1. Phytochemicals What are they? How are they beneficial?
Can I just take a pill containing these substances?
Are there any negative effects?
How do I know whether phytochemicals are research-proven?

2. Current "Buzzwords" in Nutrition
Chemoprevention -- Using one or several chemical compounds to prevent, stop, or reverse the development of cancer.
Designer Food -- Processed foods that are supplemented with food ingredients naturally rich in disease-preventing substances.
Functional Food -- Any modified food or food ingredient that may provide a health benefit beyond the traditional nutrients it contains.
Nutraceutical -- Specific chemical compounds in food, including vitamins and additives, that may aid in preventing disease.
Pharmafood -- Food or nutrient that claims medical or health benefits, including the prevention and treatment of disease.
Phytochemical --Nonnutrient plant chemicals that contain protective, disease-preventing compounds.
Research has demonstrated that cancer is a largely avoidable disease. It is estimated that more than two-thirds of cancer may be prevented through lifestyle modification (1). Nearly one-third of these cancer occurrences can be attributed to diet alone, secondary to our American diet of high-fat, low-fiber content. Fruit and vegetable consumption have been consistently shown to reduce the risk of many cancers (2). A major prevention strategy has been the "5 A Day for Better Health" program sponsored by the National Cancer Institute (NCI), encouraging the public to include more fruits and vegetables in their diet.
The American Cancer Society has developed guidelines for nutrition and cancer prevention. These guidelines are similar to the Dietary Guidelines for Americans and include the following:
Choose most of the foods you eat from plant sources.
Limit your intake of high-fat foods, particularly from animal sources.
Be physically active. Achieve and maintain a healthy weight.
Limit consumption of alcoholic beverages if you drink at all.

3. Most Commonly Studied Phytochemicals
Food
Phytochemical(s)
Allium vegetables (garlic, onions, chives, leeks)
Allyl sulfides
Cruciferous vegetables (broccoli, cauliflower, cabbage, Brussels sprouts, kale, turnips, bok choy, kohlrabi)
Indoles/glucosinolates Sulfaforaphane Isothiocyanates/thiocyanates Thiols
Solanaceous vegetables (tomatoes, peppers)
Lycopene
Umbelliferous vegetables (carrots, celery, cilantro, parsley, parsnips)
Carotenoids Phthalides Polyacetylenes
Compositae plants (artichoke)
Silymarin
Allium foods. Garlic, onions, shallots, leeks, and chives belong to the Allium family, which contain allyl sulfides. Besides making your eyes water, allyl sulfides have been shown to inhibit tumors in animals. And studies have shown that people who eat a lot of garlic and onions reduce their risk of stomach and colon cancer. The more pungent the Allium food, the higher its content of allyl sulfides.
The Brassica family. Broccoli, cabbage, and many others belong to the Brassica family of vegetables and contain the important phytochemicals sulforaphane, indoles, and isothiocyanates. Sulforaphane has been shown to prevent breast cancer in lab animals. Indoles work against the dangerously high levels of estrogen associated with breast cancer, potentially reducing the risk. Isothiocyanates have been associated with prevention of stomach and lung cancers.
Carotene-containing foods. Beta-carotene, probably the best known of the phytochemicals and responsible for the color of carrots, is a potent antioxidant. (Antioxidants thwart oxidation, a normal metabolic process that, when left unchecked, can leave the body vulnerable to accelerated aging, cancer, cardiovascular disease, and degenerative diseases like arthritis.) Other carotenes, especially alpha-carotene, have recently been associated with reduced lung cancer risk.
Tomatoes. Tomatoes contain as many as 10,000 phytochemicals. One of the most well-studied is lycopene, an antioxidant that has been shown to help prevent heart disease and cancer. Regular tomato consumption has been associated with a reduction in the risk of prostate and stomach cancers.
Soy. Phytoestrogens are phytochemicals found predominantly in soy foods like tofu, tempeh, and miso. During a woman's childbearing years, phytoestrogens help prevent breast cancer by inhibiting the action of naturally occurring estrogens. Because they also regulate other hormones, phytoestrogens may help prevent cancer of the prostate, another hormone-dependent cancer.
Genistein, another phytochemical in soy, has been shown to reduce the size of LDL-cholesterol particles (harmful cholesterol) and lower the build-up of coronary artery plaque in primates. By consuming about half of your protein in the form of soy (31 to 47 grams per day), you may be able to reduce your risk of heart disease and cancer.
Other sources. Other plant foods--beverages, condiments, seasonings, and vegetable oils--contain substantial amounts of phytochemicals. Monoterpenes, for example, are associated with a reduction in the risks for cancer of the breast, skin, liver, lung, stomach, and pancreas. The polyphenols found in green tea have antioxidant properties, and research indicates that they may be protective factors against cancers of the skin, lung, and stomach.
Vegetable oils contain alpha-linolenic acid and are the greatest source of vitamin E. These nutrients have a dual role as antioxidant phytochemicals. For people who exercise, antioxidants are important because they help guard against the muscle-cell membrane damage and inflammation associated with hard exercise. Compounds in alpha-linolenic acid may also help prevent heart disease.

4. Food Phytochemical(s)
Citrus fruits (oranges, lemons, grapefruit) Glucarates
Monoterpenes (limonene) Carotenoids
Other fruits (grapes, berries, cherries, apples, cantaloupe, watermelon, pomegranate)
Ellagic acid Phenols Flavonoids (quercetin)
Beans, grains, seeds (soybeans, oats, barley, brown rice, whole wheat, flax seed) Protease inhibitors
Flavonoids (isoflavones) Phytic acid Saponins
Herbs, spices (ginger, mint, rosemary, thyme, oregano, sage, basil, tumeric, caraway, fennel)
Gingerols Flavonoids Monoterpenes (limonene)
Licorice root Green tea Polyphenols
Glycyrrhizin Catechins
Capsaicin - This chili pepper-derived spice packs the wallop in your hot tamale, but it is also a digestive aid, a topical painkiller, and a potential cancer-fighting compound.
Catechin Hydrate - Never mind the fortunetellers and soothsayers. Thanks to their cancer-fighting properties, tea leaves could give everybody a great future.
Coumarin - Rats could live longer without this blood thinning agent that doubles as a rat poison, but warfarin (a coumarin derivative) is the most commonly used oral anticoagulant medication.
Coumesterol - An isoflavone coumarin derivative found in soy products, this phytoestrogen appears promising as a naturally-occurring cancer preventative.
Genistein - Found in soy products, genistein is an isoflavone derivative that is proving to be a strong inhibitor of cancer and may be useful in the creation of new anti-cancer drugs.
Saponin - The plant biochemicals that produce suds in root beer are also effective antimicrobial, cholesterol-lowering, and anticancer phytochemicals. Some saponins, such as digitalis, are also used as heart medications.

5. How do phytochemicals work?
Antioxidant -
Hormonal action -
Stimulation of enzymes -
Interference with DNA replication -
Anti-bacterial effect -
There are many phytochemicals and each works differently. These are some possible actions of phytochemicals:
Antioxidant - Most phytochemicals have antioxidant activity and protect our cells against oxidative damage and reduce the risk of developing certain types of cancer. Phytochemicals with antioxidant activity: allyl sulfides (onions, leeks, garlic), carotenoids (fruits, carrots), flavonoids (fruits, vegetables), polyphenols (tea, grapes).
The most studied antioxidants are Vitamins C and E and beta carotenes. The benefits of taking high doses of vitamin E remain to be established.
There is no convincing evidence that taking supplements of vitamin C prevents any disease.
No one should take beta carotene supplements [12].
studies have found that antioxidants may interfere with the protective action of drugs intended to improve cholesterol levels.
Of nine studies on vitamin E and cardiovascular disease (CVD), five showed no effect on CVD events, three showed beneficial effects, and one showed a negative effect.
Of four studies of beta-carotene, three showed no effects on CVD and one showed a negative effect.
Of five studies of antioxidant "cocktails," two showed no effects and three showed negative effects.
Two studies of vitamins E and C together showed beneficial effects [21].
There is widespread scientific agreement that eating adequate amounts of fruits and vegetables can help lower the incidence of cardiovascular disease and certain cancers. With respect to antioxidants and other phytochemicals, the key question is whether supplementation has been proven to do more good than harm. So far, the answer is no, which is why the FDA will not permit any of these substances to be labeled or marketed with claims that they can prevent disease.
Hormonal action - Isoflavones, found in soy, imitate human estrogens and help to reduce menopausal symptoms and osteoporosis.
Phytoestrogens are estrogens contained in plants. They have a chemical structure similar to the human hormone estrogen. They have a weak estrogen effect when eaten. The most commonly studied are the isoflavones, found in soybeans and other legumes. The benefits of adding phytoestrogens to the diet appear very promising. But researchers caution against adding large amounts. Too much of them may cause problems with development and fertility. No one suggests that they replace regular treatment for osteoporosis, heart disease, or high cholesterol. Plant estrogens should be avoided by people who take certain medications. These include tamoxifen, which is used to treat breast cancer.
Stimulation of enzymes - Indoles, the phytochemical found in cabbages, stimulate enzymes that make the estrogen less effective and could reduce the risk for breast cancer. Other phytochemicals, which interfere with enzymes, are protease inhibitors (soy and beans), terpenes (citrus fruits and cherries).
Interference with DNA replication - Saponins found in beans interfere with the replication of cell DNA, thereby preventing the multiplication of cancer cells. Capsaicin, found in hot peppers, protects DNA from carcinogens.
Anti-bacterial effect - The phytochemical allicin from garlic has anti-bacterial properties

6. Which phytochemicals have been research-proven?

7. Reduce heart disease risk Yes
Functional Food
Effective Nutrient
Possible Health
Benefit
FDA Approved
Health Claim
Fruits and vegetables
Vitamins,
Phytochemicals, fiber
Reduce cancer risk
Reduce heart disease risk
Yes
Calcium-fortified orange juice
Calcium
Reduce risk for osteoporosis
Oatmeal
Soluble fiber
Reduce cholesterol
Milk, low-fat
Psyllium-containing pasta, bread, snack foods
Psyllium fiber
Soy
Soy protein
Broccoli
Sulforaphane No
Tomato Products
Lycopene
Reduce risk for prostate cancer and heart attack
Tea
Catechins
Reduce risk for heart disease and some types of cancers
Garlic
Organosulfur compounds
Reduce risk for cancer, heart disease, control high blood pressure
Some basic things to look for in a phytonutrient supplement include:
1) a wide variety from fruits and vegetables of all the colors, "...fruits and vegetable phytochemical extracts ...from the combination of phytochemicals...the additive and synergistic… "complex mixture" of phytochemicals...are responsible for these the benefits...no single antioxidant can replace the combination of natural phytochemicals ...."- Lui RH, J Nutr. Potential synergy of phytochemicals in cancer prevention: mechanism of action. Department of Food Science, Cornell University, Ithaca, NY Dec;134(12):3479S-85S.
2) the preferred source should not just be a pill with a grab bag of isolated phytonutrients, but include whole food and juice powders, "...phytochemicals often appear in nature as families of related compounds (that)...may behave synergistically... and... activate metabolic enzymes...as a network ".- Heber D., Phytochemicals beyond antioxidation, J Nutr Nov;134(11):3175S-3176S.
3) they should have some measure of potency, the best of which presently is antioxidant capacity, "...people may be able to reduce risk of diseases of aging--including senility--simply by adding high-ORAC foods to their diets," Floyd P. Horn, administrator, Agricultural Research Service's Human Nutrition Research Center on Aging at Tufts University in Boston.
4) they should be made manufactured at cGMP (NNFA – A rated), ISO 9001 (2000), Organic & FDA approved facilities.
5) to insure long term compliance,   they should taste good in plain cold water, without mixing with high glycemic juices, or high levels of binding fibers.
Table adapted from: Journal of the American Dietetic Association, Vol. 99, No. 10, p1280