Kale and spinach: two leafy greens we are equally familiar with – and which are equally icky when you are but a small child, not allowed to leave the table until you eat your vegetables. But then you grow up and you realize that no, you can’t actually survive on a diet of ice cream and Reese’s Pieces: not if you care about your health, at least. This prospect leaves you suddenly faced with a terrible choice: kale or spinach? You wouldn’t want to overload on healthy, wholesome nutrients: that would be horrible! And you wouldn’t want to get overwhelmed so early on, while you’re still making those first baby steps into the world of healthy eating. Wouldn’t it be great if we could stage an ultimate face-off where two greens enter, one green leaves? Imagine the tender shoots charging at each other and screaming “There can be only one!”, before slicing each other’s sprouts off. Unfortunately, we cannot have that, but we can at least compare them in a more mundane, down-to-earth fashion. For science!
Before we get on with it, let’s just make it clear that we are talking about raw kale vs. raw spinach, comparing nutrients in a 100-gram serving size.
In addition to having a cooler name, kale got spinach beaten in a number of other categories. It contains more fat (also saturated fat), carbs, fiber, sugar and protein. Still, when it comes to these macronutrients, the differences are quite negligible, since both contain around one percent or less of the Recommended Daily Intake of each of these nutrients. The exception here is fiber, with kale accounting for 14 %, and spinach for 9%. What we really care about are vitamins, minerals, antioxidants and other nutrients with quantities measured in milligrams and micrograms.
Of these, kale has more:
- Vitamin A, although not by a large margin. It contains a higher level of Alpha-Carotene, while their Beta-Carotene levels are close.
- Vitamin B1 (Thiamin)
- Vitamin B3 (Niacin)
- Vitamin B5 (Pantothenic Acid)
- Vitamin B6
- Vitamin C, with 200% of the RDI, compared to 47% of spinach.
- Vitamin K, although both vegetables overshoot the RDI by several hundred percent (kale 881% vs. spinach 604%).
- Copper (Kale 75% RDI vs. spinach 7% RDI)
- Omega 3 fatty acids (180 mg vs. 138 mg)
- Omega 6 fatty acids (138 mg vs. 26 mg)
Spinach is Popeye’s favorite, certain to make you big and strong, but is it better than kale? In some ways, yes. While kale contains no amino acids, spinach is relatively high in both essential amino acids and other amino acids, including arginine, known for heart benefits, wound healing and improved kidney function. Here are some more amino acids, courtesy of spinach:
- Aspartic Acid
- Glutamic Acid
When it comes to essential amino acids, spinach contains more than 10% of the RDI of the following:
Additionally spinach has the upper hand when it comes to several metals, including iron, magnesium, potassium and manganese, as well as the following vitamins:
- Vitamin B2 (Riboflavin)
- Vitamin B9 (Folate), although kale is comparatively rich in folate, too (49% to 35% of RDI)
- Vitamin E
Kale is a rich dietary source of sulforaphane, a chemical which is currently under research for potential uses in fighting cancer, lowering cholesterol levels, and others.
Other benefits of kale include:
- Stronger immune system (thanks to iron and vitamin C)
- Healthier hair, skin and nails (thanks to the omega-3 and omega-6 fatty acids)
- Bone health (thanks to vitamin K)
- Cardiovascular health (folic acid, vitamin B6)
- Healthier eyes, better vision (vitamin A)
- Weight loss
- Improved brain function and brain development (infants and children)
- Relief with asthma, arthritis and autoimmune disorders
Coincidentally, due to coenzyme Q10, an antioxidant, it is true that eating spinach every day helps strengthen muscles and improve muscle efficiency by reducing the amount of oxygen required to power the muscles during exercise. Was Popeye right after all? Maybe, if we take into account that spinach has these benefits as well:
- Reduces risk of skin and colon cancer
- Has anti-aging properties
- Improves cardiovascular health
- Lowers high blood pressure
- Has anti-inflammatory benefits
- Is beneficial for eyesight
- Has neurological benefits (due to potassium and folate)
Why Not Both?
We can clearly see that both of these leafy greens are exceptionally rich in a number of different nutrients, which makes them invaluable as an integral part of every healthy diet. Their health benefits often overlap, since both vegetables are an excellent source of vitamin A, vitamin C, manganese and others, which makes them similar in a lot of ways. There are many differences between them, however, so if you are looking to supplement your diet with a higher level of amino acids, you should choose spinach, while kale is an excellent source of omega-3 and omega-6 fatty acids. Kale is better fresh, since boiling adversely affects the levels of a lot of the nutrients it contains. On the other hand, spinach is better cooked. Cooking reduces the oxalate content of spinach, which frees up more nutrients, primarily calcium.
Despite their differences, kale and spinach can always shake hands and make up in the end, usually when they run into each other in a nice green smoothie. Since both of these vegetables are equally accessible, there’s really no need to choose one over the other. It all depends on your taste preferences and whether you can find a good recipe you will love.