12 Reasons Fennel Is So Good for You, According to a Nutritionist

Fennel (Foeniculum vulgare) may be less familiar than broccoli or zucchini, but this bulbous fall vegetable and its seeds deserve to be part of your regular rotation. Fennel boasts nutrients such as fiber, potassium, and vitamin C.

A member of the carrot family, this slightly sweet vegetable may support brain health, digestive health, and more. Here is more about fennel's nutrients and potential health benefits, what it tastes like, and how to incorporate it into raw and cooked dishes.

Benefits of Fennel

Fennel boasts health-protective nutrients and may improve the health of your skin, bones, digestive system, and more.

Abundant in Health-Protective Nutrients

Studies show that fennel contains health-protective antioxidants and valuable antimicrobial, antiviral, anti-fungal, and anti-inflammatory compounds.1 It's no surprise, then, that fennel has long been used as a medicinal plant for a wide range of issues related to digestive, endocrine, reproductive, and respiratory systems and as a milk stimulant for lactating parents.2

Alleviates Symptoms of Menopause

For people going through menopause, the health benefits of fennel are primarily tied to its oil. A 2019 paper reviewed the positive effects of fennel oil in the management of painful menstruation, premenstrual syndrome, missing periods, menopause, lactation, and polycystic ovary syndrome.3

The paper cites one study in which postmenopausal women taking 100 milligrams of fennel oil twice daily for eight weeks improved their scores on a menopause rating scale compared with women on a sunflower oil placebo. They experienced a reduction in symptoms such as hot flashes, insomnia, and night sweats.

Consult with a healthcare provider to determine if you can benefit from fennel oil, which formulation to buy, and how to use it—as well as to monitor any potential interactions, allergic reactions, or other side effects. This is especially important if you're pregnant or trying to conceive. Fennel supplements may also interfere with the effectiveness of birth control pills.

Eases Menstrual Cramps

Fennel may soothe menstrual cramps, which can be helpful if your cramps keep you from attending school or work or participating in your daily activities.4

This might be because fennel may decrease the number of prostaglandins in your body.3 Prostaglandins are chemicals that help your uterine muscles contract and shed the tissue that lines the inside of your uterus (also called the endometrium). People who have excessive prostaglandins may experience more frequent, painful contractions than normal.5

Additionally, fennel has nitrites, which aid blood flow.6 Therefore, nitrites may also help the endometrium shed more easily and quickly than normal.

Helps Ease Pain

A 2020 study looked at the effect of fennel on people with knee osteoarthritis. Sixty-six patients were randomly assigned to receive either a capsule containing powdered fennel extract, or a placebo, daily for two weeks. The fennel group experienced a reduction in pain and stiffness that was higher than in the control group.7

Improves Bone Health

Fennel is also an excellent source of calcium, which keeps your bones healthy. Calcium is vital for bone strength. A lack of calcium can increase your risk of developing osteoporosis and bone fractures.8

May Aid Weight Management

One of the organic compounds found in fennel—anethole—may naturally suppress appetite, which can be beneficial if you're trying to manage your weight.

In a study published in 2015, researchers gave nine women three different teas, one of which included fennel.9 After the participants consumed the teas, the researchers presented them with a buffet and analyzed the food the participants consumed. All in all, the researchers found that after drinking fennel tea, participants reported less hunger and more feelings of being full, compared to those who drank placebo tea.

However, it is important to remember that the sample size of that study is small, and the supposed appetite-suppressing qualities of fennel may not be true for every person.

May Benefit Digestion

The seeds from fennel plants are commonly used as a type of spice to season food. Medicinally, fennel seeds have also been used to treat bloating and gas via a tea made from a small spoonful of the seeds and hot water, steeped for 20 minutes, and sipped a half hour after a meal.

This may work because fennel and its seeds offer fiber, which supports digestion.10

May Promote Healthy Skin

Fennel packs vitamin C, an antioxidant that reduces cell damage caused by free radicals, which are harmful substances partly produced by ultraviolet (UV) exposure. Free radicals may contribute to skin cancer and premature aging.11

Although more research is needed, foods that pack antioxidants (like fennel) might help reduce the damage from UV exposure.12 Either way, you should also limit your UV exposure and wear SPF of at least 30.13

May Protect Against Chronic Diseases

The vitamins and minerals and compounds found in fennel may help prevent certain chronic diseases, like cardiovascular diseases and cancer.10

For instance, fennel packs fiber. Fiber is one nutrient that can lower your risk of heart disease.10

Also, the anethole found in fennel might help lower the risk of developing or furthering the growth of certain cancers. In a study published in 2021, researchers found that anethole helps trigger apoptosis.14 Apoptosis is programmed cell death, an essential process to prevent the development and spread of cancer cells.

Promotes Brain Health

Some research has pointed to fennel helping prevent degenerative diseases, like Alzheimer's disease.

In a 2017 study, researchers studied the antioxidants found in the essential oils (EOs) and aqueous extracts of four herbs, including fennel.15 After evaluating the herbs, the researchers found that they may help reduce oxidative stress, which damages your cells.

Based on their findings, the researchers concluded that fennel is among the herbs that can help reduce cognitive decline.

Reduces Risk of Anemia

Iron is one of the minerals found in fennel. Iron is an important component of hemoglobin, which is a protein that transports oxygen from your lungs to different parts of your body.16

People who have low levels of iron may develop anemia, a condition that can cause weakness and fatigue, among other symptoms. Because of the iron content, fennel can help replenish some of the iron in your body if you have—or are trying to avoid—a deficiency.17

Supports Eye Health

Fennel packs antioxidants that fight eye diseases, like macular degeneration. For example, per a study published in 2013, vitamin C—found in fennel—helps support your eyes. Vitamin C even helps regenerate other antioxidants that support eye health, such as vitamin E.18

Nutrition of Fennel

According to the United States Department of Agriculture, one cup of raw fennel slices has the following nutritional profile:19

• Calories: 27 calories
• Fat: 0.17g
• Sodium: 45.2mg
• Carbohydrates: 6.35g
• Fiber: 2.7g
• Protein: 1.08g
• Vitamin C: 10.4mg

A cup of raw fennel slices contains just 27 calories, with nearly three grams of fiber, which is essential for digestive health. It packs nearly 12% of the daily goal for immune-supporting vitamin C. Fennel also contains potassium, manganese, calcium, iron, and B vitamins.19

Risks of Fennel

Like all foods, you should enjoy fennel in moderation. Too much fennel may expose you to estragole, a carcinogen found in fennel, and may promote the growth of cancer cells.20

Children may be particularly vulnerable to the effects of estragole. Research from 2014 found that children have a margin of exposure when drinking one to three cups of fennel tea a day which calls for priority for risk management. The margin of exposure is a measurement of safety concerns within the food.20

Moreover, some herbs (including fennel) may cause nipple discharge.21 Fennel can also interact with certain medications, such as Tamoxifen, which is a treatment for breast cancer.22

Additionally, fennel can negatively affect pregnant people and developing fetuses. For example, in one study published in 2015, researchers found that regular use of fennel during pregnancy was associated with a lower gestational age.23

People with seizure disorders should avoid fennel essential oil since it can induce seizures in some people.24

You should check with a healthcare provider before using fennel as an oil or supplement, especially if you have any underlying conditions.

Tips for Consuming Fennel

Fennel has a licorice-like aroma, but the fresh bulb is light, bright, and mild. The taste is slightly sweet with a hint of perfumy flavor, but it's delicate and not overpowering.

When shopping for fresh fennel, look for a small- to medium-sized heavy, intact white bulb that's unbruised, with bright green firm stalks and feathery leaves. Fennel seeds have a stronger anise flavor that's warm and sweet. This is why they're typically used as a seasoning, rather than eaten like sunflower or pumpkin seeds.

You can eat fennel raw or cooked. Consider preparing it in one of the following ways:

• Shave or thinly slice the bulb and add the shavings to salads along with sliced apples.
• Marinate in a lemony extra virgin olive oil (EVOO) vinaigrette.
• Sauté it in EVOO on the stovetop.
• Oven roast in EVOO that's been seasoned with sea salt and black pepper.

Most recipes call for the bulb, but the delicate green tops are also edible. You can mince and use them as a garnish for everything from mashed cauliflower to roasted spaghetti squash and lentil soup.

Look for fennel seeds in the spice aisle. Add them to hearty dishes, like lentil bolognese, potato or white bean soup, or homemade bread.

A Quick Review

Fennel is a delicious and slightly sweet vegetable that makes a great addition to a healthy diet. Among other benefits, it may aid in weight management, help relieve pain, and reduce your risk of chronic diseases.

Just be sure to contact a healthcare provider before using fennel in the form of oils or supplements.