The supplement effects seem marginal, from your description. And focusing on them may detract from focusing on what is likely to help, which is the laundry list of measures to reduce exposure. So, when you talk to your parents, discussing potential changes in their routine might be a more useful approach.
If consistently confirmed and not offset by “I’m taking supplements/wearing a mask and therefore can go out more”, then yes. But the uncertainty in that 40% decrease in risk is probably on the order of 200%.
The supplement effects seem marginal, from your description. And focusing on them may detract from focusing on what is likely to help, which is the laundry list of measures to reduce exposure. So, when you talk to your parents, discussing potential changes in their routine might be a more useful approach.
A 40-50% decrease in infection risk seems pretty big to me.
If consistently confirmed and not offset by “I’m taking supplements/wearing a mask and therefore can go out more”, then yes. But the uncertainty in that 40% decrease in risk is probably on the order of 200%.