You probably often think about how you can get enough vitamins to stay healthy and happy. These essential substances are mostly ingested through plant sources - fruits, vegetables, etc.
But have you also heard of any of the following?
Polyphenols, EGCG, antioxidants, bioflavonoids, caffeine, carotenoids?
These are secondary plant substances. They are secondary because they do not play an essential role in the survival of the plant, such as the basic requirements like minerals, water or light. In addition, they are usually found only in specialized cell types, carrying out specialized tasks.
Their functions serve the well-being of the entire plant instead of just the individual cell, as with substances of the primary metabolism. They are a result of the adaptation of the plant to its environment1.
What can secondary plant substances do for you?
Chances are you're wondering how to eat healthier, how to avoid stimulants and risk factors for disease.
You wonder if too much coffee is bad for you, or chocolate, or fructose.
But coffee plants don't produce caffeine to keep us awake, right? Grapevines also don't produce antioxidants to protect our cells from free radicals.
In most cases, it was just a lucky coincidence of evolution that plants produce molecules to which our bodies react biochemically.
Coevolution2 plays a role here. Various properties - such as colors or aromas to attract insects - were beneficial to the plants that formed them in the long run. Plants whose secondary substances gave us or other animals an advantage were consumed more frequently. The seeds could be distributed more effectively and the plant species spread. Of course, this connection also led to corresponding cultural changes, as humans cultivated popular wild plants agriculturally at some point.
For centuries, secondary plant substances have found a firm place in medicine due to their biological activity. Some are additionally modified after extraction and used as drugs. Other plant components have psychopharmacological effects, such as morphine or THC.
Many secondary plant compounds are derived from amino acids and nucleotides, which is why they are structurally similar and seem complicated.
In recent decades, the analysis of these substances has also become increasingly advanced. Chromatography, electrophoresis, isotope techniques and enzymology have greatly advanced knowledge in the field of secondary plant compounds3.
Your body reacts to secondary plant compounds when:
- they perform a general chemical function applicable to various organisms, such as antioxidation.
- the molecules are very similar to our own signaling molecules and bind to receptors that trigger a reaction - like caffeine.
9 Types of secondary plant compounds4
Many secondary plant substances are poisonous for us. They serve the plant as defense substances against predators or parasites. Among the plant substances with positive effects for our health are:
These are dyes (red, light yellow, blue, violet) from various types of fruit, such as apples, pears or grapes, but also from onions or kale. In in vitro studies and animal experiments antioxidative, antithrombotic, antihypertensive, anti-inflammatory and antibiotic properties were found.
These are defense substances from various sources, such as tea, whole grain or nuts. In in-vitro studies and animal experiments, antioxidant properties were found.
These are dyes (red, orange, yellow) from many red vegetables, such as tomatoes or carrots. In in-vitro studies and animal experiments, antioxidant, immunomodulating and anti-inflammatory properties were found.
These are plant hormones similar to human estrogen, e.g. from legumes or cereals (such as soybeans). In in-vitro studies and animal experiments, antioxidant and immunomodulating properties were found.
These are defense substances from various types of cabbage or mustard. In in-vitro studies and animal experiments, antioxidant and immunomodulating properties were found.
These are sulfurous flavors, e.g. from onions or garlic. They showed antibiotic, antioxidant, antithrombotic, blood pressure-lowering and cholesterol-lowering effects in vitro or in animal experiments.
These are fragrances and aromas from e.g. mint, lemon or caraway seeds. They showed a cholesterol-lowering effect in vitro or in animal experiments.
These are bitter substances from various legumes, oats or soy. They showed an antibiotic and antifungal effect in vitro or in animal experiments.
Those are plant hormones with similarity to cholesterol from e.g. nuts, seeds or legumes. They showed a cholesterol-lowering effect in vitro or in animal experiments.
Most of these are already contained in a balanced diet.
This leads us to the last question: Why are plants so full of antioxidants?
Oxidation5 is a threat to all living beings, plants or humans. Toxic metabolites, UV radiation or environmental toxins can make oxidation dangerous for any organism because it damages cellular macromolecules such as proteins or DNA.
Plants, therefore, developed antioxidant substances to protect their seeds. Since this is where the DNA for future generations lies, this is essential for the health of the species. Your body, too, is a daily victim of oxidation. Caused by:
- our own metabolites
- sleep deprivation
- .. and the list goes on.
Theoretically, we have our own neutralization system for free oxygen radicals (ROS). But when this system is confronted with too many free radicals...
it often can't catch everything and gives free rein to oxidation6, which can then really harm us. Because oxidation weakens us and makes us more susceptible to chronic diseases.
Here is the good news for you
When stress becomes rampant and we cannot cope with the wave of oxidation that floods our cells, we can take plant antioxidants7. Simply because plants face the same problems!