Watercress vs Spinach - Health impact and Nutrition Comparison
Leafy green vegetables or leafy greens, salad greens, or simply greens are well known for their beneficial health impact on our bodies. Besides introducing the main differences between spinach and watercress, this article will also show what they are exactly good for.
Spinach (Spinacia oleracea) belongs to the Spinacia genus, subfamily Chenopodioideae and the family Amaranthaceae. Most species in this family are annual or perennial herbs or subshrubs.
Watercress or yellowcress also has a botanical name called Nasturtium officinale. Watercress belongs to the Nasturtium genus and the Brassicaceae family. Brassicaceae or Cruciferae is commonly known as the mustard, the crucifer, or the cabbage family. Most plants in this family are herbaceous plants, some are shrubs.
Spinach has simple, ovate to triangular leaves that are very variable in size.
Taste and Use
Spinach is mostly said to be originated from ancient Persia and was known as a Persian vegetable. It is used both raw, in salads and burgers and sauteed as a side dish.
Watercress was first cultivated in the United Kingdom. Watercress is best eaten raw as it loses a proportion of its health benefits when cooked. However, it’s still a useful ingredient when used in cooked dishes, such as soups, stews and stir-fries.
Raw spinach has a mild, slightly sweet taste and is more acidic and robust when it is cooked. Watercress has a pungent, spicy and peppery taste.
Spinach is divided into three main types: savoy, semi-savoy and flat-leafed. Savoy spinach has very crinkled leaves which grow pretty low and also take the cold better than the other types of spinach. Its popular varieties are Bloomsdale and Regiment.
Semi-savoy grows more upright than savoy spinach, therefore it also stands up a bit straight. Its leaves are much less crinkly, which makes washing them easier. It is also disease and bolt resistant. Indian summer, Tyee, Catalina belong to this type.
The smooth-leafed spinach has a very smooth surface that makes it pretty easy to clean. They are the ones used as the canned and frozen varieties, but can also be sold fresh. Space spinach and Red Carnival belong to the flat-leafed spinach.
There are also alternative spinach varieties such as New Zealand and Malabar spinach.
In addition to traditional watercress, there are different plant species, all having a bit different flavour and texture. Garden Cress (Lepidium sativum) has a spicier flavour, like horseradish. Upland Cress (Barbarea verna) has thinner stems and a more delicate flavour, while Korean Watercress is more bitter and crunchy.
The nutritional values in this article are presented for raw spinach and raw watercress.
Macronutrients and Calories
Spinach and watercress have very close nutritional contents. Spinach contains a little bit more protein and carbohydrates. Both spinach and watercress consist of 94% water, spinach being only a little more dense in nutrients.
The average serving size of spinach and watercress is one cup, which is 30g for spinach and 34g for watercress.
Both spinach and watercress are low calorie foods.
A 100g serving of spinach contains 23 calories and watercress contains only half of that.
Protein and Fats
Leafy vegetables are not rich in macronutrients in general and yet spinach contains a little more protein.
Both of the vegetables contain some amounts of all essential amino acids, making their protein quality high.
Spinach and watercress contain very low amounts of fats, spinach being only slightly higher in fats.
The dominating fats are polyunsaturated fats, which are considered to be healthy.
There is no cholesterol in these vegetables.
As said before, they have little amounts of carbs, and yet spinach contains three times more carbs compared to watercress.
Spinach has twice more sugar and four times more dietary fiber, compared to watercress.
Vitamin content difference in these vegetables is huge. Spinach contains 20 times more folate, 3 times more vitamin A and vitamin B3, while watercress has almost 5 times more vitamin B5.
Watercress has more vitamin B1 and C, while spinach has higher levels of vitamins B2, B3, B6, vitamin A, vitamin E and vitamin K.
Both spinach and watercress are absent in vitamin B12 and vitamin D.
Spinach is richer not only in vitamins but in minerals as well.
Spinach has 15 times more iron, 5 times more zinc and nearly 4 times more magnesium compared to watercress. Spinach is also richer in potassium, copper and contains higher levels of sodium.
Watercress contains more calcium and phosphorus.
Leafy green foods are a rich source of inorganic nitrate. Nitrates stimulate the production of nitric oxide that regulates muscle blood flow and participates in mitochondrial respiration.
Spinach is over two times richer in nitrates compared to watercress (1).
Depending on the season, the nitrate content differs. According to studies, the nitrate content of leafy greens is higher in autumn (2).
Spinach and watercress are non-starchy dark green leafy vegetables with low glycemic index values (3).
Dark green leafy vegetables are considered to be superfoods or powerhouse foods and are good for diabetes due to many factors, one of which is their low GI (4).
Spinach pH value can be anywhere from 5.38 making it acidic, to 7.18 making it alkaline or basic.
Watercress is acidic with its pH value ranging between 5.88 to 6.18 (5).
The pH values can change depending on the growing conditions and processing methods of the greens.
The PRAL (potential renal acid load) value is another way of looking at the acidity of the foods, based on how much acid is produced in the organism from the given food.
Spinach has the PRAL value of -11.8, while watercress has only -5.7. The more negative PRAL value of spinach shows that it’s more base producing.
Weight Loss & Diets
A 100g serving of spinach has 23 calories, while watercress has 11 calories, making it a better choice for a low calorie diet. Between these two, watercress is also a better choice for low carbs and low fats diets.
Both of the greens are low in carbs, fats and calories, making them a great choice for weight loss diets, such as keto, Atkins and Mediterranean diets.
Non-starchy greens are also part of the Dukan diet “Cruise” and “Consolidation” phases. Leafy green vegetables are also part of the anti-inflammatory diet, as they are high in natural antioxidants, polyphenols, carotenoids and vitamins, which protect cells from free-radical damage and reduce inflammation (6).
Structures found in plants named thylakoids are shown to reduce appetite and help in the weight loss journey. The mechanisms behind these effects are thylakoids increasing and reducing levels of some hormones that are related to your appetite and desire to eat and preventing a drop in blood sugar after meals, helping you feel full for longer (7).
As we already know, both spinach and watercress are rich in minerals, vitamins, antioxidants, nitrates, fiber and other compounds which play their roles inside the organism, showing mostly favourable impacts on health.
A lot of studies have reported the inverse associations of leafy green vegetables with cardiovascular disease outcomes. Increasing the intake of leafy green may provide the greatest cardiovascular health benefits due to the number of nutrients and phytochemicals they contain (8).
Inorganic dietary nitrate from the greens is converted to nitrite and NO in vivo. The NO leads to the widening of blood vessels and lowers both systolic and diastolic blood pressures, thus fighting against hypertension. NO also has cardioprotective effects on the heart by attenuating cardiac hypertrophy and fibrosis (9).
Several studies show that increasing daily intake of leafy vegetables could significantly reduce the risk of type 2 diabetes due to high concentrations of β carotene and vitamin C, both of which confer antioxidant properties (10).
The low glycemic index and high level of magnesium are also good for preventing and treating type 2 diabetes. High levels of magnesium lowers glucose intolerance and/or insulin resistance (11).
There is limited data on the influence of vegetable consumption on obesity and metabolic health. Consumption of greens is associated with positive metabolic outcomes, including reduced visceral and liver fat (12).
Prospective and retrospective studies suggest that carotenoids may reduce the risk of certain cancers and the low intake of carotenoids is associated with an increased risk of lung cancer (13).
Xanthophyll carotenoids were found to reduce cell viability through apoptosis induction in the human prostate cancer cells (14).
Dietary fiber also has its role here. It helps to keep the microbiome (community of microbes living in the digestive tract) healthy and a healthy microbiome has been linked with a lower risk of cancer (15).
Vitamins also partake in lowering the risks of cancer, for example, people with low folate levels have a higher risk of breast, pancreatic and colon cancer (15).
More than half of the women in menopausal transition or postmenopausal age have the risk of osteoporosis, which can be diagnosed after sudden and unexpected bone fracture.
Leafy greens due to their high magnesium, calcium and vitamin K levels help prevent the disease by maintaining normal storage levels of those minerals (16, 17).
Carotenoids from green vegetables, mainly lutein and zeaxanthin, play a major role in eye health. They show antioxidant effects and absorb near-to-UV blue light (18).
Consumption of leafy greens lowers the chances of diseases, for example, night blindness and age-related macular degeneration and reduces the chances of eye cancer.
Downsides and Risks
Vitamin K and Drugs
A fairly high amount of vitamin K can be found in leafy greens. Vitamin K participates in coagulation (blood clotting), while Warfarin (Coumadin) does the exact opposite - makes your blood clot more slowly. Therefore, some researchers suggest if you take warfarin, to make sure that consumed vitamin K is about the same every day. There’s a risk of bleeding (if you consume less) or making blood clots (if you consume more) (19).
Spinach has twice as many vitamins and minerals, containing huge amounts of folate,
vitamins A, E and B3, Iron, Zinc, Magnesium. Notably, watercress has more Calcium and Phosphorus.
Spinach contains four times more dietary fiber than watercress.
Spinach has been known worldwide for centuries, therefore is studied more in the area of health.
Vitamin and Mineral Summary Scores
Comparison summary table
|Lower in Sugar|
|Lower in Sodium|
|Lower in Saturated Fat|
|Lower in price|
|Rich in minerals|
|Rich in vitamins|
|Lower in Cholesterol||Equal|
|Lower in glycemic index||Equal|
Which food is preferable for your diet?
|Low Calories diet|
|Low Fats diet|
|Low Carbs diet|
|Low glycemic index diet||Equal|
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