Nutrition – Polyphenols

Tuesday 08 May 2018

The idea for this blog came about after I read a very good article from a recent newsletter that I received from a leading supplement company. The article focused on yet another fruit that has been esteemed as being highly nutritious called Aronia berry pomace (also known as black chokeberry). Basically it has been found to be very high in a type of polyphenol. I am not going to focus on this fruit but on polyphenols generally.  

Although some foods may be individually very nutritious, my message has always been not to focus on one particular food because of its reported health benefits but to eat a good mixed diet which includes some of these foods. By doing this we will benefit from the synergistic effect that the foods will bring and give a broad spectrum of polyphenols. This is far more beneficial to our health. No one nutrient works in isolation.

Anyway about Polyphenols – I want to look at what they are, where they can be found, why they are beneficial, some examples, and a recipe.

So what is a polyphenol?
• Polyphenol is a generic term used for the several thousands of plant based molecules found in natural foods.
• They are the largest class of phytochemicals (plant chemicals) found in nature.
• They are the molecules that are responsible for the bitter astringent properties associated with certain foods
• They have a strong anti-oxidant effect. Their chemical structure is ideal for absorbing free radicals.
• There is increasing attention being paid to the molecules they contain, particularly in the field of cancer. Research is growing because the activities of these molecules has shown to have many health protective actions.

Where can they be found?
Polyphenols can be found in abundance in fresh vegetables and fruits, teas and herbs. Some are in pulses, nuts and seeds and whole grains.

Potential benefits of polyphenols
Many individual polyphenols have been shown to have different activities and therefore different benefits to the body. The whole subject of how they work in the body is extremely complex but this is a list of their general benefits:
• They have been described as compounds that ‘correct and protect’.
• As I have already explained, they have strong antioxidant activity which neutralises free radical activity.
• They have been shown to be anti-inflammatory by inhibiting the COX-2 enzyme. We do know that inflammation can drive disease.
• Some polyphenols have been shown to hijack the cancer cell signalling process, switching it off which leads to cancer cell death.
• They have been shown to have the ability to repair damage already done to the DNA.
• They have cancer preventing activities and have been shown to curb the spread of cancer.
• They have been shown to restrict the action of freely circulating  insulin growth-like factor (IGF-1)
• Have been shown to boost the immune system.

Quite an impressive list of positives and research goes on.

The health effects of polyphenols depends a great deal on the amount consumed and their bioavailability. As I have already said and want to repeat that, It is well understood that eating a wide variety of natural foods in the diet will give a wide variety of polyphenols and in turn a wide variety of benefits.

Some polyphenols have been researched more than others. Not more so than by Professor Robert Thomas who has won awards for his research into the effects of polyphenols and cancer. He focused on broccoli, green tea, pomegranate and curcumin (found in Turmeric). To read more about his research, google Pomi T.

Here are a few examples of polyphenols: some have been researched far more than others. As I explained there are thousands of these polyphenols and we certainly would not have a checklist or worry about knowing them all.

Ellagic acid found in berry fruits. Its anti-cancer properties have been studied in cancer cells in the laboratory. They have been shown to inhibit the growth of tumour cells and interfere with angiogenesis. This is when a cancer develops its own blood supply to be nourished. I have read in some books that 100g a day is needed to get sufficient Ellagic acid to benefit.

Citrus fruits contain about 60 polyphenols and the principle one is called Terpene which has been identified many times during research. These have been shown to interfere with the processes leading to cancer by blocking tumour growth. It is worth noting here about the citrus fruit grapefruit. This particular fruit  blocks the liver's enzyme responsible for drug metabolism (cytochrome P450). It is common knowledge that with some medications grapefruit should be avoided. Check with your cancer care specialist about which drugs this affects.

Beetroot contains polyphenols called anthocyanin’s. These polyphenols are also found in black currants, dark olives, figs, deep red plums, blueberries, blackberries, and red vegetables like aubergines and red onions. They have been seen to protect the DNA, reduce the rate of cell growth, have anti-oestrogen activity and stimulate the immune system. According to research carried out by Ohio State University they can inhibit cancer enzymes and can directly kill cancer cells. Eating purple foods slowed the rate of growth of colon cancer and actually killed up to 20% of cancer cells.

Dark Chocolate!! Yes – chocolate contains an abundance of polyphenols called catechins proanthocyanidins. A small square of dark chocolate has twice the polyphenol content of a glass of red wine and about as much as a cup of green tea. These polyphenols have been shown by scientists to slow the development of certain cancers and may cause a sharp drop in levels of EGFR, a receptor essential for angiogenesis (when a cancer cell grows its own blood supply for nourishment).

This list could go on and on but these few examples explain the huge benefits that eating a good mixed natural diet,high in colourful fruits and vegetables, and rich in polyphenols, could possibly have.

Any recipe that is high in fruits and or vegetables will be rich in polyphenols. Here is one that you might like to try:

Barley Risotto with beetroot and peas. (taken from the book The Royal Marsden Cancer Cookery Book). Serves 4

500g of fresh beetroot peeled and diced (you can skip this step and buy the ready vacuumed beetroot)
25g of butter
1 onion finely diced
2 cloves garlic crushed

250g of pearl barley
100 ml  water
2 pts of vegetable or chicken stock
200g of frozen peas

1. If using fresh beetroot put it into a pan and cover with water and bring to the boil. Reduce to a simmer and cook for 15mins till soft.
2. Melt the butter in a large pan and fry the onion and garlic on a low heat until soft. Add the pearl barley and cook for a few minutes to coat the grains in the butter. Add the water. Turn up to a medium heat and allow the water to reduce.
3. When the beetroot is tender, blitz in a food processor and mix with the stock. Add this a ladle full at a time to the pearl barley in the pan, allowing the barley to absorb the liquid before adding more. Repeat this until the pearl barley is swollen soft and a bit sticky (about 30mins)
4. Toss in the frozen peas and cook for a few minutes. Season and serve.

If you try this I hope that you enjoy the results.


If you are interested in knowing more about polyphenols then the book called Foods that Fight Cancer by Professor Richard Beliveau and Dr Denis Gingrass may be worth a read. It is an easy to read, colourful book which is well illustrated.

Foods to Fight Cancer: What to Eat to Reduce your Risk Paperback – (Mar 2017)
by Richard Béliveau  (Author), Denis Gingras  (Author) 

Blog originally written by Caroline June 2015 – links updated April 2020

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