One of the other concepts emphasized in my nutrition classes in chiropractic school was that there are many things beneficial to humans in whole foods that we haven't discovered yet. The current research on phytochemicals is proving this statement accurate. I think all DCs should take pride in the fact that many who came before us emphasized the importance of a healthy diet while our allopathic friends under-emphasized or ignored the importance of the link between good fuel and good health. Although I have and do advocate vitamin and mineral supplementation, vitamins and minerals are no substitute for the proper diet.
Phytochemicals are definitely the new hot topic in nutritional research. I predict they will continue to make headlines the rest of this decade and into the 21st century. Research on these plant chemicals is so rapid that by the time you read this article, we will probably have discovered more new compounds and have a better understanding of the phytochemicals we have already isolated. Initial research on many phytochemicals concerns their anticarcinogenic properties. When scientists reviewed the literature about diet and cancer, they consistently found that people who consumed high amounts of fruits and vegetables seemed to have lower risk for various types of cancer, depending on the fruits and vegetables they consumed. This trend was particularly powerful when contrasted to vitamin studies which have had both positive and negative outcomes in reducing the risk of cancer. Researchers began to difficult task of isolating chemicals in plants and realized there are hundreds, perhaps thousands of bioactive compounds in whole foods. In the years to come, it will be fascinating to see new substances identified and how they function alone, cooked, uncooked, and in combination with other chemicals.
Many of the chemicals I will list for you today have only recently been isolated and studied. The top chemical on the list, allyl sulfides, which come from garlic and onions, have been extensively studied for many years. The effects of this family of phytochemicals should serve as a clue that as studies on other phytochemicals continue, their functions and effects will be expanded from what we currently understand. Finally, this list is not all-encompassing, but it is designed to give you a ball park idea of some of the chemicals that are now receiving attention and that you will undoubtedly be reading about this year.
| allyl sulfides | garlic and onions | antibacterial, antifungal, antiseptic, antithrombotic, anti-inflammatory, anti- carcinogenic |
| alpha carotene | carrots and pumpkins | antioxidant with powerful anticarcinogenic properties |
| betacrypto- | oranges, tangerines papaya | carotenoid with antioxidant xanthin properties |
| brassinin | cabbage | antioxidant properties which in animal studies reduce tumors in the breasts and skin |
| caffeic acid | apples | free radical scavenger |
| capsaicin | peppers | antioxidant especially good at protecting DNA |
| chlorogenic acid | tomatoes, bell peppers, pineapple, strawberries | blocks nitrosamine formation (nitrosamine is a powerful carcinogen) |
| ellagic acid | grapes, strawberries, raspberries | antioxidant adept at protecting DNA |
| dithiolthiones | broccoli | antioxidant which specifically stimulates enzymes in the glutathione family (which are powerful free radical scavengers) |
| epigallo- | green tea | This phytochemical in the catechin polyphenol family gallate gallate has been one of the best anticarcinogenic compounds ever tested in animals, inhibiting not only many kinds of tumors but also tumors in many different stages (many natural compounds can only fight metastatic disease in the early stages). |
| genistein | soybeans | inhibits angiogenesis |
| indoles | cruciferous vegetables | stimulates the breakdown of estrogen to estriol; other estrogen breakdown products, estradiol and estrone, have been shown to be both mutagenic and carcinogen |
| isoflavones | beans | inhibits estrogen metabolized from penetrating cell membranes in breast and ovarian tissue; thus, it may decrease the risk or incidence of cancer in these tissues |
| limonene | citrus fruit | antioxidant |
| lutein | spinach, romaine lettuce, red peppers, collard greens, Swiss chard, mustard greens, okra | carotenoids with antioxidant properties that have been shown to reduce the incidence of cataracts |
| lycopene | watermelon, guava, pink grapefruit, tomatoes | carotenoid and an antioxidant which, in at least one study, was found to be twice as powerful as beta carotene, and has been shown to be especially beneficial in cancers of the digestive tract. Interestingly, this chemical is quite stable and is much higher in canned tomato juices, pastes, and sauces than in raw tomatoes. |
| oltipraz | cabbage and other cruciferous vegetables | antioxidant which stimulates glutathione production |
| p-coumaric acid | tomatoes, bell peppers, pineapple, strawberries | blocks nitrosamine formation |
| phenethyl | cruciferous vegetables | antioxidant especially good at protecting DNA; |
| isothiocyanates | reduces estrogen to the nontoxic metabolite estradiol | |
| phytosterols | beans | May inhibit some types of colon cancer by a mechanism that is not yet fully understood. |
| sulforaphane | broccoli, brussels sprouts, cauliflower, kale | antioxidant which in animal studies has been very powerful at reducing breast cancer in animals |
| zeaxanthin | spinach, romaine lettuce, red peppers, collard greens, Swiss chard, mustard greens, okra | Carotenoids with antioxidant properties that have been shown to reduce the incidence of cataracts. |
Chlorophyll, which is found in all green vegetables, is turning out to also have anticarcinogenic properties. Finally, all fruits and vegetables also contain members of the flavonoid family, which is a large family of compounds that have been shown to have anti-inflammatory, immune-stimulating, and antioxidant properties. There are hundreds, possibly thousands, of flavonoids just waiting to be discovered.
In the coming years we will see many phytochemicals in tablet and capsule form, as more are isolated and understood. There is no doubt that as phytochemicals are put into tablet and capsule form there will be uses and benefits for them. There is also no doubt that the best source of these powerful nutrients is whole foods. I hope marketers don't take the angle that cheeseburgers, fries, and shakes are okay as long as you take a handful of their "phytotabs."
G. Douglas Andersen, DC, DACBSP, CCN
Brea, California
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