Cucumbers are members of the Cucurbitaceae or gourd family, which includes melons, including bitter melon, squash and pumpkins. There are over 30 species of cucumber, Cucumis sativus having the most economic value. Cucumber is an annual, easily grown vine with the fruits being technically classified as berries. The three main types are classified as slicing, pickling and seedless. Cucumber’s fruits are a major food worldwide but the peel, leaves, flowers and seeds also have medicinal properties. Cucumbers have a very low glycaemic index (GI) ranking and they are consumed fresh in salads, fermented as pickles or eaten as a cooked vegetable.
Cucumbers contain cucurbitacins (a class of triterpenoids), apigenin, glycosides, antioxidants, lignans, flavonoids, vitexin, alkaloids, tannins, saponins and phenolic compounds. They are a nutritious food with a high water content of 96 per cent, vitamins A, B, C and K, minerals calcium, magnesium, manganese, potassium and zinc, electrolytes and fibre, but are low in calories, cholesterol and sodium.
Adequate hydration in the body is critical in maintaining health. Cucumbers, with their high water and electrolyte content, are one of the most hydrating foods available, and this ability to rehydrate the human body constitutes an important health-promoting property.
Inflammation and oxidation play a critical role in the pathogenesis of cardiovascular disorders including hypertension, atherosclerosis, chronic heart disease and chronic renal failure, and angiotensin II is considered a major source of both inflammation and oxidative stress. An interesting in vitro research study was done on cucumbers which found that this food significantly downregulated the inflammatory and oxidative effects of angiotensin II, potentially indicating cucumber as an excellent food for cardiovascular and kidney protection.
Cucumbers have shown multiple positive effects on gut function, including reducing constipation through its rehydrating property and fibre content, antiulcer activity in ulcerative colitis, anthelmintic activity, particularly against tapeworms and pinworms, and antidiarrhoeal. Studies have also shown antiulcer activity of the fruit, seeds and leaves to be equivalent to the drug ranitidine.
Cucumber, especially the peel, has been shown to have a glucose-regulating role. While more studies need to be done, the cucurbitacins are known for their cardiovascular and antidiabetic activities.
The vitamin K content of cucumbers with the peel supplies over 20 per cent of the daily requirements for vitamin K, a main nutrient required for bone formation.
A study was conducted to determine the antioxidant levels of cucumber and its impact in healthy subjects over the age of 60. Blood test results showed that plasma glutathione peroxidase activity, vitamin C and total phenolics were significantly increased, while uric acid and the DNA injury rate of blood mononuclear cells decreased, all positive measures of increased antioxidant levels.
Fresh cucumber juice soothes skin irritations, reduces swelling, stops itching and reduces the pain of sunburn. In skin health, cucumber reduces hyperpigmentation and has measurable antiwrinkle and anti-ageing activity, with the anti-hyaluronidase and anti-elastase activities having great potential for cosmetic use.
Cautions and contraindications
For maximum benefit, eat the whole cucumber including the peel and seeds. Ensure you only eat cucumbers you know are edible, as some varieties have high levels of cucurbitacins which can be toxic. People taking blood thinners such as warfarin will need to be careful eating too many cucumbers due to the high vitamin K content.
Dr Karen Bridgman is a holistic practitioner at Lotus Health and Lotus Dental in Neutral Bay.