When a person starts learning about food, the first lesson is often to understand fats, proteins and carbohydrates — the macronutrients. The next topic is usually about micronutrients (e.g., vitamins and minerals). For many people this is as far as the nutrition education goes, which is a shame because these two topics alone imply that it doesn’t matter where these nutrients come from. If you are drinking a protein shake and popping a multi-vitamin, you have all the nutrition you need, right?
If only it were that simple!
Several decades ago, scientists began to notice that people who ate mostly plant foods (like vegetables and fruits) were less likely to experience chronic conditions and diseases than people whose diets were heavy in meat and processed foods. This phenomenon piqued their curiosity and kicked off the studies which eventually would reveal a new set of biologically active compounds found only in plants.
These non-nutritive compounds were termed phytonutrients or phytochemicals, indicating that they come only from plants. (Any time you see “phyto-” at the start of a word, it means the rest of the word comes from or relates to plants.) These phytochemicals give plants their color, flavor and odor, and probably help keep the plant healthy in whatever environment they find themselves in.
Since the early 1990s, scientists have found tens of thousands of different chemicals in vegetables, fruits, legumes, grains, nuts and seeds… and the number keeps growing, so who knows when we will have a “complete” list?!
Also during this time, researchers have found connections between specific phytonutrients and certain aspects of health. Here are just a few examples:
- Diets rich in lignans have been shown to reduce the risk of cardiovascular disease and, for post-menopausal women, the risk of endometrial cancer.
- Diallyl disulfides, ellagic acid, saponins and sulforaphanes play a role in preventing and/or inhibiting the growth of cancer cells.
- Anthocyanins reduce the risk of developing type 2 diabetes.
- Organosulphides help lower serum lipids, reduce the formation of blood clots, lower blood pressure, prevent cancer formation, help keep blood sugar under control, act as antioxidants, and enhance immune activity.
- Flavonoids (of which there are more than 6,000!) are antioxidants, metal chelators (i.e., substances that can bind heavy metals in and carry them out of the body), anti-diabetic compound and neurotrophin stimulators, just to name a few of their physiological effects.
Needless to say, we already know that many of these tiny plant compounds have a positive impact on our health and these connections to well-being are only going to grow with time and interest.
Unfortunately, because we haven’t known about these compounds for very long and the research about their effects in the body is in very early stages, there is no recommendation for how much of each compound should be consumed. Until such time as some very smart scientists provide us with more information and a specific recommendation can be made, these compounds are not considered essential by the people responsible for making such designations. (You can rest assured that many healthcare practitioners, including me, believe these amazing substances are essential for optimal health! But we aren’t in the right positions of power to declare essentiality. At least I’m not; I won’t speak for all other functional healthcare peeps.)
Another “problem” as it relates to recommendations is that it’s not clear if a phytochemical can be isolated from the other phytonutrients and micronutrients in the plant and still work as well. For example, we don’t know if you can simply pop a supplement of resveratrol and get the same life-extending benefit as getting the resveratrol from grapes, which would also include fiber, flavonols, flavanols, phenolic acids, carotenoids, other stilbenes, copper, vitamins B1, B2, B6, K, and potassium.
I can hear you now… asking in your head… so what am I supposed to do with this information?
I’m going to tell you. Drum roll, please…
Eat a wide variety of real foods.
Now we’ve gotten to the simple part. Or at least the part that sounds simple, even if implementation takes a bit of work.
Here are two suggestions for how to increase your phytonutrient intake:
- Increase your intake of vegetables and fruits until you are eating at least 6 servings every day. (I mentioned this as one of my top 5 ways for eating healthier, and now you know one of the reasons why!)
- Make legumes (including lentils and beans) a go-to source of protein and nuts and seeds one of your regular snack options.
- Eat one food from each of the color categories for plant foods every day.
- Track how many different plant foods you eat for 1 – 3 months, and then look for ways to increase the variety based on your habits. (You can read about the outcome of my variety experiment here.)
As I said, you simply need to eat real food all of the time. On top of this, be sure you are limiting foods that fall into the “rarely” or “sometimes” categories, as the phytonutrients in these foods is limited (if present at all), and focusing on real food will allow you to get all of the macro-, micro- and phytonutrients your body needs.
— American Institute for Cancer Research. A Closer Look at Phytochemicals. Revised January 2008. Accessed 13 December 2016.
— Linus Pauling Institute. Phytochemicals. In Dietary Factors. Accessed on 13 December 2016.
— Pickett-Bernard D. Advanced Culinary Nutritional Medicine. Webinar from Integrative and Functional Nutrition Academy Track 3. Attended 30 June 2016.
— The World’s Healthiest Foods. Grapes. Accessed on 13 December 16.
— Webb D. Phytochemicals’ Role in Good Health. Today’s Dietitian. 2013;15(9):70.