Many sites list watercress as a good food because it high in vitamins. The following chart shows otherwise. It is said that kale and turnip greens are bad because of their goitrogenic and oxalate properties. But watercress is the highest in glucosinolate (goitrogens) ¹ Some eperts believe that all the Brassicae family should be avoided like the plague due to this. However Kuzmin and others observe that plants from this family are regularly eaten². A recent paper outlines in detail the diet of Russian Tortoises³ .
In reality life isn't that cut and dry. Dandelions come highly recommended on these sites by the same experts that say that there is no acceptable levels of oxalates. But dandelions have almost twice as much oxalates as kale and turnip greens and watercress is the lowest.t4
And oxalates have some interesting properties in animals. Seems animals can use them in the immune response
plant | oxalates mg/100g |
Kale | 13 mg |
Watercress |
10 mg |
Dandelion greens | 24.6 mg |
Turnip greens | 14.6 mg |
Data from the USDA and Canadian nutritional databases
KALE, RAW Gram Weight: 100.0 Calories (kcal): 41.0 Energy (kJ): 170.0 Protein (g): 4.3 Carbohydrates (g): Fat (g): 1.2 Total Dietary Fiber (g): 4.3 Vitamin A (RE): Thiamin (mg): 0.15 Riboflavin (mg): 0.29 Niacin (mg): 2.8 Pantothenic Acid (mg): Vitamin B-6 (mg): Total Folate (mcg): 60.0 Vitamin B-12 (mcg): 0.0 Vitamin C (mg): 124.0 Vitamin D (IU): 0.0 Vitamin E (IU): 8.046 Biotin (mcg): Vitamin K (mcg): Calcium (mg): 135.0 Chloride (mg): Chromium (mcg): 8.3 Copper (mg): 0.091 Fluoride (mg): 0.02 Iodine (mcg): 1.4
Iron (mg): 2.0 Magnesium (mg): Manganese (mg): Molybdenum (mcg): 2.0 Phosphorus (mg): Potassium (mg): Selenium (mcg): 5.0 Sodium (mg): 35.0 Zinc (mg): 0.3
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WATERCRESS, RAW Gram Weight: 100.0 Calories (kcal): 11.0 Energy (kJ): 46.0 Protein (g): 2.3 Carbohydrates (g): Fat (g): 0.1 Total Dietary Fiber (g): 1.5 Vitamin A (RE): Thiamin (mg): 0.09 Riboflavin (mg): 0.12 Niacin (mg): 0.2 Pantothenic Acid (mg): 0.31 Vitamin B-6 (mg): Total Folate (mcg): Vitamin B-12 (mcg): Vitamin C (mg): 43.0 Vitamin D (IU): Vitamin E (IU): 1.49 Biotin (mcg): Vitamin K (mcg): Calcium (mg): 120.0 Chloride (mg): Chromium (mcg): Copper (mg): 0.077 Fluoride (mg): Iodine (mcg):
Iron (mg): 0.2 Magnesium (mg): Manganese (mg): Molybdenum (mcg): Phosphorus (mg): Potassium (mg): Selenium (mcg): 0.9 Sodium (mg): 41.0 Zinc (mg): 0.11 |
DANDELION GREENS, RAW Gram Weight: 100.0 Calories (kcal): 45.0 Energy (kJ): 188.0 Protein (g): 2.7 Carbohydrates (g): Fat (g): 0.7 Total Dietary Fiber (g): 3.5 Vitamin A (RE): Thiamin (mg): 0.19 Riboflavin (mg): 0.26 Niacin (mg): 0.806 Pantothenic Acid (mg): 0.084 Vitamin B-6 (mg): Total Folate (mcg): Vitamin B-12 (mcg): Vitamin C (mg): 35.0 Vitamin D (IU): Vitamin E (IU): 3.725 Biotin (mcg): Vitamin K (mcg): Calcium (mg): 187.0 Chloride (mg): Chromium (mcg): Copper (mg): 0.171 Fluoride (mg): Iodine (mcg): Iron (mg): 3.1 Magnesium (mg): Manganese (mg): Molybdenum (mcg): Phosphorus (mg): Potassium (mg): Selenium (mcg): 0.5 Sodium (mg): 76.0 Zinc (mg): 0.41
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TURNIP GREENS, RAW Gram Weight: 100.0 Calories (kcal): 27.0 Energy (kJ): 113.0 Protein (g): 1.5 Carbohydrates (g): 5.73 Fat (g): 0.3 Total Dietary Fiber (g): 3.2 Vitamin A (RE): 760.0 Thiamin (mg): 0.07 Riboflavin (mg): 0.1 Niacin (mg): 0.6 Pantothenic Acid (mg): 0.38 Vitamin B-6 (mg): 0.263 Total Folate (mcg): 194.0 Vitamin B-12 (mcg): 0.0 Vitamin C (mg): 60.0 Vitamin D (IU): Vitamin E (IU): 4.321 Biotin (mcg): Vitamin K (mcg): Calcium (mg): 190.0 Chloride (mg): Chromium (mcg): Copper (mg): 0.35 Fluoride (mg): Iodine (mcg): Iron (mg): 1.1 Magnesium (mg): 31.0 Manganese (mg): 0.466 Molybdenum (mcg): Phosphorus (mg): 42.0 Potassium (mg): 296.0 Selenium (mcg): 1.2 Sodium (mg): 40.0 Zinc (mg): 0.19
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1. McNaughton SA, Marks GC. Development of a food composition
database for the estimation of dietary intakes of glucosinolates,
the biologically active constituents of cruciferous vegetables.
Br J Nutr. 2003 Sep;90(3):687-97. "The highest
glucosinolate values were for cress (389 mg/100 g)"
2. Kuzmin, S. L. 2002. The Turtles of Russia and Other Ex-Soviet Republics. Edition, Chimaira Frankfurt am Main (pg. 101-130)
4. oxalates.pdf
I feel its very erroneous to eliminate a green just because it belongs to a particular family or because it contains a particular nutrient. One must look at the whole picture and base decisions on current research and nutritional databases. That is exactly what I have done on this site.
The other factor to consider is variety. Feeding a wide variety minimizes and negative effects while at the same time allowing our animals to reap the positive benefits.
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