This post I’m going to chat to you about leafy green veggies, and why it’s a great idea to eat your greens. I know that certain veggies get a lot of good press for being super-nutritious, but one of the things I’d like to get across here is that there are many, many veggies out there which are all fantastic sources of vitamins and minerals. So, here’s the low down on a few of my favourite green leaves!
Currently growing in abundance in my Dad’s allotment is kale: big, green, leafy and increasingly fashionable. In fact, kale can be grown here in Britain almost year-round, so it’s a good veggie if you want to cut down on air miles and support your local farmers (or even save some pennies and grow your own).
Kale is a member of the brassica family (think cabbages and brussel sprouts), and there a few different types ranging from curly kale often seen at the supermarket, to ‘dinosaur’ kale with flatter, taller leaves and even bright purple kale (otherwise known as Redbor kale).
You’re probably already aware that it packs a nutritional punch. Here’s the score:
1 cup (67g) provides 133% of your RNI of vitamin A1 in the plant-based form, β-carotene. Vitamin A is needed for night vision, healthy skin and mucous membranes. β-carotene is a compound known as a ‘carotenoid’ which has antioxidant properties and may help to protect the body against oxidative stress. It’s also found in other colourful fruit & veggies such as carrots, sweet potato, red peppers, mango, papaya and apricots. A good rule of thumb is the darker the leaf, the more β-carotene – so darker plants like kale have the edge on lighter ones like cabbage or peas2.
It’s also full to the brim with vitamin C, with 1 cup providing about 80mg1 , which is over 100% of the RNI for non-smoking adults. It’s essential for the health of connective tissues and also acts as an antioxidant. Vitamin C deficiency can cause bleeding gums, and if untreated can develop into scurvy. Fruits and vegetables in general are fab sources of vitamin C, so make sure you’re getting your 5-a-day. Be aware that vitamin C is easily lost in preparation and cooking, and boiling your veg can dramatically impact its vitamin C levels2. My advice is to stick to cooking methods which don’t involve too much water such as steaming, microwaving, stir-frying, or adding to smoothies and soups.
1 cup gives you a whammy of over 400µg vitamin K1 , needed for bone health and for blood to clot effectively. Again, vitamin K is found in abundance in other green leafy veg, peas and cereals. The bacteria in our guts are busy synthesising it too, which is handy2. That said, excessive amounts of vitamin K may not be suitable for people on certain medications (such as blood-thinners like warfarin) so keep your individual circumstances in mind.
Kale is low in fat and sugar, and a whole cup weighs in at around 33kcal (less than a rich tea biscuit!), giving it a low energy density that’s ideal if you’re watching your weight. It also provides smaller amounts of calcium and vitamin B6, and moderate amounts of potassium, magnesium, iron and protein1 .
For a protein-packed meal or snack, try mixing kale with eggs in an omelette or frittata
If you’re craving something salty, try making kale crisps
Try some kale pesto on your pasta or salad
What’s in a name? Arugula is a Mediterranean vegetable also known as salad rocket, rucola, rucoli, rugula, colewort or roquette. It’s the same peppery leaf that you may find atop your pizza or on the side of your plate when you go out for a meal.
Like it’s relative Kale, it is very low in calories, providing around 25kcal per 100g. It also contains vitamin A and vitamin C, however it’s less nutrient-dense – although 100g of rocket can provide you with almost 50% of your daily vitamin A1, in reality that would see you eating 5 cups of the stuff. However, when compared to regular iceberg lettuce, arugula packs in more calcium, vitamins A, C & K and iron making it a savvy substitution.
One of the things that sets arugula aside is it’s notably high nitrate content (480mg per 100g)3. There is an increasing body of evidence that suggests dietary nitrates act to reduce blood pressure in both normotensive4,5 and hypertensive6 individuals, indicating potentially beneficial health effects (i.e. reduced stroke risk). However, further methodologically robust research is needed to confirm this association. Research also suggests that this increase in nitrate levels may be short-lived, requiring daily consumption of nitrate-rich foods to reap any potential health benefits7.
Pop it on a pizza
Top up on omega-3 & vitamin D by pairing it with salmon
Toss with veggies and grains for a filling salad
Swiss chard is a pretty vegetable, with big green leaves and colourful stalks of white, yellow or red. It’s in the same family as the beetroot; you can see its resemblance to beet leaves. It’s most popular as part of the nourishing Mediterranean diet and is frequently used in Italian and French cooking. The leaves of chard can be eaten like spinach, whilst the crunchy stems can be cooked and served like asparagus.
One cup of swiss chard provides just 7kcal, but manages to squeeze in 44% of your daily vitamin A and 300µg of vitamin K. It also provides smaller amounts of vitamin C, magnesium, iron and fibre1.
Chard also contributes to intake of other minerals including copper. Copper is a trace element which we need to effectively absorb iron. This is why iron-deficiency anaemia sometimes resolves more efficiently by increasing both iron and copper intake8. It’s also needed for healthy connective tissues, skin and hair. Other dietary sources include animal foods, legumes, nuts and in water via copper water pipes9.
Green leafy vegetables- including swiss chard- are also a rich source of non-nutritive compounds called polyphenols, namely flavonoids. The levels of these flavonoids increase with ripeness, and there is evidence to suggest that they exhibit a range of physiological effects – these are outlined these as9:
- anticarginogenic (inversely associated with cancer risk)
- antimicrobial (antibacterial)
- antioxidative (provides protection against cell damage by free radicals)
- antithrombotic (protection against blood clots)
- influence on blood pressure
- modulating effect on glucose
This is not to say that these effects are from a single factor, but rather it is likely that these positive health effects are due to a combination of non-nutritive compounds, vitamins, minerals, trace elements, fatty acids and dietary fibre found in fruits and vegetables9.
Mix your greens with some beans for a veggie main or side-dish
Swap your fajitas for these veggie tacos with swiss chard pesto
Stir into a hearty vegetable soup
Spinach is a hardy little leaf in the same family as swiss chard and beetroot, and it’s available all year round. My favourite thing about it is its versatility; it’s so easy to eat, and is available tinned, frozen and fresh. Fresh spinach really reduces in size when cooked, meaning that it’s possible to consume a large volume of it without having to munch through a huge plate of leaves. Tinned, frozen or fresh spinach is ideal to throw in a curry, pasta sauce, or stew. Raw, it’s good in salads, sandwiches, wraps and smoothies, as it’s less bitter than some of the other leafy greens.
Perhaps most well-known for it’s iron content, spinach packs in a mighty 7mg of iron per pack (almost half of your daily recommendations)1. Iron deficiency is the most common nutritional deficiency in humans, with many people experiencing depleted iron stores and an estimated 500-600 million people suffering from iron-deficiency anaemia 9. The iron found in spinach and other vegetables is known as ‘non-haem’ iron, of which 5-15% is absorbed. There are several known compounds which can either enhance (e.g. vitamin C) or reduce (e.g. phytates and polyphenols) uptake of non-haem iron, so try eating your spinach with a squeeze of lemon or a small glass of orange juice to make the most of what it has to offer. It may be a good idea to avoid drinking tea and coffee with your meals, as they contain polyphenols which decrease iron absorption2.
One pack of spinach also provides 8g of protein (about the same as an egg), making it a valuable addition to a plant-based diet. Spinach also provides similar nutrients to kale; good amounts of vitamin A , C and K, as well as vitamin B6, magnesium, potassium, calcium and fibre1. However, it’s useful to consider the availability of these nutrients: calcium from spinach is actually one of the least bio-available forms out there due to it’s oxalic acid content, with only 5% absorbed by our bodies. Comparatively, we absorb 50% of the calcium from broccoli, again highlighting the importance of variety in our diets10 .
Whip up some eggs florentine for a lazy Sunday brunch
Chuck it in a cheap and easy curry
Mash spinach & peas for a lighter take on mashed potato
Green leafy vegetables can be little powerhouses of nutrients and there are many ways to incorporate them into a healthy balanced diet. Other green leafy vegetables include collard greens, watercress, romaine lettuce and cabbage. Generally, they’re good sources of vitamins A, C and K as well as minerals, including iron, and non-nutritive polyphenols like flavonoids. They’re low in fat, sugar and energy but high in fibre, meaning that they’re ideal to bulk up your meals without adding lots of extra calories.
I hope this has inspired you to get a little creative in the kitchen (and the garden) and try something new,
Thanks for reading! Feel free to leave any comments, criticisms or questions below,
1 United States Department of Agriculture Agricultural Research Service, (2015). Foods List. [online] National Nutrient Database for Standard Reference Release 27. Available at: http://ndb.nal.usda.gov/ndb/foods [Accessed 20 Aug. 2015].
2 Department of Health, (2012). Manual of Nutrition. 12th ed. Norwich: TSO.
3 Hord, N., Tang, Y. and Bryan, N. (2009). Food sources of nitrates and nitrites: the physiologic context for potential health benefits. American Journal of Clinical Nutrition, 90(1), pp.1-10.
4 Ashworth, A., Mitchell, K., Blackwell, J., Vanhatalo, A. and Jones, A. (2015). High-nitrate vegetable diet increases plasma nitrate and nitrite concentrations and reduces blood pressure in healthy women. Public Health Nutr., pp.1-10.
5 Siervo, M., Lara, J., Ogbonmwan, I. and Mathers, J. (2013). Inorganic Nitrate and Beetroot Juice Supplementation Reduces Blood Pressure in Adults: A Systematic Review and Meta-Analysis. Journal of Nutrition, 143(6), pp.818-826.
6 Kapil, V., Khambata, R., Robertson, A., Caulfield, M. and Ahluwalia, A. (2014). Dietary Nitrate Provides Sustained Blood Pressure Lowering in Hypertensive Patients: A Randomized, Phase 2, Double-Blind, Placebo-Controlled Study. Hypertension, 65(2), pp.320-327.
7 Bondonno, C., Liu, A., Croft, K., Ward, N., Puddey, I., Woodman, R. and Hodgson, J. (2015). Short-Term Effects of a High Nitrate Diet on Nitrate Metabolism in Healthy Individuals. Nutrients, 7(3), pp.1906-1915.
8 Sanders, T. and Emery, P. (2003). Molecular basis of human nutrition. London: Taylor & Francis.
9 Mann, J. and Truswell, A. (2002). Essentials of human nutrition. Oxford: Oxford University Press.
10 Whitney, E. and Rolfes, S. (2002). Understanding nutrition. Belmont, CA: Wadsworth.