and minerals (higher than natural foods can provide), ensures that a high level of Vitamin A and E are included. But of course, as mentioned above while these are potent anti-oxidants, they have a multitude of functions and other antioxidants cover a host of other health benefits that these basic vitamins can’t do.
You will also see that many dog foods show a big bowl of blueberries on the front of the pack, but they are so far down on the ingredients list, it’s a sure bet that you are getting very few in the mix.
One of the powerful reasons that you will want to add MORE antioxidants to your dog’s food besides those included in dog food are helping them with joint conditions or body allergies that lead to a dog having inflammation.
The value of shark cartilage and Omega 3 in avoiding dog inflammation.
While this article is mostly about the value of blue and other berries, we should mention that shark cartilage active ingredients (chondroitin and glucosamine) go a long way in joint support, assisting the reduction in the cause of inflammation. Also, Omega 3 in fish and roo treats, is also a powerful anti-inflammatory. Hence using these treats, ALSO decreases the chances of inflammation and the work that an anti-inflammatory has to do in the first place.
“Inflammation is a normal body process by which the body repairs itself or attacks foreign invaders such as viruses, bacteria, fungi, etc. Reactive oxygen species are produced during the process of inflammation. The body has a built-in ability to neutralize these reactive compounds once they have done their work. When inflammation persists, the body’s own natural antioxidants may become depleted, allowing reactive oxygen species to accumulate and damage normal healthy cells. A well-known and much feared consequence of reactive oxygen species is damage to DNA that results in the formation of cancer cells.“ Ref 9
Another article suggests Antioxidants can be found in the vitamins and minerals of the fruits and vegetables .. particularly in the skin of apples and carrots. The most common antioxidants are beta carotene, selenium, and lycopene.” Ref 10
A lack of anti-oxidants (cause dog diseases and local swelling), as well as muscle loss. One article suggests using the following antioxidant-rich foods
- Green beans, steamed broccoli, spinach
- Sweet potatoes, cooked yellow squash
- Strawberries, blackberries, blueberries
- Mangoes, tomatoes ( Ref 10)
At this point the question should be what is the difference between all of these sources?
Firstly, you will see that anti-oxidants seem to be the province of vegetables and fruits, and since the first two rows (vegetables like beans, broccoli and sweet potato) are often used to bulk up commercial dog food – ie cheaper than meat), your dog might already get enough of these. And they aren’t as POTENT as the safe high potency berries.
As far as the berry class of fruit goes, they contain something EXTRA … but as significantly to me, they are one of the MOST NATURAL methods of getting anti-oxidants into your dog. While wild wolves are mostly carnivores, and dogs are exclusively evolved from the grey wolf 20 to 30 thousand years ago, when they were unable to complete a hunt, they would for survival supplement their diet with easy to eat sugary (high energy) berries.
“.. 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. “ Ref 3
In 1996 Tufts scientist James Joseph found that ORAC (oxygen-radical absorbance capacity) test on different fruits and vegetables to measure their antioxidant abilities show that blueberry for its antioxidant properties (even higher than acai berry).
Why oxidants are so bad for your dog
“Oxidation is the common cause of cellular damage and aging. Over time, metabolic by-products 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.” Ref 3
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.” Ref 3
“Free radicals aren’t only a by-product 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.” Ref 3
At this point you should be aware that some lesser quality commercial dog foods have been found to contain “preservatives, starches and rancid fats”. Ref 3
“Free radicals take electrons from neighboring molecules. And that is called “oxidation.” when oxidized molecules don’t find a new electron, they become new free radicals. … 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.” Ref 3
Now that is pretty powerful knowledge, right?
Imagine a situation where dog food is supposed to be whole and complete, and even contains anti-oxidants (big letters on the front of the dog food bag). But dog food typically also contains preservatives and starches – the very things that cause oxidation. AND then you find that the few berries that they add, aren’t enough to combat them.
Perhaps you need to add some of the RIGHT berries to your dog’s diet?
Now we will look at the SPECIFIC value of berries, and blueberry in particular, for anti-oxidant and OTHER benefits.
2 Why Blueberries specifically are one of the best anti-oxidants for your dog’s health, and what other benefits do they provide.
“blueberries contain a large amount of a special antioxidant that’s not found in many other foods. “ Ref 3
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.
They’re also said to be high in vitamins A, C, E and K, as well as trace minerals. But we will. Look at these specific claims below. Blueberries can :
- Reduce free radicals (oxidised molecules)
- inhibit tumor growth,
- prevent cell mutations
- lower blood sugar
- decrease chronic inflammation.
- protect the dog’s brain “your dog suffers from senility or neurodegenerative disorders … it’s mainly caused by free radical damage. they contain a special antioxidant that can cross the blood-brain barrier. ” (ref 3)
“A study on blueberry supplements, showed that mice eating blueberries were less likely to develop Alzheimer’s disease” ref 3
What is the blueberry DOG super power?
When TUFT researchers looked at the rats’ brains, they found blueberry pigments … and little antioxidants from blueberries called “anthocyanins”.
Anthocyanins (ACN’s) are the phytochemicals that give blueberries their blue-red colour. They also help give blueberries their potent antioxidant properties. Blueberries are said to contain more anthocyanins than any other food.
This is where the rabbit hole of TRUTH gets interesting.
The following is the most succinct technical explanation of Anthocyanins that I have found
Concentrations of Anthocyanins (ACN) in Common Foods in the United States and Estimation of Normal Consumption 2006
“Anthocyanins (ACNs) are water-soluble plant pigments responsible for the blue, purple, and red color of many plant tissues. They occur primarily as glycosides or acylglycosides of their respective aglycone anthocyanidins (1). Aglycones are rarely found in fresh plant materials. There are about 17 anthocyanidins found in nature (1), whereas only 6 of them, cyanidin (Cy), delphinidin (Dp), petunidin (Pt), peonidin (Pn), pelargonidin (Pg), and malvidin (Mv), are ubiquitously distributed (Figure 1).
Thus far, over 600 naturally occurring ACNs have been reported, and they are known to vary in (1) the number and position of hydroxyl and methoxyl groups on the basic anthocyanidin skeleton; (2) the identity, number, and positions at which sugars are attached; and (3) the extent of sugar acylation and the identity of the acylating agent.” Ref 7
The diagram below shows the chemical structure of the SIX most common Anthocyanins (ACNs)
ACNs are vital to plant physiology in pollination and seed dispersal, but we are interested in their anti-oxidant value and other health benefits to your dog.
“Not only does the concentration of Anthocyanins vary in each food, but the specific ACNs present in foods are also quite different. The potential dietary intake of ACNs is among the greatest of the various classes of flavonoids.” Ref 7
To see how each of the major anti-oxidant laden vegetables and fruits stack up against each other and in particular blueberries, lets look at a comparison of these plants in relation to their SIX common Anthocyanins concentrations AND their total ACN Count:
Concentration of Anthocyanins Grouped by Aglycones in Common Foods in the United States
Now that is one big table, but here is the take away ..
While Apples and peaches etc have been touted for their anti-oxidant capabilities, much of that was simply because of their basic Vitamin A and E content. And these are often amply provided in commercial dog food.
However, Anthocyanins are not required by aafco nutrition tables, nor are they typically listed in ingredient lists on labels. And that is why it’s very useful to read the above table and see why blueberry is so important as a supplemental treat.
You will notice that vegetables are shown at the bottom of the above table, but these are typically included BULK in dog food (commercial or home-made), And some of these are both poisonous, or not pleasant smelling or tasting to dogs. Sour or salty tastes are not typically pleasant to a dog’s taste buds.
You should also note that fruits and vegetables high in carbs potentially limit the amount of meat and bio available animal products you can add without exceeding their energy requirement for the day. What you are really after is a HIGH quality anti-oxidant with few calories – hence the blue and blackberry …
You will see that many of the Fruits listed on the Anthocyanins table are berries. Dark blue to red in colour. Three of the most common berries fed to dogs, and readily available in supermarkets (fresh or frozen) that are in this table are:
mg/100 g (of fresh /wet form consumed)
Anthocyanins (ACN s) in the main commercial BERRIES
|Moisture %||Dp-ACN||Cy-ACN||Pt-ACN||Pg-ACN||Pn-ACN||Mv-ACN||total ACN|
Things to note.
black raspberry has ACN of 845 cf red raspberry 93 mg/ 100g, but black raspberries are not very common at supermarkets.
Concord grape has an ACN of 192, but grapes are generally poisonous to dogs.
Black Current has an ACN of 476, but is poisonous to dogs.
Chokeberry has an ACN of 1480, but is relatively rare, and “parts of these plants other than the ripe pulp around the seeds are considered toxic and contain cyanide “ and not palatable to dogs.
elderberries have an ACN of 1375 … but “Unripe elderberries contain a toxic alkaloid, as well as cyanogenic glycosides. … and so is listed on the Deerfield Veterinary Clinic and the Pet Education websites as being toxic to dogs.
BERRIES ok for dogs to eat:
Blueberries. Blackberries. Raspberries. Strawberries. Cranberries. Acai berries. Cherries. Barberries. Mulberries.
Berries Dogs Can’t Eat – ref 8
Grapes, Baneberry, huckleberries. Holly berry. Mistletoe berries. Jerusalem cherries. Bittersweet (woody nightshade berries). Ivy berries
acai berries contain theobromine – same component in chocolate that causes problems in dogs.
3 How much blueberries they actually need in their diet (and what type) . . Is there a ‘safe range’ you can feed?
Some sites say you can only substitutive 10% of a dog’s total calories in treats. But when they are single ingredient MEAT dog treats that value is closer to 25 – 50 %. If you substitute more than 25% adding a dog multivitamin might be advised (to achieve inflated aafco requirements).
The minor caveat with blueberries seems to be that too much fructose can lead to loose stools. But remember that fructose only constitutes 5% of raw blueberries.
So now that we see that blueberries might be one of the healthiest non meat supplements on earth, what form should you take them in? Did you know that there are profound differences in cultivated and raw blueberries as well as blueberry extracts and powders?
The science journals seem to only differentiate two types of blueberries: wild and cultivated. Wild blueberries are much smaller and darker blue than the cultivated version. As the Anthocyanins levels seem to be proportionate to the darkness of the berry, it makes sense that the above table shows that the wild blueberry had around 486 mg/ 100g compared to the cultivated (supermarket) variety having only 386 mg/ 100g.
Whether you pick wild berries or buy from a shop, a big thing to do is ensure that you wash them thoroughly to remove any surface pesticides and herbicides that will produce more free radicals in your dog (the very thing that the anti-oxidants in the fruit are attempting to reduce.
‘Dogsnaturally’ magazine suggest that you can add up to 5% of a fresh diet as blueberries, or up to 10% on a commercial diet (to counter the affects mentioned before (preservatives etc)).
They say many dogs enjoy fresh blueberries (sugar taste), but if they won’t eat these that freeze dried are acceptable (ie water mostly removed). Since the berries are up to 85% water, that means that you might only need 10% by weight of the raw full berry (so 1% freeze dried for a commercial diet), if the freeze dried has the water mostly removed. They estimate that as being ¼ teaspoon for a medium or large sized dog.
To check what that means nutritionally we look at the ‘nutrtiondata’ tables and see what that equates to.
These tables say that 100g of blueberries has:
239 KJ of energy (216 KJ from carbs).
Carbs make up 14.5 g of the 100g of blueberry (84% is water). Of which 10 grams is SUGAR, and 2.4 grams fibre.
SUGARS: the two main sugars making up the 10g are:
- Glucose 4.88 grams
- Fructose 4.97 grams
Fats: Blueberry only has 0.3g of total fat, of which there is 88 mg of Omega6 and 58 mg of Omega 3.
PROTEIN is a negligible 0.7g
Vitamins: Contrary to many optimistic blogs, Blueberry only has TWO significant vitamins. Vitamin C at 9.7 mg (16% human RDA), and Vitamin K 19.3 mg (24% human RDA).
AAFCO tables set an Adult Maintenance Minimum Vitamin levels for A,D and E and the B series, but not for Vitamin C or K that blueberries are rich in.
MINERALS: All of the minerals in blueberry are less than 3% of the human daily value except for Manganese that at 0.3mg is 17% of the human requirement
For instance 100g of blueberries has only 0.3 mg of Iron (2% human DV) and the affco requirement for adult dogs is 1.25 mg .
Manganese in blueberry is 0.3 mg and dogs require 1.25 mg
So how much of a daily dog Energy intake do blueberries take up?
Working with the information that 100g of blueberry has 239 KJ (no you wouldn’t typically feed that much).
Many articles suggest that an average adult dog should have a maximum of 3% of its weight as dry food per day. So a 20 Kg dog would have 600g of dried pellets equivalent.
The trick with this is to note that while Protein and Carbs have the same KJ value per gram, FAT has 2.5 times the KJ value. Too much fat, and it limits the very important protein amount you can have.
From the aafco site, if dog food pellets have Calorie content of (ME ) = 3688 kcal/Kg
For 600g of dry dog food the calories per cup = 3688/1000 x 600 = 2212 kcal,
Dogs naturally magazine suggested adding 5-10% raw blueberries or ¼ teaspoon (1/10the raw amount) to a dogs diet.
Foodnewsnews and lovetoknow sites recommends 10 blueberries for small dogs. And unfortunately, this is the random quote that All sites use, without any science or proof.
HOW MUCH DO BLUEBERRIES WEIGH?
Most sites suggest one blueberry on average weighs 0.5 – 0.8 grams
If we say 0.7 grams, then 10 blueberries (for a small dog (under 12 kg) weighs 7 grams.
The Energy content is 7/100 x 239 KJ = 16.73 KJ
Mydog ‘Gourmet beef’ wet tin food says it has 68 kcal/ 100g and a medium dog 25 Kg should eat 3.6 cans per day.
At 400grams per can, a 20 kg dog would need approximately 3 x 400 g = 12 x 68 kcal = 816 kcal = 3427 Kj
Gentledogtrainers say that a medium 25 Kg dog should get around 1100 calories = 4600 KJ
It is clear from these calculations that blueberries are fairly low in energy compared to the total energy consumed by a dog in a day. So they have negligible impact on adding weight to your dog.
What if you overfeed a dog blueberry?
Typically, we hear the worst that can happen is loose stools (unless they are diabetic or have blood sugar issues). Because of the fructose content. At near 5g of fructose per 100g of blueberries, and most small punnets of blueberries weighing 125 gram, half a small punnet of blueberries in Australia would be 62g of raw blueberries and 120 KJ of energy and about 6g of sugar (half glucose and half fructose).
Compared the carbs your dog is getting in their commercial dog food, this is negligible.
Since aafco has NO limit on the amount of carbs that can be fed to a dog, it will mostly be their tolerance level and palatability to eating blueberries. Remember if your dog isn’t partial to raw blueberries, you can always give the powdered version mixed in with their dry food (as you will only have to give around one tenth the amount you were planning to with the raw.
If you have a medium dog and every second or third day give them maximum one quarter of a punnet of blueberries (if their stools are still firm), you would be giving them about 30g raw blueberries at only 60 KJ energy equivalent. This would be equivalent to 386 x 0.3 Total ACN = 115 mg ACN TOTAL.
For comparison, the main reference table article says that in 2001, the average American diet saw intake of ACN by people to be ab out 12.5 mg/day/person. Yet a 1970’s paper said that back then (less processed food period) that “total ACNs was estimated to be 215 mg a day during the summer and 180 mg during the winter.”
Since most dogs weigh considerably less than the average human a quarter of a 125 g punnet seems acceptable for almost any sized dog, every day or so.
Ref 4 warns Wild blueberries are safe for dogs as long as they haven’t been sprayed with any type of chemical. “Products like blueberry juices or preserves, canned or stewed blueberries, and other processed blueberry products usually contain loads of sugar”.
They can also contain chemicals and other additives not listed on the package, including ingredients toxic to dogs, such as types of alcohol. Hence “only feed dogs fresh or frozen blueberries”
Yes, dogs can eat blueberries in yogurt and other fillers, but you are just adding KJ and carbs that are taking the place of quality meat protein.
The main issue would then seem to be, will your dog eat blueberries willingly or will you need to disguise it. Perhaps sprinkling dried liver among them, or adding them to wet food in a bowl?
Looking at the nutrition value of blueberries and the very conservative 10 blueberry limit of many sites, it would seem that you could feed a 20Kg dog up to a quarter of a punnet of blueberries (30g, without any major issue of energy or sugar overdosing, but giving them a GREAT boost in anti-oxidants.
If you can find any actual science sites recommendations for maximum doses of blueberries for a given sized dog, we would be happy to amend this article !
PS, I am not a vet or a doctor, so if you are looking at changing your dogs diet, substantially for the better, please consult your vet for a second opinion …
1 Are Blueberries Good for Dogs? Darwinspet
2 , Superfruit-positioned dog foods Creature Companion 2016; October: 52, 54. Anton C. Beynen
3 Can Dogs Eat Blueberries? Here’s The Truth About This “Superfood” dogsnaturallymagazine Dana Scott November 5, 2021
4 Can Dogs Eat Blueberries? 10 Things Veterinarians Want You to Know, thehealthy, Jennifer Huizen Updated: Jun. 23, 2021
5 Which Fruits Can Dogs Eat?, petmd Written by: Ellen Malmanger, DVM
6 Blueberries, raw Nutrition data – from nutritiondata site
7 Concentrations of Anthocyanins in Common Foods in the United States and Estimation of Normal Consumption XIANLI WU, † GARY R. BEECHER, § JOANNE M. HOLDEN, # DAVID B. HAYTOWITZ, # SUSAN E. GEBHARDT, # AND RONALD L. PRIOR*,† J. Agric. Food Chem. 2006, 54, 4069−4075
8 What Berries Can Dogs Eat? 9 To Enjoy & 7 , Written by Matt in Health
9 What are antioxidants? Vcahospitals site
10 Where Can You Find Antioxidants? Careah site
11 Anthocyanidins and anthocyanins: colored pigments as food, pharmaceutical ingredients, and the potential health benefits Food Nutr Res. 2017; 61(1): 1361779. Published online 2017 Aug 13