Karen O’Hare, student dietian, Queen Margaret Uiniversity.

 

Spring greens

Spring greens are a member of the cabbage family and like other vegetables in this family, they pack a nutritional punch. Spring greens are actually young cabbage plants and are the first cabbages of the year1. They do not have a hard core which is found in the middle of most fully grown cabbages. They are dark green with quite a strong flavour, which some people may be put off by, although when prepared correctly and added to the right dishes they can be very tasty. Spring greens are quite a tough plant and are mainly grown in Northern Europe where they can tolerate harsh winters. They are at their peak season from April to June1.  Spring greens are most commonly found in supermarkets as loose heads of thick, green leaves. They can also be found in pre-washed bags salad leaves, alongside spinach and other types of lettuce or cabbage leaves. When buying spring greens and other leafy, green vegetables, look for fresh and firm leaves and avoid any wilted or discoloured plants. They should be stored in a refrigerator, and ideally used within 2-3 days, as the taste will begin to deteriorate after this period.

Like other vegetables, one portion of spring greens is approximately 80g2. The full nutritional composition of this portion and the corresponding reference nutrient intakes (RNI) can be seen in Table 1.

Table 1: Nutritional composition of a portion of raw spring greens (80g) and UK RNI’s

Nutrient Amount RNI
Children Teens

(11-17 years)

Adults

(over 18 years)

2-5 years 5-11 years
Macronutrients  
Energy (kcals) 26
Carbohydrate (g)

Of which sugars (g)

Fibre (NSP) (g)*

3.1

2.1

2

15

20

25

30

Protein (g) 2.4
Fat (g) 0.8
Micronutrients
Vitamin A (retinol equivalent) (µg) 350 400 500 600-700 600-700
Vitamin C (mg) 144 30 30 35-40

 

40
Vitamin K (µg) 714 1 µg/kg
Folate (µg) 73 70-100

 

100-150 200 200

*AOAC value unavailable3; Nutritional composition of raw spring greens3; Reference Nutrient Intakes4

Macronutrients

Like other leafy-green vegetables, spring greens are very low in calories and fat, and therefore can be a very useful food to bulk out a meal, especially if trying to lose or maintain weight and reduce portion sizes. Spring greens also have a low glycaemic index. Glycaemic index is a measure of how fast your blood glucose levels rise after consuming a food. Therefore, spring greens and other green, leafy vegetables are beneficial for people with type 2 diabetes to consume as they can help manage glucose levels. Spring greens also contain fibre, which can help keep you fuller for longer, and therefore help with appetite control and weight management. Fibre has also been found to lower cholesterol and aid digestion5.  New evidence has emerged showing that fibre also plays a role in reducing the risk of cardiovascular disease and type 2 diabetes5. It has also been found to reduce the risk of colo-rectal cancer, which is the third most common cancer in the UK5. Due to these health benefits, the recommended nutrient intake for fibre was raised to 30g per day for adults5.

Micronutrients

Spring greens are a great source of beta-carotene, providing 2104µg per 80g portion. Beta-carotene is a pre-cursor to vitamin A meaning that it is converted to vitamin A by the body3. By consuming foods rich in beta-carotene such as spring greens, you can ensure that you are getting enough vitamin A. Vitamin A is a fat-soluble vitamin. This means that any vitamin A that our body doesn’t use immediately is stored for future use. It is essential for our immune system and to ensure that we can fight off any infection or disease effectively6.  Vitamin A also has a role in ensuring good vision, particularly in dim light6. If someone has vitamin A deficiency, they can get a condition called night blindness, although this is quite rare. Lastly, vitamin A ensures that our skin and mucous membranes are healthy6. Mucous membranes line the nose, mouth and sinuses and have an important function in the immune system by acting as a barrier against the outside world. The UK RNI for vitamin A is listed in Table 1, and as you can see one portion of spring greens can provide half of the RNI for adults.

Spring greens are also a rich source of vitamin C, containing 144mg per 80g portion, which is well over the UK RNI for adults. Unlike vitamin A, vitamin C is a water soluble vitamin meaning that our bodies excrete any vitamin C that isn’t used or needed7. Therefore it is essential that we get enough through our diet every day.  Vitamin C is essential for growth and repair of tissues all throughout the body7. Specifically, vitamin C helps make collagen which is a protein used to make skin, cartilage, ligaments etc. Vitamin C is also needed for effective wound healing as it helps the body make new tissue7. Vitamin C aids iron absorption from non-haem sources. Non-haem sources of iron are foods of vegetable origin that are not as well absorbed in the body as haem iron from animal sources8. Therefore, combining vitamin C rich foods with sources of non-haem iron can significantly improve absorption8. Lastly, vitamin C is a powerful antioxidant.  Antioxidants play a role in limiting the damage caused by free radicals, which are substances that can cause oxidative stress in the body and can lead to the development of certain cancers and cardiovascular disease in the body8.  They can also contribute to the ageing process. Deficiency in vitamin C can lead to a condition called scurvy where you get swollen, bleeding gums, tiredness and muscle and joint pain7. Eating a healthy, balanced diet with plenty of fruit and vegetables will ensure that you get enough vitamin C to meet the RNI.

Spring greens also contain a decent amount of folate, 73µg per portion. Folate is the form of folic acid that is found naturally in food. Folic acid is actually a B vitamin and its main role is in the formation of red blood cells9. It performs this role in combination with vitamin B12. It also plays a role in the formation of DNA within each cell in the body and ensures that each cell replicates effectively9.  Deficiency of folic acid is quite common and can lead to a condition called macrocytic or large cell anaemia, where red blood cells have a reduced ability to carry oxygen9. Symptoms of anaemia are often tiredness, weakness and can also lead to weight loss9. Folic acid also plays a role in brain function and mental and emotional health10.  The UK RNI for folate can be seen in Table 1. Women who are considering pregnancy or who are pregnant or lactating should take a folic acid supplement of 400µg/day, as well as eating a diet rich in folate9. This is to reduce the risk of neural tube defects occurring in the foetus.

Vitamin K is another fat-soluble vitamin that spring greens are high in, containing 714µg per portion. Vitamin K is also known as the clotting vitamin as it is essential for effective blood clotting11. It also plays a role in maintaining health bones, particularly in the elderly population11.  Low levels of vitamin K have been linked to low bone mineral density11. Vitamin K deficiency is very rare and it is easy to get the amount you need through eating a varied and balanced diet and including leafy-green vegetables such as spring greens. Also, as it is a fat-soluble vitamin, you don’t need to include it in your diet every day.

Phytochemicals

Spring greens also contain an abundant amount of phytochemicals in the form of carotenoids.  Carotenoids are natural, fat soluble pigments that promote the vibrant colour of dark, leafy green vegetables. They serve as anti-oxidants and can be a pre-cursor for vitamin A, for example beta-carotene which is present in spring greens. Other carotenoids present in spring greens are lutein and zeaxanthin. Both of these carotenoids are the two main components of the macular pigment of the retina12. Diets rich in lutein and zeaxanthin may hold off age-related eye deterioration, such as cataracts and macular degeneration, which are the main causes of blindness in the elderly12.

Spring greens are also rich in glucosinolates, which are sulphur-containing compounds that are commonly found in cruciferous vegetables13. These glucosinolates are broken down to substances such as sulforaphane and indoles during food preparation, chewing and digestion13. Sulforaphane and indoles are both phytochemicals and are common in cruciferous vegetables. It has been found that these phytochemicals may have anti-cancer effects by inactivating carcinogens and inhibiting DNA cell damage, although further research is needed in humans13.

Incorporating spring greens into your diet

There are a number of different ways that spring greens can be prepared and consumed.  When cooking spring greens and any other vegetables, ensure that you don’t cook for too long. This will avoid the loss of important micronutrients.  It is also important to try and steam where possible, for approximately 5-7 minutes, to ensure no water soluble vitamins or phytochemicals are lost during boiling.

  • Add to a stir fry, towards the end of cooking
  • Add to soups, stews or a vegetable bake
  • Have raw in a sandwich
  • Can be used as a side dish, fried with some garlic and chilli alongside beef, lamb, pork etc.
  • Added shredded to a curry
  • Use within a mixed leave salad
  • Add to a green smoothie
  • Shred spring greens, roll them up and then fly them in a little oil to get Chinese-like crispy rolls

 

References:

  1. (2016).Spring greens. Available: https://www.bbcgoodfood.com/glossary/spring-greens. Last accessed 20th Mar 2017.
  2. Public Health England. (2015).5 a day portion sizes. Available: http://www.nhs.uk/Livewell/5ADAY/Pages/Portionsizes.aspx. Last accessed 20th Mar 2017.
  3. McCance, R. (2002).McCance and Widdowson’s The composition of foods. 6th ed. Cambridge: Royal Society of Chemistry.
  4. British Nutrition Foundation. (2016). Nutrition Requirements.Available: https://www.nutrition.org.uk/attachments/article/234/Nutrition%20Requirements_Revised%20Oct%202016.pdf. Last accessed 20th Feb 2017.
  5. Public Health England. (2015). SACN Carbohydrates and Health Report.Available: https://www.gov.uk/government/publications/sacn-carbohydrates-and-health-report. Last accessed 21st Feb 2017.
  6. Public Health England. (2017). Vitamin A.Available: http://www.nhs.uk/Conditions/vitamins-minerals/Pages/Vitamin-A.aspx. Last accessed 21st Mar 2017.
  7. Ehrlich, S.D. (2013). Vitamin C (Ascorbic acid).Available: http://umm.edu/health/medical/altmed/supplement/vitamin-c-ascorbic-acid. Last accessed 21st Mar 2017.
  8. National Institute for Health. (2016). Vitamin C. Available: https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/. Last accessed 21st Mar 2017.
  9. British Dietetic Association. (2016). Folic acid.Available: https://www.bda.uk.com/foodfacts/FolicAcid.pdf. Last accessed 21st Mar 2017.
  10. Ehrlich S.D. (2015). Vitamin B9 (Folic acid). Available: http://umm.edu/health/medical/altmed/supplement/vitamin-b9-folic-acid. Last accessed 21st Mar 2017.
  11. Ehrlich, S.D. (2013). Vitamin K.Available: http://umm.edu/health/medical/altmed/supplement/vitamin-k. Last accessed 17th Feb 2017.
  12. Wachler, B.S. (2016). Lutein and Zeaxanthin for Vision. Available: http://www.webmd.com/eye-health/lutein-zeaxanthin-vision. Last accessed 21st Mar 2017.
  13. National Cancer Institute. (2012). Cruciferous Vegetables and Cancer Prevention. Available: https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cruciferous-vegetables-fact-sheet. Last accessed 22nd Mar 2017