Phytonutrients 101
As of right now, phytonutrients (also known as phytochemicals) are not considered nutrients in the typical sense. They do not fall into either the macro or the micronutrient categories, even though they have important health functions.
First, we will consider the root of the word. The term phyto is Greek and means “plant”, while nutrient means “a substance in food that contributes to growth and health”. Therefore, you can easily conclude from the name, that these nutrients are received through the ingestion and metabolism of plants.
Phytonutrients first gained notoriety in a 1991 publication by Steinmetz and Potter(1), in which more than a dozen biologically active plant chemicals were identified. It is estimated that there are thousands of the plant nutrients that may or may not significantly affect the human body. The average American diet contains about 50 known common phytonutrients. Unfortunately, the specific actions of the phytonutrients are still not well researched in regards to chronic diseases, or their effect on sports performance. For now, I will not be going into detail on each individual phytonutrient, mainly because there isn’t enough information available as of yet. However, I will be explaining three classifications of phytonutrient in which I feel there is a decent amount of research into their health protective roles. These classifications are: phenolic compounds, organosulfides, and carotenoids.
Once again, I need to re-iterate the point that much more research needs to be done into these nutrients. And while the existing research is not based upon sports performance, but rather on overall health; this article still has a direct relation to us as athletes. If we think about this rationally, we cannot build optimal amounts of muscle if our body is pre-occupied with other conditions (illness or otherwise). So anything that provides significant health promoting qualities is indirectly going to aid us in building muscle.
What are phenolic compounds?
The phenolic compounds are a large and relatively varied group of phytonutrients (which might get sub-categorized in the future). Phenolic compounds include both phenolic acids and flavonoids, which have some solid research behind them. These compounds are of high interest because of their ability to positively influence heart disease prevention, and to prevent LDL oxidation.
Flavonoids first came to light when research was published in regards to red wine consumption and a decreased risk for heart disease. Red wine was specifically noted over white wine because the seed and skins of grapes are included into the fermentation process, which are great sources of polyphenolic tannins(2). Other phenolic compounds greatly found in grapes are anthocyanin and catechin(3). Now, I understand that many athletes do not drink (because of personal choice) and may not desire to consume alcohol on a daily basis. However, there are very effective alternatives. 100% grape juices are a great choice because they contain very high amounts of these phytochemicals.
What are organosulfides?
Organosulfides have a growing amount of evidence associated with decreased risk of developing certain cancers. These phytochemicals are found mainly in cruciferous vegetables such as brussel sprouts, broccoli, cabbage, rutabaga, and cauliflower. The organosulfides compounds specifically researched for their anti-cancerous properties are glucosinolates, indoles, and isothiocyanates(4). Onions, grarlic, leeks, chives, and shallots have been found to contain high amounts of allyl compounds which have been studied for their use in reduce blood cholesterol levels, reducing risk of specific cancers, and anti-hypertensive possibilities.
*Special Note: Because these foods mentioned above can produce gastrointestinal distress and/or bloating, it is not recommended that these foods be consumed within several hours of training or competition.
What are carotenoids?
To the best of my knowledge, there are well over 500 different carotenoids that have been identified, so because of the vast amount research on many of them is extremely limited. However, it is believed that they all (or most) have anti-oxidant properties, because of the excellent results of the more heavily studied ones. Due to the incomprehensible volume of these phytonutrients, I will simply speak about the one that has undoubtedly been studied most, lycopene. Lycopene has been found to be the most abundant carotenoids in the prostate(5), and that diets rich in lycopene decreased the risk of prostate cancer by greater than 50%(6). Possibly the greatest source of this phytonutrient, is from tomatoes. However raw tomatoes have significantly less bioavailable lycopene than processed tomatoes, because cooking releases the lycopene stored in the cell walls. It is also noteworthy that lycopene absorption is significantly greater with the simultaneous intake of fat. Lycopene has only one sports related study that I am aware of, which shows 30mg supplementation of lycopene helped to prevent exercise-induced asthma(7). But, it is my firm belief that more research will lead to other great uses carotenoids, both in sports performance and general health.
As of now, there have not been any DRI’s established for any phytonutrients; however I believe there will be in the future. And with all the potential that these phytonutrients are showing, they should be a focus in any diet, both for general health and an athletic stand-point. Just as every other part of life, variety is key here, so listen to your mother and eat your fruits and veggies.
References:
(1) Steinmetz KA, Potter JD. Vegetables, fruit, and cancer II mechanisms. Cancer Causes Control. 1991; 2:427-442.
(2) Yilmaz Y, Toledo RT. Major flavonoids in grape seeds and skins; antioxidant capacity of catechin, epicatechin, and galic acid. J Agric Food Chem. 2004; 52(2):255-260.
(3) Palma M, Taylor LR. Extraction of polyphenolic compounds from grape seeds with near critical carbon dioxide. J Chromatogr. 1999; 849:117-124.
(4) Verhoeven DTH, Goldbohm RA, van Poppel G, Verhagen H. Epidemiological studies on brassica vegetables and cancer risk. Cancer Epidemiol Biomark Prev. 1996; 5(9):733-748.
(5) Clinton SK, Emenhiser C, Schwartz SJ, et al. Cis-trans lycopene isomers, carotenoids, and retinol in the human prostate. Cancer Epidemiol Biomark Prev. 1996; 5:823-833.
(6) Giovannucci E, Ascherio A, Rimm EB, Stampfer MJ, Colditz GA, Willet WC. Intake of carotenoids and retinol in relation to risk of prostate cancer. J Natl Cancer Inst. 1995; 87(23):1767-1776
