Fennel seeds come from a flowering plant that is also a relative of carrots. As a naturally wild flower fennel grew into several other plant species including the giant fennel, sea fennel (or rock samphire) and fennel flower. Farming and cultivation of fennel produced a root vegetable with a large white bulb and green stalks. Seeds from flowers possess unique and refreshing flavour profile, making it a popular ingredient in cuisines around the world. Besides being one of the kitchen’s favourite spices, many cultures utilize fennel for its medicinal properties. Dried fennel seeds are used in tonics for soothing sore throat to increasing milk production in breastfeeding mothers. But, fennel’s biggest attribute is the digestive health. In this article, we’ll take a look and cover some of fennel seed health and wellness powers.

Heart Health—Lowers Cholesterol

Heart Health—Regulates Blood Pressure

Improves Liver and Kidney Health

Promotes Weight Loss

Promotes Bone Health

Treats All Inflammation

Helps Heal Wounds

Strong Anti-Cancer Agent

Helps Fight Bacterial Infections

Brain Health and Cognition

Improves Eyesight

Promotes Healthy Skin

Micronutrient Profile

Possible Drawbacks

Final Thoughts

History of Fennel

Fennel (Foeniculum vulgare) is a perennial herb with yellow flowers and feathery looking leaves. It belongs to a parsley family (Umbelliferae), a large assembly of herbs and spices including dill, anise, cumin, caraway, and others. Originating from the Mediterranean shores of southern Europe wild fennel plants quickly gained popularity with native populations, and steadily spread to many other parts of the globe. Flowers of fennel plant contain a sweet licorices-like aroma  with similar taste the anise plant.

Florence Fennel or finocchio is a fennel cultivated into a root vegetable that has a large swollen bulb stem. Finnochio carries many of the same taste and health profiles as its seed variety and is a popular dish in many cultures. [1]

Fennel’s history dates back to the Ancient Romans and Greeks, often mentioned within their traditional texts. Hippocrates (430 – 370 BC) “Father of Medicine” (physician’s oath is named after him) suggested fennel to wet nurses to increase their milk supply. Ancient Greeks believed that when fennel is steeped as a tea or tonic, it can help with weight lose. The Greeks called fennel Marathron – meaning to grow thin, as it was mentioned in their old texts of the famous battle between Marathon and Persia (490 BC). Courier Pheidippides used fennel stalk during his extreme long-distance runs between Athens and Sparta. He ran a distance of 280 km (~175 miles) in three days, requesting help and delivering news of victory back to Athens.

Pliny (23 – 79 AD), the Roman author wrote of fennel’s abilities to treat ailments from observing snake’s behaviour around this herb. Romans, Chinese and Hindus, all used fennel as part of traditional remedies and as an antidote for poisonous mushrooms, and snake bites. Fennel has also made its way into cultural rituals and superstitions to drive away evil spirits. [2]

Old Anglo-Saxons also held fennel in high regard. The 10th century Old English term finule described this herb in their Nine Herbs Charm. King Edward I of England, would purchase over four kilograms (8.5 pounds) of fennel seed per month, to help suppress appetite during Church’s fasts.

Due to its ability to grow wildly within dry soils close to sea and river beds, fennel continued to spread out and cultivate the rest of Europe. In 15th century, the Portuguese settlers of Madeira noticed wild fennel in abundance calling it funcho, and later naming new town after it – Funchal. Henry W. Longfellow was an American poet and educator who’s 1842 poem “The Goblet of Life” repeatedly mentions fennel and its power to strengthen eyesight. [1]

As a wild plant, fennel evolved in numerous climates, becoming a common cultural ingredient of many countries. The seeds are used as a cooking spice, eaten raw or with a sweetener. Currently, India is the largest producer of fennel, boosting approximately 60% of world’s production. China and Bulgaria are the other leading producers of this herb.

What is Fennel?

Native to southern Europe, fennel’s popularity grew all over the globe. This herbaceous plant can grow up to two meters (6 feet 8 inches) tall with green feathery / lacy looking leaves and yellow flowers in umbels. Fennel seeds closely resemble anise seeds in appearance, are long and light brown in colour with vertical thin stripes.

Fennel seeds have been used throughout history to also treat various health conditions. As an herb, it symbolizes longevity, courage and strength. From ancient times, fennel was used as an antidote against snake bites, treating digestive discomforts and eyesight. [3,4]

The strong flavour and aroma of fennel comes from its active compound anethole, also found in similar tasting spices such as anise and star anise. Since the Renaissance, European merchants extracted oil form fennel, which led to research and identity of its active compounds. In 1866, anethole was correctly identified from fennel oil extracts. [5]

Fennel contains numerous phytonutrients with wide range of health benefits. The list is extensive packed with various antioxidants, dietary fiber, minerals and vitamins. Some of fennel’s powerful antioxidants include flavonoids like kaempferol, and quercetin, both are big anti-cancer research targets. Besides anethole, fennel also contains other well established active compounds which promote digestive health, fight pathogens, detoxify body systems, boost immunity and reduce inflammation. [3,6]

Fennel’s Immense Benefits

Fennel seed’s aromatic and sweet flavour makes it a popular addition to many dishes and drinks. The aromatic compounds within the herb also possess many medicinal properties. From the ancient Greeks to modern science, fennel’s popularity, research and applications continues on. Lets take a closer look into the powers of this abundant seed.

Antioxidant Benefits

As we discussed in other articles, our metabolism produces free radicals [also known as reactive oxygen species (ROS)] as byproducts of various biochemical pathways. The body maintains an internal balance between ROS and antioxidants which comes handy in form of the immune response against foreign invaders. But when that balance is tilted and free radical levels rise, the solutions turn to problems in every body system. ROS overflow disrupt, destabilize and damage many of the compound type enzymes, structural cells and genetic material (DNA). This influx of free radicals is referred to oxidative stress, which invokes body’s immune system to work non-stop, seeking out and destroying the damage compounds. The main form of immune response is through inflammation of affected area, and oxidative stress causes continuous or chronic inflammation.

Traditionally fennel symbolized longevity, courage and strength. Its flavours and health benefits come from numerous phytonutrients within. Fennel’s active compounds comprise of various types of powerful antioxidants, including: [3,4,5,6,7,8]

  • Numerous polyphenols – Polyphenols consist of four types of molecules. Flavonoids being the biggest one (with over 4,000 identified compounds), which include eriodictyol, kaempferol and quercetin. These antioxidants possess strong anti-inflammatory and antibacterial properties.
  • Phenolic acids like caffeoylquinic acid, rosmarinic acid and chlorogenic acid. All these polyphenols, are also powerful antioxidants, scavenge and neutralize harmful free radicals, and reduce oxidative stress. Flavonoids are big research topics showing protective properties against various infections, aging, neurodegenerative diseases and cancers.
  • Anethole is the main active ingredient of the fennel seed. It is a strong antioxidant and antibacterial agent. This chemical is classified as a terpene, a large family of plant produced compounds, far smaller in size to polyphenols, but none-less important. Terpenes are the major building blocks of many vital compounds (like steroids), and possess extensive health properties. Anethole participates in various biochemical pathways but also has unique ability to effect women’s health by mimicking estrogen—an important sex and metabolic hormone. Also, anethole can affect another hormone prolactin—responsible for milk production in breastfeeding females.
  • Besides anethole, fennel’s essential oil carry other health-benefiting terpenes like limonene, anisic aldehyde, pinene, myrcene, fenchone, chavicol, and cineole. Due to smaller size, these ingredients come in slight chemical arrangements (isomers) and variations (chemotypes). All of these compounds have shown substantial antioxidant, detoxification, digestive, and anti-cancer properties.
  • Fennel seeds contain a large list of vitamins such as Vitamin-A, vitamin-E, vitamin-C as well as many B-complex (thiamin, pyridoxine, riboflavin and niacin). Some of these vitamins come in high concentrations and are strong antioxidants (like vitamins E and C).
  • Fennel is also a good source of minerals like copper, iron, calcium, potassium, manganese, selenium, zinc, and magnesium. Important for bone health, manganese plays various roles including the function the antioxidant enzyme, superoxide dismutase (SOD).

Decreases Colic in Children

Adding fennel to dishes will not only enhance flavour profiles but overall digestive process.  Fennel seeds have been used for generations to treat various indigestion ailments, including heart burn, bloating and flatulence. 

Being antispasmodic, fennel products reduce intestinal cramping and improve gastrointestinal (GI) flow. The term colic is focused around young children, particularly infants who are in discomfort, which is believed to stem from gas accumulation in the stomach. Fennel is well known for soothing GI tract, and used as a traditional remedy for colic infants. This cultural remedy has been supported by science. Numerous studies show that fennel (be it in ground, oil, or steeped tea form) produced relief from various digestive issues and effective treatment in colic children. [9,10]

Current colic medication such as dicyclomine hydrochloride comes with serious side effects and is inconsistent in treating related symptoms. Researchers concur fennel traditional remedies to reduce stomach discomfort and improve the flow within small intestine. Furthermore, fennel products have been extensively used from young infants to elderly, showing to be completely safe. For example, a 2003 study with 125 infants using fennel seed oil eliminated colic discomfort in 65% of tested infants, compared to only 24% decrease in symptoms within the placebo/control group. [11]

Digestive Aid and Protection

The anti-inflammatory and antispasmodic properties of fennel also alleviate variety of digestive conditions. The seeds and oils are full of active compounds like estragole (slight structural variation of anethole), fenchone and anethole—which help treat diarrhea, constipation and irritable bowel syndrome (IBS). Human trials showed that fennel decreased abdominal pains and overall IBS symptoms. The seed extract improved digestion by increasing gastric enzymes and relieving bloating and flatulence. [12]

Abdominal cramping and bloating can result by number of things, many of them relating to what we eat. Adding fennel to your diet is shown to minimize such discomforts. Wether the seeds are consumed raw, in form of essential oils or steeped in tea, the phytonutrients within relieve constipation, clear the bowels and reduce gas. Fennel can further eliminate formation of additional gases. [12-14] 

Eating raw fennel seeds before or after a meal is common in many Asian cultures. The reasoning lies within fennel’s active ingredients of antioxidant, antispasmodic and anti-flatulent properties, which stimulate digestive juices and speed up the gastrointestinal (GI) process. [15]  Anethole has been credited with numerous health benefits, and shown to improve functional dyspepsia (FD) and gastric emptying in small animals. [16]

Furthermore, fennel seeds are high in dietary fiber. 100 grams of fennel pack 39.8 grams of fiber, much of which is the insoluble type (non-digestible carbohydrates). [17] It absorbs water adding bulk to foods, producing quicker emptying times of the GI tract. This improves the function of overall digestive system and eases any constipation or bloating issues. Also, dietary fiber binds to bile salts (produced from cholesterol) reducing their re-absorption in the colon, and lowering serum LDL (aka “bad”) cholesterol levels as the result.

Another health claim of fennel is that it can decrease and even prevent alcohol causing stomach ulcers. Alcohol behaves as a reactive oxygen species (ROS) and can cause cellular damage, including the thinning of the stomach lining. Science points to anethole as the major antioxidant, anti-inflammatory compound which seeks outs and directly reacts with alcohol, decreasing stomach ulcers. [18]

Reduces Asthma and Congestion

Traditional and ancient medicines like Ayurveda have been using spiced teas to treat common colds and flu symptoms. Fennel is a popular remedy used in oil or steeped tea form producing a potent liquid against respiratory infections. Antispasmodic and anti-inflammatory properties found in fennel help clear the sinuses and relieve asthma symptoms by soothing the throat and the airways. [3]

Science also confirmed fennel’s ability to improve respiration. Though the exact mechanism is not fully understood, studies shown fennel extracts to significantly relax animal tracheal airways improving overall respiration. [19]

Dopamine is a catecholamine (benzene ring with amine and alcohol attachments) class molecule which acts as a chemical messenger and a neurotransmitter in the brain. Outside the central nervous system (CNS) dopamine plays numerous messaging roles in blood vessels, kidneys, lungs, GI tract and various glands. [20] Dopamine can also relax or inhibit soft muscle tissue within blood vessels, trachea and bronchial passages of the lungs (acting as a vasodilator). [21] Anethole is structurally similar to dopamine and may mimic its effect on various systems, therefore achieving similar results.

Improves Breast Milk Production

As a traditional remedy, fennel has been given since ancient times to new mothers and wet nurses, to increase breast milk production. Hippocrates of ancient Greece prescribed fennel to lactating women. We couldn’t find research that directly investigated this physiological effect.  However, some studies explain the biochemical process which revolves around anathole’s ability to mimic body’s natural producing chemicals, messengers and hormones.

As previously mentioned, anethole can mimic dopamine, as both compounds having similar chemical size. So, anethole can pretend to be dopamine not just in blood vessels, but everywhere else dopamine has an effect. Dopamine blocks another hormone prolactin, which stimulates breast milk production. Anethole competes for dopamine receptors, blocking the inhibitory action on prolactin. [3] A female study showed that fennel supplements increased blood prolactin levels. [22] More prolactin translates into greater breast milk production. The research is mixed on this topic and more direct studies are needed to quantify galactagogue effect of fennel. But, all of fennel studies regardless of effect were shown to be safe. [23]

Improves Women’s Health

Estrogenic Effect

As we shared earlier with comparison to dopamine, fennel’s active ingredients have the ability to mimic other hormones; estrogen is another one. Because of these estrogenic properties, fennel has been shown to reduce menstrual pains and menopause symptoms while increasing sex drive. [3]

Relieves menstrual pain

Fortify Turmeric Tulsi Tea

Fortify Tea with Fennel Seed Benefits

Dysmenorrhea is a medical term for painful menstruation. The pain usually occurs within female pelvis and lower abdomen, lasting less than 72 hours. Fennel has a long history of being used to treat these types of discomforts, reducing menstrual pains and cramps. This traditional remedy has also been investigated in human trials. Fennel capsules consumed before the period’s onset reduced the overall cycle, while decreasing symptoms like nausea and feeling weak in 40 tested women. [24] 

Another study tested the effectiveness of a natural antioxidant blend containing fennel extract and vitamin E. This potent antioxidant mixture showed to be more effective than ibuprofen (non-steroidal anti-inflammatory drug (NSAID) often used by women during menstruation) in decreasing pain intensity of the menses in 68 females. The fennel / vita-E elixir reduced pain strength faster and lasted longer (almost 48 hours) than ibuprofen. [25]

Can help with PMS

According to science, premenstrual syndrome or PMS is a range of physical and emotional symptoms within one to two weeks of women’s period. These symptoms may include acne, fatigue, irritability, food cravings and others. Now, if you’re known to experience some of these effects, don’t worry and keep some fennel around. A study of 90 young women showed that fennel extract effectively reduced severity of PMS symptoms. [26]

Helps during menopause

Menopause is a gradual process, which occurs as women’s ovaries stop functioning, and menstruation absent for more than 12 months. Menopause symptoms include various vaginal and urinary symptoms, mood changes, hot flashes, fatigue, anxiety, joint and muscle aches.  Some of these symptoms may lead to complications including osteoporosis and heart disease.  There are various pharmaceutical treatments like hormone therapy (HT). 

However, more and more women are concerned with negative side effects of hormone therapy and continuously search for natural / herbal remedies, to help with menopausal signs. Fennel is often a popular choice. One study analyzed 90 postmenopausal women with moderate symptoms. After a two month trial, fennel group showed significant improvements in menopausal indicators compared to the placebo counterparts, without any adverse side effects. [27]

Freshens Breath

Fennel has a natural sweet, anise / licorice-like flavour which expels fragrant aroma and taste once the seed is mechanically broken down (chewed, ground, etc). Chewing fennel seeds is one method which can freshen your breath, and is a common practice of many South Asian cultures. Chewing increases saliva production which is mixed with exposed essential oils from the broken down seeds and coated around the mouth cavity. Essential oils contain many phytonutrients with powerful antibacterial properties that combat oral pathogens and increase freshness. [28]

Regulates Blood Sugar and Diabetes

Diabetes is a metabolic disorder which involves improper function of the hormone insulin producing chronic high blood-sugar levels. Pancreas gland is either not generating insulin; or the body cells not adequately responding to the available insulin (insulin resistance). Insulin is the main switch in the body that shuttles sugars from blood into cells and is critical to healthy carbohydrate metabolism. 

Science is constantly examining various options in dealing with diabetes mellitus. Current drugs are effective in managing this disease, but they come with side effects, especially over long term use. In search for a better solution, science is turning to all natural ingredients which have been extensively used in traditional practices. Even the World Health Organization understands the hidden powers of all natural ingredients and has recommended the development of herbal medicines, including anti-diabetic agents. [29]

Fennel is one of such herbs, low on the glycemic index with an impressive list of active compounds including powerful antioxidants. Fennel seeds are high in vitamin C, a strong antioxidant that combats ROS and shown to lower blood sugar levels. Fennel also has beta-carotene (another antioxidant and vitamin A precursor) which has been linked to lowering cholesterol levels in type 2 diabetes patients. Animal trials testing fennel’s abilities are shown to reduce blood sugar levels by almost 50 percent while protecting and improving kidney and pancreas function. [30] Continuous fennel use improves not only hyperglycaemia (high blood-sugar levels), but also cholesterol and glycated hemoglobin (HbA1c). [31]

Glycated hemoglobin (HbA1c) is formed when glucose attaches to hemoglobin of the red blood cell (RBC). RBCs are exposed to glucose in the blood. The higher the blood glucose levels, the more HbA1c forms within the four month lifespan of RBCs (around 106 days in women and 117 days for men). [32] Though HbA1c levels vary slightly in populations, it’s shown as a precise measurement for identifying diabetes symptoms in glycemic patient. [33] Now, scientists are discovering that HbA1c is also an important marker for other glycemic (blood sugar) conditions like cardiovascular disease (CVD) [34-36], kidney disease [37,38] and neurodegenerative diseases [39] to name a few. Its high levels have been linked to metabolic syndrome and obesity. [37,38,40-41]

Heart Health—Lowers Cholesterol

As previously mentioned, fennel is naturally high in fiber, both insoluble and soluble variety (about 3 grams of fiber per tablespoon). Research shows fiber to reduce LDL-cholesterol (often referred to as the bad cholesterol) in blood. Animal studies revealed that fennel extracts decrease total cholesterol levels including triglycerides and LDL-cholesterol while increasing HDL-cholesterol (also referred to as the good cholesterol), by binding to bile salts and preventing the reabsorption of LDL-cholesterol. Also, fennel contains numerous phenol compounds including anethole and other antioxidants (vitamin C and B9 (folic acid)) which protect tissues (preventing lipid peroxidation), enhance HDL-cholesterol, antioxidant enzymes (like superoxide dismutase (SOD) and catalase (CAT)). [3,42]

Heart Health—Regulates Blood Pressure

Ayurvedic medicine and other traditional practices use fennel to improve blood circulation and regulate blood pressure. Fennel helps reduce blood pressure through its high potassium (K+) and low sodium (Na+) contents. Potassium is a natural vasodilator and is an important component of moving body fluids for cells, including blood in terms of pressure and heart rate. Higher potassium intake decreases hypertension and other sodium related effects, through relaxation of soft muscles of blood vessels. [43] 

Fennel teas are a popular remedy against arterial tension which reduces the risk of coronary disease, heart attack and stroke. Science supports this ancient practice by studying fennel on hypertensive animals. The main active compound anethole within fennel tea (hot water extract) reduces blood pressure by acting as a diuretic and removing excess water out of the body, without affecting heart rate or respiratory rate. [3,44,45].

Also, anethole within fennel’s essential oils has been shown to have impressive anti-platelet properties, disrupting the formation of blood clots (or thrombus). Already an established vaso-relaxant, anethole decreases platelet aggregation (platelets clumping together in blood vessels) without any side effects (such as prohemorragic and bleeding times) often seen with blood thiner drugs like aspirin (acetylsalicylic acid), and alcohol induced gastric ulcers. [46]

Improves Liver and Kidney Health

Liver is the largest solid organ within the body, weighting up to 3 pounds (1.5 kg) in adults. It’s an organ which breaks down or converts different molecules, extracting energy and removing them from the blood stream. Some of these molecules are byproducts, and toxins, which liver makes less harmful. Liver is made up of thousands and thousands of cells (hepatocytes) which filter the blood from the portal vein and determine:

  • what is a nutrient, which can be either stored or put back into the blood stream,
  • what is energy, which needs to be extracted and saved, and
  • what is a byproduct and/or toxin, which has to be broken down and removed as waste?

Essentially, liver is one giant filter and a very complex one at that. Liver possesses an army of enzymes and reactive molecules for all involved biochemical tasks. For example, liver produces up to a litre of bile per day, which is transported to small intestine (for breakdown of fats) and gallbladder (for storage). Liver also breaks down proteins, separating Nitrogen ends of amino acids and compiling them into ammonia, which can be toxic in large amounts. To avoid the toxic build up, liver converts ammonia into urea and transports it to kidneys via blood where it is excreted from the body as urine. 

Because of the complex nature and function of the liver, it’s always subjected to various stresses and can develop number of disorders. More and more liver conditions have been attributed to increased levels of oxidative stress.

Research shows that fennel’s anti-inflammatory properties can help improve liver’s health and function. Fennel seeds are rich in selenium and fiber which assist with detoxification process and removal of toxins from the body. [3]  Also, fennel tea has been used for centuries as a natural diuretic, thus removing excess fluids and byproducts from hepatic tissues. [44]

Fennel’s numerous phytonutrients play many protective roles from oxidative stress in liver and kidneys. Studies identified beta-Myrcene and Limonene to possess hepato-protective properties in animals with drug-induced kidney damage. [3,47]  Fourteen powerful phytochemicals (including anethole) have been identified as strong free radical scavengers, protecting kidney tissue integrity against oxidative damage. [3,48,49]  All noted studies showed a decrease in numerous liver-damage markers and improvement of chronic liver disease symptoms.

5-Methoxypsoralen is a phytochemical within fennel seed shown to inhibit human liver cytochrome P450-3A4 (CPY3A4). [50]  CYP3A4 is an important enzyme in liver which breaks down foreign organic molecules (like toxins or drugs), deactivating some of the drugs while activating others. [51]  By decreasing CPY3A4 activity, fennel improves bioavailability of many of the drugs. This greatly benefits treatments, as medications can be prescribed in smaller doses or shorter course, generating less overall stress on the body and fewer side effects (often experienced with pharmaceutical drugs).

Promotes Weight Loss

Arise Brain Boost Tea cup

Arise Tea with Fennel Seed Benefits

Fennel has a long history of being used as a weight-loss agent. Historically, during religious Lent and 

fasts fennel seeds were eaten to extend satiety. The big reason behind fennel’s ability to keep hunger at bay is fiber. The body identifies fiber as food and employs energy for break down and digestion, but unable to do. This process increases metabolism while suppressing overall appetite by sending chemical messages (hormones) back to CNS in order to decrease hunger. The result is overall weight loss from body energy reserves along with lower risk of metabolic syndrome and other related conditions. [52,53] Research shows fiber improved satiety and weight loss in both animal and humans (of all ages) trials. [54-56] 

Drinking fennel based teas showed noticeable weight-loss in overweight individuals. The fiber suppressed appetites, while the diuretic effect of the fennel tea helps with weight loss by removing excess water and waste from the body. [57]

Promotes Bone Health

Fennel’s extensive antioxidant and anti-inflammation properties have been used for centuries as remedies against different type of infections, bruises and scrapes. These active compounds have shown to improve organ and tissue function, including maintenance of bones. Low bone mass affects tens of millions of people in North America and can lead to injury or bone related diseases like osteoporosis. 

Fennel seeds are element rich with calcium (Ca2+), magnesium (Mg2+), phosphorus (common ion form: H2PO3- or P3-) and vitamin K, which all partake in bone strengthening process. Though research is limited, fennel studies show prevention of bone loss in osteoporotic animals by improving bone mineral levels and density (size). [58]

Treats All Inflammation

Fennel’s extensive phytonutrient profile includes vitamins, minerals, proteins and carbohydrates making it a powerful anti-inflammatory agent. Fennel has been shown to prevent various type of inflammations including allergic reactions, which often present themselves within two days.  Antioxidants within fennel:

  • protect cellular integrity (preventing lipid peroxidation);
  • improve antioxidant enzymes (like catalase (CAT) and superoxide dismutase (SOD)); and
  • raise high-density lipoproteins (HDL) type cholesterol. [42] 
  • Trans-anethole (within fennel) shown to inhibit 5-lipoxgenase (5-LOX), an protein enzyme that produces leukotrienes. [59] Leukotrienes are inflammatory mediators which cause various inflammation and allergic response. [60] This is an active research area, as fennel’s ability to decrease 5-LOX’s activity can be used to treat many inflammatory disorders including: asthma, rheumatoid arthritis, atherosclerosis, autoimmune disease and all types of allergic conditions. [60]

MAPK/ERK pathway is a cell signalling system consisting of proteins stretched in a row from cell surface receptors, moving deep into the cellular nucleus and DNA. This complex system works similar to a domino effect with initial activation of the surface receptor, cascading the signal downwards into the nucleus, and activating specific genes within DNA to produce coded products. Mutation with any protein in this “domino” line can cause the entire system to malfunction and get stuck either in the “on” or “off” mode, generating cancerous cell growth. [61] 

  • Trans-anethole can also reduce other inflammation causing proteins (cytokines) such as TNF-alpha and interleukin 1 beta (IL-1b). [64]
  • Limonene and anisole (other antioxidants) possess anti-inflammatory effects by suppressing interleukin 6 (IL-6), TNF-alpha, and several inflammatory agents: NF-kB, nitric oxide (NO) and matrix metalloproteinase-9 (MMP-9). [65]

NF-kB is a protein complex inside cell nucleus that controls the decoding (transcription) of DNA genes that code inflammatory response proteins (cytokines). [62,63]  Matrix metalloproteinase-9 is a zinc-dependent enzyme of MMP family involved in body tissue repair and replacement process. MMP-9 specifically is an important factor in tissue growth like bone, blood vessels, ovulation and embryonic development. MMP-9 is a key player in the immune response by breaking down extracellular matrix. [66]

Helps Heal Wounds

Traditionally fennel essential oils have been used as a natural remedy to help heal various cuts and wounds. Antibacterial and anti-inflammatory compounds within fennel protect our cuts from getting infected as well as speed up the recovery time. [67]

Fenchone and limonene within fennel hold both antimicrobial and anti-inflammatory properties.  Studies with small animals showed significantly faster wound recovery (including production of collagen and other epithelial cells) compared to controls. [68] Also, anethole’s anti-inflammatory properties shown to decrease pain without causing sedation. The mechanism is not completely understood, as it’s hard to find out exact pain tolerance and feedback from animals. Most of the studies focus on the reduction in inflammatory mediators. [42,69]

Strong Anti-Cancer Agent

As part of Chinese and Ayurvedic medicines, fennel seeds are extensively used to treat various conditions. The same fragrant antioxidant phenol-based compounds that scavenge free radicals and fight oxidative stress have also been identified as effective anti-carcinogenic agents. [3]

Test tube and animal experiments show that fennel’s antioxidants improve overall detoxification process and power actions of related enzymes. Such processes include tissue protection against ROS damage and fighting tumors within skin, stomach, breast and liver cells. [3,8,70,71]

Anethole is fennel’s major component and has been continuously investigated by researchers for its ability to fight inflammation and various types of cancers. Anethole’s great antioxidant abilities show a decrease in breast and prostate cancer cells. [71,72] Scientists also noticed that anethole contributes to tumor cell self-destruction mechanism (apoptosis). Number of test tube studies reveal anethole’s effect to decrease tumor growth (metastasis) by increasing self destructing proteins (like: TIMP1, caspase-3, caspase-9, p21 and p27) while reducing activity and expression of inflammatory proteins (like: NF-kB, MMP2, MMP9, p38, p53). [71,72]

Helps Fight Bacterial Infections

The phytonutrients in fennel seeds also possess strong antibacterial and antimicrobial properties, and may help in preventing the spread of various infections. [3] Test tube studies show that fennel extracts prevent the growth of several bacterial strains including Mycobacterium. tuberculosis (M. tuberculosis), Escherichia coli (E. coli) and Samonellosis (Samonellla). Such bacteria causes coughs, chills, fever, digestive discomfort, cramps, diarrhea and fatigue. [3] Fennel also contains antifungal benefits. This includes fighting harmful molds and yeast strains such as Candida albicans (C. albicans), which is the most common strain responsible for human infections. [3]

Brain Health and Cognition

Acetylcholine (ACh) is a chemical compound that transmits messages of nerve impulses within central (CNS) and peripheral (PNS) nervous systems. It sends messages to many cells including neurons, muscle and gland variety. Acetylcholine is the main neurotransmitter of parasympathetic nervous system (PSNS), part of PNS and is responsible for stimulating unconscious actions of “rest-and-digest” or “feed and breed” activities. Within CNS, acetylcholine is both a neurotransmitter (transmits synaptic messages between nerve cells) and a neromodulator (regulates – increasing/decreasing activity of – other neurons). As a neurotransmitter, ACh is released in neuromuscular junctions to stimulate muscle contractions, while in the brain it modulates attention, memory, motivation and arousal. [73] The brain has number of cholinergic areas, each one with distinct functions. Deterioration within these important cholinergic pathways (in CNS) have been associated with memory loss and onset of Alzheimer’s disease. [74] 

Studies show that fennel extracts can prevent drug induced memory loss in small animals. Fennel’s phytonutrients protect brain tissue against oxidative damage while decreasing acetylcholinesterase (enzyme that breaks down ACh) activity, resulting in greater ACh levels and greater cognition. [75,76] As always, anethole is a big player, also shown to reduce anxiety within small animals, as effectively as common anxiolytic drugs (diazepam). [77]

Improves Eyesight

Fennel’s health benefits also reach up to your vision. Ancient Ayurvedic remedies used fennel extracts to treat various eye conditions including glaucoma symptoms. Due to its antibacterial effects, fennel tea is often used to wash out the eye infections (such as conjunctivitis).

Macular degeneration is a common condition of vision loss among people over the age of 50. A large scale study involving over 41,000 participants showed that consuming high antioxidant and flavonoid diet resulted in lower risk of developing age-related macular degeneration (AMD). [78] Fennel seeds contain vitamin A, vitamin C, beta carotene (precursor of vitamin A) and zinc; all possess antibacterial and immune boosting properties. These flavonoids, minerals and vitamins repeatedly show improvement in vision and decrease of cataract development. [79]

Promotes Healthy Skin

The UV radiation from sun exposure damages skin cells and is one of the environmental factors of oxidative stress within the body.  As many aware, continuous sun exposure increases risk of developing skin cancer; and fennel has been shown to protect against ROS damage including reducing skin tumors and early signs of aging. [3,8]

Nuclear factor-like 2 or NFE2L2 or Nrf2 is a transcription factor protein in humans which regulates antioxidant proteins and protects against oxidative stress caused by toxins or inflammation. [80,81]  Glutathione or GSH is a powerful antioxidant and is considered one of the most important ROS scavengers. Reduced GSH levels within blood stream are often used as a maker for oxidative stress, including in cancer patients. [82,83]

Animal studies showed that fennel protects against sun exposure and skin damage. The powerful ingredients within the seeds increased production of structural proteins like collagen, elastin and immune boosting proteins (cytokines) such as TGF-beta1, while decreasing inflammatory causing proteins (lMMPs and p38). Fennel also lowers oxidative stress by enhancing GSH and Nrf2 blood concentration levels. [84]  Trans-anethole of fennel show lightening of skin and prevention of blemishes by decreasing melanogenesis (production of melanin from sun exposure). [85]

Micronutrient Profile

Fennel seeds are packed with powerful ingredients. As with all spices, fennel contains very few calories but holds potent micronutrients which boost digestion, internal health and immunity.  Just one tablespoon (6 grams) of ground fennel seeds contains:

  • about 20 Calories
  • 0.92 grams of Protein
  • 3.03 grams of Carbohydrates, most of which is Fiber (2.3 grams)
  • no sugar
  • 0.86 grams of Fats, big chunk of which are essential monounsaturated (found in nuts, avocados and seeds) and polyunsaturated fats (omega-3 and omega-6)

Here’s a more complete list of macro-, micro- and phytonutrients [17]:

  • protein
  • carbohydrates
  • dietary fiber
  • polyunsaturated fats (omega-3 and omega-6 fatty acids)
  • monounsaturated fats
  • vitamin A
  • vitamin B1 (thiamin)
  • vitamin B2 (riboflavin)
  • vitamin B3 (niacin)
  • vitamin B6
  • vitamin B9 (folate)
  • vitamin B12
  • vitamin C (L-ascorbic acid)
  • vitamin D
  • vitamin K
  • calcium
  • copper
  • potassium,
  • phosphorus,
  • manganese,
  • magnesium,
  • sodium
  • zinc,
  • selenium,
  • iron

Nutrients within fennel seeds are shown to fight oxidative stress, protect tissues, fight many type of inflammation and pathogen causing conditions. [3]

Possible Drawbacks

Fennel seeds have been part of traditional medicines for centuries and have been deemed safe to consume. However, as with anything, a word of caution is warranted when using this spice extensively and/or excessively.

Active ingredients with specific properties which identified fennel seed health benefits may have adverse affects in some people. For example, the main component anethole mimics estrogen, which may produce some hormonal imbalances within the body. This may be a caution to anyone who has some hormonal sensitivity including cancer patients. In young children, fennel can trigger premature sexual characteristics and early development of breasts. However, by stopping fennel consumption, the breast development side effect reverts to normal. [86] Keep in mind that studies of human children and infants showed very few side effects with short-term use of fennel. [11]

Fennel may also cause hyperprolactinemia, as it has been shown to increase prolactin levels.  As already mentioned, anethole can also mimic dopamine and thus inhibit prolactin receptors without the actual effect. This is a benefit for females who want to increase breast milk production, but may have a negative effect on others who may already have high prolactin levels.

Fennel is naturally a fragrant spice, and some people may be allergic or develop allergies.

Studies show fennel to improve bioavailability of several compounds and drugs by decreasing CYP2D6 and CYP3A4 enzymes found in liver. CYP2D6 and CYP3A4 metabolize (break down) variety of prescription drugs including antidepressants, antipsychotics, opioid type painkillers, antibiotics, blood pressure (beta-blockers), and cholesterol (statins) medications. [51,87] This is actually a benefit, as patients can use less drugs for greater effect and fewer side effects. However, a word of caution to patients who concurrently use such drugs and fennel products, as the final blood stream concentrations of such pharmaceuticals can be higher than calculated and may have unexpected or undesirable side effects.

Final Thoughts

Fennel is an aromatic herb, containing anise type smell, and flavour. Ancient medicinal practices used this spice to heal numerous conditions including stomach indigestion, eye sight, wounds and infections.

Fennel products are packed with anethole. It prevents inflammation, oxidative stress and holds enormous potential in fighting many serious diseases like in diabetes, cancers and various bacterial infections. Other phytonutrients within this seed increase immune response, balance hormones as well as improve organ function and bone health.

Fennel seeds are delicious and easily incorporated into a diet, dishes and drinks. Fennel teas are a popular drink after a meal and have often been used as an elixir in traditional remedies.  Compared to other spices, fennel is inexpensive and comes with numerous health benefits.  This herb is capable of enhancing all kitchen creations as well as internal well being.

You can experience the sweet taste, fragrant smell and multitude of health benefits of fennel seed listed above in our Arise and Fortify Chai blends. In terms of it’s addition to Chai, fennel adds a greater biodiversity of phytonutrients which enhance numerous benefits while resisting and reversing health risks such as osteoporosis.


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