Polyphenol-Rich Foods to Eat Daily
Polyphenols, the micronutrients found in various plants, are undoubtedly one of the bet most essential dietary components to a healthy diet. While I dislike the term “super food,” polyphenols are admittedly just that. They are well studied for their role in positive health outcomes. Long term epidemiological studies have shown that populations who consume the most dietary polyphenols, experience lower rates of common chronic diseases like heart disease and cancer. Individual polyphenols have also been studied to better understand their mechanisms of action in the body.
To recap from a prior post, polyphenols are important dietary components for those with chronic conditions like fibromyalgia and chronic fatigue syndrome for several reasons:
Polyphenols are potent antioxidants. They don’t simply quench free radicals but also inhibit the enzymes that produces free radicals. They also bind metals like iron to buffer them from causing undue oxidative stress.
Polyphenols are natural anti-inflammatories. They block enzymes related to inflammatory pathways, including COX and LOX. COX and LOX are target enzymes of popular anti-inflammatory drugs like ibuprofen. Not only do polyphenols block these enzymes, they also bock the release of arachidonic acid—the molecule that sets these enzymes in motion.
Polyphenols are anti-inflammatory in their ability to block one of the master regulators of inflammatory pathways, NF-κB. This effect is not only in the body, but also in the brain.
Polyphenols boost the body’s natural defense against oxidative stress. Dietary polyphenols stimulate the master regulator of protection, Nrf2, which pushes for the release of the body’s own antioxidant (glutathione) and protective genes.
Many polyphenols can cross the blood-brain barrier and can be found at physiologically relevant concentrations to exert effects. At the brain, they may exert their antioxidant and anti-inflammatory effects on key brain cells (microglia) that promote neuroinflammation. This makes them viable options to reduce brain fog.
Numerous polyphenols have been studied for their ability to improve endothelial function. That is, they improve the tone and permeability of blood vessels to improve blood flow.
Polyphenols exert profound effects on the gut micro-environment. Gut bacteria help metabolize dietary polyphenols and in turn, produce important short-chain fatty acids that modulate the immune system in the gut. There is also some preliminary evidence that polyphenols can improve intestinal permeability, strengthening a “leaky gut.”
With over 10 years of experience creating nutrition plans for patients, I invite you to create your own personalized nutrition plan with me.
If those aren’t enough reasons to consume polyphenols every day, I don’t know what is! As I often say, nutrition is a long-game for those with chronic illnesses. While it is unlikely a single nutrient or food will dramatically change your chronic condition, continual focus on nutrition specific to your condition can in the long run stabilize the condition and provide more health resilience. Take care to consume foods and beverages rich in polyphenols daily. Here are my top picks based on the research. Consume these 4 daily.
Dark Chocolate
Yes, chocolate. Cocoa is a polyphenol that no one should feel guilty about. In a study of older adult brains, consumption of a flavanol-rich cocoa for just 2 weeks improved cerebral blood flow.
Cocoa polyphenols have even been studied in chronic fatigue syndrome. A small (n=10) double-blind, randomized (not a bad design!) trial gave patients either a high cocoa liquor/polyphenol rich chocolate or a zero cocoa/polyphenol low chocolate drink. After 8 weeks, the intervention group self-reported functional benefit and improved symptoms. Most surprisingly, when the group was switched and given the zero cocoa drink, the benefits were no longer reported.
Last example. A trial of 5 days of 150mg of cocoa flavanols in healthy adults was given a cognitive test and administered a fMRI. This showed improvement in the cognitive task as seen by a bolder fMRI image, suggestive of improved cerebral blood flow.
Tea
Tea is one of the oldest beverages known to man. Tea extracts have been studied in HIV and the virus that leads to SARS—coronavirus. In these studies, the active component in tea, theaflavin, was able to inhibit proteins essential for the virus replicating. Black tea polyphenols are reported to be helpful in mineral absorption in the gut and are therefore related to improved bone mineral density.
Green tea is also well-studied. Its main polyphenol, epigallocatechin gallate (EGCG), is of great interest for cardiovascular health and cancer prevention. However, a meta-analysis of human trials showed that it also has positive effects on anxiety, working memory, and cognition. A cup a day may keep brain fog at bay.
A word of caution. Too much EGCG has been shown to cause mild, reversible liver damage in genetically susceptible individuals. If any EGCG-containing beverage or supplement causes darkening of the urine, it should be immediately discontinued to protect liver function.
Also know that other varieties of tea contain polyphenols, including the naturally caffeine-free rooibos. And it goes without saying, that the addition of copious amounts of sugar and industrial processing reduces the positive benefit of polyphenols found in tea or any other food/beverage.
Broccoli
Regular readers of my blog will know that I’m an avid broccoli lover. Its prime polyphenol is sulforaphane (SFN). Read all about this important compound in a prior post.
To reiterate, a clinical trial of 81 diabetic patients, given a 10g supplement of SFH daily for 4 weeks produced 9% reduction in markers of oxidative stress and a 16% increase in total antioxidant capacity. In another, men fed Brussels sprouts or cabbage (other sources of SFN) in quantities of about 200g daily showed elevated levels of glutathione after just 6 days.
Blueberries
Blueberries are high in anthocyanidin. This polyphenol has been extensively studied mechanistically in animal models. Here, it has been shown to increase neuronal signaling in specific brain centers, influence memory function, and improve glucose disposal to improve brain metabolism.
A 12-week intervention trial of blueberry juice in older adults showed significant improvement in memory function. In a randomized, double-blind, placebo-controlled trial of older adults were given a blueberry supplement for 16 weeks. They were given a cognitive task and administered fMRI, the blueberry-treated group showed enhanced neural response—a sign of neurocognitive benefit.
Last one. A 3-month intervention study of aged individuals given a 100mg blueberry extract, showed improved episodic memory performance and reduced cardiovascular risk factors.
A Word on Polyphenol Supplements
Getting a diverse range of polyphenols from natural foods is the best option. Remember that there are over 8,000 discovered polyphenols! Not just the few mentioned here. Natural foods also contain other food matrix components like fiber and phytonutrients. Nonetheless, therapeutic supplementation may be a viable option for those with chronic conditions like fibromyalgia and chronic fatigue syndrome. When dosed correctly and taken in bioavailable forms, supplemental polyphenols may further reduce inflammatory burden and have positive impacts on the gut microbiome.
In addition to those above, other popular (well-studied) polyphenol supplements include curcumin, resveratrol, quercetin, and baicalin (skull cap). Some of my favorite supplements that include a combination of these polyphenols include Th1 Support and Balanced Immune—both from Pure Encapsulations. Find these and others in the FullScript store.
References
Vauzour, D. (2012) Dietary Polyphenols as Modulators of Brain Functions: Biological Actions and Molecular Mechanisms Underpinning Their Beneficial Effects. Oxid Med Cell Longev. 914273.
Sharma V & Rao LJ. (2009) A thought on the biological activities of black tea. Crit Rev Food Sci Nutr. 49(5):379-404.
Mancini E. et al (2017) Green tea effects on cognition, mood and human brain function: A systematic review. Phytomedicine. 34:26-37.
Ma L. et al (2018) Molecular Mechanism and Health Role of Functional Ingredients in Blueberry for Chronic Disease in Human Beings. Int J Mol Sci. 19(9).
