Indoles are naturally occurring compounds found in certain vegetables. They’re known for their significant health benefits, including cancer prevention, hormonal balance, enhanced liver detoxification, reduced disease risks, and more. Explore the top foods containing indoles below and their contribution to a healthy diet.
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What Are Indoles?
Indoles are phytochemicals found in plants and some vegetables, including cabbage, broccoli, and cauliflower. Their chemical composition consists of heterocyclic aromatic compounds with fused benzene and pyrrole bicyclic rings. Indoles are derived from the breakdown of glucosinolates (sulfur-containing phytochemicals) found in cruciferous vegetables.
Indoles promote good health, as research touts numerous advantages for people struggling with viral and microbial infections, cancer, depression, inflammation, migraines, vomiting, high blood pressure (hypertension), and other chronic conditions.
The Health Benefits of Indoles
Consuming indoles appears to offer an array of health benefits based on research studies, including:
Cancer Prevention
Indoles may help prevent cancer by promoting the elimination of carcinogens and protecting DNA from damage. These phytochemicals also repair mutated genes, help irregular cells die more quickly, and slow cancer growth.
Research supports the potential use of indoles as a supplementary treatment for certain types of cancer, including cervical cancer and leukemia.
Studies show that a type of indole called indole-3-carbinol is a plant hormone that combats cancer and that consuming cauliflower, broccoli, cabbage, and other cruciferous vegetables is part of a cancer-protective diet.
Indoles are being studied for their helpful effects on the prevention of prostate cancer, breast cancer, colon cancer, and other forms of cancer.
Hormonal Balance
Foods containing indoles also play a role in maintaining hormonal balance, particularly in reducing the risk of estrogen-related cancers.
Researchers demonstrate that indole-3-carbinol may influence estrogen metabolism, reducing the risk of hormone-dependent cancers like breast, endometrial, and ovarian cancers.
Another study found that while estrogen can promote tumor growth, dietary indole-3-carbinol (I3C) does the opposite by suppressing it.
Researchers found that increasing indole-3-carbinol intakes by eating cruciferous vegetables or taking indole supplements increases the conversion of estrogen from a cancer-producing form to a non-toxic products.
Detoxification Support
Indoles also support liver health and detoxification processes, aiding in the elimination of toxins from the body. Researchers found that indole-3-carbinol, the phytochemical present in vegetables in the cabbage family, is an antioxidant that stimulates natural detoxifying enzymes in the human body.
Indole-3-carbinol helps modulate the activity of enzymes involved in the metabolism and elimination of carcinogens (cancer-causing substances), steroid hormones, drugs, and other toxins.
Anti-Inflammatory Effects
The anti-inflammatory properties of foods containing indoles have profound potential impacts on chronic disease prevention.
Studies show that indoles contribute to anti-inflammatory activity and immune system functioning, improving intestinal health by reducing inflammatory bowel disease (IBD), colorectal cancer, and hemorrhagic colitis (large intestine bacterial infection).
Researchers found that indoles may help protect against type 2 diabetes, obesity, and other metabolic diseases.
Indoles’ antioxidant and anti-inflammatory properties may offer neuroprotection from Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, and neurological distress.
Top Foods Rich in Indoles
It’s beneficial to be familiar with foods containing indoles to take full advantage of these superfoods and their health benefits.
Broccoli
Broccoli is a known superfood that’s a potent source of indoles. A 1-cup portion of broccoli contains about 31 calories, 3 grams of protein, 6 grams of carbohydrates, 2 grams of fiber, and 0 grams of fat.
In addition to indoles, broccoli is also a rich source of calcium, potassium, vitamin A, vitamin C, vitamin K, and folate. A 100-gram serving of raw broccoli contains 62 milligrams of glucosinolates, which are phytochemicals that produce indoles.
You might eat broccoli raw to retrain the majority of indoles and nutrients, lightly steam it, or sauté it. Studies show that steaming broccoli is a cooking method that preserves the most glucosinolates and indoles while boiling or stir-frying typically causes more nutrient losses.
Add broccoli to salads, soups, pasta dishes, or stir fry. You can even add fresh broccoli to green smoothies.
Brussels Sprouts
Brussels sprouts are loaded with indoles and essential nutrients. These nutrient-packed vegetables contain about 38 calories, 3 grams of protein, 8 grams of carbohydrates, 3 grams of fiber, and 0 grams of fat per serving. Brussels sprouts are a good source of vitamin C, potassium, vitamin K, folate, and iron.
100 grams of these superfoods provide 237 milligrams of indole-producing glucosinolates.
Lightly steaming or roasting Brussels sprouts helps preserve many of the nutrients and indoles without sacrificing flavor.
Cabbage
Green, red, Savoy and other varieties of cabbage are also excellent sources of indoles and provide diet versatility. Green cabbage nutritional facts include 21 calories, 1 gram of protein, 5 grams of carbohydrates, 2 grams of fiber, and 0 grams of fat per serving. This vegetable is also a good source of vitamin C, vitamin K, folate, manganese, vitamin B6, and potassium.
100 grams of chopped Savoy cabbage provides 59 milligrams of glucosinolates.
Add cabbage to salads or soups; make coleslaw or sauerkraut with it; or roast, steam, or air fry your favorite type of cabbage.
Cauliflower
Rich in indoles, cauliflower has gained popularity as a low-carb substitute in numerous recipes.
The nutritional content of 1 cup of cauliflower is 25 calories, 2 grams of protein, 5 grams of carbohydrates, 3 grams of fiber, and 0 grams of fat. It’s also a good source of potassium, vitamin C, vitamin K, vitamin B6, folate, pantothenic acid, manganese, choline, and 43 milligrams of glucosinolates in each 100-gram portion.
Eat cauliflower raw, steam it, or roast cauliflower. Add it to salads or soups, replace rice with cauliflower kernels, use cauliflower as an ingredient in veggie burgers, or make cauliflower crust instead of using regular pizza crust.
Kale
Kale is a nutrient-dense, versatile vegetable rich in indoles. Its role in a healthy diet expands beyond its indole content.
The nutritional value of 1 cup of kale is 7 calories, less than 1 gram of protein, 1 gram of carbohydrates, 1 gram of fiber, and 0 grams of fat. Kale is also rich in vitamin K, vitamin C, manganese, vitamin A, riboflavin, and calcium. Its glucosinolate content is 89 milligrams per 100 grams of raw kale.
Mix kale into soups, salads, or smoothies — or make healthy homemade kale chips.
Collard Greens
Collard greens are excellent sources of indoles and provide 12 calories, 1 gram of protein, 2 grams of carbohydrates, 1 gram of fiber, and 0 grams of fat in each 1-cup portion. These superfoods are loaded with vitamin K, vitamin C, calcium, vitamin A, folate, and magnesium.
A 100-gram serving of raw collard greens contains 201 milligrams of glucosinolates.
Add collard greens to salads, smoothies, sandwiches, salads, pestos, or wraps. You can mix them in with stews, omelets, soups, or casseroles. Eat them raw, sauté collard greens, or roast them.
Mustard Greens
Mustard greens are loaded with indoles and offer a slightly spicy flavor when added to your favorite recipes. The nutritional content of a 1-cup portion of mustard greens is 15 calories, 2 grams of protein, 3 grams of carbohydrates, 2 grams of fiber, and 0 grams of fat. Mustard greens are also a source of vitamin E, vitamin K, vitamin A, vitamin C, copper, and vitamin B6.
1 cup of chopped mustard greens contains 158 milligrams of indole-producing glucosinolates.
Add mustard greens to salads, soups, stews, casseroles, green juices, and smoothies.
Incorporating Indole-Rich Foods into Your Diet
There are numerous ways to incorporate foods containing indoles into your daily meal plan. Simply add cruciferous vegetables to:
- Green juices
- Smoothies
- Protein shakes
- Soups
- Stews
- Salads
- Slaws
- Stir fry
- Side dishes
- Casseroles
- Sandwiches
- Rice dishes
- Pasta dishes
- Sauerkraut
- Veggie burgers
- Wraps
- Hummus or other healthy dips
It’s vital to consume a variety of cruciferous veggies (broccoli, cauliflower, kale, Brussels sprouts, collard greens, mustard greens, cabbage, etc.) regularly to reap the most health and nutritional benefits of these superfoods.
Eat foods containing indoles raw or lightly steamed cruciferous vegetables to retain as many of the original nutrients as possible. Avoid boiling them, as this cooking method decreases the nutritional content of the veggies.
Indole supplements are also available, but ask your doctor before taking them to ensure they’re appropriate and the dosage you’re taking is safe.
Considerations When Consuming Indole-Rich Foods
Despite the many benefits of consuming foods containing indoles, potential concerns could exist when eating large amounts of cruciferous veggies or taking indole supplements.
In high amounts, indole-rich vegetables may cause gas or bloating, interactions with blood-thinning medications or other medicines, or problems in people with thyroid diseases. That’s why it’s important to check with your healthcare provider before taking indole supplements or eating very large quantities of cruciferous veggies.
Many people consuming a 2,000-calorie diet benefit from eating 2.5 cups of vegetables (or 5 cups of leafy green vegetables) daily. However, the exact amount of vegetables you should consume depends on your recommended daily calorie intake and your health.
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Key Takeaways
Take advantage of significant health benefits by incorporating indole-rich foods into your daily meal plans. Explore the variety of these nutritious vegetables in various recipes or simply eat them raw.
Enjoy foods containing indoles regularly as part of a balanced, health-promoting diet to reduce the risk of inflammation, toxin buildup, hormone imbalances, cancer, and other chronic diseases.
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