Shallots for Cholesterol and Heart Health

Search for "shallot cholesterol" and you will find confident claims that shallots lower LDL, thin the blood, relax arteries and reduce heart-attack risk. Follow the citations and you will nearly always land on a study of garlic, a study of common onion, or a trial of isolated quercetin. Almost none of it was done on shallots.

That does not make the claims worthless. Shallots share real chemistry with those plants, and they are unusually rich in one compound — quercetin — that has been tested in humans in its own right. But borrowed evidence has to be labelled as borrowed, because the size of an effect measured in a garlic trial is not transferable to a different species eaten in different amounts in a different form. This page separates the two piles carefully and tells you what is left when it is done.

Table of Contents

1. What Is Actually Being Claimed
2. The Compounds That Could Plausibly Do It
3. What Garlic's Trials Show — and Why They Are Not Shallot's
4. What Onion Trials Show
5. Quercetin: The Strongest Bridge From Shallot to Artery
6. Shallot-Specific Cardiovascular Evidence
7. Blood Pressure
8. Platelets, Clotting and the Anticoagulant Question
9. Fructans, the Microbiome and an Indirect Route
10. The Dietary-Pattern Argument, Which Is the Honest One
11. How to Eat Shallots If Your Heart Is the Reason
12. What Would Change This Page
13. Cautions
14. Key Research Papers
15. Connections

What Is Actually Being Claimed

Four distinct claims usually travel together under "shallots are good for your heart," and they need to be separated because they have different amounts of evidence behind them.

1. Shallots lower total and LDL cholesterol. No human trial of shallots has tested this. The claim is an inheritance from garlic.
2. Shallots lower blood pressure. No human trial of shallots has tested this either. There are randomized trials of garlic, of onion-skin extract and of isolated quercetin, all with modest effects.
3. Shallots reduce platelet stickiness. Plausible from allium chemistry and from human quercetin work, untested in shallots. This one matters clinically because it runs in both directions — see the anticoagulant section.
4. Eating alliums is associated with less cardiovascular disease. This is a population-level observational finding about vegetable-rich diets, and it is the only one of the four that has direct human data behind it. It is also the weakest kind of evidence for a single food, because it cannot separate the shallot from everything else the shallot-eater does.

The Compounds That Could Plausibly Do It

Three chemically separate systems in a shallot have a defensible link to cardiovascular biology. Understanding them is what tells you which borrowed evidence is reasonable and which is not.

Organosulfur compounds and hydrogen sulfide

Cutting a shallot lets alliinase reach its substrates and produce reactive thiosulfinates. Downstream, those decompose into sulfides and polysulfides that can release hydrogen sulfide in tissue, and hydrogen sulfide is a genuine endogenous vasodilator. Benavides, Squadrito, Mills and colleagues demonstrated that garlic's vasoactivity is mediated by hydrogen sulfide, in the Proceedings of the National Academy of Sciences in 2007 — an elegant piece of work that gave the old "garlic relaxes arteries" folklore a real mechanism. Tier: preliminary, isolated tissue.

The shallot caveat is chemical, not rhetorical. Garlic's precursor is alliin, which yields allicin and then the diallyl sulfides used in that PNAS work. Shallots are dominated by isoalliin, which yields propenyl- and propyl-derived thiosulfinates instead. The families overlap; they are not identical. Rose, Whiteman, Moore and Zhu reviewed the whole class in Natural Product Reports in 2005. Whether a shallot delivers the same hydrogen-sulfide yield per gram as garlic has, as far as the published record goes, not been measured.

Quercetin and other flavonols

Quercetin inhibits NF-kappa-B signalling, reduces oxidation of LDL particles in vitro, and has been tested for blood-pressure effects in humans. Shallots are a strong dietary source in a well-absorbed form. This is the best-supported bridge between shallots and the artery and gets its own section below.

Fructans and the gut

Shallots supply inulin-type fructans that reach the colon undigested and are fermented into short-chain fatty acids. Prebiotic fibre intake has plausible links to lipid metabolism and blood pressure. It is also the reason shallots trouble people with IBS, so the same compound is a benefit and a problem depending on the reader.

What Garlic's Trials Show — and Why They Are Not Shallot's

Garlic is the reason people believe alliums help the heart, so it is worth being precise about what its literature contains. Tier: randomized clinical trials and meta-analyses of those trials — but all of garlic.

Lipids. Ried, Toben and Fakler published an updated meta-analysis of the effect of garlic on serum lipids in Nutrition Reviews in 2013, pooling randomized trials and finding modest reductions in total cholesterol and LDL, concentrated in people with raised baseline values and in trials lasting at least a couple of months. Zeng, Zhang, Zhao and Xie reviewed the same question in Critical Reviews in Food Science and Nutrition in 2013. An earlier meta-analysis by Stevinson, Pittler and Ernst in Annals of Internal Medicine in 2000 had already concluded that garlic's cholesterol effect was smaller than the early enthusiasm suggested and that trial quality was a serious limitation.

The trial that cooled the field. Gardner, Lawson, Block and colleagues ran a randomized controlled trial comparing raw garlic against two commercial garlic supplements and placebo in adults with moderate hypercholesterolaemia, published in Archives of Internal Medicine in 2007. Over six months, none of the garlic arms produced a statistically significant reduction in LDL. It is a well-designed, adequately powered negative trial in the plant with the best case, and it is the single most useful reference point for calibrating expectations of any allium.

Blood pressure. Ried, Frank, Stocks, Fakler and Sullivan published a systematic review and meta-analysis of garlic and blood pressure in BMC Cardiovascular Disorders in 2008, and Ried returned to the question in Experimental and Therapeutic Medicine in 2020 with a review and meta-analysis covering blood pressure, arterial stiffness and gut microbiota. The pooled effect in hypertensive participants is real but modest, in the range of a few millimetres of mercury.

Why this cannot be handed to the shallot. Three reasons, all concrete. The trials used aged garlic extract or standardized garlic powder at defined doses, not a vegetable. Garlic's active chemistry is allicin-derived and shallots produce very little allicin. And the effect sizes were small even in the plant that was actually tested, which means there is no headroom for the effect to survive a species change plus a dose reduction. If someone tells you shallots lower LDL "like garlic does," the honest reply is that garlic's own best trial found no LDL effect at all.

What Onion Trials Show

Onion is the shallot's own species, so its evidence transfers better than garlic's — though it still transfers imperfectly, because the trials used concentrated extracts rather than food.

Onion-skin extract and blood pressure. Brull, Burak, Stoffel-Wagner and colleagues ran a randomized, double-blinded, placebo-controlled crossover trial of a quercetin-rich onion-skin extract in overweight-to-obese patients with pre-hypertension or hypertension, measuring 24-hour ambulatory blood pressure and endothelial function, published in the British Journal of Nutrition in 2015. They found a reduction in daytime systolic ambulatory blood pressure in the hypertensive subgroup. Tier: randomized clinical trial — of onion-skin extract, not of onions or shallots.

Onion-peel extract and lipids. Kim, Cha, Lee and Park reported a randomized, placebo-controlled, double-blind crossover trial of onion-peel extract on the lipid profile and antioxidative status of healthy young women in Nutrition Research and Practice in 2013. Choi, Lee, Woo and colleagues tested onion-peel extract on endothelial function and endothelial progenitor cells in overweight and obese individuals in Nutrition in 2015.

Whole raw onion. Ebrahimi-Mamaghani, Saghafi-Asl, Pirouzpanah and Asghari-Jafarabadi ran a randomized controlled clinical trial of raw red onion consumption on metabolic features in overweight or obese women with polycystic ovary syndrome, published in the Journal of Obstetrics and Gynaecology Research in 2014 — one of the few trials to test the vegetable itself rather than an extract.

Where this leaves the shallot. Notice what all but one of these have in common: they used the skin, the part you peel off and discard. Shallots are the same genus, arguably richer in the relevant flavonols, and their outer layers are proportionally larger — which is a coherent argument that a shallot delivers more quercetin per gram of edible flesh than a yellow onion. It is not an argument that eating shallots reproduces a trial done on concentrated peel extract.

Quercetin: The Strongest Bridge From Shallot to Artery

If any part of the shallot cardiovascular story is defensible, it runs through quercetin, and it rests on two things being true at once: shallots contain a lot of it, and the form they contain is absorbed.

Shallots are quercetin-rich. This is shallot-specific and measured. Yang, Meyers, van der Heide and Liu compared phenolic content and antioxidant and antiproliferative activity across onion varieties and shallots in the Journal of Agricultural and Food Chemistry in 2004; shallots ranked at or near the top of the range, well above mild sweet onion types. Slimestad, Fossen and Vagen's survey "Onions: a source of unique dietary flavonoids" in the same journal in 2007 gives the underlying chemistry: the dominant forms are quercetin 4'-glucoside and quercetin 3,4'-diglucoside, concentrated in the outer layers.

Shallot quercetin is absorbed. Wiczkowski, Romaszko, Bucinski and colleagues studied this directly in humans using shallots, which they identified as Allium cepa L. var. aggregatum, in The Journal of Nutrition in 2008, comparing the bioavailability of quercetin aglycone against its glucosides. Onion-family quercetin glucosides are efficiently taken up in the small intestine — better than the rutinoside form in tea and buckwheat. Mullen, Edwards and Crozier traced the resulting methyl-, glucuronyl-, glucosyl- and sulpho-conjugates in human plasma and urine after onion ingestion in the British Journal of Nutrition in 2006, and Lee and Mitchell compared quercetin pharmacokinetics from apples and onions in healthy humans in the Journal of Agricultural and Food Chemistry in 2012. Tier: human pharmacokinetics.

What quercetin does when it gets there — in trials of the isolated compound. Serban, Sahebkar, Zanchetti and colleagues published a systematic review and meta-analysis of randomized controlled trials of quercetin and blood pressure in the Journal of the American Heart Association in 2016, finding a small but statistically significant reduction. Sahebkar reviewed quercetin's effect on lipid profile across randomized trials in Critical Reviews in Food Science and Nutrition in 2017. Edwards, Lyon, Litwin and colleagues reported that quercetin reduced blood pressure in hypertensive subjects in The Journal of Nutrition in 2007, and Egert, Bosy-Westphal, Seiberl and colleagues found reduced systolic blood pressure and plasma oxidized LDL in overweight subjects at high cardiovascular risk in a double-blinded placebo-controlled crossover study in the British Journal of Nutrition in 2009. Tier: randomized clinical trials — of supplemental quercetin at doses of roughly 150 to 730 mg per day.

The gap you must not step over. Those trial doses are far above what food delivers. A high-quercetin diet supplies a few tens of milligrams a day. So the honest formulation is: shallots deliver a well-absorbed dose of a compound that produces small blood-pressure effects when given as a supplement at several times the dietary amount. That is a reason to prefer shallots over a sweet white onion. It is not a reason to expect your blood pressure to move.

Shallot-Specific Cardiovascular Evidence

Here is the entire shallot-specific pile, stated without padding. Tier: preliminary — animal and cell studies only.

Kidney and vascular protection in rats. Wongmekiat, Leelarugrayub and Thamprasert reported that shallot (Allium ascalonicum L.) extract reduced cyclosporine-induced nephrotoxicity in rats, in Food and Chemical Toxicology in 2008. This is a study of drug-induced oxidative kidney injury, not of cardiovascular endpoints, but it is often cited in cardiovascular contexts because the mechanism invoked is antioxidant.

Antioxidant capacity compared with garlic. Leelarungrayub, Rattanapanone, Chanarat and Gebicki published a quantitative evaluation of the antioxidant properties of garlic and shallot preparations in Nutrition in 2006 — a direct shallot-versus-garlic chemical comparison, which is genuinely useful and genuinely not a health outcome.

Insulin resistance in rats. Jalal, Bagheri, Moghimi and Rasuli tested aqueous shallot and garlic extracts in rats with fructose-induced insulin resistance, in the Journal of Clinical Biochemistry and Nutrition in 2007. Because insulin resistance is upstream of dyslipidaemia, this is sometimes offered as cardiovascular evidence. It is a rodent glucose study; the Blood Sugar page covers it properly.

What is not on this list: any human trial of shallots on cholesterol, blood pressure, arterial stiffness, endothelial function, platelet aggregation or cardiovascular events. Not a small one, not an unblinded one. The category is empty.

And one paper that gets misused. A double-blind randomized trial published in 2025 reported effects of "Persian shallot" extract on serum markers and blood pressure in metabolic syndrome. That is a real trial, but Persian shallot is Allium hirtifolium / Allium stipitatum — a wild Iranian mountain allium, not the bulb in your kitchen. It appears in shallot marketing anyway. If you see a citation supporting shallot blood-pressure claims, check the species first; it is usually this.

Blood Pressure

Because blood pressure is the endpoint people most often ask about, it is worth compressing the whole picture into one place.

• Garlic supplements: randomized trials, pooled reductions of roughly 5 to 8 mmHg systolic in hypertensive participants, smaller or absent in normotensive ones. Real, modest, and about garlic.
• Onion-skin extract: one good randomized crossover trial showing reduced daytime systolic ambulatory blood pressure in the hypertensive subgroup. Real, modest, and about an extract.
• Supplemental quercetin: meta-analysed randomized trials showing a small systolic reduction, most visible at higher doses and longer durations. Real, small, and about a purified compound.
• Dietary shallots: no trials at all.

If you have hypertension, the interventions with large, reliable effects are the boring ones: sodium reduction, weight loss, exercise, alcohol reduction, potassium-rich whole foods, and medication when indicated. Shallots belong in the food column, and the food column matters — but as part of a pattern, not as a treatment. See Hypertension.

Platelets, Clotting and the Anticoagulant Question

This is the one part of the shallot cardiovascular story with a genuine clinical consequence, and the consequence is a caution rather than a benefit.

The evidence. Garlic's antiplatelet effect is reasonably well documented and is the basis of standard advice to stop concentrated garlic supplements before surgery. On the flavonol side, Hubbard, Wolffram, Lovegrove and Gibbins reported that ingestion of quercetin inhibited platelet aggregation and key components of the collagen-stimulated platelet activation pathway in humans, in the Journal of Thrombosis and Haemostasis in 2004 — a pilot study, but a human one. Tier: human pilot study for quercetin; randomized and observational for garlic; nothing for shallot.

What it means in practice.

• Culinary shallots are not a bleeding risk. There is no reason to avoid shallots in cooking because you take warfarin, a direct oral anticoagulant, clopidogrel or aspirin. Being told to avoid a vegetable is a common and unhelpful over-reading of this literature.
• Concentrated allium supplements are a different matter. If you take a garlic, onion-extract, quercetin or shallot-extract supplement alongside an anticoagulant or antiplatelet drug, tell your prescriber. The interaction is plausible and, for garlic, documented.
• Surgery. Stop concentrated allium and quercetin supplements one to two weeks before a planned procedure and tell the surgical team what you have been taking. Keep eating normally.
• Warfarin and vitamin K. A separate point occasionally muddled with this one: shallots are not a significant vitamin K source, so they do not destabilize an INR the way large swings in leafy-green intake can.

Fructans, the Microbiome and an Indirect Route

Shallots contain inulin-type fructans, which human enzymes cannot digest. They arrive in the colon intact and are fermented by resident bacteria into short-chain fatty acids, mainly acetate, propionate and butyrate. Propionate in particular has been studied for effects on hepatic lipid handling, and Ried's 2020 review of garlic explicitly folded gut microbiota into its account of how an allium might affect blood pressure. Tier: mechanistic, with human data on prebiotic fibre in general rather than on shallot fructans specifically.

Two honest observations about this route. First, it is a fibre argument, not an allium argument — the same case can be made for leeks, garlic, Jerusalem artichokes, chicory root and green bananas. Second, it is the single most common reason shallots make people feel worse rather than better. Fermentation produces gas. In people with irritable bowel syndrome, or with small intestinal bacterial overgrowth, that gas is the symptom. See Irritable Bowel Syndrome and SIBO.

The Dietary-Pattern Argument, Which Is the Honest One

Set aside the extracts and the isolated compounds and there remains a real, well-replicated body of human evidence — it is just evidence about eating patterns rather than about shallots.

Hertog, Feskens, Hollman, Katan and Kromhout reported in The Lancet in 1993, from the Zutphen Elderly Study, that dietary flavonoid intake was inversely associated with coronary heart disease mortality; onions were among the main contributing foods in that population. Knekt, Kumpulainen, Jarvinen and colleagues examined flavonoid intake and risk of chronic diseases in The American Journal of Clinical Nutrition in 2002. More recently, Bondonno, Dalgaard, Kyro and colleagues reported that flavonoid intake was associated with lower mortality in the Danish Diet, Cancer and Health cohort, in Nature Communications in 2019. Tier: human observational.

What observational data can and cannot tell you. It can tell you that people who eat more flavonoid-rich vegetables have fewer cardiovascular events. It cannot tell you that the flavonoids caused the difference, because those people also tend to smoke less, move more, weigh less and eat more of everything else that is good for them. Residual confounding in nutritional epidemiology is not a technicality; it is the reason large trials of isolated antioxidants have repeatedly failed to reproduce the associations found in cohorts.

So the defensible claim is modest and worth stating plainly. Shallots are a low-calorie, nutrient-dense, polyphenol-rich vegetable that makes vegetables, legumes and whole grains taste better. Diets built that way are associated with better cardiovascular outcomes. Nothing about that claim requires the shallot to be medicinal, and it does not collapse when you point out that no shallot trial exists.

How to Eat Shallots If Your Heart Is the Reason

Practical, and honest about what each step buys you.

• Choose the deeply coloured small ones. Asian purple shallots carry anthocyanins that yellow onions lack, and their high surface-to-volume ratio means proportionally more of the flavonol-rich outer layers. This is the most defensible single choice on the list.
• Keep the outer fleshy layers. Peel the papery skin and stop. The layer immediately beneath it is the most flavonol-dense edible tissue in the bulb, and it is routinely stripped off out of habit.
• Chop and wait ten minutes before heat if you want the sulfur chemistry. Alliinase needs time and is destroyed by heat, so shallots dropped whole into hot oil never make much thiosulfinate.
• Eat some raw. Minced raw in vinaigrette, sliced into salads, or quick-pickled. Raw preserves both the volatile sulfur compounds and the heat-sensitive vitamin C.
• Do not rely on fried shallot crisps. They are delicious and they are a different food chemically: alliinase denatured, volatiles driven off, sugars browned, and a substantial load of frying oil. Ratseewo and colleagues quantified how drying changes shallot composition in Food Chemistry: X in 2025.
• Use the shallot to displace something worse. The realistic cardiovascular value of a shallot is that it makes lentils, brown rice, beans, greens and fish taste like something you want to eat again. That substitution is worth more than any polyphenol.
• Skip the capsules. No shallot extract has an established dose, a standardization measure or any human efficacy data, and some products labelled shallot contain a different species entirely.

What Would Change This Page

Stating in advance what evidence would move a conclusion is a good discipline, and it is short here.

• A randomized controlled trial of a defined daily quantity of whole shallot against a matched control, with lipid panel, ambulatory blood pressure or endothelial function as the primary endpoint, in people with an abnormal baseline value.
• A measurement of hydrogen sulfide yield from shallot-derived thiosulfinates comparable to what exists for garlic's diallyl compounds, which would tell us whether the vasodilator mechanism transfers at all.
• A dose-response study establishing how much quercetin a realistic portion of shallot actually delivers into plasma, and whether that reaches the range where the supplement trials saw effects.

None of these exist. Until one does, this page will keep saying that shallots are a good vegetable and not a cardiovascular treatment.

Cautions

FODMAP intolerance and IBS. Shallots are high in fructans and are excluded during the elimination phase of a low-FODMAP diet. If you have irritable bowel syndrome, they are one of the more reliable triggers of bloating, wind and pain. Because fructans are water-soluble but not oil-soluble, shallot-infused oil with the solids strained out is generally tolerated, which lets you keep the flavour. Fried shallot crisps are the solids and are not a workaround.

Reflux and gastritis. Alliums, especially raw, are a common trigger for gastro-oesophageal reflux — relevant here because raw shallot is exactly what this page suggests for polyphenol retention. If onions cause you heartburn, shallots will too. See GERD.

Anticoagulants, antiplatelets and surgery. Culinary shallots are fine. Concentrated allium or quercetin supplements should be cleared with your prescriber and stopped one to two weeks before planned surgery.

Botulism risk from alliums in oil. Shallot-infused oil is recommended above as an IBS workaround, so this warning is not optional. Alliums held in oil at room temperature create the anaerobic, low-acid conditions Clostridium botulinum requires, and garlic-in-oil has caused documented outbreaks. Make small batches, refrigerate immediately, use within a few days, or freeze in portions. Never leave a jar of shallots in oil on the counter.

Allergy and contact dermatitis. Allium allergy is uncommon but real and can cause oral allergy symptoms, rhinitis, asthma or, rarely, anaphylaxis. Occupational contact dermatitis from handling alliums is well documented in cooks.

Toxic to dogs and cats. All alliums cause oxidative damage to red blood cells in dogs and cats, producing Heinz-body haemolytic anaemia; cats are especially sensitive. This includes cooked shallots, shallot powder, fried shallot crisps and leftovers containing them. Contact a vet if a pet eats a meaningful quantity.

Do not substitute food for treatment. Shallots do not replace a statin, an antihypertensive or an antiplatelet drug. If your cholesterol or blood pressure is being managed with medication, adding shallots to your diet is a fine idea and stopping the medication is not.

Key Research Papers

Each entry states the plant actually studied. Links are PubMed topic searches rather than direct record links, so you can see the paper in its full context alongside related work.

1. Shallot, human. Wiczkowski W, Romaszko J, Bucinski A, et al. Quercetin from shallots (Allium cepa L. var. aggregatum) is more bioavailable than its glucosides. The Journal of Nutrition, 2008. Find on PubMed
2. Shallot vs onion, food analysis. Yang J, Meyers KJ, van der Heide J, Liu RH. Varietal differences in phenolic content and antioxidant and antiproliferative activities of onions. Journal of Agricultural and Food Chemistry, 2004. Find on PubMed
3. Shallot vs garlic, chemical assay. Leelarungrayub N, Rattanapanone V, Chanarat N, Gebicki JM. Quantitative evaluation of the antioxidant properties of garlic and shallot preparations. Nutrition, 2006. Find on PubMed
4. Shallot, rats. Wongmekiat O, Leelarugrayub N, Thamprasert K. Beneficial effect of shallot (Allium ascalonicum L.) extract on cyclosporine nephrotoxicity in rats. Food and Chemical Toxicology, 2008. Find on PubMed
5. Garlic, randomized trial. Gardner CD, Lawson LD, Block E, et al. Effect of raw garlic vs commercial garlic supplements on plasma lipid concentrations in adults with moderate hypercholesterolemia. Archives of Internal Medicine, 2007. The important negative trial. Find on PubMed
6. Garlic, meta-analysis. Ried K, Toben C, Fakler P. Effect of garlic on serum lipids: an updated meta-analysis. Nutrition Reviews, 2013. Find on PubMed
7. Garlic, meta-analysis. Ried K, Frank OR, Stocks NP, Fakler P, Sullivan T. Effect of garlic on blood pressure: a systematic review and meta-analysis. BMC Cardiovascular Disorders, 2008. Find on PubMed
8. Garlic, mechanism. Benavides GA, Squadrito GL, Mills RW, et al. Hydrogen sulfide mediates the vasoactivity of garlic. Proceedings of the National Academy of Sciences, 2007. Find on PubMed
9. Onion-skin extract, randomized trial. Brull V, Burak C, Stoffel-Wagner B, et al. Effects of a quercetin-rich onion skin extract on 24-hour ambulatory blood pressure and endothelial function in overweight-to-obese patients with (pre-)hypertension. British Journal of Nutrition, 2015. Find on PubMed
10. Onion-peel extract, randomized trial. Kim J, Cha YJ, Lee KH, Park E. Effect of onion peel extract supplementation on the lipid profile and antioxidative status of healthy young women. Nutrition Research and Practice, 2013. Find on PubMed
11. Quercetin, meta-analysis of randomized trials. Serban MC, Sahebkar A, Zanchetti A, et al. Effects of quercetin on blood pressure: a systematic review and meta-analysis of randomized controlled trials. Journal of the American Heart Association, 2016. Find on PubMed
12. Quercetin, randomized trial. Egert S, Bosy-Westphal A, Seiberl J, et al. Quercetin reduces systolic blood pressure and plasma oxidised LDL concentrations in overweight subjects with a high cardiovascular disease risk phenotype. British Journal of Nutrition, 2009. Find on PubMed
13. Quercetin, human pilot. Hubbard GP, Wolffram S, Lovegrove JA, Gibbins JM. Ingestion of quercetin inhibits platelet aggregation and essential components of the collagen-stimulated platelet activation pathway in humans. Journal of Thrombosis and Haemostasis, 2004. Find on PubMed
14. Human observational. Hertog MG, Feskens EJ, Hollman PC, Katan MB, Kromhout D. Dietary antioxidant flavonoids and risk of coronary heart disease: the Zutphen Elderly Study. The Lancet, 1993. Find on PubMed
15. Human observational. Bondonno NP, Dalgaard F, Kyro C, et al. Flavonoid intake is associated with lower mortality in the Danish Diet Cancer and Health cohort. Nature Communications, 2019. Find on PubMed
16. Onion review. Galavi A, Hosseinzadeh H, Razavi BM. The effects of Allium cepa L. (onion) and its active constituents on metabolic syndrome: a review. Iranian Journal of Basic Medical Sciences, 2021. Find on PubMed

Live PubMed searches

1. Allium ascalonicum and cardiovascular endpoints
2. Shallot quercetin bioavailability
3. Onion flavonoids, cardiovascular, randomized trials
4. Allium organosulfur compounds and hydrogen-sulfide vasodilation
5. Quercetin and human platelet aggregation
6. Persian shallot (Allium hirtifolium) and metabolic syndrome — the other plant

Connections

• All Herbs
• Shallot Benefits hub — how this section labels evidence, and the species-confusion problem in full.
• Shallot (Allium ascalonicum) — the main topic page.
• Shallots for Blood Sugar Control — the insulin-resistance studies mentioned above, covered properly.
• Garlic: Cholesterol and Atherosclerosis — the trials this page declines to borrow.
• Garlic: Cardiovascular and Blood Pressure — the blood-pressure meta-analyses in detail.
• Quercetin: Cardiovascular Health — the isolated-compound trials at supplemental doses.
• Onions — the shallot's own species and the source of the onion-skin trials.
• Atherosclerosis — the disease process behind the endpoint.
• Hypertension — where the interventions that actually move blood pressure are listed.
• Lipid Panel — how to read the numbers these claims are aimed at.
• ApoB — the particle-count measure that has largely superseded LDL cholesterol alone.
• Irritable Bowel Syndrome — the fructan problem and the infused-oil workaround.

This page is educational and is not medical advice. It documents what has and has not been studied about shallots so that you can judge the claims yourself. Shallots are food, not a treatment: they do not replace a statin, an antihypertensive or an antiplatelet drug, and nothing here should prompt you to change a prescription. If you have raised cholesterol, high blood pressure, established cardiovascular disease, or you take an anticoagulant, discuss any concentrated allium or quercetin supplement with your doctor or pharmacist before starting it.

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