Nutritional Analysis

The nutrients present in watercress and the health benefits of watercress has been known for decades with the ‘working classes’ in the early 19th century eating bunches of watercress in the mornings known as ‘Poor Man’s Bread’ . Hippocrates the father of medicine built his first hospital close to a stream to ensure a fresh supply of watercress was present for his patients.

The nutritional value of watercress shows that if eaten as part of a daily healthy diet will supply high levels of Calcium (more than an average glass of milk), Vitamin A, E, K, C and Iron.

In the USA, Whole Foods Market has adopted ANDI nutrition rating system. The aggregate nutrient density index measures the amount of nutrients in a food (carbohydrates, fats, proteins, vitamins and minerals) related to the amount of energy (calories) in a food.

The ANDI score is based on a scale of 1 to 1000, with 1000 being the highest nutrient density possible. Whole Foods is the first food store to begin to label certain foods with their specific ANDI score, in an effort to help shoppers make smart, nutritious decisions.

Keep in mind that nutrient density scoring is not the only factor that determines good health. For example, if we only ate foods with a high nutrient density score our diet would be too low in fat. So we have to pick some foods with lower nutrient density scores (but preferably the ones with the healthier fats) to include in our high nutrient diet.

Per Average Portion of Fruit or Vegetables (per 80g of edible produce)

(Figures in brackets are the % of the Recommended Daily Allowance (RDA) for that nutrient – no figures, means there is no RDA for that nutrient)

 

Watercress
(raw)
Broccoli
(raw)
Broccoli
(boiled)
Tomato
(raw)
Apple
(raw)
Calories (kcal) 18 26 19 14 38
Protein (g) 2.4 3.5 2.5 0.6 0.3
Fat (g) 0.8 0.7 0.6 0.2 0.1
Fibre (g) 1.2 2.1 1.8 0.8 1.4
Beta-carotene (mcg) 2016 460 380 451 14
Vitamin A equivalent (mcg) 336 (42%) 77 (10%) 63 (8%) 75 (9%) 2 (0.3%)
Vitamin B1 (mg) 0.13 (9%) 0.08 (6%) 0.04 (3%) 0.07 (5%) 0.02 (2%)
Vitamin B6 (mg) 0.18 (9%) 0.11 (6%) 0.09 (5%) 0.11 (6%) 0.05 (3%)
Vitamin C (mg) 50 (83%) 70 (117%) 35 (58%) 14 (23%) 5 (8%)
Vitamin E (mg) 1.17 (12%) 1.04 (10%) 0.88 (9%) 0.98 (10%) 0.47 (5%)
Folate (mcg) 36 (18%) 72 (36%) 51 (26%) 18 (9%) 1 (0.5%)
Vitamin K (mcg)* 200 81 113 6 2
Calcium (mg) 136 (17%) 45 (6%) 32 (4%) 6 (0.8%) 3 (0.4%)
Iodine (mcg) 12 (8%)** 1.6 (1%) 1.6 (1%) 1.6 (1%) Not known
Iron (mg) 1.8 (13%) 1.4 (10%) 0.8 (6%) 0.4 (3%) 0.1 (0.7%)
Magnesium (mg) 12 (4%) 18 (6%) 10 (3%) 6 (2%) 4 (1%)
Manganese (mg) 0.5 0.2 0.2 0.1 0.1
Phosphorus (mg) 42 (5%) 70 (9%) 46 (6%) 19 (2%) 9 (1%)
Potassium (mg) 184 296 136 200 96
Zinc (mg) 0.6 (4%) 0.5 (3%) 0.3 (2%) 0.1 (0.7%) 0.1 (0.7%)
Lutein and Zeaxanthin (mcg)* 4614 1353 1214 98 23
Selenium (mcg) 1.6** Trace Trace Trace Trace
Quercetin (mcg)*** 6000 2000 168 472 3416

 

Data Sources:

Food Standards Agency (2002) McCance & Widdowson’s The Composition of Foods, 6th Summary Edition. Cambridge: Royal Society of Chemistry.

* U.S. Department of Agriculture, Agricultural Research Service. USDA National Nutrient Database for Standard Reference, Release 19, 2006.

** Direct Laboratories analysis of watercress, 2006.

*** USDA Database, Flavonoid Content of Selected Foods, Release 2, 2006.

SUMMARY – per average portion (80g edible weight)

Compared to raw and boiled broccoli, raw tomato and a raw apple:

Watercress is the better source of vitamins B1 and B6, vitamin E, beta-carotene and vitamin A equivalents, iron, calcium and zinc (very small differences for zinc).

For vitamin C and magnesium, watercress is a better source than all of the others listed, except for raw broccoli (but this isn’t the way that it’s typically consumed in the UK).

All are low in calories and fat.