Spinach and kale are both excellent leafy greens, and neither is clearly “healthier”: they’re strong in different nutrients. Per 100 g raw, kale has more than three times the vitamin C and about two and a half times the calcium of spinach, while spinach has about three times the folate, more iron, more magnesium and more potassium, according to USDA FoodData Central. Both are very high in vitamin K. Spinach is also high in oxalate, which reduces how much of its calcium and iron your body absorbs. The best approach is to eat both, along with other greens, and choose whichever suits the dish: spinach for quick wilting and smoothies, kale for salads, chips and hearty soups.
Spinach vs kale: nutrition compared
Per 100 g (3½ oz) raw, from USDA FoodData Central:
| Nutrient | Spinach | Kale | Winner |
|---|---|---|---|
| Calories | 23 kcal | 35 kcal | Spinach (lower) |
| Protein | 2.9 g | 2.9 g | Tie |
| Fiber | 2.2 g | 4.1 g | Kale |
| Vitamin C | 28 mg | 93 mg | Kale |
| Vitamin K | 483 mcg | 390 mcg | Both very high |
| Folate | 194 mcg | 62 mcg | Spinach |
| Calcium | 99 mg | 254 mg | Kale |
| Iron | 2.7 mg | 1.6 mg | Spinach |
| Magnesium | 79 mg | 33 mg | Spinach |
| Potassium | 558 mg | 348 mg | Spinach |
Where spinach shines
Folate
Spinach is one of the best vegetable sources of folate, which helps make red blood cells and is especially important before and during early pregnancy. Our guide to spinach nutrition covers it in detail.
Iron and magnesium
Spinach has more iron and magnesium than kale, though its oxalate content means you absorb less of the iron. Eating it with vitamin C, from lemon, peppers or tomatoes, helps. Our guide to iron-rich foods explains more.
Versatility
Spinach is mild and wilts in seconds, so it’s easy to add to soups, curries, pasta, eggs and smoothies.
Where kale shines
Vitamin C
Kale provides more than three times as much vitamin C as spinach. A large handful of raw kale can cover a day’s needs.
Calcium you can absorb
Kale is low in oxalate, so its calcium is well absorbed, making it a useful source for people who don’t eat dairy. Spinach contains calcium too, but its oxalate binds much of it.
Fiber
Kale has nearly twice the fiber of spinach.
Cruciferous compounds
Kale belongs to the cabbage family and contains glucosinolates, plant compounds found in cruciferous vegetables. Our guide to cruciferous vegetables explains what’s known about them.
Things to watch
Oxalate and kidney stones
Spinach is one of the richest sources of oxalate. For most people this isn’t a problem, but the US NIDDK says people who’ve had calcium oxalate kidney stones may want to limit high-oxalate foods. Kale is a lower-oxalate choice.
Vitamin K and warfarin
Both greens are very high in vitamin K. The NHS advises talking to your doctor before making big changes to your diet if you take warfarin, as foods high in vitamin K, such as green leafy vegetables, can affect how it works. You don’t need to avoid them, but keep your intake steady.
Raw kale and the thyroid
Very large amounts of raw cruciferous vegetables can interfere with iodine uptake in people who are short of iodine. Normal portions, especially cooked, aren’t a concern for most people.
Raw or cooked?
Both are healthy either way:
- Cooking spinach reduces its volume dramatically, so you eat more, and it lowers oxalate somewhat, especially if boiled and drained. Some vitamin C and folate is lost.
- Raw kale keeps the most vitamin C, but it’s tough; massaging it with a little dressing makes it tender. Our keto kale salad shows how.
- Steaming or sautéing briefly keeps most nutrients and makes both easy to digest.
Our guide on how to cook kale has more methods.
Which should you choose?
| Your goal | Better choice |
|---|---|
| More vitamin C | Kale |
| More absorbable calcium | Kale |
| More folate | Spinach |
| More iron and magnesium | Spinach (eat with vitamin C) |
| Fewest calories | Spinach |
| History of calcium oxalate kidney stones | Kale |
| Smoothies and quick wilting | Spinach |
| Salads that keep well | Kale |
Easy ways to eat more greens
- Stir a handful of spinach into soups, curries and pasta sauces at the end of cooking.
- Add spinach or kale to smoothies; our green smoothie recipe uses both.
- Bake kale chips: tear leaves, toss with a little olive oil and salt, and bake at 150°C (300°F) for 15 to 20 minutes.
- Sauté either with garlic and olive oil as a side.
- Use baby spinach or massaged kale as a salad base.
A day with both greens
- Breakfast: a smoothie with a handful of spinach, banana, berries and yogurt.
- Lunch: a kale salad with chickpeas, avocado and lemon dressing.
- Dinner: salmon with garlicky wilted spinach and brown rice. Our salmon with spinach and orange sauce is a quick option.
- Snack: baked kale chips.
Mixing greens through the week, including others such as broccoli, cabbage, chard, rocket and watercress, gives you the widest range of nutrients. Our list of green foods has more ideas.
Common questions
Which is better in smoothies?
Spinach, because its mild flavor and soft leaves blend easily. Kale works too but has a stronger taste and tougher texture, so use baby kale or remove the stems.
Are baby spinach and baby kale as nutritious?
Yes. Baby leaves are picked earlier and are more tender, with similar nutrients to mature leaves.
Is kale the healthiest vegetable?
Kale is very nutritious, but no single food is essential. A variety of vegetables gives you the widest range of nutrients.
Can I eat spinach every day?
Yes, for most people. If you’ve had kidney stones or take warfarin, follow your doctor’s advice.
Is frozen spinach as good as fresh?
Yes. Frozen spinach is nutritious, convenient and more concentrated by weight. Our comparison of frozen vs fresh produce explains why.
This article is general information, not medical advice. Talk to your doctor or a registered dietitian before making big changes to how you eat, especially if you have a health condition, take regular medication, or are pregnant or breastfeeding.
