Introduction 

Polyphenols are a group of naturally occurring compounds found in plants that are gaining increasing attention for their wide-ranging health benefits. Known primarily for their antioxidant and anti-inflammatory properties, polyphenols are also linked to protecting against cancer, heart disease, and neurodegenerative disorders, and improving the gut microbiome health. These plant compounds are abundant in many healthy foods and drinks, including fruits, vegetables, dark chocolate, cacao, tea, red wine, and spices, which makes them easy to incorporate into your diet. In this blog post, we will explore what polyphenols are and why they are so important for your health. 

What Are Polyphenols and Why Should You Eat Them?

Polyphenols are plant-based bioactive compounds that are naturally produced by plants to protect themselves against UV radiation, pathogens, and stress. These compounds also play a significant role in the human diet by providing a variety of health benefits.  

There are over 8000 different polyphenols, and they are classified into two categories: 

Flavonoids – Compounds that are known for their antioxidant and anti-inflammatory effects. 

Some foods that contain them include… 

• purple sweet potatoes 

• berries 

• red onions 

• Cocoa and dark chocolate 

• tea 

Non-flavonoid polyphenols –  

Such as phenolic acids, stilbenes, and lignans which are found in… (among other things) 

• coffee 

• cereal grains 

• berries 

• resveratrol in red grapes 

• flaxseeds and sesame seeds  

Polyphenols also support cellular health and have been linked to disease prevention and improvement beyond cancer and cardiovascular health, such as diabetes by influencing multiple aspects of glucose metabolism.  

Polyphenols and Human Diets: Essential or Optional?

Certain diets, such as strict carnivore diets, contain little to no polyphenols because they exclude plant-based foods, which are the primary sources of these compounds. Polyphenols are not considered essential nutrients like vitamins or minerals, which are compounds the body cannot function without. However, research suggests that a lack of polyphenols in the diet may lead to reduced protection against oxidative stress, chronic inflammation, and diseases such as cardiovascular issues or neurodegeneration over time. While not strictly necessary for survival, polyphenols contribute significantly to optimizing long-term health and wellness. 

Theoretical Dosing Suggestions for Polyphenol-Rich Foods (ChatGPT info and sources)

1. General Polyphenol Intake Recommendations:
   Studies suggest that an average daily intake of 500–1000 mg of polyphenols is associated with optimal health outcomes, such as reduced oxidative stress and improved cardiovascular health (Frontiers in Nutrition, 2024). This can be achieved by consuming a variety of fruits, vegetables, nuts, and beverages like tea or coffee. 
2. Polyphenol-Rich Beverages:
   Green tea and coffee, consumed in moderate amounts (1–2 cups daily), contribute significantly to daily polyphenol intake. A study on athletes found that regular intake of green tea enhanced cognitive and physical performance, highlighting its benefit in active populations (Frontiers in Sports and Active Living, 2024). 
3. Role of Spices:
   Incorporating spices such as turmeric and cinnamon in small amounts (e.g., 1 teaspoon daily) is linked to anti-inflammatory benefits. Research indicates that curcumin, the active polyphenol in turmeric, supports immune health and reduces inflammation-related risks. 
4. Cooking Methods Matter:
   Heat-sensitive polyphenols can degrade during high-temperature cooking. Gentle methods like steaming or light roasting preserve more of these beneficial compounds (Journal of Education and Health Sciences, 2024). 
5. Moderation with Alcohol:
   While red wine is a popular source of resveratrol, excessive consumption negates its benefits and poses health risks. Recommendations limit intake to one glass daily for women and two for men to balance benefits and risks (Alcohol and Cardiometabolic Health, 2024). 
6. Iron Absorption and Polyphenols:
   Studies confirm that polyphenols can inhibit non-heme iron absorption from plant-based foods. Avoid pairing tea or coffee with meals rich in plant-derived iron to prevent deficiency risks (Journal of Education and Health Sciences, 2024). 
7. Supplementation Caution:
   High doses of polyphenol supplements can act as pro-oxidants, leading to adverse effects like oxidative stress. Whole-food sources are generally safer and more bioavailable (Frontiers in Nutrition, 2024). 

Top Polyphenol Benefits 

Anti-Cancer Properties

Polyphenols have been extensively studied for their anti-cancer effects. These compounds exhibit potent anti-cancer activity through various mechanisms: 

• Inhibition of cancer cell proliferation: Polyphenols, such as those found in green tea (epigallocatechin gallate or EGCG) and berries (anthocyanins), have been shown to slow down the growth of cancer cells. (1) 

• Induction of apoptosis: Some polyphenols promote apoptosis, or programmed cell death, in abnormal cells, which can prevent cancer cells from surviving and spreading. 

• Inhibition of metastasis: Polyphenols may reduce the ability of cancer cells to spread to other parts of the body by affecting the enzymes that enable metastatic behavior. (1) 

Foods like grapes, berries, and turmeric (rich in curcumin) are especially noted for their cancer-fighting properties. 

Anti-Inflammatory Effects

Chronic inflammation is at the root of many diseases, including heart disease, diabetes, and autoimmune disorders. Polyphenols help reduce inflammation by: 

• Immune System Modulation: Polyphenols can influence the immune system by regulating immune cell populations and reducing pro-inflammatory signals. For example, green tea polyphenols (EGCG) increase beneficial regulatory T cells (Treg), which help maintain immune balance, and reduce pro-inflammatory Th1 and Th17 cells, among other cells. (2) 

• Blocking Inflammatory Pathways: Key polyphenols like resveratrol (in red wine and nuts) and curcumin (in turmeric) inhibit inflammatory enzymes (e.g., COX-2, LOX) and suppress the production of cytokines like TNF-α and IL-6. These actions reduce inflammation at the cellular level, offering benefits for conditions like cardiovascular disease and chronic inflammation. (2) 

• Reducing oxidative stress: By neutralizing free radicals, polyphenols help reduce and prevent oxidative stress, a key driver of inflammation. (2) 

Foods rich in flavonoids (like apples and onions) and phenolic acids (found in coffee and whole grains) have been shown to significantly lower markers of inflammation, thus helping to manage chronic inflammatory conditions.  

Neuroprotective Effects

The brain benefits greatly from the neuroprotective effects of polyphenols. Studies show that polyphenols: 

• Protect against neurodegenerative diseases: Polyphenols such as resveratrol (found in grapes, red wine, etc.) and curcumin (from turmeric) may reduce the risk of Alzheimer’s and Parkinson’s by protecting neurons from damage and promoting neural repair. 

• Boost cognitive function and lower dementia risk: Polyphenols have been linked to a reduced likelihood of developing dementia, enhanced cognitive performance during normal aging, and better cognitive progression (3). 

Research indicates that polyphenols’ anti-inflammatory and antioxidant properties play a key role in preserving brain function and protecting against the loss of neurons in age-related diseases. 

Antioxidant Activity

One of the most well-known benefits of polyphenols is their powerful antioxidant activity. Polyphenols neutralize harmful free radicals in the body, which are byproducts of metabolism and environmental factors like pollution and UV radiation. Excessive free radical damage can accelerate aging and contribute to diseases like cancer, heart disease, and diabetes. 

• Supporting the body’s own antioxidant defenses: Polyphenols also enhance the production of the body’s natural antioxidants, like glutathione and superoxide dismutase, helping to maintain a healthy balance. 

• Polyphenols, with their powerful antioxidant properties stemming from hydroxyl groups in their structures, effectively neutralize reactive oxygen species (ROS) and help combat diseases and pathological conditions caused by oxidative stress. (4) 

Eating polyphenol-rich foods such as dark chocolate, green tea, and berries can provide a constant supply of antioxidants, supporting long-term health. 

Improved Gut Health 

Polyphenols also support a healthy gut microbiome, which is crucial for digestion, immune function, and overall well-being. Research suggests that: 

• Promoting beneficial gut bacteria: Polyphenols act as prebiotics, stimulating the growth of beneficial bacteria like Bifidobacterium and Lactobacillus, which are essential for a healthy gut. (5) 

• Improving gut barrier function: Polyphenols help maintain the integrity of the gut lining, preventing harmful pathogens and toxins from entering the bloodstream. 

A healthy gut microbiome is linked to a reduced risk of inflammatory bowel diseases (IBD), digestive issues, and even mood disorders, as the gut and brain are closely connected through the gut-brain axis. 

Heart Health and Blood Sugar Regulation

Beyond their antioxidant and anti-inflammatory effects, polyphenols also support heart health by: 

• Lowering blood pressure: Polyphenols, particularly those in dark chocolate and grapes, have been shown to improve blood vessel function and reduce blood pressure. (6) 

• Regulating blood sugar: Polyphenols from berries and green tea may improve insulin sensitivity and help regulate blood sugar levels, reducing the risk of type 2 diabetes. (7) 

By improving cholesterol levels, reducing inflammation, and enhancing endothelial function, polyphenols are a key player in cardiovascular health. 

Are Polyphenols Always Safe? Understanding Their Potential Toxic Effects 

Polyphenols are celebrated for their health benefits, but like many things, moderation is key. Excessive consumption or unique individual circumstances can lead to adverse effects. For example, in high doses, polyphenols may act as pro-oxidants, causing oxidative stress instead of preventing it. They can also interfere with iron absorption, increasing the risk of deficiency (8), particularly in vulnerable groups like vegetarians or pregnant women. Certain polyphenols may interact with medications by altering drug metabolism, while others, such as isoflavones, can disrupt hormonal balance. Additionally, consuming polyphenols in concentrated supplement forms increases the risk of side effects like gastrointestinal issues, allergic reactions, or toxicity. While polyphenols are not inherently harmful, responsible consumption ensures you gain their health benefits without the risks. 

Conclusion – Embrace Polyphenols for Better Health 

Polyphenols are powerful compounds that offer a wide range of health benefits. From their anti-cancer and anti-inflammatory properties to their ability to support brain health and gut function, polyphenols are essential for maintaining overall well-being. To maximize these benefits, aim to include a variety of polyphenol-rich foods in your diet, such as fruits, vegetables, tea, coffee, nuts, seeds, dark chocolate, and hot cocoa (we recommend sugar free KetoSpike cacao).  

By adding more polyphenol-rich foods to your plate, you’re giving your body the tools it needs to fight inflammation, oxidative stress, and chronic disease. So, whether you’re sipping a cup of green tea, enjoying a bowl of berries, or savoring a piece of dark chocolate, you’re boosting your health with every bite. 

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References

1. Stoner, G. D., & Wang, L. S. (2019). The role of polyphenols in cancer prevention. Journal of Nutritional Biochemistry, 66, 18–27. http://doi.org/10.1016/j.jnutbio.2018.12.004 
2. Yahfoufi, N., Alsadi, N., Jambi, M., & Matar, C. (2018). The Immunomodulatory and Anti-Inflammatory Role of Polyphenols. Nutrients, 10(11), 1618. https://doi.org/10.3390/nu10111618 
3. Vauzour, D. (2012). Dietary Polyphenols as Modulators of Brain Functions: Biological Actions and Molecular Mechanisms Underpinning Their Beneficial Effects. Oxidative Medicine and Cellular Longevity, 2012, 1–16. https://doi.org/10.1155/2012/914273 
4. Rudrapal, M., Khairnar, S. J., Khan, J., Dukhyil, A. B., Ansari, M. A., Alomary, M. N., Alshabrmi, F. M., Palai, S., Deb, P. K., & Devi, R. (2022). Dietary Polyphenols and Their Role in Oxidative Stress-Induced Human Diseases: Insights Into Protective Effects, Antioxidant Potentials and Mechanism(s) of Action. Frontiers in Pharmacology, 13(1). https://doi.org/10.3389/fphar.2022.806470  
5. Singh, R. K., Chang, H. W., Yan, D., et al. (2017). Influence of diet on the gut microbiome and implications for human health. Journal of Translational Medicine, 15, 73. http://doi.org/10.1186/s12967-017-1175-y 
6. Iqbal, I., Polrat Wilairatana, Saqib, F., Nasir, B., Wahid, M., Muhammad Farhaj Latif, Iqbal, A., Naz, R., & Mubarak, M. S. (2023). Plant Polyphenols and Their Potential Benefits on Cardiovascular Health: A Review. Molecules, 28(17), 6403–6403. https://doi.org/10.3390/molecules28176403 
7. Aryaeian, N., Khorshidi Sedehi, S., & Arablou, T. (2017). Polyphenols and their effects on diabetes management: A review. Medical Journal of the Islamic Republic of Iran, 31(1), 886–892. https://doi.org/10.14196/mjiri.31.134 
8. Speer, H., D’Cunha, N. M., Botek, M., McKune, A. J., Sergi, D., Georgousopoulou, E., Mellor, D. D., & Naumovski, N. (2019). The Effects of Dietary Polyphenols on Circulating Cardiovascular Disease Biomarkers and Iron Status: A Systematic Review. Nutrition and Metabolic Insights, 12, 117863881988273. https://doi.org/10.1177/1178638819882739  

 

Image 1: https://www.laboratoiresactiva.com/en/the-power-of-polyphenols/ 

Image 2:  https://www.sciencedirect.com/science/article/pii/S0963996921000880 

Image 3: https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2022.806470/full 

 

Written by: Vivian Silva-Dallenbach