QuercetinKey Food Groups: Berries, Leafy Greens, Tea
Quercetin: Role in Brain Health
Quercetin is one of the most well-studied flavonols (a class of plant-based nutrients) with a wealth of information on the neuroprotective roles it plays. These include anti-oxidative roles and additional strengths, such as anti-inflammatory promotion and metabolic balance. Quercetin directly collects and neutralizes reactive oxygen species, which are unwanted and harmful by-products created from metabolic reactions.1
Accumulation of neurotoxic proteins like beta-amyloid are one of the many mechanisms implicated in the progression of Alzheimer’s Disease.2 Quercetin has not only been shown to lower the amount of beta-amyloid that builds up in neurons, but studies also report it decreases adverse neuroinflammatory signals released from astrocytes (a type of neuronal support cell), another of the mechanisms implicated in neurodegeneration.1
Energy balance and metabolic regulation can also be tied to the influence of quercetin due to it increasing the activity of a specific metabolic receptor in the brain, whose activity has been linked to reduced risk of Alzheimer’s disease and Parkinson’s disease.3,4 Without quercetin, your brain health could be susceptible to decline.
Intake Deficiency and Relevance
Quercetin is plant-derived, especially found in fruits, teas, onions, and green leafy foods, which unfortunately Americans do not consume enough of. Based on the US Dietary Guidelines, there is a deficiency in fruits that affects up to 50% of people and a deficiency in leafy green vegetables that affects up to 90% of people.5 This is concerning, since prospective observational studies have reported a significant association between quercetin intake and a reduction in beta amyloid concentration in the brain, as well as trends between quercetin intake and reduced cognitive decline and incident Alzheimer’s Disease.6
RELEVATE’s Form of Quercetin
We chose our form of quercetin to be high-purity (for efficiency of dosing) and for its synergistic (mutually amplifying) effect with our other nutrients. Purity and consistency are important, since the content of flavonols in food can be affected by seasonal variation, light conditions, climate, degree of ripeness.7,8
Concluding Thoughts to Consider
Studies show that quercetin distributes in many tissues in the body, including the brain. Also, research is showing that quercetin works together with many other nutrients to amplify their effects (synergies). For example, quercetin intake when given in combination with fish oil shows an enhanced neuroprotective outcome compared to quercetin being given independently.9,10 Quercetin also shows synergy with other nutrients found in RELEVATE, namely kaempferol and pterostilbene, which significantly reduced the number inflammatory markers.11 Finally, studies suggest that when taken in combination with alpha-tocopherol (vitamin E), the amount of quercetin in the brain was larger than when it was administered by itself.12 Also, evidence continues to build that indicates quercetin may be neuroprotective in humans.13,14 Clinical and observational research are showing reduced cognitive decline, reduced risk of developing Alzheimer’s disease, and significantly reduced amyloid burden, as well as supporting its safety in supplements.15,16 This provides solid support for quercetin as a nutrient worth boosting for a brain healthy regimen, especially given its broad presence in fruits and vegetables.Return to RELEVATE BENEFITS
- Costa, L. G., Garrick, J. M., Roquè, P. J. & Pellacani, C. Mechanisms of Neuroprotection by Quercetin: Counteracting Oxidative Stress and More. Oxid. Med. Cell. Longev. (2016). doi:10.1155/2016/2986796
- Maria, S. A. et al. The flavonoid quercetin ameliorates Alzheimer’s disease pathology and protects cognitive and emotional function in aged triple transgenic Alzheimer’s disease model mice. Neuropharmacology 93, 134–145 (2015).
- Tyagi, S., Gupta, P., Saini, A., Kaushal, C. & Sharma, S. The peroxisome proliferator-activated receptor: A family of nuclear receptors role in various diseases. J. Adv. Pharm. Technol. Res. 2, 236–240 (2011).
- Lee, S. M., Moon, J., Cho, Y., Chung, J. H. & Shin, M. J. Quercetin up-regulates expressions of peroxisome proliferator-activated receptor γ, liver X receptor α, and ATP binding cassette transporter A1 genes and increases cholesterol efflux in human macrophage cell line. Nutr. Res. 33, 136–143 (2013).
- Moore, L. V & Thompson, F. E. Adults Meeting Fruit and Vegetable Intake Recommendations – United States, 2013. MMWR. Morbidity and mortality weekly report 64, (U.S. Centers for Disease Control, 2015).
- Holland, T. M. et al. Dietary flavonols and risk of Alzheimer dementia. Neurology 94, e1749–e1756 (2020).
- Mageney, V., Neugart, S. & Albach, C. D. A Guide to the Variability of Flavonoids in Brassica oleracea. Molecules 22, (2017).
- Aherne, S. A. & O’Brien, N. M. Dietary flavonols: chemistry, food content, and metabolism. Nutrition 18, 75–81 (2002).
- Denny Joseph, K. M. & Muralidhara. Combined Oral Supplementation of Fish Oil and Quercetin Enhances Neuroprotection in a Chronic Rotenone Rat Model: Relevance to Parkinson’s Disease. Neurochem. Res. 40, 894–905 (2015).
- Denny Joseph, K. M. & Muralidhara. Enhanced neuroprotective effect of fish oil in combination with quercetin against 3‐nitropropionic acid induced oxidative stress in rat brain. Prog. Neuro-Psychopharmacology Biol. Psychiatry 40, 83–92 (2013).
- García-Mediavilla, V. et al. The anti-inflammatory flavones quercetin and kaempferol cause inhibition of inducible nitric oxide synthase, cyclooxygenase-2 and reactive C-protein, and down-regulation of the nuclear factor kappaB pathway in Chang Liver cells. Eur. J. Pharmacol. 557, 221–229 (2007).
- Ferri, P. et al. Enhancement of flavonoid ability to cross the blood-brain barrier of rats by co-administration with alpha-tocopherol. Food Funct. 6, 394–400 (2015).
- Nishimura, M. et al. A randomized, double-blind, placebo-controlled study evaluating the effects of quercetin-rich onions on cognitive function in elderly subjects. Functional Foods in Health and Disease 7, (2017).
- Nakagawa, T. et al. Improvement of memory recall by quercetin in rodent contextual fear conditioning and human early-stage Alzheimer’s disease patients. Neuroreport 27, 671–676 (2016).
- Ferry, D. R. et al. Phase I clinical trial of the flavonoid quercetin: pharmacokinetics and evidence for in vivo tyrosine kinase inhibition. Clin. Cancer Res. 2, 659 LP – 668 (1996).
- Okamoto, T. Safety of quercetin for clinical application (Review). Int. J. Mol. Med. 16, 275–278 (2005).