These are the 10 healthiest foods in the world (and most of them we never eat)

When it comes to healthy eating, we all tend to know the general rules. Preferably five fruits and vegetables a day, plus healthy carbs from whole grains, proteins and high-quality unsaturated fats.

But which foods really help us get those all important nutrients? Researchers have now compiled a list of the 10 most healthiest foods as informed by a new study - and you'll be interested to learn that the top 10 doesn't include any fruit.

What was examined in the study?

Researchers at William Paterson University in New Jersey, USA, examined the nutrient density of 41 foods. Specifically, they checked the concentration of 17 essential nutrients in the foods examined and put this proportion of nutrients such as vitamin A, B12 or fibre in relation to the number of calories. So essentially, the higher this value, the healthier the food. Surprisingly, only one food managed to provide 100 percent of the nutrients needed for daily consumption at 100 calories. But without further ado, let's look at what other foods made it into the top 10 healthiest.

These are the top 10 healthiest foods

Not only are there no fruits in the top 10, but moreover it's a line up of all green vegetables. What each food variety does have in common, however, is that they are all low in calories while still being very rich in nutrients.

In first place is watercress, which is full of vitamin C, vitamin A, iron, calcium, potassium and magnesium, as well as many antioxidants. Further benefits: Through essential oils, it has a soothing effect on respiratory diseases and, according to the study, detoxifies the body and purifies the blood.

Chinese leaf lettuce comes in second place, with those who eat it covering off a quarter of their daily vitamin C requirement with just 100 grams. Chinese leaf lettuce also contains plenty of vegetable protein and high-quality amino acids.

Chard takes third place. Among other things, it contains a lot of vitamin C and B vitamins as well as beta-carotenes, the precursors of vitamin A (i.e what is then converted into vitamin A). It also provides minerals such as magnesium, magnesium oxide, iron and calcium.

Fourth place may come as a surprise: It's not the beet itself that ranks here, but the leaves of the beet. The greens actually contain more beta-carotene and calcium than the root we typically consider ‘beetroot' itself. It's also very high in other minerals and vitamins.

The fact that spinach is healthy and helps you grow big and strong is something that's instilled in most people from a young age. It ranked fifth in the study, thanks to a large number of nutrients that are similar to those in chard, though less concentrated. These are B vitamins, vitamin C and beta-carotenes, as well as lots of minerals.

Chicory is the sixth healthiest food, with a lot of fibre that fills you up for a long time and regulates intestinal function. It's also rich in potassium, folic acid and zinc, as well as vitamins A, B and C.

Even though leaf lettuce is up to 95 percent water, most varieties also contain beta-carotenes, B vitamins, folate, and vitamin C. The content varies, however, with lamb's lettuce and arugula being the winners. This puts leaf lettuce in seventh place.

Parsley makes it to eighth place. Super easy to grow, this veg is of much more nutritional value than simply being a garnish or seasoning! It contains vitamins of the B group, beta-carotene (which is converted to vitamin A), vitamin E as well as folic acid and numerous minerals.

Romaine lettuce or Romanasalat is another superfood from the study, reaching ninth place through its high content of beta Carotinoiden, B-Vitaminen, folic acid and mineral materials.

Finally, in tenth position is kale which is high in vitamin C as well as vitamin A, D, E and K. It also has high quantities of potassium.

The top 10 healthiest foods at a glance

• Watercress
• Chinese leaf lettuce
• Swiss chard
• Beet leaves
• Spinach
• Chicory
• Leaf lettuce
• Parsley
• Romaine lettuce
• Kale

How can you integrate the healthiest foods into your own meals?

Most of the vegetables from the top 10 healthiest foods are suitable for use in salads, toppings, and dips. Another great option, however, is starting the day with a green smoothie packed full of as many of these high ranking vegetables as possible.

Those of you finding that to be a little much taste wise can of course always add some fruit into the mix. Just because they don't appear in this top 10 doesn't mean that fruits like apples or pears aren't healthy, they're just not quite as nutritious as these green vegetables.

For reference, the healthiest fruit is considered to be the lemon in 28th place, but strawberries (30th), oranges (33rd) or blackberries (38th) definitely taste sweeter in a smoothie! Enjoy.

This feature originally appeared in Glamour Germany.