Fennel vs. Onion
Nutrition comparison of Fennel and Onion
Ever wonder how your favorite foods stack up against each other in terms of nutrition?
We compared the nutritional contents of
fennel
versus
onion
(100g each)
below using 2020 USDA and NIH data[1].
For a quick recap of significant nutrients and differences in fennel and onion:
- Fennel is a great source of calcium.
- Fennel is an excellent source of dietary fiber and potassium.
- Onion has more thiamin and Vitamin B6, however, fennel contains more niacin and pantothenic acid.
USDA sources for nutritional information: Fennel (Fennel, bulb, raw) and Onion (Onions, raw) . Have a correction or suggestions? Shoot us an email.
Calories and Carbs
calories
Fennel and onion contain similar amounts of calories - fennel has 31 calories per 100 grams and onion has 40 calories.
For macronutrient ratios, fennel is lighter in carbs, heavier in fat and similar to onion for protein. Fennel has a macronutrient ratio of 14:81:6 and for onion, 11:88:2 for protein, carbohydrates and fat from calories.
Macro Ratios from Calories:
| Fennel | Onion | |
|---|---|---|
| Protein | 14% | 11% |
| Carbohydrates | 81% | 88% |
| Fat | 6% | 2% |
| Alcohol | ~ | ~ |
carbohydrates
Fennel and onion contain similar amounts of carbs - fennel has 7.3g of total carbs per 100 grams and onion has 9.3g of carbohydrates.
dietary fiber
Fennel is an excellent source of dietary fiber and it has 82% more dietary fiber than onion - fennel has 3.1g of dietary fiber per 100 grams and onion has 1.7g of dietary fiber.
sugar
Fennel and onion contain similar amounts of sugar - fennel has 3.9g of sugar per 100 grams and onion has 4.2g of sugar.
Protein
protein
Fennel and onion contain similar amounts of protein - fennel has 1.2g of protein per 100 grams and onion has 1.1g of protein.
Fat
saturated fat
Both fennel and onion are low in saturated fat - fennel has 0.09g of saturated fat per 100 grams and onion has 0.04g of saturated fat.
Vitamins
Vitamin C
Fennel has 62% more Vitamin C than onion - fennel has 12mg of Vitamin C per 100 grams and onion has 7.4mg of Vitamin C.
Vitamin A
Fennel has more Vitamin A than onion - fennel has 48ug of Vitamin A per 100 grams and onion does not contain significant amounts.
Vitamin E
Fennel and onion contain similar amounts of Vitamin E - fennel has 0.58mg of Vitamin E per 100 grams and onion has 0.02mg of Vitamin E.
Vitamin K
Fennel has 156 times more Vitamin K than onion - fennel has 62.8ug of Vitamin K per 100 grams and onion has 0.4ug of Vitamin K.
The B Vitamins
Onion has more thiamin and Vitamin B6, however, fennel contains more niacin and pantothenic acid. Both fennel and onion contain significant amounts of riboflavin and folate.
| Fennel | Onion | |
|---|---|---|
| Thiamin | 0.01 MG | 0.046 MG |
| Riboflavin | 0.032 MG | 0.027 MG |
| Niacin | 0.64 MG | 0.116 MG |
| Pantothenic acid | 0.232 MG | 0.123 MG |
| Vitamin B6 | 0.047 MG | 0.12 MG |
| Folate | 27 UG | 19 UG |
Minerals
calcium
Fennel is a great source of calcium and it has 113% more calcium than onion - fennel has 49mg of calcium per 100 grams and onion has 23mg of calcium.
iron
Fennel has 248% more iron than onion - fennel has 0.73mg of iron per 100 grams and onion has 0.21mg of iron.
potassium
Fennel is an excellent source of potassium and it has 184% more potassium than onion - fennel has 414mg of potassium per 100 grams and onion has 146mg of potassium.
Antioxidants and Phytonutrients
flavonoids
Naturally occuring in fruits and vegetables, flavonoids are associated with many health benefits and used in a variety of medicinal and pharmaceutical applications. [2][3]
For specific flavonoid compounds,
| Fennel | Onion | |
|---|---|---|
| Quercetin | 0.23 mg | 20.3 mg |
| apigenin | ~ | 0.01 mg |
| luteolin | ~ | 0.02 mg |
| isorhamnetin | ~ | 5.01 mg |
| kaempferol | ~ | 0.65 mg |
| myricetin | ~ | 0.03 mg |
Omega-3 and Omega-6
omega 6s
Comparing omega-6 fatty acids, fennel has more linoleic acid than onion per 100 grams.
| Fennel | Onion | |
|---|---|---|
| linoleic acid | 0.169 G | 0.013 G |
| Total | 0.169 G | 0.013 G |
Customize your serving size
The comparison below is by common portions, e.g. cups, packages. You can also see a more concrete comparison by weight at equal weight (by grams) comparison.
Fennel g
()
|
Daily Values (%) |
Onion g
()
|
|||||
|---|---|---|---|---|---|---|---|
| KCAL % |
|
5% | calories | 5% |
|
KCAL % | |
| G % |
|
5% | carbohydrates | 5% |
|
G % | |
| G % |
|
5% | dietary fiber | 5% |
|
G % | |
| G | 5% | sugar | 5% | G | |||
| G % |
|
5% | total fat | 5% |
|
G % | |
| G % |
|
5% | saturated fat | 5% |
|
G % | |
| G | 5% | monounsaturated fat | 5% | G | |||
| G | 5% | polyunsaturated fat | 5% | G | |||
| G | 5% | trans fat | 5% | G | |||
| MG | 5% | cholesterol | 5% | MG | |||
| MG % |
|
5% | sodium | 5% |
|
MG % | |
| 5% | Vitamins and Minerals | 5% | |||||
| UG % |
|
5% | Vitamin A | 5% |
|
UG % | |
| MG % |
|
5% | Vitamin C | 5% |
|
MG % | |
| IU % |
|
5% | Vitamin D | 5% |
|
IU % | |
| MG % |
|
5% | calcium | 5% |
|
MG % | |
| MG % |
|
5% | iron | 5% |
|
MG % | |
| MG % |
|
5% | magnesium | 5% |
|
MG % | |
| MG % |
|
5% | potassium | 5% |
|
MG % | |
| MG % |
|
5% | thiamin (Vit B1) | 5% |
|
MG % | |
| MG % |
|
5% | riboflavin (Vit B2) | 5% |
|
MG % | |
| MG % |
|
5% | niacin (Vit B3) | 5% |
|
MG % | |
| MG % |
|
5% | Vitamin B6 | 5% |
|
MG % | |
| MG % |
|
5% | pantothenic acid (Vit B5) | 5% |
|
MG % | |
| UG % |
|
5% | folate (Vit B9) | 5% |
|
UG % | |
| UG % |
|
5% | Vitamin B12 | 5% |
|
UG % | |
| MG % |
|
5% | Vitamin E | 5% |
|
MG % | |
| UG % |
|
5% | Vitamin K | 5% |
|
UG % | |
| G % |
|
5% | protein | 5% |
|
G % | |
| UG % |
|
5% | biotin (Vit B7) | 5% |
|
UG % | |
| MG % |
|
5% | choline | 5% |
|
MG % | |
| MG % |
|
5% | chlorine | 5% |
|
MG % | |
| UG % |
|
5% | chromium | 5% |
|
UG % | |
| MG % |
|
5% | copper | 5% |
|
MG % | |
| UG % |
|
5% | fluoride | 5% |
|
UG % | |
| UG % |
|
5% | iodine | 5% |
|
UG % | |
| MG % |
|
5% | manganese | 5% |
|
MG % | |
| UG % |
|
5% | molybdenum | 5% |
|
UG % | |
| MG % |
|
5% | phosphorus | 5% |
|
MG % | |
| UG % |
|
5% | selenium | 5% |
|
UG % | |
| MG % |
|
5% | zinc | 5% |
|
MG % | |
| G | 5% | Water | 5% | G | |||
| G | 5% | Starch | 5% | G | |||
| G | 5% | Alcohol | 5% | G | |||
FAQ
Does fennel or onion contain more calories in 100 grams?Fennel and onion contain similar amounts of calories - fennel has 31 calories in 100g and onion has 40 calories.
Does fennel or onion have more carbohydrates?
By weight, fennel and onion contain similar amounts of carbs - fennel has 7.3g of carbs for 100g and onion has 9.3g of carbohydrates.
Does fennel or onion contain more potassium?
Fennel is a rich source of potassium and it has 180% more potassium than onion - fennel has 414mg of potassium in 100 grams and onion has 146mg of potassium.