Researchers in Japan found that phytonutrients in such plant foods as fruits, vegetables, tea leaves, and beans can block the effects of dioxins in vitro.  The only catch was that these phytonutrient effects lasted only a few hours, meaning you may have to keep eating healthy foods, meal after meal.[3]  Other than blocking toxins, phytonutrients have been studied widely for their potential health benefits, for example, including anti-cancer effects.

Phytochemicals

Phytochemicals under research can be classified into major categories, such as carotenoids and polyphenols, which include phenolic acids, flavonoids, and stilbenes/lignans. Flavonoids can be further divided into groups based on their similar chemical structure, such as anthocyanins, flavones, flavanones, and isoflavones, and flavanols. Flavanols further are classified as catechins, epicatechins, and proanthocyanidins. 

Classification of Phytochemicals

Flavonoids in Cancer Metastasis

In [9], it reports the anti-cancer effects of flavonoids, which target all phases of carcinogenesis including metastatic progression by:

• • Regulating key signaling pathways involved in the migration and invasion of cancer cells and metastatic progression

  • Modulating the expression of genes associated with the progression of cancer

  • Improving inflammatory status

    • Which is a part of the complex process involved in the development of metastasis

  • Improving the anti-cancer effectiveness of conventional chemotherapeutic agents

How to Get More Dietary Phytochemicals Into Your Diet

To naturally increase the flavonoids in your diet, consider eating more of the following foods:[4-7]

• Flavonols: 

  • Onions, apples, kale, broccoli, garbanzo beans, almonds, turnip greens, sweet potatoes, quinoa

• Flavan-3-ols (sometimes referred to as flavanols): 

  • Apples, tea (including black, green, white and oolong), blueberries, peaches, pears, strawberries, cocoa

• Flavones: 

  • Parsley, bell peppers, celery, apples, oranges, watermelon, chili peppers, cantaloupe, thyme

• Flavonones: 

  • Oranges, grapefruit, lemons, tomatoes

• Anthocyanins:

  • Strawberries, cherries, red cabbage, cranberries, plums, raspberries, blueberries, bilberries, black currants, purple grapes, purple potatoes

• Quercetin: 

  • Garlic, apples, plums, red grapes, citrus fruit, dark cherries and dark berries such as blueberries, blackberries and bilberries, capers, olive oil. Small amounts also found in parsley, sage, elder flower, gingko biloba and St. John's Wort

• Apigenin: 

  • Celery, parsley, thyme, basil, oregano, cilantro, chamomile, broccoli, leeks

• Epicatechin: 

  • Cocoa, dark chocolate, apples, black grapes, blackberries, black tea, cherries

To naturally increase the organosulfur compounds in your diet, consider eating more of the following foods:[8]

• Isothiocyanate

  • Brussels sprout, cabbage, cauliflower, bok choy, kale, collards, Chinese broccoli, broccoli raab, kohlrabi, mustard, turnip, radish, arugula, and watercress 

• Lenthionine

  • Shiitake mushroom 

• Allylic sulfur compounds

  • Garlic, onions, shallots, leeks

References

1. Potential Synergy of Phytochemicals in Cancer Prevention: Mechanism of Action

2. Education & Research Center for Pharmaceutical Sciences

3. Ashida H, Fukuda I, Yamashita T, Kanazawa K. Flavones and flavonols at dietary levels inhibit a transformation of aryl hydrocarbon receptor induced by dioxin. FEBS Lett. 2000;476(3):213-7.

4. World’s Healthiest Foods, Flavonoids

5. Linus Pauling Institute, Flavonoids

6. Superfoodly, September 8, 2017

7. Phenol-Explorer, Foods Containing Epicatechin

8. Chemistry in a salad bowl: Comparative organosulfur chemistry of garlic, onion and shiitake mushrooms

9. Liskova A, Koklesova L, Samec M, Smejkal K, Samuel SM, Varghese E, Abotaleb M, Biringer K, Kudela E, Danko J, Shakibaei M, Kwon TK, Büsselberg D, Kubatka P. Flavonoids in cancer metastasis. Cancers. 2020;12:1498. doi: 10.3390/cancers12061498.