Brussels Sprouts

Tiny Cabbages Packed with Nutrition

Brussels sprouts (Brassica oleracea) are a cruciferous vegetable derived from a species of wild cabbage.^1,2 Although native to the Mediterranean, Brussels sprouts got their name from the city in Belgium due to their long-standing popularity in the area.²

Brussels sprouts grow as a single erect plant with 20 to 40 evenly distributed buds, or sprouts, running the length of its stalk.^2,3,4,5 They can grow as tall as three feet, with each sprout resembling a one-inch diameter cabbage.^3,4,5

Brussels sprouts are typically a sage-green color, but some varieties may also have a red hue.³

And both you and your dog can enjoy this tasty and nutritious vegetable.

Are Brussels Sprouts Good for Dogs?

Similar to broccoli, Brussels sprouts are packed with good-for-your-dog vitamins and nutrients that can help support their overall health and wellbeing.^1,3,4,6,7 They are also 90% water and only contain 50 to 60 calories per cup, making them an excellent low-calorie, high reward food to add to your dog’s diet.¹

While not inclusive, this list gives you a good idea of what’s found in Brussels sprouts. Let’s focus on some of the heavy hitters first.^1,3,4,7

Calcium D-Glucarate

A naturally occurring chemical with several lines of evidence showing its ability to protect against cancer and other diseases.⁶

Fiber

Just one cup of Brussels sprouts contains 4 grams of fiber.³ Fiber can nourish the cells of the colon, helping to keep them free of developing precancerous changes.⁷

Glucosinolates and Isothiocyanates

Glucosinolates are phytochemicals and arguably one of the most important things that Brussels sprouts contain.^3,8

When glucosinolates are broken down by enzymes they produce isothiocyanates, which are potent anti-carcinogens. While the mechanism of action is not fully understood, isothiocyanates directly cause cell death in cancer cells.⁹

They’re also known to break down and metabolize carcinogens, quickly excreting them from the body before they have a chance to do any damage.⁹

Glucobrassicin is one example of a glucosinolate. It gets broken down into several products, one of the dominant ones being indole-3-carbinol (I3C).^4,5

I3C has shown some incredible potential in inhibiting leukemia, colon cancer, prostate cancer, and breast cancer by working at the genetic level to prevent inflammatory responses from gearing up in the body at the very early beginning stages of cancer.⁵

Brussels sprouts have greater glucosinolate content than other closely related foods such as cabbage, kale, cauliflower, or broccoli.⁷ As an example, Brussels sprouts have three times more glucosinolates than a head of red or green cabbage.⁸

Indoles

These stimulate the immune system and make it easier for the body to excrete toxins.⁶

Sulfur Compounds

D3T is a sulfur compound known to help tissues in the body defend against oxidative and inflammatory stress.¹⁰

Sulforaphane is a sulfur compound that helps detoxify the body of cancer-causing chemicals.^5,7

Superoxide Dismutase

This helps neutralize superoxide radicals and slow down cell destruction rate.

Vitamin C

Brussels sprouts are loaded with vitamin C – only 1 cup of Brussels sprouts is equivalent to eating two oranges!¹

Other Beneficial Compounds

In addition to the above, they also contain:^1,3,4,5,7

• Antioxidants
• Beta-carotene
• Coumarins
• Dithiolethiones
• Flavonoids (quercetin, isorhamnetin, kaempferol)
• Folic acid
• Iron
• Phenols
• Phosphorus
• Potassium
• Thiamine
• Vitamins A, B2/Riboflavin, B6, E, and K

That’s quite a list!

Brussels Sprouts and Cancer

The relationship of Brussels sprouts to cancer has been relatively well studied. Of 100 studies involving Brussels sprouts available on PubMed, over 50% of them involve some facet of their relationship to cancer.⁴ Unfortunately, rodents and humans, rather than dogs, dominate the literature.

Regardless of there being little work on the effects of Brussels sprouts on canine cancer, the similarities between cancer in humans and cancer in dogs can help shed light on its potential benefits and applications.

Overall, Brussels sprouts have been linked to the prevention of:^3,7

• Bladder cancer
• Breast cancer
• Colon cancer
• Lung cancer
• Prostate cancer
• Ovarian cancer

This is thought to be thanks to the high number of glucosinolates.

Brussels sprouts have the ability to limit the damage caused to DNA, making them useful in preventing all types of cancer.^3,7,8 DNA damage is a starting point for many cancers because it can encourage unregulated cell growth. Reducing this risk is paramount in reducing the likelihood that cancer will develop in the first place.

In a study that examined two groups of healthy male volunteers, one group was given 300 grams of cooked Brussels sprouts daily while the other group consumed a diet that was free of cruciferous vegetables. After three weeks, the group given Brussels sprouts had a 28% reduction in the rate of damage to their DNA.¹¹

Bladder Cancer

The International Journal of Cancer published research showing that a higher intake of Brussels sprouts was associated with a 29% reduced risk of bladder cancer. This was found to be especially true for males, smokers, and older individuals.⁷ The study suggested that this may be due to the high content of isothiocyanates found in Brussels sprouts, which are excreted from the bladder. The high level of antioxidants in the vegetable have also been suggested as beneficial to humans with bladder cancer.⁶

Colon Cancer

Brussels sprouts can also benefit colon cancer because they can reduce appetite and promote healthy regular bowel movements.³ Research with rats in a controlled laboratory setting found that those who were given water with Brussels sprouts and red cabbage juice had reduced precancerous lesions on the liver and colon.¹³

Another study testing the impacts of Brussels sprouts consumption with colorectal cancer found that glutathione S-transferase (GST) enzyme activity increased after study subjects consumed Brussels sprouts for one week.¹⁴ GST is responsible for detoxification, so its increased activity may help decrease the risk of developing colon cancer.⁴

Research involving the study of colon cancer has also found that Brussels sprouts may protect against heterocyclic amines, which are carcinogenic compounds that form when meat is grilled or charbroiled.⁷ Animal studies with precancerous cells in the colon saw a reduction of 41 to 52% when Brussels sprouts were added to their diets, and 85 to 95% of precancerous lesions were reduced in the liver.⁷

Breast or Mammary Cancer

Sulforaphane, a sulfur-containing compound found in Brussels sprouts that triggers the liver to produce enzymes that break down cancer-causing chemicals and detoxify the body, has been directly connected to inhibiting breast cancer in animal studies.^7,8

A study in the Journal of Nutrition also found that sulforaphane interrupts the cell cycle during cell division, or mitosis, making it unable to adequately split from one breast cancer cell into two.¹⁵

Prostate Cancer

For males, research on prostate cancer and Brussels sprouts has happened in the lab, animal studies, and human patients.⁵ Results overall show that sulforaphane can interfere with prostate cancer at multiple stages of its development by triggering cells to spontaneously die and preventing the creation of new blood vessels that help cancerous tumors grow. These mechanisms ultimately prevent metastasis and stop prostate cancer from spreading.

In one particular study involving 1,000 men, researchers found a 35% decrease in the risk of getting prostate cancer with 28 servings of cruciferous vegetables.^5,7 When an additional three servings of cruciferous vegetables were added, this increased to 44% lower risk.

Glucosinolates Help in a Variety of Cancers

In addition to sulforaphane, the benefits of glucosinolates found in Brussels sprouts have also been well supported through a variety of studies across several cancer types.¹⁶

One review paper demonstrated the anticarcinogenic properties of glucosinolates through the results of six cohort studies (studies that follow participants over a longer period of time, typically years) and 74 case-control studies.¹⁷

Results of the cohort studies showed an inverse relationship with the consumption of Brassica vegetables and risk of lung and stomach cancer, while the case studies showed a 64% inverse association with the consumption of Brassica vegetables and the risk of several cancer types.

Basically, eating more cruciferous veggies meant less risk of cancer. Results were most consistent for lung, stomach, and colorectal cancer, and less certain for prostate, endometrial, and ovarian cancer.

When to Not Feed to Dogs

You should first consult with your veterinarian before adding Brussels sprouts to your dog’s diet. This helps ensure that your dog reaps all the benefits that can be gained from anti-cancer foods while not interfering with any of your dog’s current health or treatment plans and practices.

For example, Brussels sprouts aren’t great for dogs with underactive thyroids.⁶ Chemicals in the sprouts can block the uptake of iodine into the thyroid gland and contain substances that can cause the thyroid gland to swell.^1,3 However, this is not usually a problem unless your dog consumes Brussels sprouts raw in hefty amounts or has a pre-existing history of iodine deficiency.³

This risk can be mitigated by cooking the Brussels sprouts you feed your dog, watching how much you give them, and supplementing their diet with iodine, which can be found in iodized salt, seafood, and seaweed if your dog is hypothyroid.¹

How to Prepare Brussels Sprouts for Dogs

Quality Brussels sprouts are typically firm, compact, appear fresh, and are a bright green color.^1,4,16

Avoid sprouts with wilted or yellowing leaves, leaves that appear to have been eaten by worms or insects, and any that may have a dirty or “smudgy” appearance. Aged Brussels spouts could have aphids on the inner surfaces of their leaves, and may overall be unfit to feed your dog.^1,3

When preparing Brussels sprouts for your dog to eat, first remove any stems with yellow or discolored leaves.³

Next, wash the Brussels sprouts under cold running water or soak them in a bowl with water to remove insects and any dirt that could be hiding in the inner leaves.³ It’s typically best to purchase organic Brussels sprouts, but if that’s not possible, you should soak them in water with a mild solution of additive-free soap, then wash and rinse them.³

You can boil, steam, microwave, or fry Brussels sprouts,^1,3,4,5 but steaming is the best method. They’re typically cooked whole, but can be cut up if desired. It’s helpful to cut an “X” in the bottom of the stem prior to cooking, as this will allow heat to permeate through the vegetable’s leaves, leading to a better texture.

Steaming is the best method to cook Brussels sprouts and maintain all of their powerful nutrients.³ To steam, simply fill the bottom of a steamer pot with two inches of water, wait for a rapid boil, and lightly steam anywhere from 5 to 14 minutes.^3,5

If boiling, allow Brussels sprouts to cook between 5 to 15 minutes. Fresh Brussels sprouts take longer to cook than frozen ones because frozen Brussels sprouts are typically “pre-cooked” with boiling water or steam prior to packaging.

Though easy, boiling is known to cause a large loss of glucosinolates and ultimately isothiocyanates.⁵ This means that many of the scientifically supported components that make Brussels sprouts so beneficial to dogs with cancer are lost in the process. However, one study that boiled Brussels sprout and red cabbage together for 10 minutes in 100 milliliters of water observed no loss in their chemoprotective effects.¹³

Be mindful of cooking times, as overcooked Brussels sprouts are just outright not good, and your dog that’s a picky eater or suffering from a lack of appetite due to their cancer or cancer treatment will probably agree.

Overcooked Brussels sprouts have a strong sulfur smell and won’t incur many benefits due to loss of nutritional components.⁷ Alternatively, perfectly cooked Brussels sprouts will have a crisp dense texture with a semi-sweet, bright, and fresh “green” taste.⁷

How Much Brussels Sprouts Can Dogs Eat?

Start by giving your dog a small amount of cooked Brussels sprouts, such as half to one sprout. If your dog tolerates that well and has no ill-effects after 24 hours, you can continue feeding them and gradually increase the amount depending on your dog’s size.¹⁸

For large dogs, you can work up to as many as three Brussels sprouts in a serving.¹⁸

Signs that you gave your dog too many too soon include stomach upset and increased flatulence.¹⁸

Storing Brussels Sprouts

Raw, unwashed, and untrimmed Brussels sprouts can be kept for three to four days in a perforated plastic bag in your refrigerator’s vegetable compartment³ or up to ten days in a plastic bag.⁷

Cooked Brussels sprouts can be kept up to three days in the refrigerator.³

Frozen Brussels sprouts can be stored for as long as four to six weeks and even up to two months depending on the temperature and humidity of your freezer.^1,2 Blanching them first for three to five minutes will extend that life even further – up to one year.^3,4

Sourcing Brussels Sprouts for Dogs

Brussel sprouts are available fresh or frozen. Over 95% are sold frozen, while the remaining 5% are sold fresh.¹

They’re grown throughout Europe and the United States, with the bulk of them produced in California.⁷ Farmers walk through Brussels sprouts fields and pick the mature sprouts from the lower stem of the plant first and subsequently collect the sprouts on the higher end of the plant as they develop.¹

Buying organic has numerous benefits, but if that’s not possible, you’ll just want to take the extra step of soaking non-organic certified Brussel’s sprouts in water with a mild solution of additive-free soap followed by washing and rinsing.³