Superfoods – myth or truth?

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‘top 10 superfoods…’

’… superfoods to boost a healthy diet’

‘…superfoods you should be eating’

What are these foods and why are they so super? With all the hype should I be eating more of them you may ask?

A quick internet search yields numerous so-called superfoods, some of which are listed below…

Chia seeds
Dark chocolate
Olive oil
Sunflower seeds

Let’s examine a few items from the above list in more detail.

Kale – a leafy vegetable, green or purple, which is part of the cabbage or brassica family. Along with other vegetables its growth was encouraged as part of the ‘Dig for Victory’ campaign in the UK during World War II (WWII), providing vital nutrients often missing from the diet due to rationing. Kale is not a new phenomenon though. It has been cultivated for years and years around the world, even prior to WWII.

Its rise to prominence as a ‘superfood’ will not have been hindered by the promotion of ‘kale chips’ by Gwyneth Paltrow on the Ellen DeGeneres show in 2011; also the first Wednesday in October is traditionally National Kale Day in the US.

There is no denying it, kale packs a punch with its vitamin and phytochemical content, but then so too do other green leafy vegetables.

Eggs – with six grams of protein, nine essential amino acids (see the post ‘Polypeptides and Protein’), rich in vitamins and minerals, one egg will certainly get you to work. “Go to work on an egg” was in fact an advertising slogan used by the UK’s Egg Marketing Board during the 1950s and 1960s. They are very convenient to eat on the go, have in a packed lunch and extremely versatile as part of a healthy balanced meal.

Eggs were one of several foodstuffs in short supply during WWII in the UK and it is now hard to imagine during that time adults were rationed to one fresh egg, per person, per week.

Eggs have had their fair share of bad press. For many years dietary cholesterol, and by association eggs which have a high cholesterol content, was implicated in an increased risk of heart disease1. Subsequent research has found no evidence to support this and their popularity has since had a resurgence.

Blueberries – are certainly nutritious with numerous studies documenting their high antioxidant* content. Clinical research and in vitro studies have shown the phytochemicals in blueberries, and specifically anthocyanins which give blueberries their red/blue/purple colour as they ripen, are responsible for conferring the health benefits of antioxidants2. See the post ‘Phyto… about plants’ for more detail on plant chemicals.

*antioxidants are molecules which protect cells from damage caused by an increase in free radicals and resulting oxidative stress; high levels of free radicals in the body are linked to illnesses such as heart disease, diabetes and cancer

Quinoa – once cultivated in South America by the ancient Incas, technically a seed but classed as a wholegrain, quinoa is gluten-free, contains all nine essential amino acids and has a vitamin content on a par with other grains such as wheat, rice and maize. In addition to its nutritional qualities, production costs are also low given the plant’s ability to tolerate extreme growing conditions, e.g. drought, frost, high salinity3. Over the last two decades healthy food trends have resulted in an increased demand for this crop.

The following table compares the micronutrient values of five differing raw foods, namely kale one of the latest ‘on trend’ foods, carrots, savoy cabbage, tomatoes and chard. All values are taken from the US Department of Agriculture’s nutritional database and illustrate that whilst kale does contain mighty doses of calcium and vitamins A and C, the other ‘lowlier’ contenders can match or even surpass the mineral/vitamin content of kale.

Table 1: Mineral and vitamin content of raw foodstuff per 100g portion – for conciseness some minerals and vitamins have been omitted

Component Unit Kale Carrots Cabbage
Tomatoes Chard
Calcium mg 254 33 35 11 51
Magnesium mg 32.7 12 28 8.1 81
Sodium mg 53 69 28 <2.5 213
Copper mg 0.053 0.045 0.062 0.032 0.179
Manganese mg 0.92 0.143 0.18 0.087 -
Vitamin C mg 93.4 5.9 31 17.8 30
Thiamin mg 0.113 0.06 0.07 0.056 0.04
Riboflavin mg 0.347 0.058 0.03 0.1 0.09
Folate µg 62 19 80 10 14
Vitamin A µg 241 835 50 24 306
Carotene, Beta µg 2870 8280 600 276 3650
Carotene, Alpha µg 0 3480 0 1 45
Lycopene µg 0 1 0 2860 0
Lutein and
µg 6260 256 77 56 11000
Vitamin K µg 390 13.2 68.8 - 830

Of the foodstuffs in the above table the data shows:

  • chard contains more magnesium, sodium, copper, beta carotene, lutein and zeaxanthin, and vitamin K than kale
  • carrots have more vitamin A, beta carotene, and alpha carotene than kale
  • only tomatoes contain lycopene
  • savoy cabbage contains more folate than kale

So, let’s be clear, ‘superfood’ is a media term, not a scientific term and was probably coined as a means of influencing food trends.

Rather than be limited to a small range of on trend foods, enjoy these as part of a balanced, healthy diet alongside a wide variety of other nourishing foodstuffs.

For an online searchable database of foodstuffs and their nutritional value try the US Department of Agriculture food composition database, USDA FoodData Central, linked here.


  1. Soliman, G. A. Dietary Cholesterol and the Lack of Evidence in Cardiovascular Disease. Nutrients. 2018 Jun; 10(6): 780. Available from: 10.3390/nu10060780
  2. 2. Kalt, W., Cassidy, A., Howard, L. R., Krikorian, R., Stll, A. J., Tremblay, F., Zamora-Ros, R. Recent Research on the Health Benefits of Blueberries and Their Anthocyanins. Advances in Nutrition. 2020 Mar; 11(2): 224–236. Available from: 10.1093/advances/nmz065
  3. Angeli, V., Silva, P. M., Massuela, D. C., Khan, M. W., Hamar, A., Khajehei, F., Graeff-Hönninger, S., Piatti, C. Quinoa (Chenopodium quinoaWilld.): An Overview of the Potentials of the “Golden Grain” and Socio-Economic and Environmental Aspects of Its Cultivation and Marketization. Foods.2020 Feb; 9(2): 216. 2020 Feb 19. Available from:  10.3390/foods9020216

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