raw veggies contain toxins that can interfere with thyroid and iodine actions. stuff like kale broccolli and other brassica contain them, they are inactivated by cooking at high heat, so consuming them raw is not a healthy option. only fresh fruits are meant to be eaten raw, veggies should be cooked, veggie should not be juiced. refer to a google search for more information, it is a scientific fact.
Eating them raw is fine.
And it is a very healthy option.
But if you are worried, then the best thing to do is to rotate your greens.
Spinach contains high levels of oxalic acid, which binds to iron. But bear in mind, that you would have to consume HUGE quantities per day - every day, to be negatively impacted.
One cup of raw spinach contains:
27 calories
0.86 grams of protein
30 milligrams of calcium
0.81 grams of iron
24 milligrams of magnesium
167 milligrams of potassium
2813 IUs of Vitamin A
58 micrograms of folate
And the very best way to obtain all this; is by juicing. Since much of this goodness is lost during the heating and cooking process.