Biting Into Phytonutrients

If you are sick, want to prevent disease or love junk food way too much, then maybe you should be taking a bite out of phytonutrients.

The term “phytonutrient” is relatively new to the lexicon and it comes to us from the scientific research on the parts of nature’s foods that serve to heal, prevent disease and feed cells. Often, the word phytonutrient is used in conjunction with certain whole food supplements such as SuperGreens PhytoFood.

What are phytonutrients and where are they found?
The term “phyto” originated from a Greek word meaning plant. Phytonutrients are certain organic components of plants, and these components are thought to promote human health. Fruits, vegetables, grains, legumes, nuts and teas are rich sources of phytonutrients. Unlike the traditional nutrients (protein, fat, vitamins, minerals), phytonutrients were not considered “essential” for life, so some people prefer the term “phytochemical.” Yet the more food scientists discover, the more they are apt to say that phytonutrients are the missing link between vitamin pills and real nutrition. Again, this is a case not only for the consumption of natural, organically grown foods, but also for whole food supplements that do not contain isolated chemicals. (Read more here).

Some of the common classes of phytonutrients include:

• Carotenoids
• Flavonoids (Polyphenols) including Isoflavones (Phytoestrogens)
• Inositol Phosphates (Phytates)
• Lignans (Phytoestrogens)
• Isothiocyanates and Indoles
• Phenols and Cyclic Compounds
• Saponins
• Sulfides and Thiols
• Terpenes

About Carotenoids
Of all the phytonutrients, we probably know the most about carotenoids, the red, orange and yellow pigments in fruits and vegetables. The carotenoids most commonly found in vegetables (and in plasma) are listed below along with common sources of these compounds. Fruits and vegetables that are high in carotenoids appear to protect humans against certain cancers, heart disease and age related macular degeneration.

About Polyphenols
Polyphenolic compounds are natural components of a wide variety of plants; they are also known as secondary plant metabolites. Food sources rich in polyphenols include onion, apple, tea, red wine, red grapes, grape juice, strawberries, raspberries, blueberries, cranberries, and certain nuts. The average polyphenol / flavonoid intake in the U.S. has not been determined with precision, in large part, because there is presently no U.S. national food database for these compounds. (USDA scientists and their colleagues are in the process of developing a database for foods rich in polyphenols.) It has been estimated that in the Dutch diet a subset of flavonoids (flavonols and flavones) provide 23 mg per day. Earlier estimates of dietary intake that approximated 650 mg per day (Kuhnau, World Review of Nutrition and Dietetics, 1976;24:117) are generally thought to be too high as the estimate was based on data that were generated by “old” (less specific) methodology. Scientists at the Food Composition Laboratory, Beltsville Human Nutrition Research Center are currently developing new methodology for the accurate measurement of polyphenols in foods.

Polyphenols can be classified as non-flavonoids and flavonoids. The flavonoids quercetin and catechins are the most extensively studied polyphenols relative to absorption and metabolism.How do phytonutrients protect against disease?

The following are commonly proposed mechanisms by which phytonutrients may protect human health. More research is needed to firmly establish the mechanisms of action of the various phytochemicals.

Phytonutrients may:

• serve as antioxidants
• enhance immune response
• enhance cell-to-cell communication
• alter estrogen metabolism
• convert to vitamin A (beta-carotene is metabolized to vitamin A)
• cause cancer cells to die (apoptosis)
• repair DNA damage caused by smoking and other toxic exposures
• detoxify carcinogens through the activation of the cytocrome P450 and Phase II enzyme systemsWhat is the evidence that fruit and vegetable consumption protects human health?

Evidence that fruit and vegetable consumption protects human health is accumulating from large population (epidemiological) studies, human feeding studies, and cell culture studies. Listed below are a few selected population studies from the literature linking fruit and vegetable consumption to health. For an excellent review concerning vegetables, fruit and cancer prevention, see Steinmetz and Potter, Journal of the American Dietetic Association 1996;96:1027.

Evidence that Carotenoids are Protective
Fruit and vegetable consumption has been linked to decreased risk of stroke — both hemorrhagic and ischemic stroke. Each increment of three daily servings of fruits and vegetables equated to a 22% decrease in risk of stroke, including transient ischemic attack (Gillman et al. Journal of the American Medical Association. 1995;273;1113).

Elderly men whose intake of dark green and deep yellow vegetable put them in the highest quartile for consumption of these vegetables had about a 46% decrease in risk of heart disease relative to men who ranked in the lowest quartile. Men in the highest quintile had about a 70% lower risk of cancer than did their counterparts in the lowest quintile. The differences in vegetable consumption between high and low intake rankings was not striking. Men in the highest quartile or quintile consumed more than two (>2.05 and >2.2) servings of dark green or deep yellow vegetable a day; those in the lowest quartile or quintile consumed less than one serving daily (<0.8 and <0.7). This suggests that small, consistent changes in vegetable consumption can make important changes in health outcomes (Gaziano et al. Annals of Epidemiology 1995;5:255 and Colditz et al. American Journal of Clinical Nutrition 1985;41:32).

Consumption of tomato products has been linked to decreased risk of prostate cancer. Men in the highest quintile for consumption of tomato products (10 or more servings a week) had about a 35% decrease in risk of prostate cancer compared to counterparts whose consumption put them in the lowest quintile (1.5 or fewer servings of tomato products a week) (Giovannucci et al. Journal of the National Cancer Institute 1995;87:1767).

People in the highest quintile for consumption of spinach or collard greens, plants high in the carotenoid lutein, had a 46% decrease in risk of age-related macular degeneration compared to those in the lowest quintile who consumed these vegetables less than once per month (Seddon et al. Journal of the American Medical Association. 1994;272:1413).

Evidence that Polyphenols are Protective
Flavonoid consumption has been linked to lower risk of heart disease in some, but not all, studies. Elderly Dutch men in the highest tertile of flavonoid intake had a risk of heart disease that was about 58% lower than that of counterparts in the lowest tertile of intake. Those in the lowest tertile consumed 19 mg or less of flavonoids per day, whereas those in the highest tertile consumed approximately 30 mg per day or more (Hertog et al. Lancet. 1993;342:1007). Similarly, Finnish subjects with the highest quartile of flavonoid intake had a risk of mortality from heart disease that was about 27% (for women) and 33% (form men) lower than that of those in the lowest quartile (Knekt et al. British Medical Journal. 1996;312:478).