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Spinach vs. Kale — Health Impact and Nutrition Comparison

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Article author photo Victoria Mazmanyan by Victoria Mazmanyan | Last updated on June 01, 2023
Medically reviewed by Elen Khachatrian Article author photo Elen Khachatrian
Spinach
vs
Kale

Summary

Kale is somewhat higher in calories and carbohydrates due to net carbs, while spinach is richer in protein and dietary fiber.

Spinach is a better source of both vitamins and minerals, containing 11 times more folate or vitamin B9, about 3 times more vitamins B2 and B5, 5 times more magnesium, 4 times more iron, and 3 times more zinc.

However, kale is 4 times richer in vitamin C and overall richer in vitamins A and K.

Spinach contains 66 times more oxalates, an increased intake of which leads to the formation of calcium oxalate kidney stones.

 

Introduction

Spinach and kale are leafy green vegetables widely recognized for their nutritional value. At times they’re even used interchangeably in salads and other dishes. However, these two greens have distinct nutritional properties and health impacts, which will be discussed in this article.

Classification and Appearance

Kale belongs to the Brassica family of vegetables, which includes other members like broccoli, cauliflower, and Brussels sprouts. Conversely, Spinach is part of the Amaranthaceae family, which also includes beets and chard.

Kale leaves are usually darker, with a bluish-green or even purplish hue. They are curly or frilly, with a central rib running down the middle. Spinach leaves are typically bright, vibrant green with a more oval or heart-shaped appearance. They are also thinner and more delicate than kale leaves.

Taste and Use

Kale has a more bitter and earthy taste than spinach, which has a milder and sweeter flavor. Spinach has a softer texture than kale, which can be tough and fibrous. 

However, kale can be massaged or cooked to make it more tender.

Both spinach and kale are versatile vegetables that can be used in a variety of dishes. Spinach is commonly used in salads, sandwiches, and smoothies, while kale is often used in soups, stews, and stir-fries.

Nutrition

The nutritional infographics in this article are presented for 100g servings of boiled spinach and kale, drained, without salt.

However, the average serving size of these greens per person is one cup, which weighs around 30g for spinach and 21g for kale.

Macronutrients and Calories

Kale and spinach are of equal density, consisting of 91% water and 9% nutrients. 

The primary macronutrient in these vegetables is carbohydrates, followed by protein. Kale is higher in carbohydrates, while spinach is richer in protein.

Macronutrient Comparison

Macronutrient breakdown side-by-side comparison
:
2
Kale
Contains more Protein +56.3%
Contains more Other +108%
Contains more Fats +53.8%
Contains more Carbs +50.1%
Equal in Water - 91.2
3% 4% 91% 2%
Protein: 2.97 g
Fats: 0.26 g
Carbs: 3.75 g
Water: 91.21 g
Other: 1.81 g
2% 6% 91%
Protein: 1.9 g
Fats: 0.4 g
Carbs: 5.63 g
Water: 91.2 g
Other: 0.87 g
Contains more Protein +56.3%
Contains more Other +108%
Contains more Fats +53.8%
Contains more Carbs +50.1%
Equal in Water - 91.2

Calories

These two leafy greens are very low-calorie foods, with kale being only a little higher in calories.

In a 100g serving, kale provides 28 calories, while spinach has 23 calories.

Carbohydrates

Kale is 1.5 times higher in carbohydrates, being 2.7 richer in net carbs. However, spinach contains 0.4g more dietary fiber per 100g serving.

A 100g serving of spinach and kale provides 3.75g and 5.63g of carbohydrates, respectively. Of this, 60% is dietary fiber, and 40% is net carbs for spinach, while in kale, these numbers are 55% for dietary fiber and 45% for net carbs.

Kale is 3 times higher in sugar.

Protein

While leafy greens are not the best source of protein, spinach is higher in this nutrient. A 100g serving of spinach and kale contains about 3g and 2g of protein, respectively.

Fats

These two leafy greens are very low in fats, containing less than 1g per 100g serving.

Fat Type Comparison

Fat type breakdown side-by-side comparison
:
2
Kale
Contains less Saturated Fat -17.3%
Contains more Monounsaturated Fat +400%
Contains more Polyunsaturated fat +77.1%
27% 4% 69%
Saturated Fat: 0.043 g
Monounsaturated Fat: 0.006 g
Polyunsaturated fat: 0.109 g
19% 11% 70%
Saturated Fat: 0.052 g
Monounsaturated Fat: 0.03 g
Polyunsaturated fat: 0.193 g
Contains less Saturated Fat -17.3%
Contains more Monounsaturated Fat +400%
Contains more Polyunsaturated fat +77.1%

Vitamins

Spinach is overall richer in vitamins, being 11 times higher in folate or vitamin B9, about 3 times higher in vitamins B2 and B5, and 2 times higher in vitamin E.

Spinach also contains more vitamin B1 and vitamin B6.

At the same time, kale is 4 times richer in vitamin C and overall richer in vitamins A and K.

Vitamin Comparison

Vitamin comparison score is based on the number of vitamins by which one or the other food is richer. The "coverage" charts below show how much of the daily needs can be covered by 300 grams of the food.
:
4
Kale
Contains more Vitamin E +144.7%
Contains more Vitamin B1 +79.2%
Contains more Vitamin B2 +237.1%
Contains more Vitamin B5 +195.9%
Contains more Vitamin B6 +75.4%
Contains more Folate +1023.1%
Contains more Choline +4825%
Contains more Vitamin A +30%
Contains more Vitamin C +318.4%
Contains more Vitamin K +65.5%
Equal in Vitamin B3 - 0.5
Vitamin A Vitamin E Vitamin D Vitamin C Vitamin B1 Vitamin B2 Vitamin B3 Vitamin B5 Vitamin B6 Folate Vitamin B12 Choline Vitamin K 629% 42% 0% 33% 24% 55% 10% 9% 56% 110% 0% 11% 1234%
Vitamin A Vitamin E Vitamin D Vitamin C Vitamin B1 Vitamin B2 Vitamin B3 Vitamin B5 Vitamin B6 Folate Vitamin B12 Choline Vitamin K 818% 17% 0% 137% 14% 17% 10% 3% 32% 10% 0% 1% 2043%
Contains more Vitamin E +144.7%
Contains more Vitamin B1 +79.2%
Contains more Vitamin B2 +237.1%
Contains more Vitamin B5 +195.9%
Contains more Vitamin B6 +75.4%
Contains more Folate +1023.1%
Contains more Choline +4825%
Contains more Vitamin A +30%
Contains more Vitamin C +318.4%
Contains more Vitamin K +65.5%
Equal in Vitamin B3 - 0.5

These leafy greens are both excellent sources of vitamin K. A 100g serving of spinach and kale covers 411% and 681% of the daily needed value for this vitamin.

Minerals

Leafy greens are an excellent source of minerals. Spinach falls in the top 16% of foods as a source of iron, while a 100g serving of kale covers 18% of the daily needed value of manganese.

Spinach is also the ultimate winner in the mineral category. It provides 5 times more magnesium, 4 times more iron, and 3 times more zinc. Spinach is richer in manganese, potassium, phosphorus, calcium, selenium, and copper.

Spinach is also an excellent source of nitrates (1).   

Kale is lower in sodium.

Mineral Comparison

Mineral comparison score is based on the number of minerals by which one or the other food is richer. The "coverage" charts below show how much of the daily needs can be covered by 300 grams of the food.
:
1
Kale
Contains more Calcium +88.9%
Contains more Iron +296.7%
Contains more Magnesium +383.3%
Contains more Phosphorus +100%
Contains more Potassium +104.4%
Contains more Zinc +216.7%
Contains more Copper +11.5%
Contains more Manganese +124.8%
Contains more Selenium +66.7%
Contains less Sodium -67.1%
Calcium Iron Magnesium Phosphorus Potassium Sodium Zinc Copper Manganese Selenium 41% 134% 63% 24% 42% 10% 21% 58% 122% 9%
Calcium Iron Magnesium Phosphorus Potassium Sodium Zinc Copper Manganese Selenium 22% 34% 13% 12% 21% 3% 7% 53% 55% 5%
Contains more Calcium +88.9%
Contains more Iron +296.7%
Contains more Magnesium +383.3%
Contains more Phosphorus +100%
Contains more Potassium +104.4%
Contains more Zinc +216.7%
Contains more Copper +11.5%
Contains more Manganese +124.8%
Contains more Selenium +66.7%
Contains less Sodium -67.1%

Glycemic Index

There are no specific glycemic index values measured for kale and spinach. However, these values are considered to be low, as kale and spinach are rich in dietary fiber and relatively low in net carbs.

Health Benefits

Cardiovascular Health

Consuming green leafy vegetables, including kale and Spinach, has been linked to a lower risk of cardiovascular disease and mortality (2).

A high green leafy vegetable intake may also reduce the risk of stroke, coronary heart disease, and atherosclerotic vascular disease. Spinach, in particular, is high in a phytochemical called glucosinolate, which has a strong anti-inflammatory potential (3).

Regularly using kale juice with meals can positively impact the antioxidant systems and serum lipid profiles, which can help lower the risk of coronary artery disease in people with high cholesterol levels (4).

The nitrates found in spinach are also good for heart health. They can help lower blood pressure and decrease cardiovascular disease risk (5).

Diabetes

As mentioned above, kale and spinach are low glycemic index foods, meaning the intake of these vegetables does not increase blood glucose levels rapidly.

Kale consumption has also been researched to suppress blood glucose levels after meals (6).

Spinach can be a potential dietary supplement for preventing insulin resistance as its nitrate content can increase NO status, improve lipid homeostasis, reduce inflammation, and boost endothelial function (7). 

Downsides 

Kidney Stones and Oxalates

Dietary oxalates are excreted through urine. The amount of oxalates excreted in urine is essential in calcium oxalate stone formation. Thus, continuous high amounts of oxalate intake increase the risk of developing kidney stones (8).

Spinach is very high in oxalates, providing 6.6mmol per 300g serving, whereas spinach falls in the very low oxalate category, containing only 0.1mmol oxalates in the same serving size (9).

The oxalate content of spinach can vary widely, ranging from 490 to 12576mg per 100g serving, depending on the study; however, this value is always high (10, 11).

A high oxalate content is also associated with decreased magnesium absorption (9). 

Article author photo Victoria Mazmanyan
Education: General Medicine at YSMU
Last updated: June 01, 2023
Medically reviewed by Elen Khachatrian

Infographic

Spinach vs Kale infographic
Infographic link

Comparison summary table

Pay attention to the rightmost column. It displays the amounts side by side, giving a clearer understanding of the difference.
Spinach Kale
Lower in Sugar ok
Lower in Saturated Fat ok
Rich in minerals ok
Lower in Sodium ok
Lower in Glycemic Index ok
Lower in price ok
Lower in Cholesterol Equal
Rich in vitamins Equal

All nutrients comparison - raw data values

Nutrient Spinach Kale Opinion
Net carbs 1.35g 3.63g Kale
Protein 2.97g 1.9g Spinach
Fats 0.26g 0.4g Kale
Carbs 3.75g 5.63g Kale
Calories 23kcal 28kcal Kale
Sugar 0.43g 1.25g Spinach
Fiber 2.4g 2g Spinach
Calcium 136mg 72mg Spinach
Iron 3.57mg 0.9mg Spinach
Magnesium 87mg 18mg Spinach
Phosphorus 56mg 28mg Spinach
Potassium 466mg 228mg Spinach
Sodium 70mg 23mg Kale
Zinc 0.76mg 0.24mg Spinach
Copper 0.174mg 0.156mg Spinach
Manganese 0.935mg 0.416mg Spinach
Selenium 1.5µg 0.9µg Spinach
Vitamin A 10481IU 13621IU Kale
Vitamin A RAE 524µg 681µg Kale
Vitamin E 2.08mg 0.85mg Spinach
Vitamin C 9.8mg 41mg Kale
Vitamin B1 0.095mg 0.053mg Spinach
Vitamin B2 0.236mg 0.07mg Spinach
Vitamin B3 0.49mg 0.5mg Kale
Vitamin B5 0.145mg 0.049mg Spinach
Vitamin B6 0.242mg 0.138mg Spinach
Folate 146µg 13µg Spinach
Choline 19.7mg 0.4mg Spinach
Vitamin K 493.6µg 817µg Kale
Tryptophan 0.04mg 0.023mg Spinach
Threonine 0.127mg 0.085mg Spinach
Isoleucine 0.152mg 0.114mg Spinach
Leucine 0.231mg 0.133mg Spinach
Lysine 0.182mg 0.114mg Spinach
Methionine 0.055mg 0.018mg Spinach
Phenylalanine 0.134mg 0.097mg Spinach
Valine 0.168mg 0.104mg Spinach
Histidine 0.066mg 0.04mg Spinach
Saturated Fat 0.043g 0.052g Spinach
Monounsaturated Fat 0.006g 0.03g Kale
Polyunsaturated fat 0.109g 0.193g Kale

Which food is preferable for your diet?

ok
ok
is better in case of low diet
Spinach Kale
Low Fats diet ok
Low Carbs diet ok
Low Calories diet ok
Low Glycemic Index diet ok

People also compare

Vitamins & Minerals Daily Need Coverage Score

The summary scores indicate the extent to which this food can fulfill your daily vitamin and mineral requirements if you consume 3 servings, consisting of 100 grams of each (an approximation of 3 serving sizes).
Vitamins Daily Need Coverage Score
170%
Spinach
238%
Kale
Minerals Daily Need Coverage Score
52%
Spinach
22%
Kale

Comparison summary

Which food is lower in Sugar?
Spinach
Spinach is lower in Sugar (difference - 0.82g)
Which food is lower in Saturated Fat?
Spinach
Spinach is lower in Saturated Fat (difference - 0.009g)
Which food is richer in minerals?
Spinach
Spinach is relatively richer in minerals
Which food contains less Sodium?
Kale
Kale contains less Sodium (difference - 47mg)
Which food is lower in glycemic index?
Kale
Kale is lower in glycemic index (difference - 32)
Which food is cheaper?
Kale
Kale is cheaper (difference - $0.2)
Which food contains less Cholesterol?
?
The foods are relatively equal in Cholesterol (0 mg)
Which food is richer in vitamins?
?
It cannot be stated which food is richer in vitamins. See the charts below for detailed information. See the charts below for detailed information. See the charts below for detailed information.

References

All the values for which the sources are not specified explicitly are taken from FDA’s Food Central. The exact link to the food presented on this page can be found below.

  1. Spinach - https://fdc.nal.usda.gov/fdc-app.html#/food-details/168463/nutrients
  2. Kale - https://fdc.nal.usda.gov/fdc-app.html#/food-details/169238/nutrients

All the Daily Values are presented for males aged 31-50, for 2000-calorie diets.

Data provided by FoodStruct.com should be considered and used as information only. Please consult your physician before beginning any diet.