5 Fennel Health Benefits: Fiber, Vitamin C, Potassium

Jul 03, 2023

Plus vitamin C!

Seraphina is a health writer with a background as a registered dietitian.

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Want a vegetable that adds depth of flavor to the dish you’re making? You can't go wrong with fennel, a vegetable that's also an herb—and that's full of healthy properties. Fennel's bulb has a distinctive fragrance that resembles anise or licorice (which is, admittedly, not everyone's favorite), but when eaten raw, it has quite a sweet, mild flavor and fresh, crispy texture, which is why it works well when it's shaved into salads. Cooking fennel brings out even more of its natural sweetness. It's utterly delicious when braised, roasted, sautéed, or grilled.

This uniquely flavored veggie is also packed with nutritional benefits, helping to support gut health, blood pressure levels, your immune system, and more. Registered dietitians explain fennels’ top health benefits. Then find our favorite fennel-studded recipes to try any day of the week.

Adults should ideally consume 25 to 30 grams of fiber per day according to the American Heart Association recommendations. A cup of sliced fennel provides you with 10 percent of the recommended DV of fiber. You may link fiber to gut health, and it's true, Fiber does wonders for maintaining a healthy gut microbiome (the collection of bacteria and other microorganisms living naturally in your gut lining) and for keeping your trips to the bathroom regular and easy.

What's more, "fiber can help with blood sugar control by slowing down the digestion and metabolism of carbohydrates, and can help with lowering cholesterol, which can help prevent heart disease," says Talia Follador, RDN, LDN, registered dietitian and owner at Follador Nutrition Services.

A cup of sliced fennel contains 360 milligrams of potassium, which is 7 percent of the recommended daily value (DV). Potassium is a mineral that helps to keep your blood pressure at a healthy range, Follador explains. It does this by helping blood vessels relax and increasing the amount of sodium the kidney removes from your blood. (Note: If you have kidney disease, be sure to check in with your doctor or dietitian first before consuming too much potassium.)

Move over citrus fruits—did you know a cup of sliced fennel provides up to 13 percent of the recommended DV of vitamin C? Vitamin C is needed to help build immune cells and strengthen your immunity, in order to prevent or help fight infections, Follador says. The production of collagen, which is what gives your skin its structure and firmness, requires vitamin C, too.

Vitamin C is also an antioxidant and supports the regeneration of other antioxidants in the body. Antioxidants lower the levels of reactive oxygen species, which your body produces just by doing day-to-day activities and from being exposed to things in your environment, explains Mckenzie Caldwell, MPH, RDN, fertility and prenatal dietitian at Feed Your Zest Nutrition & Wellness. According to Follador, excessive levels of reactive oxygen species can damage DNA, weaken the immune system and cause cell breakdown.

Fennel also has smaller amounts of the minerals calcium, magnesium, and iron. "Both calcium and magnesium make up the structure of your bones," Follador says. "Consuming enough calcium and magnesium can help prevent osteoporosis and promote strong bones." These minerals also help your heart and muscles contract properly.

Iron is essential for the formation of red blood cells, which carry oxygen to all parts of your body. According to Follador, not getting enough iron may lead to low levels of red blood cells, which makes it harder for the body to transport oxygen throughout the body and lead to you experiencing tiredness, weakness, or fatigue, so foods with iron are an important part of a healthy diet.

Fennel is a phytoestrogen, meaning that it mimics estrogen, a hormone in the body. In menopause, when estrogen levels fall, consuming fennel might be helpful for alleviating some symptoms, Caldwell explains. However, it might not be ideal to consume copious amounts of fennel if you have endometriosis or are pregnant or breastfeeding. "We don't want to mess with the hormones too much in these cases," Caldwell says.

Greg DuPree