SO2 is naturally present in fermented product, and as it’s a very good preservative we use it in the wine, so from only some trace to 200 mg/l the delta is huge from Natural to conventional wine making process. And unfortunately too much SO2 can be “délétère” for the taste of the wine and can have some unhealthy impact, such as bad headache, for those who are sensitive to it. Most of those who are sensitive just stop drinking a style of wine, like white wine, or Californian, this is not wrong but maybe to drastic! That’s why I suggest you to look at the kind of wine making process not at the style of wine to avoid to many SO2 and bad effects. The best option will be “Biodynamic” such as Demeter certification as in this kind of wine you will have a very good wine quality with not only small amount of SO2 but no chemical at all. Natural and SAINS (without any sulfite added) wines are an option to but be carefull as they can be fragile to the transportation and to the aging, I recommend you to consume them when you are in their production area.