# Scallions (Allium fistulosum)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/scallions
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-28
**Evidence Score:** 2 / 10
**Category:** Vegetable
**Also Known As:** Allium fistulosum, green onions, Welsh onions, spring onions, bunching onions, salad onions, Japanese bunching onions, stone leeks, cibol, eschalion

## Overview

Scallions (Allium fistulosum) are a member of the allium family whose primary bioactive compounds — organosulfur molecules including allicin and quercetin — exert antioxidant, [antimicrobial](/ingredients/condition/immune-support), and [anti-inflammatory](/ingredients/condition/inflammation) effects. These compounds act by modulating NF-κB signaling, scavenging [reactive oxygen species](/ingredients/condition/antioxidant), and disrupting microbial cell membranes.

## Health Benefits

• [Anti-inflammatory](/ingredients/condition/inflammation) activity demonstrated through inhibition of IL-10-induced CD163 expression in macrophages (preclinical evidence only)
• Antimicrobial effects attributed to organosulfur compounds like allicin (in vitro studies only)
• Anti-tumor activity shown in HeLa cell lines through total phenols and flavonoids (preliminary cell culture evidence)
• [Antioxidant](/ingredients/condition/antioxidant) properties from flavonoids including isoquercitrin and kaempferol (preclinical models only)
• Potential anti-obesity and [immunomodulatory](/ingredients/condition/immune-support) effects through modulation of iNOS, FASN, and MCP-1 pathways (animal/cell studies only)

## Mechanism of Action

Allicin, formed enzymatically from alliin by alliinase when scallion tissue is damaged, inhibits NF-κB activation and suppresses the expression of [pro-inflammatory cytokine](/ingredients/condition/inflammation)s including IL-1β and TNF-α. The flavonoid quercetin present in scallions acts as a free-radical scavenger and inhibits lipoxygenase and cyclooxygenase enzymes involved in the arachidonic acid inflammatory cascade. Additionally, organosulfur compounds in scallions have been shown to downregulate CD163 receptor expression on macrophages stimulated by IL-10, reducing the anti-inflammatory M2 macrophage polarization that can promote tumor immune evasion.

## Clinical Summary

Most evidence supporting scallion health benefits comes from in vitro cell studies and preclinical animal models rather than randomized controlled human trials. [Antimicrobial](/ingredients/condition/immune-support) activity against pathogens such as Staphylococcus aureus and Candida albicans has been demonstrated in vitro, though minimum inhibitory concentrations have not been validated in human infection models. Anti-tumor effects were observed in HeLa cervical cancer cell lines using total phenolic extracts, showing dose-dependent cytotoxicity, but these findings have not been replicated in human clinical trials. The current body of evidence is preliminary, and no standardized clinical dosing protocols exist for scallion-derived supplements.

## Nutritional Profile

Per 100 g raw scallions (Allium fistulosum): Energy ~32 kcal; Water ~89.8 g; Protein ~1.83 g; Total fat ~0.19 g; Carbohydrates ~7.34 g (including ~2.33 g sugars, predominantly fructose and glucose); Dietary fiber ~2.6 g (both soluble fructans/inulin-type fructooligosaccharides and insoluble cellulose). VITAMINS: Vitamin K1 (phylloquinone) ~207 µg (173% DV, highly fat-soluble — bioavailability significantly enhanced with dietary fat); Vitamin C (ascorbic acid) ~18.8 mg (~21% DV, moderately bioavailable but heat-labile, reduced 30–50% upon cooking); Folate (B9) ~64 µg (~16% DV, ~50–60% bioavailability from food matrix vs. synthetic folic acid); Vitamin A as provitamin A carotenoids (primarily β-carotene ~1160 µg, yielding ~997 µg RAE, ~111% DV for retinol activity equivalents; bioavailability ~3–6% from raw plant matrix, improved by cooking and fat co-ingestion); Riboflavin (B2) ~0.080 mg; Thiamine (B1) ~0.055 mg; Pyridoxine (B6) ~0.061 mg; Vitamin E (α-tocopherol) ~0.55 mg. MINERALS: Potassium ~276 mg; Calcium ~72 mg (bioavailability moderate ~20–30%, comparable to other Allium vegetables, potentially inhibited by oxalates present at low levels); Iron ~1.48 mg (non-heme form, ~5–12% bioavailability, enhanced by co-consumed vitamin C); Manganese ~0.160 mg; Magnesium ~20 mg; Phosphorus ~37 mg; Zinc ~0.39 mg; Copper ~0.083 mg. BIOACTIVE COMPOUNDS: Organosulfur compounds — allicin (diallyl thiosulfinate, generated enzymatically from alliin via alliinase upon tissue disruption, estimated ~0.5–3.5 mg/g fresh weight depending on cultivar and crushing method; highly volatile and unstable, rapidly converting to diallyl sulfide, diallyl disulfide (DADS), diallyl trisulfide (DATS), and ajoene); S-alk(en)yl-L-cysteine sulfoxides (ACSOs) including isoalliin (trans-S-1-propenyl-L-cysteine sulfoxide, predominant in A. fistulosum) and methiin (S-methyl-L-cysteine sulfoxide); γ-glutamyl-S-alk(en)yl-L-cysteines as storage precursors. Flavonoids — quercetin (primarily as quercetin-3,4'-diglucoside and quercetin-4'-glucoside in green leaves, total quercetin equivalents ~15–40 mg/100 g in green portions; substantially lower ~2–5 mg/100 g in white shaft); kaempferol glycosides in trace amounts; isorhamnetin derivatives detected in some cultivars. Phenolic acids — ferulic acid, caffeic acid, p-coumaric acid, and chlorogenic acid (total phenolic content ~50–150 mg GAE/100 g fresh weight, concentrated in green leaves). Carotenoids — β-carotene (~1.16 mg/100 g), lutein + zeaxanthin (~1.14 mg/100 g, concentrated in green tops, bioavailability enhanced by lipid co-ingestion). Fructooligosaccharides (FOS)/inulin-type fructans — ~0.5–1.2 g/100 g, acting as [prebiotic](/ingredients/condition/gut-health)s fermented by colonic Bifidobacteria and Lactobacillus spp. to short-chain fatty acids. Saponins — trace levels of furostanol and spirostanol glycosides reported in A. fistulosum. NOTE: The green leaf portions contain significantly higher concentrations of carotenoids, flavonoids, vitamin K, and vitamin C compared to the white basal portions, which are richer in organosulfur precursors. Cooking reduces vitamin C and allicin content substantially but may improve carotenoid and mineral bioavailability.

## Dosage & Preparation

No clinically studied dosage ranges are available for extracts, powders, or standardized forms of Allium fistulosum. Standardization details for active compounds like allicin or flavonoids are absent from human studies. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Scallions are generally recognized as safe when consumed as food, but concentrated extracts or supplements may cause gastrointestinal side effects including bloating, nausea, and heartburn, particularly in individuals with irritable bowel syndrome or FODMAP sensitivity. Allicin-containing allium compounds possess mild antiplatelet and anticoagulant properties, meaning high-dose supplementation may potentiate the effects of blood-thinning medications such as warfarin, aspirin, or clopidogrel. Individuals with known allium allergies may experience contact dermatitis or allergic rhinitis. Pregnant women may consume scallions safely as food, but supplemental extracts have not been evaluated for safety in pregnancy or lactation.

## Scientific Research

No human clinical trials, RCTs, or meta-analyses on Allium fistulosum were found in the research dossier. All available evidence comes from preclinical studies using cell lines and animal models, with pharmacological activities demonstrated only in laboratory settings without human study designs, sample sizes, or clinical outcomes.

## Historical & Cultural Context

Allium fistulosum has been used historically as a spice and in traditional medicine, though specific systems, durations, or indications are not detailed in available research. It is recognized as an important spice worldwide with medicinal potential attributed to its phytochemicals.

## Synergistic Combinations

Garlic, Ginger, Turmeric, Quercetin, Black Pepper Extract

## Frequently Asked Questions

### What is the main active compound in scallions responsible for their health benefits?

The primary bioactive compound in scallions is allicin, an organosulfur molecule generated when the enzyme alliinase converts alliin upon cell damage from chopping or crushing. Scallions also contain quercetin, kaempferol, and other flavonoids that contribute to antioxidant and anti-inflammatory activity.

### Do scallions have proven anticancer effects in humans?

Currently, anticancer effects of scallions have only been demonstrated in vitro, most notably in HeLa cervical cancer cell lines where total phenolic extracts induced dose-dependent cytotoxicity. No human clinical trials have confirmed these effects, so it is premature to classify scallions as a cancer treatment or prevention strategy.

### Can scallions interact with blood thinners like warfarin?

Yes, high-dose scallion extracts may pose an interaction risk with anticoagulants such as warfarin due to the mild antiplatelet properties of organosulfur compounds including allicin. Consuming scallions as a culinary herb in normal food amounts is unlikely to cause clinically significant interactions, but supplemental extracts should be used cautiously by patients on anticoagulant therapy.

### How do scallions differ from garlic in terms of allicin content?

Garlic (Allium sativum) contains substantially higher concentrations of alliin and generates more allicin upon processing, typically 2–4 mg of allicin per gram of fresh weight, compared to scallions which yield significantly lower amounts. Scallions also contain proportionally higher levels of quercetin and kaempferol relative to their total allicin output, giving them a distinct but milder phytochemical profile.

### Are scallion supplements safe for people with IBS or digestive issues?

Scallions contain fructooligosaccharides (FOS) and other fermentable carbohydrates classified as FODMAPs, which can trigger bloating, cramping, and diarrhea in individuals with irritable bowel syndrome or fructose malabsorption. Both whole scallions and concentrated extracts should be approached cautiously by those following a low-FODMAP diet, and a registered dietitian should be consulted before supplementation.

### What is the difference between fresh scallions and scallion supplements in terms of nutrient content?

Fresh scallions contain the full spectrum of heat-sensitive compounds including volatile organosulfur compounds and water-soluble vitamins that may be partially lost during supplement processing and drying. Scallion supplements are typically standardized for specific phenolic or flavonoid content, offering consistent dosing but potentially reduced antimicrobial activity from allicin degradation. Most clinical evidence supporting scallion health benefits derives from fresh or minimally processed forms rather than concentrated extracts.

### Are scallions safe to consume in large amounts during pregnancy and breastfeeding?

Scallions in normal dietary amounts (as a food flavoring or vegetable) are considered safe during pregnancy and breastfeeding, as they have been traditionally consumed in many cuisines for centuries. However, concentrated scallion supplements have not been adequately studied in pregnant or nursing populations and should be avoided without medical supervision. Pregnant individuals should consult a healthcare provider before taking any scallion supplement, especially in amounts exceeding typical culinary use.

### How strong is the current scientific evidence for scallions' anti-inflammatory and antioxidant claims?

Current evidence for scallion anti-inflammatory effects is limited to preclinical studies in cell cultures and animal models; no rigorous human clinical trials have confirmed these benefits. The antioxidant properties demonstrated through in vitro testing suggest potential, but these findings have not been translated into proven health outcomes in human populations. More high-quality human studies are needed before recommending scallion supplements specifically for inflammation or oxidative stress management.

---

*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
*License: CC BY-NC-SA 4.0 — Attribution required. Commercial use: admin@hermeticasuperfoods.com*