Collards vs Kale – Nutrition Face-Off
Published: February 3, 2019
Collard greens and kale have much more in common than just their green color. Both are members of the Brassica oleracea species, and both are loaded with nutrients and phytochemicals that have been extensively researched for their potential health benefits.
But, when it comes to packing a nutritional punch and warding off disease, which one of these green leafy vegetables reigns supreme?
To find out, we put collards and kale side by side for a nutritional comparison, plus combed through research to learn all about the potential health benefits of collard greens and its botanical cousin.
Nutritional Value of Collards vs Kale
Like most other green leafy vegetables, both collards and kale are low in calories and fat, and high in fiber. Both also contain significant amounts of vitamins C, K, E and B2, as well as calcium, manganese, folate and pro-vitamin A. The biggest difference is that kale contains more of these vitamins and minerals, with the exception of calcium.
The following nutrition facts table highlights the key differences in the nutrient content of collards vs kale. The table provides both the actual amount and the % Daily Value (%DV) for each nutrient, and the values are based on a 100-gram (3.5 oz) serving of raw collards/kale.
| Nutrient | Collards | Kale |
|---|---|---|
| Protein | 3 g | 4 g |
| Fiber | 4 g (14% DV) | 3.6 g (13% DV) |
| Calcium | 232 mg (18% DV) | 150 mg (12% DV) |
| Iron | 0.47 mg (3% DV) | 1.47 mg (8% DV) |
| Magnesium | 27 mg (6% DV) | 47 mg (11% DV) |
| Potassium | 213 mg (5% DV) | 491 mg (10% DV) |
| Vitamin A | 251 RAE (28% DV) | 500 RAE (56% DV) |
| Vitamin C | 35 mg (39% DV) | 120 mg (133% DV) |
| Vitamin K | 437 (364% DV) | 705 mcg (587% DV) |
| Thiamin | 0.05 mg (5% DV) | 0.11 mg (9% DV) |
| Riboflavin | 0.13 mg (10% DV) | 0.13 mg (10% DV) |
| Niacin | 0.7 mg (5% DV) | 1 mg (6% DV) |
| Vitamin B6 | 0.165 mg (10% DV) | 0.271 mg (16% DV) |
| Folate (B9) | 129 mcg (32% DV) | 141 mcg (35% DV) |
Source: USDA National Nutrient Database for Standard Reference, Release 28; The Daily Values have been calculated by HealWithFood.org based on the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board, the Institute of Medicine, and the National Academy of Sciences.
Health Benefits
Whether you are analyzing the nutrition data for collards or kale, one thing is very obvious: both are exceptionally rich in vitamin K. Indeed, just half a cup of either chopped kale or collards provides more than hundred times the daily value (DV) for vitamin K, a nutrient that is best known for its role in the blood clotting process.
An increasing body of evidence also suggests that a low intake of vitamin K is associated with low bone density and an increased risk of osteoporosis, while a high intake of this often-overlooked nutrient has been associated with high bone density and a lower risk of osteoporosis (1).
In addition to being rich in nutrients like vitamin K, collards and kale contain health-protecting phytochemicals. Scientists believe that eating Brassica vegetables like kale or collards may help reduce your risk of developing cancer because they contain phytochemicals called glucosinolates.
While glucosinolates themselves have limited health benefits, they act as precursors to isothiocyanates such as sulforaphane. Isothiocyanates have been extensively researched for their potential anti-cancer effects, and studies suggest that they can induce apoptosis (self-destruction of cancerous cells), combat inflammation, and influence proteins that are involved in cell division (2).
Taste and Uses
Both collards and kale have a vegetal, slightly bitter flavor, but generally, the flavor of collard greens is somewhat milder than that of regular curly kale. That said, there are also some milder-tasting kale varieties, such as lacinato kale which is less bitter than curly kale.
Because of the similar flavor and texture, collards and kale can be used interchangeably in many recipes, and, in fact, collards have been singled out as one of the best substitutes for kale.
Some great ways to use kale and collards include chopping the leaves up and incorporating them into omelets, frittatas and stir fries. The flat leaves of black kale (aka cavolo nero) and briefly cooked collard greens are also perfect for green wraps—a trendy alternative to tortilla wraps.
Storage
Both collard greens and kale are best stored in a dark, cool place, such as the crisper drawer of your refrigerator. If you have a lot of collards or kale and you think you won't be able to eat them up before they turn limp, you can also freeze them for later use.
Note, though, that regardless of whether you are freezing collards or kale, you should blanch the leaves first in order to protect their nutritional value, color and flavor.
To blanch collard greens or kale, boil or steam trimmed and roughly chopped collards or kale for two minutes, then immediately transfer to a large bowl filled with ice water for two minutes.
After that, simply drain and pat the leaves dry, press them into an ice cube tray, and freeze overnight. Next day, remove the collard or kale cubes from the tray, transfer to a ziploc bag, and store in the freezer.
Conclusion
To sum up, both collards and kale are rich in nutrients, particularly vitamin C and vitamin K. From a nutritional standpoint, the key difference between collards and kale is that kale generally contains more nutritional punch per gram.
In addition to providing a wide range of nutrients, both collards and kale contain precursors to isothiocyanates, powerful phytochemicals that have been researched for their potential anti-cancer effects.
Nutritional and health benefits aside, collards and kale also taste great, and their earthy, slightly bitter flavor makes these green leafy vegetables a great addition to a wide range of savory dishes.
More Comparisons of Green Vegetables
If you liked this article about the similarities and differences between collard greens and kale, you might also like the following articles which compare nutrient-dense green foods in terms of nutritional value, health benefits, taste, culinary uses, and more:
References
- M. Fusaro et al (2017). Vitamin K and bone. Clinical Cases in Mineral and Bone Metabolism, 14(2): 200-206.
- B. Mokhtari et al (2018). The role of Sulforaphane in cancer chemoprevention and health benefits: a mini-review. Journal of Cell Communication and Signaling, 12(1):91-101.
Book You May Like
The Book of Greens is an award-winning cookbook dedicated to greens and an invaluable resource for anyone who is tired of using green leafy vegetables in unpredictable ways. Created by one of Portland's most acclaimed chefs, Jenn Louis, this inspiring cookbook contains creative recipes for every meal of the day, from breakfast and mains to snacks and desserts. Whether you want to incorporate some new greens into your diet, or to learn new ways to use old standbys like kale or spinach, this cookbook has you covered.
