If you own a dog, it’s time to practice some serious dog mothering. Because “eat your vegetables” isn’t just for people …
Researchers at Purdue University found that dogs that ate their veggies three times a week or more had a whopping 90% decrease in cancer risk (1). But when it comes to cancer risk and chronic inflammation, there may be one group of veggies that trumps all others … cruciferous vegetables.
Cruciferous veggies are rich in a special little phytonutrient that has cancer researchers excited: sulforaphane. So let’s take a look at sulforaphane for dogs …
What Are Cruciferous Vegetables?
Cruciferous veggies are unique players in the vegetable world. They include:
All cruciferous veggies are rich in nutrients, including vitamins C, E, K and folate, and are a good source of minerals. They also contain healthy phytonutrients called carotenoids, which are immune-boosting in themselves.
But the cruciferous veggie’s biggest claim to fame is a compound called sulforaphane (or SFN). Sulforaphane has enjoyed a lot of attention from researchers because of its powerful ability to decrease chronic inflammation and fight cancer (2).
What Is Sulforaphane?
All cruciferous veggies are rich in sulfur-containing compounds called glucosinolates (3). These don’t do much for your dog, but when they’re chewed, chopped or digested, glucosinolates are converted into isothiocyanates.
Isothiocyanates are the “active ingredient” in cruciferous veggies … the ones with the potent anti-cancer and anti-inflammatory benefits. There are several different kinds of isothiocyanates, all with health-promoting properties.
The most potent of all the isothiocyanates is sulforaphane. Sulforaphane has been isolated by scientists and it carries a pretty impressive body of evidence.
Overall, sulforaphane is the most potent activator of the Nrf2 pathway (4), which reduces inflammation in your dog. But that’s oversimplified …
Let’s take a look at how sulforaphane can be your dog’s new best friend …
Top 3 Benefits Of Sulforaphane For Dogs
1. Sulforaphane Fights Cancer
- Help protect cells from damage
- Induce cancer cell death (apoptosis)
- Inhibit tumor blood vessel formation
- Inhibit metastasis
- Inactivate carcinogens
Sulforaphane’s anti-cancer actions are mainly because it’s an HDAC inhibitor (4) and inhibits DNA methyltransferases.
Both HDAC (or histone deacetylase) and methyltransferases are groups of enzymes that are involved in DNA transcription. Inhibiting these groups of enzymes helps protect your dog’s DNA by expressing special tumor suppressor genes.
But what does this mean for dogs with cancer?
Researchers from Oregon State University gave dogs broccoli sprout powder, which is the richest food source of sulforaphane. They found that sulforaphane had the same digestibility in dogs as humans … and that they also saw a better reduction in HDAC activity (9).
2. Sulforaphane Detoxifies The Liver
Every day, your dog is exposed to toxins. They’re in his food, his water and even the air he breathes. This buildup of toxins is highly inflammatory … and if this inflammation is left unchecked, it will damage or kill your dog’s cells. And eventually the organs they make up. That’s one reason why your dog has a liver. Its job is to help exit inflammatory toxins from the body.
Most toxins (and carcinogens) are fat soluble. So the liver has to convert them in two steps.
Phase I detoxification uses enzymes to prepare the toxins to be eliminated from the body by making them more water soluble. The problem is, the toxins are made into compounds that are even more toxic than the original ones.
If the second part of detox, Phase II, goes according to plan, this isn’t a problem. The toxins will be made completely water soluble and passed to the gall bladder and kidneys to be eliminated from the body.
But if Phase II detoxification doesn’t keep up, the freaky new toxins can wreak havoc with your dog.
Sulforaphane is a potent activator of phase II liver detoxification (10). It also activates enzymes that protect your dog’s cells from DNA damage by carcinogens and inflammatory toxins.
When it comes to liver health, sulforaphane is one of the top contenders.
3. Sulforaphane Is A Potent Antioxidant
I mentioned that sulforaphane is a potent activator of the Nrf2 pathway (4). Nrf2 is a protein that lives in every one of your dog’s cells. When it’s activated, it fires critical anti-inflammatory and antioxidant actions throughout the entire body by activating antioxidant enzymes. One of the most important is glutathione.
Many antioxidants will increase Nrf2 and glutathione activity … but what sets sulforaphane apart is that it’s a potent activator of Nrf2.
Like the almighty blueberry, sulforaphane can cross the blood-brain barrier and increase antioxidant activity in the brain (11). And, of course, sulforaphane increases antioxidant activity in the liver. And this has been shown in animals and humans, not just with in vitro studies.
OK, so if you’re now convinced your dog needs more sulforaphane in his life, then you’ll want to read on … because there are a few more things you need to know about sulforaphane for dogs.
Bonus: Sulforaphane And Healthy Guts
Researchers at Johns Hopkins found that a daily serving of broccoli sprouts protected against Helicobacter pylori in humans (12). H. Pylori can cause ulcers, gut inflammation and digestive cancers.
Once the subjects stopped eating the sprouts, the markers for H. Pylori returned to original levels. So sulforaphane is a potent defense against some harmful bacteria.
Sulforaphane And Myrosinase
Sulforaphane is derived from a precursor glucosinolate called glucoraphanin. The sulforaphane needs to be released from the glucoraphanin before your dog can use it. This happens when glucoraphanin is mixed with an enzyme that’s also in cruciferous veggies called myrosinase.
Myrosinase and glucoraphanin are kept separate in the cruciferous vegetables. But when the broccoli or Brussels sprout is chewed or damaged, the myrosinase is released … and sulforaphane can be produced. The gut bacteria also produce a few enzymes that can convert sulforaphane, but not many.
It’s important to know that myrosinase is needed to make sulforaphane because there are many sulforaphane products you can buy that don’t contain any myrosinase. So if you want to buy your dog a sulforaphane supplement, be sure it also contains the enzymes it needs to make sulforaphane bioavailable for your dog.
Sulforaphane Dose For Dogs
How much sulforaphane should you give your dog and how often?
Animal studies show that sulforaphane is bioactive at 0.1-0.5 mg/kg. So if you’re giving a supplement, the estimated dose for your dog would be:
5 – 25 pounds: 1 – 5 mg
25 – 50 pounds: 5 – 10 mg
50 – 100 pounds: 10 – 20 mg
A single serving of sulforaphane tends to leave your dog’s body after 24 hours (8), so be sure to feed it daily.
Of course, your dog can also get his sulforaphane from cruciferous veggies. But they contain only a small amount. They must be fed raw or steamed below 158 degrees Fahrenheit because heat destroys myrosinase (13). This means stay away from frozen broccoli and cruciferous veggies because they’re often blanched before freezing.
Just because cruciferous veggies don’t contain much sulforaphane doesn’t mean you shouldn’t feed them to your dog. They contain many other healthy phytochemicals that provide health benefits for your dog.
Preparing Cruciferous Veggies
While most cruciferous veggies contain a reasonable amount of sulforaphane and myrosinase, the highest concentration is found in broccoli. Here’s how to get the most sulforaphane out of veggies:
- Chop the broccoli or veggies into small pieces.
- Let them sit for 5 minutes. This lets the myrosinase start making sulforaphane.
- If you want to steam the veggies, steam for no more than 3 minutes and keep the temperature under 155 degrees Fahrenheit (14).
The best source of sulforaphane and myrosinase is broccoli sprouts. The younger the plant, the greater the sulforaphane content … as plants grow, they convert sulforaphane into other isothiocyanates. So broccoli sprouts can contain nearly 100 times more sulforaphane than mature broccoli plants (15).
It’s also important to note that sulforaphane studies have all been done with broccoli sprouts … we can assume that other veggies are rich in sulforaphane and myrosinase, but broccoli sprouts have dozens of research studies showing they can produce enough sulforaphane to make positive changes in the body.
So you can skip the expensive sulforaphane extracts and feed your dog broccoli sprouts or broccoli sprout powder instead.
DNM RECOMMENDS: Four Leaf Rover offers Green Rover, a blend of immune-boosting fermented greens with broccoli sprout powder, the richest source of sulforaphane. Buy Green Rover Now >>
How Much Should Your Dog Eat?
An ounce of broccoli sprouts contains about 73mg of sulforaphane. An ounce would be about half a cup, so your dog would need anywhere from a pinch to a half cup to get a good amount of sulforaphane.
If giving a broccoli sprout powder, make sure it’s freeze-dried …as mentioned earlier, heat can destroy the myrosinase. On average, your dog would need:
5 – 25 pounds: 250 mg
25 – 50 pounds: 500 mg
50 – 100 pounds: 1,000 mg
Cruciferous Vegetables And The Thyroid
You might have been told that cruciferous veggies can interfere with your dog’s thyroid and how it uses iodine. It’s true that cruciferous vegetables are “goitrogenic” which means they may cause the thyroid gland to enlarge and this can interfere with its function.
Dr Jean Dodds of Hemopet claims, “Erring on the side of caution is prudent but, in this instance, the antioxidant and Vitamin K benefits definitely outweigh the risks. The goitrogenic properties in these green leafy vegetables are minute and should not cause concern if fed in moderation.”
So even if your dog has thyroid issues, you probably shouldn’t worry about broccoli sprouts … studies on rats show they protect against thyroid damage and inflammation (16). And if you’re feeding your dog other cruciferous veggies, steaming them can remove up to 2/3 of the goitrogens.
Other Sulforaphane Risks
Overall, the risks for sulforaphane are largely outweighed by the benefits. But there are couple of watch-outs for some dogs.
Large amounts of cruciferous veggies can cause digestive upset. This might be due to their ability to reduce pathogenic bacteria populations, but it’s a good idea to start with smaller amounts.
Some studies also show that extremely high doses of broccoli and broccoli juice can stress the liver. But this hasn’t been seen in broccoli sprouts.
And finally, because sulforaphane can activate Phase II liver detoxification, it might interact with some of your dog’s medications. So if your dog is on meds, it might be a good idea to check with your vet before giving sulforaphane.
There is plenty of research showing that sulforaphane is safe and beneficial … but moderation is always best.
AKC Chief Veterinary Officer Dr Jerry Klein concludes, “Broccoli is considered safe in dogs if the total amount ingested is less than 10 percent of their daily intake; more than 25 percent is considered toxic.”
So don’t go crazy with the mature broccoli and choose sprouts whenever you can. They’re an inexpensive and rich source of one of the most potent anti-inflammatory compounds in nature.
- Raghavan M, Knapp DW, Bonney PL, Dawson MH, Glickman LT. Evaluation of the effect of dietary vegetable consumption on reducing risk of transitional cell carcinoma of the urinary bladder in Scottish Terriers. Journal of American Veterinary Medical Association 2005 Jul 1;227(1):94-100.
- Murillo G, Mehta RG. Cruciferous vegetables and cancer prevention. Nutrition and Cancer 2001;41(1-2):17-28.
- Hayes JD, Kelleher MO, Eggleston IM. The cancer chemopreventive actions of phytochemicals derived from glucosinolates. European Journal of Nutrition 2008;47 Suppl 2:73-88.
- Rajendran P, Dashwood WM, Li L, Kang Y, Kim E, Johnson G, Fischer KA, Löhr CV, Williams DE, Ho E, Yamamoto M, Lieberman DA, Dashwood RH. Nrf2 status affects tumor growth, HDAC3 gene promoter associations, and the response to sulforaphane in the colon. Clinical Epigenetics 2015 Sep 18;7(1):102.
- Wang C, Wang C. Anti-nociceptive and anti-inflammatory actions of sulforaphane in chronic constriction injury-induced neuropathic pain mice. Inflammopharmacology. 2017 Feb;25(1):99-106.
- Bai Y, Wang X, Zhao S, Ma C, Cui J, Zheng Y. Sulforaphane Protects against Cardiovascular Disease via Nrf2 Activation. Oxid Med Cell Longev. 2015;2015:407580.
- Emily Ho PhD. Beyond prevention: sulforaphane may find possible use for cancer therapy. Oregon State University. January 12 2015.
- Royston KJ, Tollefsbol TO. The epigenetic impact of cruciferous vegetables on cancer prevention. Current Environmental Health Reports 2015;1, 46–51.
- Curran KM, Bracha S, Wong CP, Beaver LM, Stevens JF, Ho E. Sulforaphane absorption and histone deacetylase activity following single dosing of broccoli sprout supplement in normal dogs. Veterinary Medicine and Science 2018 Aug 17;4(4):357-363.
- Yoshida K, Ushida Y, Ishijima T, et al. Broccoli sprout extract induces detoxification-related gene expression and attenuates acute liver injury. World J Gastroenterol. 2015;21(35):10091-10103. doi:10.3748/wjg.v21.i35.10091
- Sedlak TW, Nucifora LG, Koga M, Shaffer LS, Higgs C, Tanaka T, Wang AM, Coughlin JM, Barker PB, Fahey JW, Sawa A. Sulforaphane augments glutathione and influences brain metabolites in human subjects: A clinical pilot study. Molecular Neuropsychiatry 2018 May;3(4):214-222.
- Paul Talalay MD. Gutsy germs succumb to baby broccoli. Johns Hopkins Medicine. 2009.
- Edward B. Dosz, Elizabeth H. Jeffery. Commercially produced frozen broccoli lacks the ability to form sulforaphane. Journal of Functional Foods. Volume 5, Issue 2, 2013.
- Wang GC, Farnham M, Jeffery EH. Impact of thermal processing on sulforaphane yield from broccoli (Brassica oleracea L. ssp. italica). J Agric Food Chem. 2012 Jul 11;60(27):6743-8.
- Fahey JW, Zhang Y, Talalay P. Broccoli sprouts: an exceptionally rich source of inducers of enzymes that protect against chemical carcinogens. Proc Natl Acad Sci U S A. 1997;94(19):10367-10372.
- Chartoumpekis DV, Ziros PG, Chen JG, Groopman JD, Kensler TW, Sykiotis GP. Broccoli sprout beverage is safe for thyroid hormonal and autoimmune status: Results of a 12-week randomized trial. Food Chem Toxicol. 2019;126:1-6. doi:10.1016/j.fct.2019.02.004