Fennel is crunchy and slightly sweet, adding a refreshing contribution to the ever popular Mediterranean cuisine, but is most often associated with Italian cooking. Like many of its fellow spices, fennel contains its own unique combination of phytonutrients-including the flavonoids Rutin, Quercitin, and various Kaempferol glycosides-that give it strong antioxidant activity. The Phytonutrients in fennel extracts compare favourably in research studies to BHT (butylated hydroxytoluene), a potentially toxic antioxidant commonly added to processed foods.
The most fascinating phytonutrient compound in fennel, however, may be anethole-the primary component of its volatile oil. In animal studies, the anethole in fennel has repeatedly been shown to reduce inflammation and to help prevent the occurrence of cancer. Researchers have also proposed a biological mechanism that may explain these anti-inflammatory and anticancer effects. This mechanism involves the shutting down of a intercellular signalling system called tumour necrosis factor (or TNF)-mediated signalling. By shutting down this signalling process, the anethole in fennel prevents activation of a potentially strong gene-altering and inflammation-triggering molecule called NF-kappaB. The volatile oil has also been shown to be able to protect the liver of experimental animals from toxic chemical injury.
In addition to its unusual phytonutrients, fennel bulb is an excellent source of vitamin C. Vitamin C is the body's primary water-soluble antioxidant, able to neutralize free radicals in all aqueous environments of the body. If left unchecked, these free radicals cause cellular damage that results in the pain and joint deterioration that occurs in conditions like osteoarthritis and rheumatoid arthritis.
The vitamin C found in fennel bulb is directly antimicrobial and is also needed for the proper function of the immune system.
As a very good source of fibre, fennel bulb may help to reduce elevated cholesterol levels. And since fibre also removes potentially carcinogenic toxins from the colon, fennel bulb may also be useful in preventing colon cancer. In addition to its fibre, fennel is a very good source of folate, a B vitamin that is necessary for the conversion of a dangerous molecule called homocysteine into other, benign molecules. At high levels, homocysteine, which can directly damage blood vessel walls, is considered a significant risk factor for heart attack or stroke. Fennel is also a very good source of potassium, a mineral that helps lower high blood pressure, another risk factor for stroke and heart attack. In a cup of fennel, you'll receive 10.8% of the daily value for fibre, 5.9% of the DV for folate, and 10.3% of the DV for potassium.