This was the same reaction I had when the Covid vaccines were rolling out. “They haven’t been proven to be 100% safe and effective!” OK. Sure, but you know what is guaranteed to be bad for you? Covid. There are two choices here, and there’s a clear mitigation of harm with one option over the other.
It’s shocking that we’d rather see children die of treatable vitamin deficiencies than the off-chance that the food ‘might be unsafe’.