Phytochemicals Can Help Keep You Healthy

By Barbara Day, M.S., R.D., C.N.

It’s no secret, you are what you eat.  Phytochemicals which come from plants provide the plant color, aroma but more importantly provides protection from infection and predator cells which can cause cancer, heart disease, stroke, diabetes and aging. Phytochemicals work effectively with vitamins and minerals to help fight disease in a concerted effort.  Check out the table below to see what foods and herbs contain phytochemicals and how they are beneficial in keeping us health.

Table 1. Phytochemicals Found in Food & Herbs*

Phytochemical Family Plant Sources Possible Actions & Benefits
Allium Compounds Allicin


Allyl sulfides

Chives, garlic, leeks, onions, scallions, shallots -Slow or stop the growth of tumors.

Foods in the allum family probably protect against stomach cancer.

Garlic probably decreases the risk of developing colorectal cancer.

Laboratory studies suggest that allium compounds might also protect against leukemia and cancers of the prostate, bladder, skin and lung.

Hint: Cutting or crushing garlic at least 10 minutes before cooking makes more cancers fighters available.







Red, orange, yellow and some dark green

Fruits: apricots, cantaloupe, citrus fruits, nectarines, papayas, peaches, watermelon.

Vegetables: Bok choy, broccoli, carrots, corn, green (collards, kale, lettuce, spinach), pumpkin, red peppers, sweet potatoes, tomatoes and tomato products, winter squash

-Acts as an antioxidant.

-Inhibit cancer cell growth.

-Improve immune response.

Foods containing carotenoids probably protect against cancers of the mouth, pharynx and larynx.

Carotenoids in dark leafy vegetables might inhibit the growth of cancers of the skin, lung, stomach and some types of breast cancer cells.

Lycopene in tomatoes and tomato products may reduce the risk of prostate cancer.

Flavonoids (a group of Polyphenols)Anthocyanidins (cyanide, delphinidin, malvidin, pelargonidin, peonidin)

Flavan-3-ols (catechin, eicatechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate, theaflavins)

Flavanones (hesperetin & naringenin)

Flavones (apigenin & luteolin)

Flavanols (kaempferol, myricetin)

Flavonoids (quercetin)

Isoflavones (see separate category below)

Fruits: Apples, berries, cherries, citrus fruits, cranberries, currants, grapes, pears, plums

Vegetables: Beets, bell peppers, broccoli, celery, chard, eggplant, kale, lettuce, onions, red cabbage, radishes

Beans: Black beans, kidney beans, pinto beans

Herbs: Parsley, rosemary, thyme

Other: Cocoa powder, dark chocolate, coffee, tea

-Act as an antioxidant.

-Increase the enzymes that protect the body from cancer-causing compounds.

-Stimulate self-destruction of abnormal cells.

-Inhibit inflammation that supports cancer groups.

-Inhibit tumor growth.

-Boost immune function .

Some flavonoids may help prevent colon cancer.

In laboratory studies, the phytochemicals in apples reduced the growth of lung cancer cells.

IndolesIndole-3-carbinol Cruciferous vegetables: broccoli, Brussels sprouts, cabbage, cauliflower, horseradish, mustard greens, turnips, watercress -Act as a antioxidant.

-Increase the activity of enzymes that protect the body from cancer-causing compounds.

– Helps repair damaged DNA.

-Block the activity of hormones that influence the development of some cancer (breast & cervical).

-cause cancer cells to die.

Laboratory studies suggest that cruciferous vegetables protect against cancers of breast, endometrium, lung, colon & cervix.



InositolPhytic acid (also called inositol hexaphosphate or IP6) Whole grains: Bran from corn, oats, rice, rye, and wheat


Legumes: Soybeans and dried beans

-Act as an antioxidant.

-Slow growth of tumors.

-Cause cancer cells to die.

Laboratory studies suggest that phytic acid may prevent tumors from forming in the colon, lung, prostate & skin.

Isoflavones (a category of Flavonoids)Daidzien



Soy: Soybeans & soy products (such as edamame, soymilk, tofu) -Acts as antioxidant

-decrease production of some hormones

-inhibit growth of tumors

IsothiocyanatesAllyl isothiocyanate






Cruciferous Vegetables: Arugula, broccoli, bok choy, Brussels sprouts, cabbage (red & green), cauliflower, collard greens, horseradish, kale, mustard greens, radishes, rutabaga, turnips, watercress


-Act as antioxidants.

-Block tumor growth.

-Cause cancer cells to die.

-Inhibit inflammation that supports cancer growth.

-Increase the activity of enzymes that protect the body from cancer-causing compounds.

Laboratory studies & some small population studies suggest that cruciferous vegetables protect against cancers of the bladder, breast, endometrium, esophagus, lung, colon, liver, prostate, & cervix.

Isothiocyanates form when glucosinolates in cruciferous vegetables are broken down by an enzyme released when the vegetable is chewed or chopped.

Polyphenols (other than Flavonoids & Terpenes)Coumarin



Phenolic Acids (cafferic acid, ferulic acid, ellagic acid, gallic acid)

Stilbenes (pterostilbene, resvertrol)

Tannins (such as ellagic acid)

Fruits: Apples, blackberries, black raspberries, blueberries, cherries, red grapes, pears, pomegranates, strawberries

Other: Chestnut, peanuts, lentils, pecans, turmeric, walnuts

-Act as a antioxidant.

-Inhibit inflammation that supports cancer growth.

-Prevent cancer formation.

-Cause abnormal cells to die before they can become cancerous.

Cell culture & animal studies suggest pterostibene could help prevent colon, lung, skim stomach, pancreatic & breast cancers by inhibiting growth & stimulating destruction of abnormal cells.

In laboratory & animal studies, resverstarol has inhibited the formation or slowed the growth of cancers of liver, prostate, stomach & breast.

Resveratrol has caused the death of leukemia & colon cancer cells.

In lab studies, ellagic acid has inhibited the development of cancers of the colon, esophagus, liver, lung & skin.

In the lab, curcumin has reduced the formation & growth of breast, colon, & stomach cancer cells.

Protease Inhibitors Legumes: Beans, lentils, peas, soybeans & whole soy products (such as edamame, soymilk, tofu) -Inhibit cancer cell growth.-Prevent tumors from releasing compounds that can destroy nearby healthy cells.




Vegetables: Asparagus, beets, Brussels sprouts,



Seeds: Flax, pumpkin, sesame & sunflower seeds

Most Vegetable Oils: corn, olive, safflower & sesame oils

Whole Grains

-Cause the death of cancer cells.

-Lessen the inflammation that supports cancer growth.

Terpenes (a group of Polyphenols)Carnosol



Perillyl Alcohol

Fruits: Apples, cherries, citrus fruits, pears, prunes

Herbs: Bay leaves, dill, oregano, parsley, rosemary, sage, thyme

Other Foods: Pumpkin seeds

-Act as antioxidant.

-Slow cancer cell growth.

-Boost immune function.

-Inhibit inflammation that supports cancer growth.

Laboratory studies suggest carnosol may decrease cells’ sensitivity to reproductive hormones that promote prostate cancer.


*From the American Institute for Cancer Research handout: Facts on Preventing: The Cancer Fighters in Your Food.

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Barbara Day, M.S., R.D., C.N., is a registered dietitian with a Master’s Degree in clinical nutrition.  The former publisher of Kentuckiana HealthFitness Magazine, Kentuckiana Healthy Woman magazine and radio show host of Health News You Can Use, Barbara has over 30 years of experience in promoting healthy lifestyles to consumers.  Barbara worked as Nutrition Consultant to the Navy SEALs (8 years) and the University of Louisville Athletic Department (10 years). Barbara has private practice, DayByDay Nutrition,, where she counsels clients on weight loss, cholesterol management, performance nutrition and an array of other medical issues.  Visit Barbara’s new website which is an on-line health & wellness magazine, Barbara writes nutrition and health columns for as well as a weekly nutrition column for the Southeast Outlook. She also designs and presents employee wellness programs to small and large businesses. Barbara is a runner, cyclist, hiker and a mother and grandmother to 13 grandchildren.    


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