Food as Medicine: Guide to Phytonutrients  by Marcia Zimmerman, M.Ed., C.N.

What are Phytochemicals?

The term phytochemical (some prefer phytonutrient) refers to natural  plant-based chemicals that have been identified as active compounds in  disease prevention. These vitamin-like molecules help regulate bodily  functions. Thousands of different phytochemicals work to fine-tune metabolic  processes that help maintain health.

To be classified as a vitamin, a substance must alleviate specific symptoms  that return when the vitamin is withdrawn. An example of a classic  nutritional deficiency is scurvy, which vitamin C prevents and alleviates.  Vitamins are required in small amounts, usually measured in milligrams (mg.)  or micrograms (mcg.).

Phytochemicals, on the other hand, may be required in fairly large amounts  and haven’t yet been linked to specific nutritional deficiencies. However,  scientific research in this area is moving quickly, and we will no doubt see  some of these phytochemicals reclassified as essential in the next century.  Today, we know that phytochemicals have these functions:

reduce the risk of cardiovascular disease; reverse high cholesterol,  triglycerides, free radical damage, platelet stickiness and degeneration of  vessel walls
reduce cancer risk by activating the body’s defense mechanisms and blocking the action of carcinogens
detoxify cancer promoters and free radical inducers
modify hormone levels, reduce the risk of cancers from excess hormone action
act as potent antioxidants in both fat-soluble and water-soluble body fluids  and cellular components
influence metabolic enzymes to increase or decrease speed to benefit the  entire body boost immune response by activating different classes of immune-system  components
inhibit destructive enzymes and bacterial, viral, fungal and parasitic attack
protect the body’s structural components.

What foods contain phytochemicals?

Every plant food contains several classes of phytochemicals. That’s why a  varied diet is so important. It’s difficult to measure the benefits of one  group of phytochemicals against the benefits of others. It’s quite clear that  we need them all.

Scientists began examining the connection between diet and resistance to  disease early this century. They discovered that people who ate diets high in  fruits and vegetables had reduced incidence of heart disease, diabetes and  some cancers. Citrus fruits became popular as a means of preventing or  alleviating colds. Besides vitamin C, citrus contains phytochemicals called  bioflavonoids. Whole grains and beans were promoted for their phytochemicals,  including fiber, phytosterols and lignan. These foods help manage  cardiovascular disease, diabetes and hypoglycemia.

The sulfur compounds, also phytochemicals, in garlic were found to kill  bacteria and parasites, boost the immune system and reduce atherogenesis  (thickening of artery walls) and platelet stickiness. All members of the  cruciferous family — broccoli, cauliflower, cabbage, bok choy, Brussels  sprouts, collards, cress, kale, kohlrabi, mustard, horseradish and radishes —  contain a group of closely related sulfur compounds known as glucosinolates.

Glucosinolates, as phytochemicals, can be isolated and sold in capsules as  dietary supplements for protection against some types of cancer and  stimulation of protective liver detoxification enzymes. They may be further  divided into specific nutraceuticals within the group — sulforaphane,  indole-3-carbinol, dithiothiones and isothiocyanates. Researchers have  identified how each of these work in the body.

Soyfoods get a lot of press because scientists have discovered that people  who traditionally eat a soyfood-rich diet have reduced incidence of cancers  of the breast, colon and prostate. The soy components that have been  identified as biochemically active are isoflavones. There are six different  isoflavones: daidzin, daidzein, genistin, genistein, glycitin and glycitein.  Besides anticancer activities, soy isoflavones lower cholesterol and can  behave like estrogens. For menopausal women seeking natural relief, this is  good news. Phytoestrogens are substances that bind to estrogen receptors in  the body, conferring the benefits of estrogen but not the risks. Because  phytoestrogens resemble estrogen, they fool the body into thinking it has the  real thing. Soy isoflavones’ effects also include reduction of inflammation,  cardioprotection, free radical scavenging and protection against kidney and  gall bladder disease.

In the January 10, 1997 issue of Science, researchers discussed the  chemoprotective activity of resveratrol, a natural phytochemical derived from  grapes. Resveratrol, a phytoalexin (protective compound) is produced by  grapes in response to environmental stress. It protects the grape from mold,  bacteria and other dangers. In humans, resveratrol inhibits cellular events  associated with tumor initiation, promotion and progression. It acts as an  anti-inflammatory and chemical-detoxifying agent.

Grape seeds contain protective compounds called oligomeric proanthocyanidins  that scavenge free radicals and promote growth and repair of connective  tissue. They inhibit destructive enzymes and also reduce inflammation.

Researchers have reported on the superior antioxidant effects of oligomeric  proanthocyanidins, which are derived from grape seeds or the bark of Bordeaux  pine trees. Research has also demonstrated multiple angioprotective and  anti-inflammatory benefits from these compounds. Perhaps their most  remarkable benefit is repair of connective tissue including skin, tendons,  ligaments, blood vessels, and organ and body cavity linings.

What are nutraceuticals? Why would I need them as supplements?

In 1986, Stephen L. DeFelice, M.D., from New York formed the Foundation for  Innovation in Medicine, a nonprofit organization dedicated to promoting  natural therapies. Early in his medical career, DeFelice promoted the idea of  natural substances in foods as healing agents. These natural substances,  found only in whole, unadulterated “functional foods”: foods whose  biochemically active components haven’t been removed through processing  were called nutraceuticals, a term coined by DeFelice. The term implies the  ability of a single chemical agent to act as powerfully as, and in some cases  better than, pharmaceutical agents. Understanding the mechanism by which a  nutraceutical works in the body has been the goal of intense research.

Nutraceuticals can be isolated from natural food sources and sold as dietary  supplements. For example, a woman concerned about breast cancer but allergic  to soyfoods might supplement her diet with isoflavones isolated from  soyfoods. A man who is not particularly fond of tomatoes but wishes to  benefit from their prostate cancer-protective properties might choose a  lycopene supplement. Nutraceuticals have few side effects but may cause  adverse reactions in a few specific situations. Nutraceuticals can be found  in animal (such as shark and bovine cartilage) as well as plant sources.

What is the difference between phytochemicals and nutraceuticals?

Phytochemicals are one class of nutraceuticals. The primary difference  between phytochemicals and nutraceuticals is that phytochemicals are  plant-based, whereas nutraceuticals are plant- or animal-based.  Phytochemicals are often derived from plants that are known more for their  medicinal value than their food value.

Are there scientific studies that support the use of nutraceuticals?

Thousands of studies have defined the disease-preventing benefits of  nutraceuticals. They’re published in peer-reviewed scientific journals and  have been conducted by world renowned researchers.

This information is for educational purposes only. Visit a health care  professional if you think phytochemical supplementation might benefit you.

Marcia Zimmerman, M.Ed., C.N., is a researcher, writer and lecturer. She is  founder and CEO of The Zimmerman Group, Inc., headquartered in Alameda,  Calif.