The phenolic compounds are a very large group of phytonutrients (plant based chemical compounds that have numerous health benefits in the human body but are not classed as essential nutrients). They can be found in a wide range of fruits, nuts, teas and vegetables and can be broken down further into 8 sub-groups:
– Flavonoids (which include anthocyanins, chalconoids, coumestans, flavanones, flavanonols, flavan-3-ols, flavones, flavonols and isoflavones).
– Hydroxycinnamic Acids (which include caffeic acid, chlorogenic acid, coumarin and ferulic acid).
– Monophenols (which include apiol, carnosol, carvacrol and dilliapiole).
– Lignans (which include enterodiol, enterolactone, lariciresinol, matairesinol, pinoresinol and secoisolariciresinol diglucoside (SDG)).
– Phenolic Acids (which include capsaicin, curcumin, ellagic acid, gallic acid, salicylic acid, tannic acid and vanillin).
– Punicalagins.
– Stilbenoids (which include pterostilbene and resveratrol).
– Tyrosol Esters (which include hydroxytyrosol, oleocanthal, oleuropein and tyrosol).
Although the phenolic compounds are not classed as essential nutrients, they have a wide range of health benefits in the human body. Studies have shown that they can fight dangerous free radicals (harmful compounds that are released into your body’s cells during oxygen related reactions), prevent cancer, prevent diabetes and much more.
In this article I will be providing a full breakdown of the 8 phenolic compounds:
1) FLAVONOIDS
Health Benefits:- The flavonoids are powerful antihistamines (substances that fight histamine and reduce allergic reactions), anti-inflammatories (substances that prevent unnecessary inflammation), antioxidants (substances that protect your body’s cells from free radicals) and phytoestrogens (substances that regulate estrogen levels in the body). In addition to this, they boost your metabolism, keep your blood healthy, keep your skin healthy and support good mental health. Finally, the flavonoids act in a protective capacity and can keep you safe from arthritis (inflammation of the joints), cancer, diabetes and heart disease whilst also protecting your eyes, liver and immune system.
Recommended Daily Allowance (RDA):- There is currently no official RDA for the flavonoids. However, there are a number of unofficial recommendations which should allow you to unlock the various flavonoid health benefits. These are listed in the table below:
| FLAVONOID | UNOFFICIAL RDA |
| Flavanones | Between 10 milligrams (mg) and 100mg of hesperidin. Between 280mg and 420mg of silymarin. |
| Flavanonols | Between 50mg and 1,000mg of taxifolin. |
| Flavan-3-ols | 20mg of epicatechin. 2,000mg of epigallocatechin gallate. 8mg of theaflavin. |
| Flavonols | Between 10mg and 12mg of kaempferol. Between 200mg and 600mg of rutin. Between 200mg and 500mg of quercetin. |
| Isoflavones | Between 50mg and 100mg of isoflavones. |
Food Sources:- The flavonoids can be sourced from a wide range of foods. The table below breaks down the richest food sources by type:
| FLAVONOID | BEST FOOD SOURCES PER 100 GRAMS (G) |
| Anthocyanins | Blueberries = 16.97mg of cyanidin, 47.4mg of delphinidin, 61.53mg of malvidin, 23.49mg of peonidin, 26.42mg of petunidin. |
| Chalconoids | Ashitaba, eucalyptus, liquorice plants. |
| Coumestans | Green peas = 6.25mg of coumestrol. |
| Flavanones | Oranges = 6.25mg of flavanones. |
| Flavanonols | Milk thistle, red onions. |
| Flavan-3-ols | Green tea = 2.55mg of catechin, 8.29mg of epicatechin, 77.81mg of epigallocatechin gallate, 20.95mg of epicatechin gallate,1.03mg of theaflavin. |
| Flavones | Parsley = 225.93mg of apigenin. |
| Flavonols | Cranberries = 6.78mg of myricetin, 14.02mg of quercetin. |
| Isoflavones | Green Soybeans = 67.79mg of daidzein, 72.51mg of genistein. |
Deficiency Symptoms:- The flavonoids are not classed as essential nutrients so most of them have no reported deficiency symptoms. However, failing to consume at least 10mg of the flavanone hesperidin each day has been linked with abnormal capillary bleeding, leg cramps, pain in the extremities and weakness. Dr Norman Hollenberg has also suggested that being deficient in the flavan-3-ol epicatechin may cause cancer, diabetes, heart failure and stroke.
Overdose Symptoms:- Consuming too much of the flavan-3-ols can negate their antioxidant and cancer fighting properties. Additionally, overdosing on the flavones can inhibit their cancer fighting abilities, cause gastric hypersecretion (excessive formation of gastic juices), cause nausea and cause vomiting. Eating too many flavonols can also lead to confusion, diarrhea, dizziness, fatigue, headaches, irregular heartbeats, interference with other medications, rapid heartbeats, kidney damage and stomach upsets.
Health Benefits:- The hydroxycinnamic acids are powerful anti-inflammatories and antioxidants. In addition to this, they keep your blood and heart healthy by preventing atherosclerosis (a condition where hard plaques block your artery walls, restrict the flow of blood and increase your heart disease risk) and reducing blood levels of low density lipoprotein (LDL) cholesterol. Finally, they can lower body fat levels, prevent cancer and prevent diabetes.
RDA:- There is currently no official RDA for the hydroxycinnamic acids. However, a number of sources suggest that consuming between 100mg and 500mg of caffeic acid and between 60mg and 185mg of chlorogenic acid each day will allow you to enjoy their various health benefits.
Food Sources:- Coffee is the richest food source of hydroxycinnamic acids with a 100 millilitre serving giving you between 18mg and 88mg of caffeic acid and between 35mg and 175mg of chlorogenic acid.
Deficiency Symptoms:- The hydroxycinnamic acids are not classed as essential nutrients so have no reported deficiency symptoms associated with their consumption.
Overdose Symptoms:- Consuming too much artificial coumarin (a hydroxycinnamic acid that is added to certain foods and other products (such as perfume)) can lead to bruising, excessive bleeding, kidney damage, liver damage and lung cancer. In addition to this, drinking too much coffee (the main source of hydroxycinnamic acids) can lead to caffeine overdose. Consuming between 3 and 7 cups of coffee each day can cause mild overdose symptoms which include excitement, increased heartbeats, increased urination, muscle twitching, nervousness, restlessness, thirst and sleeping difficulties whilst drinking 8 or more cups of coffee each day can lead to serious caffeine overdose symptoms such as confusion, convulsions, disorientation and loss of consciousness.
3) MONOPHENOLS
Health Benefits:- The monophenols act as antioxidants, fight cancer, relieve pain, treat disease and treat menstrual problems.
RDA:- There is currently no official RDA for the monophenols.
Food Sources:- The monophenols are mainly found in herbs such as dill, oregano, parsley and rosemary.
Deficiency Symptoms:- The monophenols are not classed as essential nutrients so have no reported deficiency symptoms associated with their consumption.
Overdose Symptoms:- Overdosing on the monophenols is extremely dangerous and can lead to kidney damage, liver damage, problems with iron absorption, skin rashes and vomiting.
4) LIGNANS
Health Benefits:- The lignans are a group of powerful antioxidants. Early studies suggest that they may also act as anti-inflammatories, improve cardiovascular health, prevent cancer, prevent diabetes, prevent male hair loss, prevent osteoporosis (reduced bone mineral density), reduce high blood pressure and more. However, further studies are needed before these potential health benefits can be confirmed.
RDA:- There is currently no official RDA for the lignans but various sources recommend consuming between 25mg and 50mg of these phytonutrients each day.
Food Sources:- Flaxseed is the richest food source of the lignans and contains 301.59mg of these natural nutrient per 100g.
Deficiency Symptoms:- The lignans are not classed as essential nutrients so have no reported deficiency symptoms associated with their consumption.
Overdose Symptoms:- Consuming large amounts of lignans is not believed to be dangerous. However, pregnant women and people suffering from cancer are advised to check with their doctor before eating these natural nutrients. In addition to this, eating too much flaxseed (the main food source of lignans) can lead to gastrointestinal (GI) blockages and increase the risk of bleeding in people with blood disorders.
Health Benefits:- The phenolic acids are potent antibacterials (substances that kill or slow down the growth of harmful bacteria), antihistamines, anti-inflammatories, antimutagenics (substances that prevent genetic mutations), antioxidants and antitoxics (substances that fight harmful toxins in the body). In addition to this, they can boost the health of your blood, nervous system and skin. Finally, they can prevent arthritis, prevent cancer, prevent diabetes, protect the sinuses, relieve pain and soothe the stomach.
RDA:- There is currently no official RDA for the phenolic acids. However, certain sources suggest you should try to consume between 100mg and 8,000mg of the curcumin each day to activate its health benefits.
Food Sources:- The phenolic acids can be found in a wide range of fruits, nuts and vegetables. The table below highlights some of the top food sources:
| PHENOLIC ACID | BEST FOOD SOURCES PER 100 (G) |
| Capsaicin | Trinidad Scorpion Butch T Pepper. |
| Curcumin | Turmeric = 5g. |
| Ellagic Acid | Red Raspberries = 1.5mg. |
| Gallic Acid | Walnuts = 1,625mg. |
| Salicylic Acid | Turmeric. |
| Tannic Acid | Grapes. |
| Vanillin | Vanilla Beans = 2g. |
Deficiency Symptoms:- The phenolic acids are not classed as essential nutrients so have no reported deficiency symptoms associated with their consumption.
Overdose Symptoms:- Eating high levels of phenolic acids can lead to blisters, breathing difficulties, burning sensations in the mouth, convulsions, diarrhea, gallstones (small, hard stones in the gallbladder), heartburn, interference with other medications, kidney damage, liver damage, migraines, nausea, problems absorbing certain nutrients, skin irritation and stomach problems.
6) PUNICALAGINS
Health Benefits:- The punicalagins are powerful antioxidants. Provisional research suggests that they may also act as antibacterials, act as antifungals (substances that treat fungal infections), protect against ultraviolet (UV) damage, reduce blood levels of LDL cholesterol and stimulate the regeneration of skin cells. In addition to this, they may prevent atherosclerosis, cancer, diabetes, gingivitis (inflammation of the gums) and heart disease. However, additional evidence is needed before these possible health benefits can be confirmed.
RDA:- There is currently no official RDA for the punicalagins. However, various sources indicate that consuming between 300mg and 600mg of these natural nutrients each day will allow you to enjoy their health benefits.
Food Sources:- Punicalagins can only be naturally sourced from pomegranate seeds and pomegranate juice. However, it is not known exactly how much they contain.
Deficiency Symptoms:- The punicalagins are not classed as essential nutrients so have no reported deficiency symptoms associated with their consumption.
Overdose Symptoms:- There are no reported overdose symptoms associated with punicalagin consumption.
7) STILBENOIDS
Health Benefits:- The stilbenoids are impressive antioxidants. Early evidence indicates that they may also act as anti-inflammatories, act as antitoxics, protect you from mental disorders, increase your life expectancy and keep your blood healthy. In addition to this, they may also keep your kidneys healthy, keep your liver healthy, fight cancer, fight diabetes, prevent heart disease and keep your skin cells safe from UV rays. However, further studies are needed before these promising health benefits can be confirmed.
RDA:- There is currently no official RDA for the stilbenoids. However, a number of sources suggest that taking a daily dose of between 50mg and 150mg of pterostilbene and between 20mg and 40mg of resveratrol will give you access to their health benefits.
Food Sources:- Grapes are an excellent source of the stilbenoids with red grapes containing between 0.15mg and 0.78mg of resveratrol.
Deficiency Symptoms:- The stilbenoids are not classed as essential nutrients so have no reported deficiency symptoms associated with their consumption.
Overdose Symptoms:- There are no reported overdose symptoms associated with natural stilbenoids but some sources indicate that eating high levels of stilbenoid supplements could cause breast cancer and interfere with blood clotting. Therefore, people who are suffering from breast cancer and blood disorders, taking blood clotting medications or have a history of breast cancer in the family should consult their doctor before consuming any stilbenoid supplements. Pregnant women should also avoid these supplements.
Health Benefits:- The tyrosol esters are potent antibacterials, anti-inflammatories and antioxidants. They can also keep your blood healthy and relieve pain. In addition to this, provisional studies indicate the tyrosol esters may be able to protect you from mental disorders, prevent bone loss, prevent kidney disease, prevent cancer, prevent diabetes and prevent heart disease. However, further research is required before these provisional health benefits can be confirmed.
RDA:- There is currently no official RDA for the tyrosol esters. However, some sources suggest consuming 9mg of oleocanthal and 300mg of tyrosol each day will allow you to activate their health benefits.
Food Sources:- Olives and olive oil are the only natural food sources of tyrosol esters with a 100ml of olive oil supplying you with 18mg of oleocanthal.
Deficiency Symptoms:- The tyrosol esters are not classed as essential nutrients so have no reported deficiency symptoms associated with their consumption.
Overdose Symptoms:- There are no reported overdose symptoms associated with the tyrosol esters. However, people who suffer from diabetes or high blood pressure and pregnant women are advised to check with their doctor before consuming tyrosol ester supplements.
PHENOLIC COMPOUNDS SUMMARY
There is quite a lot of information here and it is probably a little overwhelming. However, the main thing I want you to take away from this article is to be aware of the power of plants. In health and fitness circles there is often a lot of focus on eating protein to build muscles or cutting your calories to burn body fat. Unfortunately, there is usually very little focus on the quality of food and the nutrients they contain.
Plant based foods might not help you pack on the muscle but they are a high quality food that are full of phytonutrients (such as the phenolic compounds), vitamins and minerals. They can do wonders for your overall health so make sure you are eating lots of fruits, herbs, nuts, vegetables and teas so that you can take full advantage of the phenolic compounds and their many health benefits.