Fennel as a food, a spice or a medicine has a wide range of actions protecting digestion, alleviating menopausal symptoms and improving respiratory function. Here, we explore the benefits of fennel in all its forms.
Fennel (Foeniculum vulgare) is a tall perennial herb of the Apiaceae or carrot family, native to the Mediterranean region but today widely cultivated worldwide. The name foeniculum comes from the Romans meaning “fragrant hay”. The whole plant is used medicinally as a culinary food, herb and spice. The stronger-tasting seeds taste like aniseed or liquorice. The seeds (actually the fruits of the plant) are used as a spice and are one component of the Chinese five-spice powder and are also used to flavour baked foods, meat and fish dishes, ice cream, alcoholic spirits and herbal teas. The fresh green seeds are the best for cooking (they go grey as they age). The root bulb, stalks and leaves are eaten as a vegetable both raw and cooked, in side dishes, salads, pastas and vegetable dishes. In India, fennel is one of the most important spices in Kashmiri, Pandit and Gujarat cooking.
Active ingredients
Fennel contains antioxidant and anti-inflammatory components such as rosmarinic acid, quercetin, rutinoside and kaempferol. The volatile oil contains anethole, estragole and fenchone. Bitter fennel has greater medicinal properties than sweet fennel. The seeds of bitter fennel contain at least 4 per cent volatile oil.
All parts of the fennel plant are used as food and medicine and contain a range of minerals, being high in calcium and potassium as well as sugars and vitamins, with the seeds being the highest concentrated source. It is also a reasonable source of fatty acids, the highest content being in the leaves. The plant is high in carbohydrates and low in protein.
The therapeutic benefits of fennel
Digestive
Fennel seeds are aromatic, stimulant, and carminative (reducing wind), so one of their main uses medicinally is to reduce flatulence and griping in adults and infants. It is commonly prescribed along with purgatives to reduce the side effects of pain and griping. As such it was a major component of the traditional “gripe water”, along with syrup and sodium bicarbonate. It is particularly useful in infants and children.
Fennel increases gastrointestinal motility and acts as an antispasmodic and anti-inflammatory, reducing pain, inflammatory bowel diseases and many digestive symptoms. It also has antiulcerogenic activity and reduces gastric mucosal damage from various sources including alcohol.
Respiratory
Fennel syrup used to be given to reduce chronic coughing as it has a secretory activity in the mucous membrane, along with increasing the mucociliary activity of the ciliary epithelium. It is particularly useful in treating bronchial conditions, even in particularly polluted environments.
Hormonal balancing
Fennel has traditionally been used as an oestrogenic agent, where it has been reported to increase milk secretion, promote menstruation, facilitate birth, alleviate symptoms of andropause (male menopause) and increase libido.
Reducing the unpleasant symptoms of menopause in women is another of the benefits of fennel. Clinical trials have demonstrated the effectiveness of a vaginal cream made from fennel in having a significant effect on improving menopausal vaginal dryness, thereby improving sexual activity in postmenopausal women. Applying the cream (five grams every night for eight weeks) showed improvement in all areas of sexual function including arousal, lubrication, orgasm, sexual satisfaction and pain relief, without any adverse side effects.
Galactagogue
The phytoestrogens in fennel improve the milk supply of a breast-feeding mother by promoting the growth of breast tissue.
Antihirsutism
Fennel has been shown to reduce excessive male pattern hair growth in women as it regulates disorders of peripheral androgen metabolism (including testosterone), particularly when used as a 2 per cent cream.
Anti-inflammatory
The compound anethole has been shown to have anti-inflammatory and antitumour properties, possibly acting through nuclear factor kappa B (NFkB)and tumour necrosis factor (TNF) and inducing apoptosis in various cancers.
The extract of fennel seeds has also shown inhibitory effects against both acute and chronic inflammatory conditions, including type IV allergic reactions.
Antithrombotic activity
The essential oil of fennel has been shown to have a safe antithrombotic activity due to broad spectrum antiplatelet activity, a clot destabilising effect and vasorelaxant action. These studies using rats also showed that fennel oil provided protection against alcohol-induced gastric lesions.
Eyesight
Rat studies have shown that fennel can reduce the incidence of glaucoma as it reduces eye pressure.
Hepatoprotective
The benefits of fennel as an essential oil also include reducing hepatotoxicity by lowering the liver enzymes AST, ALT, ALP and bilirubin.
Antibacterial and antifungal
The essential oil from fennel seeds (as well as the fennel seed extracts) have exhibited antibacterial effects against a range of food-borne pathogens including E. coli, Staphylococcus aureus, H. pylori, Camphylobacter jejuni etc, including multidrug-resistant forms.
Fennel oil and fennel seed extracts have also been shown to have antifungal activity against Candida albicans, Aspergillus niger and flavus and Fusarium moniliforme at a 6μL dose.
Using fennel
Fennel seed, including fennel oil, is not recommended in pregnancy due to its oestrogenic properties (although this is unclear and has not been determined by clinical trials), but otherwise, as a food and medicine it has been used for millennia without any documented serious adverse effects.
References available on request.
Dr Karen Bridgman is a holistic practitioner at Lotus Health and Lotus Dental in Neutral Bay.
