Reduce Allergies Quercetin, Bromelain and Vitamin C:
Allergy-Support and More
James South, M.A.
Quercetin (QRC) is a bright yellow
flavanol widely found throughout the plant kingdom. Flavanols
are one form of the better-known bioflavonoids. QRC occurs in
various common foods, including red and yellow onions, apples,
berries, black tea, broccoli, Italian squash, and some nuts and
seeds.1,2 It is estimated that the average daily human diet
provides about 25 mg QRC.3 QRC is also the "backbone" for many
other flavonoids, including rutin, hesperidin, quercetrin,
isoquercetrin, and hyperoside.1,4 These flavonoids are formed
when a specific sugar molecule (rhamnose, glucose, galactose,
etc.) replaces the OH-group in the center ring of QRC. QRC is
the "superstar" of the flavonoids. As Murray notes: "Quercetin
is consistently the most active of the flavonoids in
experimental studies, and many medicinal plants owe much of
their activity to their high quercetin content."
Quercetin vs. Allergies
Allergies represent an inappropriate immune response to
otherwise harmless substances, such as ragweed pollen, cat
dander, house dust, wheat protein, etc., that get into the body
or on the skin through air, food or water. Some allergies are
mediated through the allergic antibody IgE, while some are not.
What all allergies have in common is the antigen (allergen)
stimulation of two related cell types: mast cells and
basophils.5 Mast cells line the blood vessels in the connective
tissue of the lungs, inner eyelids, gut, ear, nose, throat and
skin.5 Basophils are a type of white blood cell. Both mast cells
and basophils are full of granules of histamine and other
allergic chemical mediators.5 When allergen/antigens in the
blood contact mast cells or basophils in sufficient numbers, a
burst of histamine and other allergic mediators is released into
the bloodstream. It is the histamine and other allergic
mediators that trigger the misery of allergic reaction: runny,
itchy nose and sneezing; watery, itchy red eyes; tickling and
itching in ears, nose and throat; skin rash; headache; asthma,
QRC is a powerful inhibitor of antigen-stimulated histamine
release from basophils and mast cells,5,6,7,8 even at low levels
of QRC (5-50 micromoles, or 1.51-15.1 mcg/ml).6 Unlike most
anti-allergy substances, QRC is highly effective at inhibiting
histamine release during both the first and second stage of
basophil histamine release: "quercetin is unique in exhibiting
activity in both stages."6 Pearce and colleagues also note that
"...quercetin appears to possess a broader spectrum of
[anti-allergy] activity than chromoglycate [the anti-allergy
drug Chromolyn™]...."5 Middleton and coworkers describe QRC as
being "instantaneous in onset of action" and they report that "...
addition of quercetin during early stages of an ongoing
histamine release reaction results in an abrupt cessation of
further histamine release...."6 Thus, QRC can both prevent
allergic reactions and stop those already underway.
The Quercetin-Bromelain Connection
Bromelain is the general name for a group of proteolytic enzymes
derived from pineapple stems.9 Bromelain is a protein-digesting
enzyme that is active at a broad range of pHs, and thus can
digest protein in both the stomach and small intestine.9 When
taken on an empty stomach approximately 40 percent of the
bromelain is absorbed into the bloodstream intact.10 Through its
action on the blood clotting-related substances fibrinogen and
fibrin, bromelain stimulates the production and release of
anti-inflammatory prostaglandins (PGs), while simultaneously
reducing the production and release of proinflammatory PGs.9,10
Allergic reactions typically involve an excess of inflammatory
PGs being released, which contributes to the swelling, redness
and itching. QRC also helps to suppress formation and release of
inflammatory PGs and thromboxanes, as well as the "slow reacting
substance of anaphylaxis," a key trigger of asthma.7
Thus, QRC and bromelain are synergistic in suppressing the
inflammation of allergic reactions, as well as the excessive
inflammation that results from bruising and tissue damage from
sports injuries, accidents, surgery, etc.9
Bromelain also potentiates QRC through another route. By itself,
QRC is somewhat poorly absorbed from the GI tract.3 Bromelain is
well known for its enhancement of absorption of various
compounds, including pentobarbital and antibiotics such as
tetracycline and amoxicillin.9 Bromelain also enhances the
absorption of QRC.4,11
The Quercetin-Vitamin C Connection
Vitamin C, also known as "ascorbate" (ASC), is a natural
antihistamine. It both prevents histamine release and increases
the detoxification of histamine. A 1992 study found that taking
2 grams ASC daily lowered blood histamine levels 38 percent in
healthy adults in just one week. However, a single dose of ASC
failed to lower histamine levels, indicating that the
antihistamine effect of ASC requires regular ongoing use.13
ASC and QRC have a mutual sparing effect on each other. ASC "...inhibits the oxidative degradation of ... quercetin..."8
"Flavonoids such as quercetin... were shown to enhance the
reduction of dehydroascorbic acid [oxidized ASC] by
glutathione,"8 thus recycling "used" ASC. Oxidized QRC is also
reduced (recycled) by ASC back to QRC.8 Thus ASC and QRC are
mutually supporting allergy fighters.
Magnesium ASC is the best form of C in an anti-allergy formula.
Once into the blood and tissues, the magnesium and ASC will
separate. Magnesium serves to activate bromelain.14 Also,
magnesium is "nature's calcium channel-blocker."15 It helps to
prevent entry of calcium into various cells, and calcium entry
into mast cells and basophils is a key part of triggering
allergic histamine release.6
Quercetin: More Benefits
A combination of QRC, magnesium ASC and bromelain makes a great
anti-allergy/asthma supplement. But there are other potential
benefits from this combination.
QRC has been extensively studied for its anticancer activity. A
1989 report found that QRC strongly inhibited the growth of
human squamous cell carcinoma cells transplanted into
immunocompetent rats.16 "In several in vitro experiments, quercetin showed growth-inhibitory effects on cells from various
human cancers: colon, breast, ovarian, gastro-intestinal and
leukemic cells."3 Verma and collaborators reported a significant
reduction in tumor size and number in rats suffering DMBA-induced
mammary cancer given QRC, compared to controls.16
Hofmann and coworkers found that QRC enhanced the anti-cancer
effect of several types of anti-cancer drugs.18 They also noted
that "quercetin... is a licensed [anti-cancer] drug in many
countries and is non-toxic at the required dose range."18
Bromelain has also shown some anti-tumor activity in both human
clinical and animal experimental studies.9
QRC and bromelain both have shown positive effects in reducing
heart disease risks. Bromelain is an effective inhibitor of
platelet aggregation and strong fibrinolytic (fibrin-dissolving)
agent.9,10 Excess fibrin production and platelet aggregation can
produce a blood clot that may clog up an already partially
closed heart artery and trigger a heart attack. QRC also helps
prevent the production of inflammatory prostaglandins/
thromboxanes that promote the pathological platelet
aggregation/clot formation that might trigger a heart attack.19
Trans-resveratrol (10-40 mg/day) is a potent synergist with
QRC's anti-tumor/ anti-heart attack activity.19
The Zutphen Elderly Study published in 1993 provides eloquent
evidence of the heart-protective power of QRC.20 This five-year
study investigated the dietary flavonoid intake and risk of
coronary heart disease in 805 men ages 65-84. The study found
that most (74 percent) of the dietary flavonoid intake came from
three foods: tea, onions and apples. Mean daily flavonoid intake
was 26 mg, about two-thirds of which was QRC. Compared to those
in the bottom third of flavonoid intake, those in the top third
of flavonoid intake had only 42 percent of the relative risk of
coronary heart disease death during the five-year study.
A Personal Note
I have suffered from severe allergies and asthma since early
childhood. In 1971, at age 23, I began taking megadose
nutrients. This immediately brought significant relief from my
allergies, yet I still suffered severely at times—especially
during the grass pollen season.
Megadose ASC was especially helpful to me, but still did not
completely control my allergies. In 1986, I added QRC to my
regimen. This brought much more relief, but still not total. In
1988, I created a QRC/bromelain/magnesium ASC formula that
finally brought the relief I needed. For the past 16 years my
allergies have been almost completely controlled through regular
use of that combination. On the rare occasion I might still have
an allergic reaction, taking an "attack" dose of three to six
capsules at once will usually quickly halt the reaction. I find
the QRC/ASC/bromelain combination to be far more effective than
any anti-allergy drug I've ever tried, without their nasty side
QRC, bromelain and magnesium ASC are all generally safe
compounds. However, anyone allergic to bee stings, olive tree
pollen or pineapple should probably avoid bromelain.9 Anyone
with a history of serious heart palpitations should limit
bromelain intake to 460 mg/day.9 Although magnesium ASC is
generally more "gut friendly" than ascorbic acid C, sensitive
individuals still might experience gas, diarrhea or gut cramping
from high dose magnesium ASC. Taking QRC/bromelain/magnesium ASC
with food should reduce the risk of gut symptoms, although for
rapid and maximum allergy relief taking them on an empty stomach
How much QRC/bromelain/magnesium ASC to take depends on one's
allergy situation. Those with only mild or occasional allergies
might only need one capsule three or four times daily of a
formula providing 1,000 mg QRC, 300 mg (720 GDU) bromelain, and
664 mg ASC per three capsules.
For those with severe allergies, or during an intensive allergy
season, it may be necessary to take two or three capsules four
to six times daily. During a severe allergy attack it may be
necessary to take up to six capsules to halt the attack. For
those who have no trouble taking high dose C, taking extra C may
increase the anti-allergy effect. For those suffering from
asthma, adding four fish oil caps/day may enhance the protective
source of nutrients and supplements.
did we qualify them ?
1. "Quercetin" (Monograph) Alt Med Rev 3 (1998): 140-43.
2. Leighton, T. Univ. Calif. Berkeley Quercetin Project,
preliminary report, 1988.
3. Stavric, B. "Quercetin in our diet: from potent mutagen to
probable anticarcinogen: Clin Biochem 27 (1994): 245-48.
4. Murray, M. Encyclopedia of Nutritional Supplements.
Roseville, CA: Prima Pub.; 1996: 320.
5. Pearce, F. et al "Mucosal mast cells III. Effect of quercetin
and other flavonoids on antigen-induced histamine secretion from
rat intestinal mast cells" J Allergy Clin Immunol 73 (1984):
6. Middleton, E. et al " Quercetin: an inhibitor of
antigen-induced human basophil histamine release" J Immunol 127
7. Foreman, J. "Mast cells and the actions of flavonoids" J
Allergy Clin Immunol 73 (1984): 769-73.
8. Middleton, E. et al " The effects of plant flavonoids on
mammalian cells: implications for inflammation, heart disease
and cancer" Pharmacol Rev 52 (2000): 673-751.
9. Kelly, G. "Bromelain: A literature review and discussion of
its therapeutic applications" Alt Med Rev 1 (1996): 243-57.
10. Taussig, S. " The mechanism of the physiological action of bromelain" Med Hypoth 6 (1980): 99-104.
11. Shoskes, D. et al "Quercetin in men with category III
chronic prostatitis: a preliminary prospective, double-blind,
placebo-controlled trial" Urol 54 (1999): 960-63.
12. Murray, op. cit. 329.
13. Johnston, C. et al " Antihistamine effect of supplemental
ascorbic acid and neutrophil chemotaxis" J Am Coll Nutr II
14. Jellin, J. et al Pharmacist's Letter / Prescriber's Letter
Natural Medicines Comprehensive Database. 5th ed. Stockton, CA:
Therapeutic Research Faculty; 2003: 224.
15. Murray, op. cit. 162.
16. Castillo, M. et al "The effects of the bioflavonoid quercetin on squamous cell carcinoma of head and neck origin" Am
J Surg 158 (1989): 351-55.
17. Verma, A. et al "Inhibition of 7, 12- dimethylbenz(a)
anthracene- and N-nitrosomethylurea- induced rat mammary cancer
by dietary flavonol quercetin" Cancer Res 48 (1988): 5754-58.
18. Hofmann, J. et al "Enhancement of the antiproliferative
effect of cis-diamminedichloroplatinum (II) and nitrogen mustard
by inhibitors of protein kinase C" Int J Cancer 42 (1988):
19. South, J "Resveratrol and quercetin: anti heart attack and
anticancer dynamic duo" www.antiaging-systems.com/extract/resveratrol.htm.
20. Hertog, M. et al "Dietary antioxidant flavonoids and risk of
coronary heart disease: the Zutphen Elderly Study" Lancet 342
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