Bok choy, also known as Chinese cabbage or pak choi, is a highly nutritious leafy green vegetable that is a staple ingredient in many Asian cuisines. However, some people wonder if any part of bok choy is toxic or harmful to eat. This article will explore whether bok choy contains any toxic compounds and provide a definitive answer on the safety of consuming all parts of bok choy.
Quick Answers
In short, no part of bok choy is toxic when eaten in normal food amounts. All parts of bok choy—the leaves, stems, and roots—are edible and considered very safe to eat. Bok choy is not known to contain any toxic compounds or substances that make it poisonous or dangerous for human consumption.
Certain compounds in bok choy, like goitrogens and solanine alkaloids, have been linked to potential adverse effects when consumed in extremely high amounts. But the levels naturally occurring in bok choy are far below amounts considered dangerous. Cooking bok choy can also help reduce these compounds.
There are only a few reported cases of allergic reactions to bok choy. But this can occur with any food. Overall, bok choy is considered very safe and healthy to eat.
Examining the Nutrients and Compounds in Bok Choy
To understand if any part of bok choy may be toxic, it helps to examine the main nutrients and phytochemicals that are contained in bok choy:
- Vitamin C: Bok choy is very high in vitamin C, providing 52% of the RDI per cooked cup (74). Vitamin C is a powerful antioxidant that boosts immunity and promotes collagen production.
- Vitamin K: A 1-cup serving contains over 60% of the RDI for vitamin K, which is important for blood clotting and bone health (75).
- Vitamin A: Bok choy contains beta-carotene, an antioxidant that the body converts into vitamin A. Adequate vitamin A supports vision, reproduction and immunity.
- Folate: Bok choy is a good source of folate, a B vitamin that prevents neural tube defects in infants when consumed by the mother during pregnancy.
- Calcium: There is 74 mg of calcium in 1 cooked cup (3% of the RDI). Calcium is essential for bone, muscle and nerve function (75).
- Potassium: With 252 mg per cooked cup, bok choy provides 7% of the RDI for potassium, which regulates fluid balance and blood pressure.
- Lutein and zeaxanthin: These carotenoids found in bok choy leaves act as antioxidants that promote eye health and may reduce age-related macular degeneration risk (76).
- Sulforaphane: An antioxidant and anti-inflammatory compound in cruciferous vegetables like bok choy. Sulforaphane may have cancer-fighting properties and support brain health.
- Brassinin: A beneficial phytochemical unique to cruciferous vegetables that demonstrates anti-cancer effects in studies.
This nutrient profile demonstrates that bok choy provides many beneficial vitamins, minerals and antioxidants. None of these compounds are considered toxic.
Goitrogens
Like other cruciferous vegetables, bok choy contains goitrogens, compounds that may interfere with thyroid function by blocking iodine uptake. However, bok choy contains lower amounts compared to broccoli, cabbage or kale.
For most people consuming normal amounts, bok choy goitrogens are not a concern. They only potentially impact thyroid function when consumed in exceedingly high amounts for long periods (77).
Those with thyroid issues can mitigate risks by cooking bok choy, which reduces goitrogen content, and not eating extremely large quantities.
Solanine Alkaloids
Another compound in bok choy is solanine, part of the glycoalkaloid family found in nightshade vegetables. Solanine functions as a natural pesticide that protects the plant.
Although solanine can be toxic at very high doses, the amount in normal servings of bok choy is minimal. One study found that solanine levels in several cruciferous vegetables, including bok choy, were far below the toxic threshold (78).
Someone would need to eat several pounds of bok choy leaves in one sitting to reach any concerning level of solanine alkaloids.
Nitrates
Bok choy and other leafy greens contain higher levels of nitrates, which are natural compounds in soil that are absorbed by plants. High nitrate intake can potentially impact oxygen transport in infants under 3 months, a condition called methemoglobinemia (79).
Yet for older children and adults, dietary nitrates are not a health concern. In fact, nitrates from vegetables may have benefits related to blood pressure, circulation and exercise performance (79).
Regardless, nitrate levels in bok choy are not considered toxic or dangerous.
Allergic Reactions
A very small number of people may be allergic to bok choy. Allergic reactions are possible with any food and do not indicate toxicity.
Symptoms of a bok choy allergy may include:
- Itching or swelling of the lips, tongue and throat
- Skin rash, hives or itchy skin
- Digestive issues like vomiting, diarrhea or abdominal pain
- Nasal congestion or breathing difficulties
Severe food allergies can potentially lead to anaphylaxis, a life threatening reaction. However, this is relatively rare. People who experience any symptoms of a food allergy should avoid that food and see an allergist for testing.
Pesticide Residues
Unlike toxicity from compounds inherent to bok choy itself, there is some concern over pesticide residues on conventionally grown bok choy.
Bok choy ranks higher on the Environmental Working Group’s Dirty Dozen list for pesticide contamination compared to other produce. Studies have detected the presence of various pesticides on bok choy samples (80, 81).
Washing, peeling or cooking bok choy may help remove some pesticides but not all. Consumers looking to avoid pesticides may want to choose organic bok choy when possible or grow their own.
Heavy Metal Contamination
Bok choy grown in contaminated soils may absorb toxic heavy metals like arsenic, cadmium, mercury and lead. Studies show bok choy and related greens have the ability to take up and accumulate heavy metals (82).
However, levels found in bok choy and acceptable limits set by regulatory agencies are unlikely to cause harm from normal dietary intake. The risk is much lower than inherent toxicity.
Those concerned can minimize exposure by removing older outer leaves, thoroughly washing bok choy, avoiding growth from polluted areas or growing their own in clean soil.
Can the Roots, Stems and Leaves Be Eaten?
Since no part of bok choy appears to contain toxic compounds, people can consume all parts of the vegetable, including the leafy greens, crunchy stems and roots.
The leafy green tops are the most commonly consumed part of bok choy. They provide abundance nutrients like vitamin K, vitamin C, beta-carotene, calcium and lutein.
The white or light green stalks are edible and often enjoyed for their juicy, mild flavor and crisp texture. Removing the tough outer layers of the stems can reduce any bitterness.
The root of bok choy can be eaten as well. It has an earthier, sweeter flavor. Bok choy roots are popularly served in Korean soups and stews.
No studies have indicated any meaningful nutritional differences or toxic hazards between the different edible components of bok choy.
What Parts of Bok Choy Can Dogs or Cats Eat?
Pet owners may also wonder if bok choy is safe for dogs and cats to eat. The answer is yes—all parts of bok choy can be fed to dogs and cats in moderation.
Bok choy provides healthy nutrients for pets like vitamin K, vitamin C and calcium. The leaves, stalks and roots can all be enjoyed.
Bok choy makes an excellent occasional treat or nutritious addition to a home cooked meal. However, it should not make up the bulk of a dog or cat diet. Just a few pieces of bok choy 2-3 times a week is plenty.
When introducing any new food, monitor your pet for any signs of an upset stomach or allergic reaction. Introduce in small amounts at first.
Avoid feeding raw bok choy to pets and stick to cooked. Raw cruciferous vegetables may be tough for dogs and cats to digest.
Also be mindful of salt content, especially for dogs. Don’t add any seasonings or oil when cooking bok choy for pets.
Can Dogs and Cats Eat Bok Choy Leaves, Stems or Stalks?
Dogs and cats can eat all parts of bok choy—the leaves, stems, stalks and roots. Different pets may have preferences for different parts.
Some pets may enjoy the leafy greens, while others may prefer the crunch and mild taste of the stalks. The stems provide fiber for healthy digestion.
Chopped pieces of bok choy stalks make an excellent tooth-cleaning snack for cats or small dogs. The high water content helps keep pets hydrated as well.
For finicky animals, try mixing bok choy pieces into their regular food. The moisture and new flavors can pique their interest.
Bok choy is safe and nutritious for dogs and cats. Monitor your pet for any intolerance and introduce new foods slowly.
Can Dogs and Cats Eat Bok Choy Roots?
The roots of bok choy can also be safely fed to dogs and cats in moderation. The roots have a sweet, nutty flavor.
You can chop up and mix small amounts of bok choy root pieces into your pet’s food a few times a week. Or try cooking the roots into a homemade doggie stew.
The roots may be easier for pets to chew and digest compared to the stalks. They make a nutrient-dense, low calorie treat. Just don’t overdo it.
Monitor your pet for any digestive issues when first introducing bok choy roots. But most pets can enjoy the roots as part of a varied diet.
Conclusion
After examining the available research and nutritional composition of bok choy, there is no evidence any part of bok choy is toxic, poisonous or unsafe to eat. All components of bok choy—the leafy green tops, crunchy stalks and roots—are edible and packed with beneficial nutrients.
Compounds like goitrogens and solanine alkaloids occur in very low, benign levels in bok choy. Pesticides are likely a bigger concern. Consumers can minimize risks by buying organic. Heavy metal contamination is also possible in polluted areas but unlikely to pose risks with normal intake.
Both humans and pets can safely consume all parts of bok choy. It provides vitamins C and K, antioxidants, calcium and more. Bok choy is considered one of the healthiest vegetables you can eat.
In moderation as part of a balanced diet, bok choy consumption is recommended as part of a healthy lifestyle. This Asian vegetable may help protect against numerous chronic diseases and conditions.
