Contrary to popular belief, the horse chestnut is not a giant horse-sized nut, nor is it something that families roast over an open fire during traditional Christmas celebrations. The horse chestnut, in fact, describes the fruit of a broadleaf tree that can be found growing in Southeastern Europe. In herbal formulations, it goes through an extraction process and is standardized for use in various dietary supplements designed to support healthy veins, joints, muscles, and skin. Keep reading to learn more about the potential benefits and uses of the horse chestnut.
What is a Horse Chestnut?
The horse chestnut (Aesculus hippocastanum) or conker tree is a large deciduous tree native to the Balkan Peninsula that belongs to the Sapindaceae family, also known as the soapberry family. The horse chestnut tree prefers growing in moist, fertile, and well-drained soils in full sun to partial shade. Under ideal conditions, it can grow at a height of 50 to 75 feet, spreading its footprint from 40 to 65 feet and living for up to 300 years. That’s why the horse chestnut tree is commonly used for ornamental landscaping and for shade in parks, in village greens, along streets, and in large lawns. (1, 2)
When the tree is young, its bark is smooth and pinkish grey. However, the bark darkens and develops scaly plates as it ages. The horse chestnut tree blooms in mid-spring, around May, and features large palmate leaves with 5-7 pointed, serrated leaflets spreading from a central stem and conical clusters of white flowers of 4-5 fringed petals with a red, pink or yellow flush at the base. In dry conditions, the edges of the tree’s leaves may scorch and turn brown. (3)
The tree’s fruit is pollinated by insects and consists of large, globular, glossy mahogany brown seeds (Semen hippocastani), known as conkers in the UK, that are encased in spiky green husks, commonly referred to as the horse chestnut or buckeye. Each autumn, the prickly green seed pod turns brown and cracks, splitting open to reveal several hard, brown seeds inside. (4)
Once extracted from the husk, horse chestnut seeds look similar to the Ohio buckeye but are distinguished differently due to the sharp spines on their seed pods. (5) However, be careful not to confuse the horse chestnut (Aesculus hippocastanum) with the Ohio buckeye (Aesculus glabra) or the California buckeye ( Aesculus californica), as these are very different plants. In addition, keep in mind that the popular edible “sweet chestnut” (Castanea sativa and other Castanea), are in the Fagaceae (beech) family and produce edible nuts. The sweet chestnut is what families roast during traditional Christmas celebrations. Unlike the sweet chestnut, horse chestnuts and buckeyes (Aesculus) are in the Sapindaceae (soapberry) family and produce poisonous nuts that should never be consumed raw.
The horse chestnut tree’s seeds, bark, and leaves are used in herbal formulas for various health issues. Traditionally, the standardized extracts from the seeds of the horse chestnut tree have been used medicinally for the treatment of hemorrhoids, circulatory health, chronic venous insufficiency, varicose veins, rheumatism, bladder and gastrointestinal disorders, fever, and leg cramps. However, not all of these medical claims can be backed by science. (6) You will, however, find horse chestnut as an ingredient in a variety of dietary supplements, including capsules, tablets, liquid extracts, and tinctures, as well as topical ointments, and more. Continue reading to find out the science behind the horse chestnut.
How It Works
The unprocessed seeds, leaves, bark, and flowers of the horse chestnut tree contain a complex mixture of compounds that are believed to have certain medical qualities, including coumarins (esculin, aesculetin), coumarin glycoside (aesculin), and saponins (aescin), which are all believed to be bioactive, as well as flavonoids (quercetin, rutin, kaempferol), tannins (condensed & hydrolyzable), fatty acids, and sterols. (7, 8)
Aesculin, in particular, is poisonous and may increase the risk of bleeding. Aescin (or escin), on the other hand, is a different compound and is considered to be safe if taken in small amounts. Aescin is a mixture of triterpenoid and steroidal glycosides referred to collectively as saponins, is the main bioactive compound in horse chestnut that is responsible for most of its medicinal properties. According to the Department of Nutritional Sciences at the University of Toronto, “Saponins have been shown to have hypocholesterolemic, anti-coagulant, anticarcinogenic, hepatoprotective, hypoglycemic, immunomodulatory, neuroprotective, anti-inflammatory and antioxidant activity.” (9, 10)
Unfortunately, when ingested raw in an unprocessed form, the bioactive compounds in the horse chestnut may cause unwanted side effects such as severe gastroenteritis, also known as the stomach flu, an intestinal infection marked by diarrhea, cramps, nausea, vomiting, and fever. At its worst, ingesting unprocessed horse chestnut plant parts could also cause paralysis or coma. (11)
Ironically, the very same compounds that make the horse chestnut toxic are what make it potentially beneficial to human health, as well. When it is properly processed and standardized so that the active chemicals are separated out and concentrated, horse chestnut seed extract is considered safe for human consumption when used in low quantities and for short periods of time. (This process removes the poisonous aesculin.) However, even the processed extract could cause temporary itching, nausea, gastrointestinal upset, muscle spasms, or headaches. (12, 13)
Aescin is poorly absorbed by the body, at less than .25%, and the total flavonoids present amount to only 0.88% or 0.3%, which weakens the extract’s potential health benefits. Nevertheless, the horse chestnut is used in homeopathic medicine, because its bioactive compounds are believed to naturally thin the blood, help prevent fluid loss from veins, capillaries, and urine, and help prevent water retention (edema), among other potential health benefits. (14, 15)
A Brief History of Horse Chestnut
Horse chestnut was first cultivated in Turkey, part of the Balkan Peninsula. The origin of the horse chestnut tree’s name is unclear, but it is believed it comes from the mark left by the leaf stalk on the twig when it falls, resembling an inverted horseshoe with nail holes. Although eating raw horse chestnut is now understood to be a dangerous and possibly fatal mistake by humans, research indicates that historical uses included grinding up the fruit and feeding it to horses to relieve cough symptoms. (16)
Horse chestnuts were introduced to the UK in the late 16th century where it eventually became a popular element in the game of conkers (also known as Kingers). The first record of the game is from the Isle of Wight in 1848, modeled after a 15th century game played with hazelnuts. Conkers is still played today in Great Britain and Ireland. In fact, the World Conker Championships is held every year at Southwick, Northamptonshire. (17)
The game of conkers involves two players who each select one uncracked, firm, and symmetrical conker (horse chestnut seed) as a game piece. Each player punches a hole through the middle of their horse chestnut seed, threading a string about 25 cm long through the hole, tying a knot at one end, and letting the seed hang down from the string whose opposite end is tied around the player’s hand. The players then take turns at hitting their opponent's seed. The first player draws the seed back for the strike, swinging it and trying to hit the opponent’s seed. The player gets three attempts for a clear strike. Extra attempts can be made if strings become tangled or if a strike causes the opponent’s horse chestnut seed to swing around in a full circle, known as ‘round the world. If the opponent drops their seed, the current player yells “Stamps” and jumps on it. The game continues until one of the horse chestnut seeds is destroyed. (18)
Historically, horse chestnut seed extract has been used for a variety of health conditions, including joint pain, gastrointestinal issues, fever, and leg cramps. Today, people take dietary supplements of horse chestnut seed extract to support health issues related to the function of veins and overall blood circulation. Common ailments involved in such supplement use include chronic venous insufficiency, varicose veins, hemorrhoids, and leg swelling after surgery. Sometimes, people also use preparations made from the bark of the horse chestnut tree to help support healing of skin sores. (19, 20)
Other uses for the horse chestnut include as an ingredient in shampoos and personal care products and as a starch substitute. In addition, due to the soft and smooth, fine texture of the horse chestnut tree’s bark, it is also a popular choice in wood carving projects.
Potential Benefits of Horse Chestnut
Usable parts of the horse chestnut tree for medical formulations include its seed, bark, and leaves. More specifically, horse chestnut seeds are used in herbal supplements to support vein health. Horse chestnut tree leaves and branch bark are used for skin care, and the leaves are also used for soft tissue health support and minor joint pain relief. However, most dietary supplements used to support optimal health are derived from its seed extracts. (21, 22)
Horse Chestnut Potential Health Benefits
- Supports Vein Health
- Supports Healthy Circulation
- Supports Heart Health
- Supports Joint and Muscle Function
- Promotes Skin Healing
Horse chestnut seed extract has been clinically proven to help support overall vein health and promote healthy blood circulation throughout the body, which in turn may promote heart health, joints and muscle health, and healthy-looking skin. Most importantly, horse chestnut seed extract is used in a wide range of homeopathic treatments to support the health of people living with varicose veins (enlarged, twisted veins, usually found in your legs and feet, that appear pink or blue), chronic venous insufficiency (when the veins of the lower leg are unable to send blood back toward the heart), and hemorrhoids (swollen veins in the lowest part of your rectum and anus). (23, 24, 25, 26).
It is estimated that 25 percent of adults have varicose veins and similar circulatory issues, caused when blood doesn’t flow properly. Potential risk factors include obesity, a sedentary lifestyle, pregnancy, and old age. Varicose veins may cause painful discomfort or heaviness in the legs, as well as unattractive, visible gnarled veins that can be seen near the outer layer of the skin. Treatment may include lifestyle changes to improve circulation, such as losing weight, exercise, and using compression stockings. In addition, some people use dietary supplements such as those formulated with horse chestnut seed extract to help support healthy veins. (27)
Investigations in animal models suggest that horse chestnut seed extract, in particular, may have anti oedematous, venotonic, and anti-inflammatory properties. An anti oedematous is a substance that prevents or alleviates edema (fluid retention). (28) A venotonic is a substance that improves the tone of a vein by increasing the flexibility of elastic fibers in the vein wall. (29, 30) An anti-inflammatory helps prevent the body from releasing chemicals that increase the blood flow to an area of injury or infection, usually visible by redness and warmth, thereby preventing the body from damaging its own tissues. (31)
Several studies are examining the possible effect of horse chestnut seed extract supplements on people suffering from chronic venous insufficiency and varicose veins. Some reports suggest that it may help reduce edema, ankle and calf circumference, and symptoms related to chronic venous insufficiency and varicose veins. (32) According to research, “17 trials conducted on horse chestnut extract for the treatment of chronic venous insufficiency noted significant reductions in leg pain, edema, leg volume.” It was discovered that standard oral doses of a horse chestnut seed extract containing 50 mg aescin twice daily for 12 weeks appears to be effective in reducing symptoms of chronic venous insufficiency. (33) Another study reported that horse chestnut seed extracts standardized for escin are as effective as compression stockings. (34)
When it comes to supporting healthy blood circulation throughout the body, research suggests that horse chestnut seed extract supplementation may have a positive effect on not only the health of the veins in the arms and legs, but also blood circulation through the ears, skin, heart, and lower bowels. This is believed to be attributed to the ability of horse chestnut to naturally thin the blood and support circulation. The improved viscosity of the blood may help prevent possible clotting and blocking of veins, which has been known to be a major cause of stroke or heart problems. (35, 36) In studies on rats, aescin also appears to help enhance the effects of corticosteroids, reducing areas of inflammation. (37)
How to Buy Horse Chestnut
Warnings and Side Effects
When eaten in its raw, unprocessed form, horse chestnut is toxic to humans and most animals. (38) Although in the wild, horse chestnuts are eaten by deer, cattle, and horses, according to the American Society for the Prevention of Cruelty to Animals (ASPCA), horse chestnuts could cause severe vomiting, diarrhea, dilated pupils, convulsions, or coma. If you notice these signs in an animal such as a family pet, call an emergency veterinarian promptly. (39)
The bioactive compounds in horse chestnut seed extracts are poorly absorbed in the digestive tract, which means that they are flushed out through the kidney and gallbladder, causing much strain on the organs. (40) It is also believed that consuming large quantities of horse chestnut seed extract may lead to liver toxicity. (41) In addition, horse chestnut may trigger allergic reactions in some people. Also, due to the potential blood thinning and known circulatory properties of this plant, horse chestnut extract should not be taken with pharmaceutical blood thinners such as Warfarin and similar medications.
Other plants and trees that contain the same toxic chemicals contained within unprocessed, raw horse chestnut seeds, leaves, flowers, and bark are the white hawthorn tree (Crataegus oxyacantha), the ash tree (Fraxinus), and the sweet bursaria (Bursaria spinosa). So be careful when you’re trying new botanical-based supplements! Always do your research first. (42)
Do not use unprocessed raw horse chestnut preparations, as they can be toxic and lethal when ingested, as indicated above. Horse chestnut seed extracts that have been processed properly to reduce the risk of toxicity may be given orally through dietary supplementation in various forms or applied topically to support healthy circulation and wound healing.
When searching for dietary supplements containing processed horse chestnut for safe consumption, look for trusted brands. If you’re interested in trying a horse chestnut supplement, shop the Natural Healthy Concepts store. All products sold through Natural Healthy Concepts have been pre-vetted for safe, quality ingredients and manufacturing processes. (43)
It’s recommended that you keep your supplemental dosage of horse chestnut between 400 – 600 mg daily, not to exceed standardization for aescin at 100 – 150 mg daily. Doses should be separated by 12 hours (one dose for morning and one for night). (44)
As with all supplements, always consult with your healthcare provider first before trying a new supplement in your daily health routine. Adhere to the instructions on the nutritional label of the product you are using for exact dosage recommendations. It is generally recommended that children, pregnant women, people with allergies, or those taking certain blood thinning medications DO NOT take horse chestnut supplements.
If you’re looking for vein and circulatory health support, try a processed horse chestnut seed extract-based supplement today! It may make a difference to your health.