Which vegies are the real nutrient powerhouses?

Written by Catherine Saxelby on Wednesday, 27 May 2015.
Tagged: health, healthy eating, nutrition, vegetables

Which vegies are the real nutrient powerhouses?

Move over kale. Watercress, followed by Chinese cabbage, silverbeet and spinach, is now top of the list as THE vegetable super food. So says a 2014 US study that ranked the top “powerhouse” fruits and vegetables according to their nutrient density score.

Next time you’re wolfing down a beef and watercress sandwich, ponder this - a new scientific report puts the peppery-tasting green at the top of a list of nutrient dense vegetables, herbs and fruits.

What is a powerhouse vegetable?

To compile the list, researchers from William Paterson University in New Jersey, USA looked at the nutrient density of more than 40 vegetables and fruits.

These foods were chosen because, on average, they provide 10 per cent or more of the daily recommended intake of 17 critical nutrients per 100 Calories.

These nutrients, which are considered of public health importance for reducing the risk of chronic diseases, are potassium, fibre, protein, calcium, iron, thiamin, riboflavin, niacin, folate, zinc plus the vitamins A, B6, B12, C, D, E and K.

Of the foods studied, 41 satisfied the powerhouse criterion providing preliminary evidence of the validity of the classification scheme which is offered as a tool for nutrition education and dietary guidance.

The top 41 winners

Watercress was the winner with a nutrient density score of 100, followed by close relatives including Chinese cabbage, collard and mustard greens.

Produce that belong to the cruciferous family (watercress, Chinese cabbage, collard green, kale, arugula – aka rocket) and the green leafy group (such as chard or silverbeet, beet greens, spinach, chicory, dark lettuces) were concentrated in the top half of the distribution of scores.

Produce belonging to the yellow/orange (carrot, tomato, winter squash, sweet potato), allium (scallion, leek), citrus (lemon, orange, lime, grapefruit), and berry (strawberry, blackberry) groups were concentrated in the bottom half.

The top fruits? Red capsicum or pepper, followed by pumpkin, tomato and lemon.

"The scores can serve as a platform for educating people on the concept of nutrient density," said study author Jennifer Di Noia. "The rankings provide clarity on the nutrient quality of the different foods and may aid in the selection of more nutrient-dense items within the powerhouse group."

However, some other nutrient-dense foods such as berries and garlic have not made the list because of the particular nutrient profiling that the study was based on, though in other nutrient density rankings they would rate highly, as Professor Di Noia acknowledged.

The 41 Powerhouse vegetables and fruit ranked by their Nutrient Density Score

1 Watercress 100.00
2 Chinese cabbage 91.99
3 Chard (silverbeet) 89.27
4 Beet greens 87.08
5 Spinach 86.43
6 Chicory (curly endive) 73.36
7 Leaf lettuce 70.73
8 Parsley 65.59
9 Romaine lettuce 63.48
10 Collard greens** 62.49
11 Turnip greens** 62.12
12 Mustard greens** 61.39
13 Endive 60.44
14 Chives 54.80
15 Kale 49.07
16 Dandelion greens*** 46.34
17 Red pepper (capsicum) 41.26
18 Arugula (rocket) 37.65
19 Broccoli 34.89
20 Pumpkin 33.82
21 Brussel sprout 32.23
22 Scallion (spring onion) 27.35
23 Kohlrabi 25.92
24 Cauliflower 25.13
25 Cabbage 24.51
26 Carrot 22.60
27 Tomato 20.37
28 Lemon 18.72
29 Iceberg lettuce 18.28
30 Strawberry 17.59
31 Radish 16.91
32 Winter squash (all varieties) 13.89
33 Orange 12.91
34 Lime 12.23
35 Grapefruit (pink and red) 11.64
36 Rutabaga (swede) 11.58
37 Turnip 11.43
38 Blackberry 11.39
39 Leek 10.69
40 Sweet potato 10.51
41 Grapefruit (white) 10.47

* Leaves from the tops of the round beetroot which look and cook up very similarly to Swiss chard or silverbeet.
** All members of the Brassica or cabbage family which are similar in appearance to kale or cabbage.
*** Dandelion is usually classified as an edible weed. Its long green leaves however are delicious and work well as a green leafy veg or in a salad.

Di Noia J. Defining Powerhouse Fruits and Vegetables: A Nutrient Density Approach. Preventing Chronic Disease 2014;11:130390.

The bottom line

You don’t have to eat just these 41 vegetables and fruits. All produce adds nutrition and variety to your meals. But these are the ones that stand head and shoulders above the rest. Any of them will add a nutrition bonus to your diet. You don’t HAVE to rely on kale.

Catherine Saxelby

About the Author

Catherine Saxelby knows nutrition! She is an accredited nutritionist, food commentator, blogger and award-winning author. Her latest book Catherine Saxelby's Food and Nutrition Companion answers all those tricky questions on healthy eating, diets and supplements. It draws together a lifetime of advice and gives you all you need to know to eat right! It's a complete A to Z. A handy desk go-to reference.