Rachel Whitehall, student dietitian, Glasgow Caledonian University.

 

Celeriac would not look out of place in a sci-fi movie with its somewhat monstrous and alien appearance. Although possibly not the most attractive vegetable around, don’t shun celeriac just yet, as like the saying goes it’s what in the inside that really matters! And this root vegetable definitely deserves a place on your dinner plate. Celeriac is an often overlooked vegetable compared to its relation celery however, it is one of the most robust and versatile foods we can include regularly within our diet, either as a side with meals or as the main focus of a vegetarian dish.

Celeriac, also known as turnip-rooted celery or knob celery, is generally classed as a root vegetable however technically it is a ‘corm’ or a ‘hypocotyl’, depending on whom you speak to. Although little is known about the vegetable’s history we do know that celeriac was derived from wild celery, originates from the Mediterranean basin where its popularity continues to this day.1 Celeriac is available year round, however it generally perceived as a winter vegetable. Generally peak season is between September and April.  It may also be grown at home and generally takes around six months to mature.2

The vegetable has subtle flavours of celery and parsley, and often is described as possessing a mellow nutty and peppery taste. When purchasing celeriac it is best to purchase it within one week of when you plan to use it. Opt for celeriac that has a heavy, firm root that is free from soft spots and avoid those that look damaged or discoloured. 1 To keep the vegetable in good condition prior to eating, store it within the fridge. To prepare celeriac you will need to wash and peel it to remove off surface dirt and soil, and then scrape off its outer skin using a sharp knife, similarly to a potato. Celeriac can be enjoyed raw or cooked however, if eating raw it would be useful to immerse the celeriac in a bowl of water first with some added lemon juice immediately after peeling, as the vegetable can discolour quickly once exposed to air. 3

A recommended portion of celeriac is 80g, which will count towards 1 of your 5 a day. One cup of celeriac (155g) contains just 66 calories, 14 grams of Carbohydrate, 2.3 grams of Protein and 0.5 grams of Fat.4 The vegetable can be used raw in salads and dishes, although a popular method is to boil celeriac to make a delicious lower calorie alternative to potatoes, although the nutritional content may be altered slightly through boiling.

Nutritional Content of Raw Celeriac (nutrient levels may differ if cooked)

Nutrient Amount per 100g Amount per cup (155g)
Energy (kcal) 42 66
Carbohydrates (g) 9 14
Of which sugars (g) 1.6 2.5
Dietary Fibre (g) 1.8 2.8
Protein (g) 1.5 2.3
Total Fat (g) 0.3 0.5
Saturated Fat (g) 0.1 0.1
Vitamin C (mg) 8.0 12.5
Vitamin K (µg) 41.0 64.0

 

Celeriac is an excellent source of Vitamin C, with one cup providing around 12.5mg of the nutrient equivalent to just over 30% of the daily, recommended nutrient intake (RNI) for adults.5 Vitamin C is a water-soluble vitamin, and as our bodies are unable to store these vitamins, it is important to make sure we are receiving adequate amounts from the foods we eat. Vitamin C, also known as ascorbic acid, is essential for the growth and regeneration of body tissues, as well as the synthesis of collagen, an important protein that helps give our skin strength and elasticity. Vitamin C also plays an important role in the maintenance of healthy bones and teeth and is a powerful anti-oxidant, protecting the body from damage caused by harmful molecules called free radicals. It also plays a role in enhancing the absorption of non-haem iron (iron from plant sources) in the gut when consumed together within the same meal. The UK recommended nutrient intake (RNI) of Vitamin C for children aged 1 to 10 years is 30mg/day, 11-14 years 35mg/day and Adults (15 years +) 40mg/day.5

Celeriac is also a fantastic source of Vitamin K, a fat-soluble vitamin that our bodies store in our fat tissues and liver. Vitamin K takes its name from the German word for blood clotting (koagulation), and perhaps is one of the main functions Vitamin K is best known for. The clotting process in the human body is very complex, requiring at least 12 proteins before the process can be initiated, of which four proteins require Vitamin K to become activated. Although some people may hear the words blood clot and think of its negative associations, in fact blood clotting is extremely important to stop bleeding due to accidental cuts or punctures to our skin. Moreover, there is growing interest that Vitamin K plays an important role in maintaining bone health. Vitamin K helps to seal calcium into the bones to increase bone density and strength, reducing the risk of fractures and in the long-term, osteoporosis.  It is thought that by helping to seal calcium into the bones, it prevents the risk of calcium accumulating in the lining of our arteries and other tissues, therefore reducing the risk of cardiovascular disease.6 A journal review in 2016 suggested that increasing dietary consumption of foods rich in Vitamin K such as Celeriac, promotes bone health through optimising bone strength and reducing fracture risk.7 One cup of celeriac will provide you with 64 µg of Vitamin K, although currently there is no RNI for this nutrient as dietary deficiency is rare. However, suggested requirements are 0.5-1.0 µg per kg of body weight, per day. 5

Celeriac also contains a moderate amount of dietary fibre, with one cup of the root vegetable containing around 2.8 grams of fibre. Dietary fibre is important for ensuring good intestinal motility, digestive health and cardiovascular health. Research indicates that diets rich in fibre are associated with reduced risk of cardiovascular disease, type-2 diabetes and bowel cancers, whereas, conversely diets low in fibre are associated with poor digestive health. 8Recent, compelling research has suggested that individuals consuming a low-fibre diet have increased cortisol levels, indicating a heightened stress response within the body, which is strongly linked to anxiety and depression. 9The UK Government recently revised their guidance on Dietary Fibre recommendations in 2015. The average population intake for adults has now increased to 30 grams per day, for children aged 2 to 5 years 15 grams per day, for children aged 5 to 11 years 20 grams per day, and children aged 11 to 16 years 25 grams per day.8

Moreover, celeriac is also a good source of some of the essential minerals we need from our diet such as phosphorous, iron, calcium, copper and manganese. Phosphorous is present in every cell within our body, and makes up 1% of an individuals total body weight, the majority of which is found in the bones and teeth. Thus, its main function is the formation of bones and teeth as well as the growth, maintenance and repair of all tissues. Iron is an essential mineral, which is required for the production of red blood cells, which carry oxygen around the body. A lack of iron in the diet can lead to feeling a lack of energy and tiredness alongside shortness of breath. 10 Generally, we can get enough vitamins and minerals through our diets alone, by including a wide range of different fruits and vegetables each day, to provide us with a variety of nutrients to optimise our health.

So don’t shun celeriac just yet, there are many ways you can begin including it in your diet. Try it roasted, boiled and mashes, steamed, or make it into soups or as an addition to salads for some serious health benefits and delicious dishes.

 

References

[1] Eat the Seasons (2004) Eat Celeriac [online] [viewed on 17/02/2017] Available from: http://www.eattheseasons.co.uk/Articles/celeriac.php

[2] Royal Horticultural Society (2017) Celeriac [online] [viewed on 17/02/2017] Available from: https://www.rhs.org.uk/advice/grow-your-own/vegetables/celeriac

[3] BBC Good Food (2017) Celeriac [online] [viewed on 17/02/2017] Available from: http://www.bbcgoodfood.com/glossary/celeriac

[4] McCance, R.A., Widdowson, E.M., Royal Society of Chemistry. Information Services, Public Health England, Institute of Food Research & Great Britain. Ministry of Agriculture, Fisheries and Food (2015), McCance and Widdowson’s the composition of foods, 7th summary edn, Royal Society of Chemistry.

[5] Gandy, J., Askews, British Dietetic Association & EBL 2014, Manual of dietetic practice, 5th edn, Wiley-Blackwell.pp.

[6] British Nutrition Foundation (2017) Vitamin K [viewed on 17/02/2017] Available from: https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/vitamins.html?limit=1&start=5

[7] O’Keefe, J.H., Bergman, N., Carrera-Bastos, P., Fontes-Villalba, M., DiNicolantonio, J.J. & Cordain, L. 2016, “Nutritional strategies for skeletal and cardiovascular health: hard bones, soft arteries, rather than vice versa”, Open heart, vol. 3, no. 1, pp. e000325.

[8] SACN (Scientific Advisory Committee on Nutrition) 2015 Carbohydrates and Health. [online] [Viewed on 07/02/2017] Available at: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/445503/SACN_Carbohydrates_and_Health.pdf

[9] Schmidt, K., Cowen, P.J., Harmer, C.J., Tzortzis, G., Errington, S. & Burnet, P.W.J. 2015;2014;, “Prebiotic intake reduces the waking cortisol response and alters emotional bias in healthy volunteers”, Psychopharmacology, vol. 232, no. 10, pp. 1793-1801.

[10] British Nutrition Foundation (2017) Vitamins [viewed on 17/02/2017] Available from: https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/vitamins.html