What are turnips
Turnips are hardy, root vegetables and members of the cabbage or mustard family. Believed to have originated in Asia, they are now grown in temperate climates worldwide. They are one of the world’s oldest cultivated vegetables and have been used since prehistoric times for their bulbous edible roots and leaves. Generally, the smaller turnips are eaten by humans and the larger ones by livestock, as they are often more bitter.
They were hugely popular vegetables in the 16th century in Britain. However, by the 17th century, there was an increase in their use as animal feed, and this may have accelerated their decline in popularity. Following this was the rapid production of sugar, which meant sweeter vegetables were no longer so desired for sweet dishes. Turnips have managed to survive the rapid changes in global food production and changing food choices and their health benefits are becoming more apparent than ever.
The root is creamy white in colour, with a green, red or purple upper portion where the root has been exposed to the sunlight. The interior flesh is white, and the leaves grow directly from the above-ground shoulder.1 It can be planted in the spring, summer or autumn and can be grown at relatively high altitudes, making it an important crop, for example, in Tibet.
Health benefits of turnips
The turnip has received significant attention due to its bioactive components. It is thought to be a Superfood! It is a good source of many vitamins, including B6, C and K, as well as folate, calcium, potassium and copper.
Multiple studies have shown that the turnip may possess the power to be:
- An antioxidant
- Fight bacteria and fungi
- Reduce pain and swelling
- Protect against cancer
- Protect the kidney and liver
- Have properties that can lower sugar level
- Have properties that help body tolerance of altitude
Turnips as an antioxidant
The process of oxidation, when oxygen is used in the body to make energy, produces unstable chemicals called free radicals, which damage cell membranes, cell protein, cell fats and DNA. This process is increased with body exposure to cigarette smoking, alcohol, stress, sunlight and other factors. The subsequent free radicals have been linked to a variety of diseases including heart disease and certain cancers. Antioxidants are substances in foods that scavenge and neutralise free radicals and evidence suggests that naturally occurring antioxidants in fruit and vegetables are the most effective.
Turnips have abundant natural antioxidants and in experiments, the leaves, stems and flower buds exhibited the highest antioxidant capacity, with the roots slightly less. However, these antioxidant elements were broken down and leached during cooking, leaving the turnip with much reduced antioxidant activity after heat treatment. The consumption of raw or lightly blanched turnips will increase its health benefits.2
The antioxidant effects of turnips can be helpful to harness in food preparations. It was noted that adding turnip powder to fried food such a chicken nuggets and falafel made them a good source of many bioactive compounds and antioxidants compared to these food prepared with traditional ingredients.3
It is known that prolonged storage conditions have a detrimental effect on the value of the antioxidants in turnips, as does freezing and canning, which alters the physical and chemical characteristics of the turnip and only a few of these alterations are desirable.
Turnips to fight bacteria and fungi
Antibiotics are widely used and there have been concerns over increasing resistance, leading to the search for other sources. Turnips have been shown to be a source of safe alternative antimicrobial agents. Turnip extractions have yielded a substance with an antibacterial action against nine types of bacteria.4 Another animal study showed the inhibitory effect of turnip on H pylori (a bacteria that can infect the stomach), which is comparable to amoxicillin. 5
It has also been shown that turnips have antifungal properties. In experiments, turnip leaf extract was able to show broad antifungal activity against wood-degrading fungi, by inhibiting their growth.6
However, if you have any concerns over an infection, please consult your doctor first.
Turnip to reduce pain and swelling
Inflammation is part of the body’s defence system against injury and infection, but sometimes it can be harmful to the body. There is a component known as flavonoids in turnips that can inhibit this reaction. These components reduce pain and swelling and research in this area is ongoing.
Do be careful to consult your doctor for proper diagnosis and management of any pain or swelling.
Turnip to protect against cancer
Cancer is one of the most serious and damaging health conditions for humans. Many vegetables, including turnips, have been shown to have anticancer properties such as isothiocyanate, a breakdown product of glucosinolates. Turnips may reduce the risk of cancer as they have high contents of glucosinolates. One study showed turnip kimchi, a traditional Korean dish made of fermented vegetables, had an anti-cancer effect on the human stomach cells.7
Turnips also contain compounds that inhibit DNA damage and therefore reduce risks of tumours and cancer in the body. Cancer is a very serious disease and you should consult your doctor if you have been diagnosed or have any health concerns.
Turnip to protect the liver and kidney
Turnips contain several components that can act as antioxidants and thus protect the structure and function of the liver.
Kidney protection has been achieved with turnip extract. There is a chemotherapy drug for the treatment of cancer called cisplatin, but its toxic effect on the kidney can limit its use. An investigation using ethanol extracts of turnip roots against this toxic effect was conducted. It achieved great results due to the vast improvement in protection for the kidney with the turnip.8 More research in this area is ongoing.
Turnips to lower blood sugar levels
Diabetes is a major worldwide health concern and is caused when the blood sugar is too high due to impaired blood glucose metabolism. It has been shown that ethanol extract from turnip root may exert an antidiabetic effect in type 2 diabetic mice by enhancing glucose and lipid metabolism. 9
In addition, turnips have high dietary fibre, making us feel fuller and preventing overeating. This function can, in turn, be an aid to weight loss. High fibre is also helpful to the bowel as it adds bulk to the stool and facilitates movement through the digestive system, regulating bowel movements.
Turnips to help with altitude tolerance
It has been shown that eating Tibetan turnips for seven days increased the body’s tolerance of the lower oxygen levels experienced when living at high altitudes. This is likely due to its ability to improve oxygen uptake and the aforementioned ability to be an antioxidant for the body. More studies are needed to identify exactly which chemical in the turnip was responsible and how this can be further investigated for use.10
Side effects and other concerns
To get the most out of a turnip, try to choose the freshest with the stem still attached, if possible. The small to medium-sized turnips will be the sweetest and use within a few days of purchase as cold storage increases their bitterness.
Turnips, like most root vegetables, are starches, a carbohydrate that the body breaks down into glucose for energy. Glucose is the main source of energy for the body’s cells, tissues and organs. If you eat a lot more carbohydrates than your body needs, it will store them as fat, leading to weight gain. In addition, the way you prepare the turnip for meals is also a potential issue. If you add lots of butter and other unhealthy ingredients, you could end up overeating and consuming a lot of calories.
Also, as mentioned, carbohydrate is broken down into glucose, so eating large quantities can spike your blood glucose level. This spiking of blood glucose levels means diagnosed diabetics may find stable blood glucose more difficult to control.
Flatulence will occur occasionally in most adults, and the cause is usually down to food digestion. The small intestine does not actually have all the enzymes needed to break down the carbohydrates in sweet, starchy foods. For this reason, this undigested food passes into the large intestine, where harmless bacteria break down the food. A byproduct of this bacterial breakdown is the formation of hydrogen, carbon dioxide and sometimes methane gasses. This process is responsible for most of the gas passed in flatulence. It is known that consuming large quantities of high-fibre foods, such as turnips, can exacerbate this issue in some people.
It is also thought that people with hypothyroidism (underactive thyroid) should avoid eating excessive amounts of raw Brassica vegetables, which include turnips. This is because, in very high amounts, they can inhibit the uptake of iodine into the thyroid gland. Steaming or briefly cooking these vegetables, reduces this effect whilst preserving nutritional content.11
The turnip is a fantastic root vegetable. It has been underrated for too long as it is a widely available, relatively cheap vegetable, which provides us with a wealth of nutritional health benefits. This superfood is a good source of many vitamins, including B6, C and K, as well as folate, calcium, potassium and copper.
The sweetest turnips are the small to medium sized ones and to maximise their nutrition, it is recommended to use them within a few days of purchase and to steam them for cooking purposes.
If you have any concerns about your health, please see a doctor for diagnosis and management, before diet adjustment and remember good nutrition comes from healthy and diverse food choices.
- Turnip - new world encyclopedia [Internet]. [cited 2023 Mar 23]. Available from: https://www.newworldencyclopedia.org/entry/Turnip
- Gharehbeglou P, Jafari SM. Antioxidant components of brassica vegetables, including turnip and the influence of processing and storage on their anti-oxidative properties. Current Medicinal Chemistry. 2019 Jul 1;26(24):4559–72.
- Mahfouz M, Abd-Elnoor AV, Abd El-Razek RI. The influence of adding turnip roots (Brassica rapa var. rapa L.) powder on the antioxidant activity and acrylamide content in some fried foods. Alexandria Science Exchange Journal [Internet]. 2019 Dec 31 [cited 2023 Mar 28];40(OCTOBER-DECEMBER):717–30. Available from: https://asejaiqjsae.journals.ekb.eg/article_68841.html
- Rahman MS, Jahan N, Khatun M, Rashid MA. Chemical and biological assays of Brassica rapa subsp. chinensis (L.) Hanelt. Bangladesh Journal of Botany [Internet]. 2015 [cited 2023 Mar 28];44(2):327–32. Available from: https://www.banglajol.info/index.php/BJB/article/view/38525
- Liu JH, Li L, Shang XD, Zhang JL, Tan Q. Anti-Helicobacter pylori activity of bioactive components isolated from Hericium erinaceus. Journal of Ethnopharmacology [Internet]. 2016 May [cited 2023 Mar 28];183:54–8. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0378874115301306
- Narayanan KB, Park HH. Antifungal activity of silver nanoparticles synthesized using turnip leaf extract (Brassica rapa L.) against wood rotting pathogens. Eur J Plant Pathol [Internet]. 2014 Oct 1 [cited 2023 Mar 28];140(2):185–92. Available from: https://doi.org/10.1007/s10658-014-0399-4
- Im GJ, Kang SA. Physicochemical of turnip baek-kimchi and anti-cancer effects of human gastric cancer cells(Ags). The Korean Journal of Food And Nutrition [Internet]. 2022 [cited 2023 Mar 28];35(2):127–36. Available from: https://koreascience.kr/article/JAKO202213251002537.page
- Kim YH, Kim YW, Oh YJ, Back NI, Chung SA, Chung HG, et al. Protective effect of the ethanol extract of the roots of brassica rapa on cisplatin-induced nephrotoxicity in llc-pk1 cells and rats. Biological and Pharmaceutical Bulletin. 2006;29(12):2436–41.
- Jung UJ, Baek NI, Chung HG, Bang MH, Jeong TS, Tae Lee K, et al. Effects of the ethanol extract of the roots of Brassica rapa on glucose and lipid metabolism in C57BL/KsJ-db/db mice. Clinical Nutrition [Internet]. 2008 Feb 1 [cited 2023 Mar 28];27(1):158–67. Available from: https://www.sciencedirect.com/science/article/pii/S0261561407001604
- Chu B, Chen C, Li J, Chen X, Li Y, Tang W, et al. Effects of Tibetan turnip (Brassica rapa L.) on promoting hypoxia-tolerance in healthy humans. Journal of Ethnopharmacology [Internet]. 2017 Jan 4 [cited 2023 Mar 29];195:246–54. Available from: https://www.sciencedirect.com/science/article/pii/S0378874116318955
- Rakel D, Minichiello V. Integrative medicine ,e-book. Elsevier Health Sciences; 2022. 1378 p.