Since “phyto” means “plant “Phytonutrients” must be nutrients from plants.
A Phytonutrient can be an essential nutrient and encompasses a huge class of compounds with numerous subclasses. After all, the name itself just means a nutrient that comes from a plant.
That covers a lot ground and they are widely distributed throughout the plant kingdom and contained in long lists of herbs, fruits, nuts, vegetables, beans and medicinal plants. For our purposes, these plant sourced nutrients refers only to those that are of some value to humans.
We don’t want to emulate Wikipedia, so rather than go into depth on each phytochemical, the scope of this section will be limited to a short description of each class and its implications for our health.
The common types of Phytonutrients are:
These are also natural pigments producing the yellows, reds and blues of flowers. They are not an essential phytonutrient in that flavonoids are synthesized in the body from the amino acid phenylalanine which we met in our discussion natural source of nutrientsof amino acids. Flavonoids have been described as “nature’s biological response modifiers” because of their ability to modify the body’s reaction to allergens, viruses and carcinogens. The healthful effects of fruit, vegetables, tea and even red wine have been attributed to flavonoid compounds rather than to known essential nutrients.
The best news of all is that dark chocolate (cocoa content of 70% or more) is a great source of flavonoids. Better still is that a study published on May 31, 2012 in the BMJ (formerly the British Medical Journal) provides more evidence that dark chocolate may decrease LDL cholesterol and raise HDL cholesterol. The study was prompted by the fact that 60-70% cocoa dark chocolate is “rich in polyphenols, specifically those flavonoids that exhibit anti-hypertensive, anti-inflammatory, anti-thrombic and metabolic effects, all of which are thought to contribute to cardio-protection”.
A group of phytonutrient organic compounds occurring naturally in the environment. They are important in that they comprise most of the phosphorus in grain seeds. Inositol phosphates are also abundant in soils and water bodies, yet a clear understanding of their behavior in the environment is still on the horizon. They do have a crucial role in cellulalar signaling. We covered phosphorus in the discussion on minerals and learned that it is important in maintaining pH balance and having a strong impact on nerve, muscle and kidney function.
Lignans are plant hormones, specifically Phytoestrogens. Flaxseed, sesame seed, sunflower seed and multi-grain bread are four of the highest content sources of phytonutrient lignans. Whole flaxseeds: lignans in the rawA positive association between high levels of lignans in the body with reduced risks of prostate cancer, ovarian cancer, breast cancer, osteoporosis, and cardiovascular disease have been reported in some randomized controlled studies.
On the other hand, some studies showed very little correlation between intake of lignans and cancer prevention, especially breast cancer. The key is in the source of the lignan. For example, whole flaxseeds or supplemented flaxseed showed significant positive results but flaxseed oil did not. One other consideration is that whole seeds may sometimes pass through the system without getting fully digested while ground seeds are more easily absorbed. So if using whole flaxseeds, chew your food throughly.
Also, many cancers take 20 years to manifest with noticeable symptoms; which begs the question as to the duration of the clinical trials.
Isothiocyanates and Indoles:
Both of these important nutrients are found in broccoli, kale, cauliflower, cabbage and brussel sprouts; commonly referred to as the cruciferous vegetables.
Epidemiological studies conducted as far back as the eighties showed that these two phytonutrient chemical have anti-cancer properties.
Phenols and Cyclic Compounds:
Think olives and extra virgin olive oil from which these are acquired. These phytonutrient wonders exhibit anti-microbial activity against gram-positive bacteria. There I go showing off again.
“Gram-positive” just refers to a type of bacteria that can be stained dark blue or violet for examination under a microscope. It includes some nasty critters like bacillus, listeria, streptococcus, staphylococcus and clostridium.
Saponins are essential nutrients found in most vegetables, beans and herbs. The best known sources of phytonutrient saponins are peas, soybeans and some herbs. Saponins have an interesting foaming effect resulting in their wide use in beer, shampoo and detergents.
Health wise, they exhibit beneficial effects on blood cholesterol levels, cancer, bone health and stimulation of the immune system as well as having antioxidant properties.
Sulfides and Thiols:
These are essential phytonutrients occurring naturally in a wide variety of foods including meats, fish, fruit and vegetables. They find heavy use as commercial flavoring agents. Sulfides and thiols have antioxidant properties that may enhance our body’s ability to remove potentially harmful compounds from pesticides or mercury in food. Specific foods high in sulfides include garlic, onions, scallions, broccoli, cabbage, bok choy and collards.
Terpenes are major biosynthetic phytochemical building blocks in almost every living thing. Steroids, for example, are a terpene derivative. Vitamin A is an excellent example of a terpene. They are also primary constituents of the essential oils of many types of plants and flowers and are used widely as natural flavor additives for food, as fragrances in perfumery, and in traditional and alternative medicines such as aromatherapy.
Mostly they come from the resin of conifers such as pine trees and the name “terpene” is derived from “turpentine”.
There is some overlap between Phytosterols and some of the other phytochemical compounds but we will go into a short discussion here as if they are a separate class.
Phytonutrients are cholesterol-like compounds that are found mostly in unrefined vegetable oils, whole grains, nuts and legumes. Foods and beverages with added plant sterols or “stanols” are now available in many countries throughout the world.
Health claims for them are now allowed in a few countries. For some reason, our FDA hasn’t figured out yet that something natural from a plant might actually have healing properties…so we will just stay away from saying that they do.
There are about 44 sterols known to exist in plants. The most abundant phytonutrient phytosterols are beta-sitosterol, campesterol, stigmasterol, campesterol and brassicasterol.
Beta-sitosterol is an essential nutrient representative of all the major plant sterols. It is found in pecans, saw palmetto, avocados, pumpkin seed, cashews, rice bran, wheat germ, corn oils, and soybeans, to name a few.
In Europe beta-sitosterol plays a major role in the herbal treatment of benign prostatic hyperplasia (BPH) as well as the treatment of prostatic carcinoma and breast cancer. These possible benefits are still being investigated in the United States.
The early hunter-gatherer diets were rich in phytosterols, however, the content in the typical Western diet today is relatively low since plant sterols can be destroyed or removed by modern food processing methods.