The Enemy of Football
Oxalic acid is an anti-nutritional factor present in numerous foods, including spinach, rhubarb, whole grains and cabbage. Once ingested, it combines with various minerals (iron, magnesium and above all calcium) forming salts, called oxalates, which they prevent absorption. Due to their ability to reduce the minerals available to the organism, oxalates favor the establishment of deficiency states (osteoporosis, anemia, etc.).
Foods rich in oxalates can be harmful even if ingested in non-lethal doses. When combined with calcium, oxalic acid gives rise to calcium oxalate, an insoluble salt that tends to precipitate in the form of crystals and accumulate in the urinary tract (kidney stones). When these hard, crystalline formations reach significant size, disorders such as urinary tract irritation, hematuria (blood in the urine) and kidney damage arise. For this reason, in the presence of oxalate stones, the diet should provide no more than 100 mg per day of oxalic acid. To deepen the topic: diet and kidney stones.
Oxalic Acid Content of Foods
Type of food
mg / 100g
Type of food
mg / 100g
Swiss chard
690
Strawberries
15
Spinach
676
Raspberries
15
Cocoa powder
450
Blueberries
15
Beetroot (roots)
338
Apricots
14
Bitter chocolate
80
Eggplant
12
Cauliflower
60
You
10
Celery (ribs)
50
Tomatoes
7,5
Milk chocolate
35
Green cabbage (savoy cabbage)
7,3
Celery from Verona
34
Bananas
6,4
Carrots
33
Pineapple in syrup
6,3
Green beans
30
Brussels sprouts
5,9
Curly chicory
27
Potatoes
5,7
Envy
27
Oats (flakes)
5,6
Escarole
27
Asparagus
5,2
Cucumbers
25
Beans
4,3
Oranges
24
Currant
4
Onions
23
Fresh peas
1,3
Blackberries
18
Peaches in syrup
1,2
Peppers
16
Coffee
1
In addition to the presence of oxalic acid in a particular food, the bioavailability of the calcium contained in it must also be assessed. This parameter is obtained from the ratio between the quantities of oxalic acid and those of calcium (g / kg). Foods in which this ratio is higher than 2.25 can be considered "descaling", as well as being a bad source of calcium. This ratio is less than one in lettuce, cabbage, pea and onion; it is around unity in potatoes and currants, while it reaches values of 7 in chard, spinach and cocoa.
