The importance of polyphenols
What are polyphenols?
Polyphenols are a category of chemicals that occur in plants. There are over 500 known polyphenols, divided into four different groups: flavonoids, stilbenes, lignans and phenolic acids.
Many of the plants that we eat as food are rich in polyphenols.
Possible health benefits of polyphenols
- Most of the research concerning the possible health benefits of polyphenol focus on their role as antioxidants.
- Your individual genetic makeup can impact how your body responds to certain polyphenols.
- Research indicate that polyphenols may be capable of impacting gene expression, but more studies are needed before we can know for sure.
Polyphenols & Inflammation
In a study where rats received tea polyphenols, they were able to keep up their physical activity longer than the rats in the control group. When the blood was tested afterwards, the group who had received tea polyphenols showed lower levels of chemicals known to signal inflammation and muscle damage. This indicate that tea polyphenol might offer some form of protection against inflammation after physical exercise.
Polyphenols & blood pressure
A review of studies found that consuming cocoa that contains cocoa polyphenols significantly decreased blood pressure and the levels of “bad” cholesterol (LDL), when the cocoa was consumed daily for at least two weeks. Also, the levels of “good” cholesterol (HDL) went up.
Polyphenols & type 2 diabetes
An analysis spanning multiple studies have shown that the people with the highest consumption of flavonoids (a type of polyphenols) are less likely to develop type 2 diabetes compared to those who has the smallest consumption. Exactly why that is remains unknown.
Some research indicate that some polyphenols may be capable of slowing down the process where the body digests and absorbs sugar. More research is needed before we can no for sure if this is true or not, and how it works. If it turns out to be correct, polyphenols could prove an important tool in preventing type 2 diabetes.
In at least one study, flavan-3-ols (which is a polyphenol belonging to the flavonoid group) showed a capacity for lowering insulin resistance.
Foods rich in polyphenols
A lot of different fruits, berries, vegetables and legumes are rich in polyphenols, and whole grains are also a significant source of polyphenols. If you want to eat nuts and similar to boost your polyphenol intake, you can for instance go for hazelnuts, almonds, pecans or walnuts.
Many fats derived from plant sources are rich in polyphenols, including sesame seed oil and virgine olive oil. Beverages such as coffee, red wine and tea are also high in polyphenols since they are derived from polyphenol rich plant sources.
Many spices are rich in polyphenols, but keep in mind that we tend to consume a much smaller amount of a spice than we do of vegetables, fruits, nuts, etc. The total intake of polyphenols from spices in a dish can therefore be quite low even if the spice has a high polyphenol content per gram. Examples of spices that contain polyphenols are saffron, cloves, ginger, cumin and cinnamon.
The exact polyphenol content of a piece of food – such as a fruit, a berry or a cup of coffee – will be greatly impacted by a multitude of factors, including as growth conditions for the plant, how the food was harvested, transported and stored, and how the food has been processed and/or cooked.
Some dietary supplements contain polyphenols in much higher quantities than what you would get from a normal healthy diet. An excessive polyphenol intake may have adverse effects, so caution is warranted. In one study on mice, a very high dose of one particular polyphenol caused kidney damage. Exceedingly high doses of polyphenols have also been linked to tumour development and thyroid hormone production disturbances.