Watercress vs. Spinach — Nutrition Comparison and Health Impact

Macronutrients and Calories

Spinach and watercress have very similar nutritional contents. Spinach contains a little bit more protein and carbohydrates.

Both spinach and watercress consist of 94% water, spinach being only a little denser in nutrients.

The average serving size of spinach and watercress is one cup, equal to 30g for spinach and 34g for watercress.

Vitamins

Vitamin content difference in these vegetables is vast. Spinach contains 21.5 times more folate or vitamin B9, three times more vitamins A and B3, whereas watercress has almost five times more vitamin B5.

Watercress has more vitamins 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.

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.

Spinach raw

8

Watercress

3

Contains more Vitamin AVitamin A	+193.9%
Contains more Vitamin EVitamin E	+103%
Contains more Vitamin B2Vitamin B2	+57.5%
Contains more Vitamin B3Vitamin B3	+262%
Contains more Vitamin B6Vitamin B6	+51.2%
Contains more Vitamin KVitamin K	+93.2%
Contains more FolateFolate	+2055.6%
Contains more CholineCholine	+114.4%

Contains more Vitamin CVitamin C	+53%
Contains more Vitamin B1Vitamin B1	+15.4%
Contains more Vitamin B5Vitamin B5	+376.9%

~equal in Vitamin D ~0µg

~equal in Vitamin B12 ~0µg

Minerals

Spinach is richer not only in vitamins but in minerals as well.

Spinach has 15 times more iron, five times more zinc, and nearly four times more magnesium than watercress.

Spinach is also richer in potassium and copper and contains higher sodium levels.

Watercress contains more calcium and phosphorus.

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.

Spinach raw

6

Watercress

3

Contains more MagnesiumMagnesium	+276.2%
Contains more PotassiumPotassium	+69.1%
Contains more IronIron	+1255%
Contains more CopperCopper	+68.8%
Contains more ZincZinc	+381.8%
Contains more ManganeseManganese	+267.6%

Contains more CalciumCalcium	+21.2%
Contains more PhosphorusPhosphorus	+22.4%
Contains less SodiumSodium	-48.1%

~equal in Selenium ~0.9µg

Nitrates

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).

Glycemic Index

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. Due to having a low glycemic index, they are good for patients with diabetes. (4).

Acidity

Spinach's pH value can be anywhere from 5.38 to 7.18.

Watercress has a pH value ranging between 5.88 to 6.18 (5).

The pH values can change depending on the greens’ growing conditions and processing methods.

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.

The PRAL value of spinach is -11.8, while the PRAL value of watercress is -5.7. The more negative PRAL value of spinach shows that it’s more base-producing.

Cardiovascular Health

Section reviewed by cardiologist Astghik Grigoryan

Many studies have reported inverse associations of leafy green vegetables with cardiovascular disease outcomes. Increasing the intake of leafy greens may provide significant 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 protective effects on the heart by attenuating cardiac hypertrophy and fibrosis (9).

Incorporating both watercress and spinach into a balanced diet, along with other fruits and vegetables, can promote heart health and reduce cardiovascular risk (the risk of fatal and nonfatal myocardial infarction, stroke, and overall cardiovascular mortality).

Diabetes

Several studies have shown that increasing the daily intake of leafy vegetables could significantly reduce the risk of type 2 diabetes due to its high concentrations of β carotene and vitamin C, both of which confer antioxidant properties (10).

The low glycemic index and high magnesium level are also effective in preventing and treating type 2 diabetes. High magnesium lowers glucose intolerance and 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).

Cancer

Prospective and retrospective studies suggest that carotenoids may reduce the risk of certain cancers. 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 (cell death) 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 as well 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).

Bone Health

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 fractures.

Due to their high magnesium, calcium, and vitamin K levels, leafy greens help prevent the disease by maintaining normal storage levels of those minerals (16, 17).

Ocular Health

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 eye diseases, such as night blindness and age-related macular degeneration, and reduces the chances of eye cancer.

Kidney Stones

Spinach is one of the highest oxalate-containing foods: 755mg in 1/2 cup (15g). Similarly, watercress also has a high oxalate content, but its level is not dangerously high.

High oxalate is the primary cause of kidney stone formation, and people with kidney stones or at high risk of kidney stones should exclude spinach from their diets and lower the level of consumed watercress (19, 20, 21).

Vitamin K and Drugs

A relatively 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 - it 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) (22).

Classification

Spinach (Spinacia oleracea) belongs to the Spinacia genus, Chenopodioideae subfamily, and Amaranthaceae family. Most species in this family are annual or perennial herbs or subshrubs.

Watercress or yellowcress (Nasturtium officinale) 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, and some are shrubs.

Appearance

Spinach has simple, ovate to triangular leaves that vary in size.

Watercress is regarded as a weed in some regions and an aquatic vegetable or herb in others. It has pinnately compound leaves.

Taste and Use

Spinach is mainly 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. It is best eaten raw as it loses a proportion of its health benefits when cooked. However, it’s still a useful ingredient 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 cooked. Watercress has a pungent, spicy, and peppery taste.