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Onions, sweet, raw

Vegetables Per 100 g · Per 100g serving

Onions, sweet, raw is a vegetable, providing just 32.0 calories per 100g. This vegetable is virtually fat-free. Vegetables provide essential vitamins, minerals, and dietary fiber with relatively few calories. They are a cornerstone of virtually every dietary guideline worldwide. Our database tracks 72 nutrients for this food, plus insulin index, polyphenol profile, environmental footprint data.

32.0
Calories
kcal
0.80
Protein
g
0.08
Fat
g
7.5
Carbs
g
0.90
Fiber
g

Top Nutrients

☀️
Vitamin B6
0.13 mg
10% DV
💎
Copper
0.06 mg
6% DV
💪
Carbohydrate
7.5 g
6% DV

Data for 72 of 150 tracked nutrients

Nutrient Fingerprint

How this food scores across key nutrient categories, as a percentage of the daily recommended value per 100 g. Based on USDA DRIs for adults.

Complete Nutrient Profile

Macronutrients 10
NutrientPer 100gUnitPer Serving% DV
Water SR91.2g
2%
Calories SR32.0kcal
Energy (kJ) SR133kj
Protein SR0.80g
1%
Total Fat SR0.08g
Carbohydrate SR7.5g
6%
Fiber SR0.90g
2%
Total Sugars SR5.0g
Starch SR0g
Ash SR0.34g
Minerals 10
NutrientPer 100gUnitPer Serving% DV
Calcium SR20.0mg
2%
Iron SR0.26mg
3%
Magnesium SR9.0mg
2%
Phosphorus SR27.0mg
4%
Potassium SR119mg
4%
Sodium SR8.0mg
0%
Zinc SR0.13mg
1%
Copper SR0.06mg
6%
Manganese SR0.08mg
3%
Selenium SR0.50µg
1%
Vitamins 29
NutrientPer 100gUnitPer Serving% DV
Vitamin A (RAE) SR1.0µg
0%
Vitamin A (IU) SR0IU
Beta-Carotene SR1.0µg
Alpha-Carotene SR0µg
Beta-Cryptoxanthin SR0µg
Lycopene SR0µg
Lutein + Zeaxanthin SR6.0µg
Vitamin C SR4.8mg
5%
Vitamin D SR0µg
Vitamin D (IU) SR0IU
Vitamin E SR0.02mg
0%
Beta-Tocopherol SR0mg
Gamma-Tocopherol SR0mg
Delta-Tocopherol SR0mg
Alpha-Tocotrienol SR0.01mg
Beta-Tocotrienol SR0mg
Gamma-Tocotrienol SR0mg
Delta-Tocotrienol SR0mg
Vitamin K1 SR0.30µg
0%
Vitamin K2 (MK-4) SR0µg
Thiamin (B1) SR0.04mg
3%
Riboflavin (B2) SR0.02mg
2%
Niacin (B3) SR0.13mg
1%
Pantothenic Acid (B5) SR0.10mg
2%
Vitamin B6 SR0.13mg
10%
Folate SR23.0µg
6%
Folate (food) SR23.0µg
Choline SR5.5mg
1%
Betaine SR0.10mg
Fatty Acids 2
NutrientPer 100gUnitPer Serving% DV
Trans Fat SR0g
Cholesterol SR0mg
Amino Acids 18
NutrientPer 100gUnitPer Serving% DV
Tryptophan SR0.009g
Threonine SR0.02g
Isoleucine SR0.01g
Leucine SR0.03g
Lysine SR0.03g
Methionine SR0.009g
Cystine SR0.009g
Phenylalanine SR0.02g
Tyrosine SR0.01g
Valine SR0.02g
Arginine SR0.11g
Histidine SR0.01g
Alanine SR0.02g
Aspartic Acid SR0.07g
Glutamic Acid SR0.18g
Glycine SR0.02g
Proline SR0.01g
Serine SR0.02g
Other 3
NutrientPer 100gUnitPer Serving% DV
Caffeine SR0mg
Theobromine SR0mg
Alcohol SR0g

Nutrient Density Score

The NRF9.3 score measures overall nutritional quality per 100 kcal. It rewards 9 nutrients to encourage (protein, fiber, vitamins A, C, E, calcium, iron, magnesium, potassium) and penalizes 3 to limit (saturated fat, added sugars, sodium). Higher is better; negative scores indicate the food is high in limit nutrients relative to its beneficial content.

55
NRF9.3 Score
Good · per 100 kcal
Poor (<0) Moderate Good Excellent (100+)

NRF9.3 index: Fulgoni et al. (2009), J Nutr 139(8). DVs based on FDA 2020 reference values.

Nutrient Interactions in This Food

Nutrients in this food that enhance or compete with each other during absorption.

✔ Synergies — nutrients that help each other

Vitamin B6 + Folate●●

Vitamin B6 is a cofactor in folate-dependent one-carbon metabolism. Together with B12, these three nutrients regulate homocysteine levels.

Selhub, J Nutr Health Aging, 2002

⚠ Antagonisms — nutrients that compete

Vitamin C vs Copper●●

High-dose vitamin C (>1,500 mg/day) may reduce copper absorption by reducing Cu²⁺ to Cu⁺, though the clinical significance at normal intakes is minimal.

Harris, Am J Clin Nutr, 2003

Amino Acid Profile

Essential amino acid composition compared to the WHO/FAO adult reference pattern. The Amino Acid Score indicates protein quality — 100 means all essential amino acid requirements are met.

53
Amino Acid Score
Moderate
Leucine
Limiting Amino Acid
18
Amino Acids Tracked

Tip: The limiting amino acid is Leucine. Pair with dairy, eggs, and meat for a complete amino acid profile.

All Amino Acids (18)
Amino Acidg / 100gmg / g protein
Tryptophan0.00911.2
Threonine0.0222.5
Isoleucine0.0117.5
Leucine0.0331.2
Lysine0.0341.2
Methionine0.00911.2
Cystine0.00911.2
Phenylalanine0.0230.0
Tyrosine0.0115.0
Valine0.0225.0
Arginine0.11138.8
Histidine0.0113.8
Alanine0.0221.2
Aspartic Acid0.0783.8
Glutamic Acid0.18221.2
Glycine0.0225.0
Proline0.0118.8
Serine0.0225.0

How Cooking Changes Nutrients

Estimated percentage of each nutrient retained after cooking, based on USDA retention factors for the “Other Vegetables” food category. Values of 100% mean no loss; lower values indicate nutrients lost to heat, water, or oxidation.

Key insights
Folate loses up to 31% when boiled (drained). Boiled (water used) retains 85%.
Choline loses up to 10% when fried. Boiled (drained) retains 100%.

Source: USDA Table of Nutrient Retention Factors, Release 6 (2007). Retention values are category-level averages — actual retention depends on cooking time, temperature, and water volume.

USDA Retention Factors

Insulin Response

The Insulin Index (II) measures the actual insulin response to food on a scale where white bread = 100. Unlike the Glycemic Index (which only measures blood sugar), the II captures the full hormonal response — including the effect of protein and fat on insulin secretion. This is why high-protein foods like meat and dairy can have significant insulin scores despite having low or zero GI values.

69
Insulin Index
High Insulin Response
Insulin Index Scale 69
0 Low ≤30 Mod ≤60 High ≤100 120
Macro Model ●● Estimated from macronutrient composition (R²=0.49)

Source: Holt et al. 1997; Bao et al. 2016; Bell 2014

Polyphenols & Bioactive Compounds

Polyphenols are plant-derived compounds with antioxidant properties. Higher intake is associated with reduced cardiovascular risk and improved gut health.

168
Total Polyphenols
mg per 100g · Rich Source
2
Polyphenol Classes
identified in this food
Flavonoids114 mg68%
Phenolic Acids54 mg32%

Processing Impact on Polyphenols

How common cooking methods affect polyphenol content in vegetables. Retention % is relative to the raw/unprocessed food.

Best Method
Freezing
92% retained
Most Loss
Canning
48% retained
🧊
Freezing92%
Minimal degradation; blanch before freezing for best results≈155 mg
♨️
Steaming90%
Best cooking method for polyphenol retention — no water contact≈151 mg
📡
Microwaving85%
Short cooking time and minimal water preserve most polyphenols≈143 mg
🫧
Blanching82%
Brief water contact limits losses; inactivates polyphenol oxidase≈138 mg
🍳
Stir-frying80%
Brief heat exposure; oil may extract some fat-soluble compounds≈134 mg
⏲️
Pressure cooking75%
Higher temperature but shorter time than boiling; moderate retent≈126 mg
🔥
Baking/Roasting72%
Extended dry heat causes moderate degradation≈121 mg
🍟
Deep frying65%
High temperature and oil immersion accelerate degradation≈109 mg
🫕
Boiling60%
Major losses from leaching; consuming cooking water recovers some≈101 mg
🥫
Canning48%
Most destructive common method — prolonged heat and water contact≈81 mg

Health Associations

Research-backed associations for the polyphenol classes found in this food. Evidence strength rated from systematic reviews and meta-analyses.

💜
↓ Cardiovascular disease riskModerate
Flavonoids: Meta-analyses of prospective cohorts show 10-20% lower CVD risk with higher flav
💜
↓ Blood pressureModerate
Flavonoids: RCTs show modest systolic BP reductions (2-5 mmHg) with flavanol-rich cocoa and
🔵
↑ Antioxidant capacityStrong
Phenolic Acids: Chlorogenic acid (coffee) and ferulic acid (grains) show consistent antioxidant
🔵
↑ Glucose metabolismModerate
Phenolic Acids: Chlorogenic acid may slow glucose absorption and improve insulin sensitivity
⚠ Most evidence is from observational studies and in vitro research. Randomized controlled trials are limited. Individual responses vary based on gut microbiome, genetics, and overall diet. Associations do not prove causation.

Polyphenol data matched from: “Red onion, raw” · ●●● high confidence

Source: Phenol-Explorer 3.6 (INRA, 2023) · Retention: Rothwell 2013, Palermo 2014 · Health: Del Bo' 2019, Grosso 2017

Environmental Impact

Environmental footprint per kilogram of food produced. Data represents the global average for the “Onions & Leeks” category.

0.50
kg CO₂e / kg
Very Low Impact
0.37
m² land / kg
Land Use
14.0
L water / kg
Water Use
2.8
g SO₂e / kg
Acidification
How this compares (GHG emissions)
Potatoes (0.5)Chicken (9.9)Beef (99.5)
Greenhouse Gas Emissions0.50 kg CO₂e / kg
Land Use0.37 m² / kg
Water Use14.0 L / kg
Eutrophication3.2 g PO₄e / kg
Acidification2.8 g SO₂e / kg
⚠️ Important context about this data
  • Global averages: These figures are production-weighted averages from a meta-analysis of ~38,700 farms across 119 countries (Poore & Nemecek, 2018). Actual impact varies enormously by farming method, geography, and supply chain.
  • System boundary: Cradle-to-retail only — does not include consumer transport, home cooking energy, or food waste.
  • Soil carbon not included: This data does not account for soil carbon sequestration. Some argue that well-managed regenerative grazing partially offsets ruminant emissions; however, full lifecycle accounting — including methane, land-use change, and the opportunity cost of using land for grazing vs. reforestation — typically makes the net footprint of ruminant meat higher, not lower. This is especially relevant in temperate grassland regions like Ireland.
  • Not gospel: This data is informational and illustrative. It is useful for understanding relative magnitudes, but should not be treated as precise measurements for any individual product or farm.

Source: Poore & Nemecek (2018), Science 360(6392). Meta-analysis of ~38,700 farms, 119 countries, 46 product categories.

Global Supply: Vegetables

Top 10 countries by per capita supply of the “Vegetables” food group (kcal/capita/day, 2023). This is food group–level data from FAO Food Balance Sheets, not specific to this individual food.

1.
China; mainland
310
2.
China
306
3.
Albania
258
4.
North Macedonia
221
5.
Guyana
209
6.
Kazakhstan
204
7.
Oman
192
8.
Uzbekistan
190
9.
Tajikistan
186
10.
Bosnia and Herzegovina
183

Global Supply Trend (1961–2023)

+76%
1961: 38 kcal2023: 67 kcal

Source: FAO Food Balance Sheets (2023). Supply = production + imports − exports − waste, converted to kcal/capita/day.

Frequently Asked Questions

How many calories are in Onions, sweet, raw?

Onions, sweet, raw contains 32.0 kcal per 100 grams, making it a low-calorie food. The energy comes from 0.80g of protein (10% of calories), 0.08g of fat (2%), and 7.5g of carbohydrates (94%). Carbohydrates are the primary energy source.

What is Onions, sweet, raw most nutritious for?

The standout nutrient in Onions, sweet, raw is Vitamin B6, providing 0.13 mg per 100g (10% of the Daily Value). It is also a notable source of Copper (6% DV). Our database tracks 72 individual nutrients for this food, allowing detailed comparison across vitamins, minerals, amino acids, and fatty acids.

Is Onions, sweet, raw high in protein?

At 0.80g per 100 grams, Onions, sweet, raw is not a significant source of protein. Pair with protein-rich foods like legumes, meat, fish, or dairy to meet daily protein needs.

How much fiber is in Onions, sweet, raw?

Onions, sweet, raw contains 0.90g of fiber per 100 grams, which is a small amount. To increase fiber intake, consider pairing with high-fiber foods such as legumes, whole grains, or vegetables.

Does Onions, sweet, raw contain polyphenols?

Yes, Onions, sweet, raw contains approximately 168 mg of polyphenols per 100g, primarily from the high class. Polyphenols are bioactive plant compounds associated with antioxidant properties. Their retention can vary with cooking and processing methods — see the processing impact section above for details.

What is the insulin index of Onions, sweet, raw?

Onions, sweet, raw has a high insulin response (II: 69) (estimated from macronutrient composition) on the insulin index scale (white bread = 100). Foods with high insulin scores stimulate significant insulin release, which may be relevant for blood sugar management. Note that the insulin index can differ substantially from the glycemic index — dairy products and high-protein foods often have higher insulin responses than their GI would suggest.