Quercetin
Quercetin is a flavonoid that has been found to have antioxidant and anti-inflammatory effects1.
When added to myelin, quercetin was observed to diminish free radical production and influence, and most importantly, the destruction of myelin by macrophages (immune cells)2.
In immune cells from MS patients, the addition of quercetin to interferon-beta treatment was found to reduce the generation of errant immune cells and levels of inflammatory cytokines released by those cells, and to inhibit production of a destructive enzyme (MMP-9)3.
In an animal model of MS, quercetin at a dose of 50 or 100 µg every other day was found to limit disease severity and duration by blocking inflammatory cytokine signaling and generation of Th1 autoimmune cells in the brain, and inhibiting inflammation and demyelination in the spinal cord4. At a dose of 10 mg/kg, quercetin reduced disease-related disability by inhibiting myeloperoxidase activity and inducible nitric oxide (iNOS) levels and lipid peroxidation in the brain tissues5.
Quercetin has been found in breastmilk of mothers consuming quercetin-rich foods, remaining for several days6.
In nursing mice, maternal intake of quercetin 50-200 mg/kg/day was associated with protection against oxidative stress7. In human nursing mothers, dietary quercetin was shown to be transferred to breastmilk at a rate of 1%8.
Quercetin is known to cross the placenta and accumulate in the fetus. Animal models of intake during pregnancy have demonstrated a positive influence on development of embryo, fetus, and placenta, with no evidence of teratogenic or abortive effects9. Most of the benefits are cardiometabolic and impact the mother as well, including against gestational obesity and diabetes mellitus, dyslipidemia, and preeclampsia, as well as malnutrition-related conditions10.
An animal study investigating 302 mg/kg feed starting before conception cautioned that while quercetin improves the bioavailability and immediate safety of iron in the fetus, too high an intake – well above that recommended for use in MS – may result in increased systemic inflammation due to increased liver iron in adulthood11.
Quercetin is highest in foods such as apples, honey, raspberries, onions, red grapes, cherries, citrus fruits, and green leafy vegetables1.
References
1.Shankar GM, Antony, J., Anto, R.J. Chapter Two. Quercetin and Tryptanthrin – Two Broad Spectrum Anticancer Agents for Future Chemotherapeutic Interventions. In: Bathaie SZ, Tamanoi, F., ed. The Enzymes. Elsevier; 2015:43-72. vol. Mechanism of the Anticancer Effect of Phytochemicals.
2.Hendriks JJ, Alblas J, van der Pol SM, van Tol EA, Dijkstra CD, de Vries HE. Flavonoids influence monocytic GTPase activity and are protective in experimental allergic encephalitis. J Exp Med. Dec 20 2004;200(12):1667-72. doi:10.1084/jem.20040819
3.Sternberg Z, Chadha K, Lieberman A, et al. Quercetin and interferon-beta modulate immune response(s) in peripheral blood mononuclear cells isolated from multiple sclerosis patients. J Neuroimmunol. Dec 15 2008;205(1-2):142-7. doi:10.1016/j.jneuroim.2008.09.008
4.Muthian G, Bright JJ. Quercetin, a flavonoid phytoestrogen, ameliorates experimental allergic encephalomyelitis by blocking IL-12 signaling through JAK-STAT pathway in T lymphocyte. J Clin Immunol. Sep 2004;24(5):542-52. doi:10.1023/B:JOCI.0000040925.55682.a5
5.Mirzazadeh E, Khezri, S., Abtahi Froushani, S/M. Effects of Quercetin on Improving the Damage Caused by Free Radicals in the Rat Models of Multiple Sclerosis. Iran South Med J. 2019;22(1):1-15.
6.Ginkgo. Drugs and Lactation Database (LactMed(R)). 2006.
7.Liu W, Zhou Y, Qin Y, et al. Quercetin Intervention Alleviates Offspring’s Oxidative Stress, Inflammation, and Tight Junction Damage in the Colon Induced by Maternal Fine Particulate Matter (PM(2.5)) Exposure through the Reduction of Bacteroides. Nutrients. Oct 11 2020;12(10)doi:10.3390/nu12103095
8.Romaszko E, Wiczkowski W, Romaszko J, Honke J, Piskula MK. Exposure of breastfed infants to quercetin after consumption of a single meal rich in quercetin by their mothers. Mol Nutr Food Res. Feb 2014;58(2):221-8. doi:10.1002/mnfr.201200773
9.Ozarowski M, Mikolajczak PL, Kujawski R, et al. Pharmacological Effect of Quercetin in Hypertension and Its Potential Application in Pregnancy-Induced Hypertension: Review of In Vitro, In Vivo, and Clinical Studies. Evid Based Complement Alternat Med. 2018;2018:7421489. doi:10.1155/2018/7421489
10.Costa P, de Souza EL, Lacerda DC, et al. Evidence for Quercetin as a Dietary Supplement for the Treatment of Cardio-Metabolic Diseases in Pregnancy: A Review in Rodent Models. Foods. Sep 8 2022;11(18)doi:10.3390/foods11182772
11.Vanhees K, Godschalk RW, Sanders A, van Waalwijk van Doorn-Khosrovani SB, van Schooten FJ. Maternal quercetin intake during pregnancy results in an adapted iron homeostasis at adulthood. Toxicology. Dec 18 2011;290(2-3):350-8. doi:10.1016/j.tox.2011.10.017