This nonsense has been going on for a long time and some of these studies are based on small samples or paid for by the organisation that most benefits from the results. In fact, it is conceivable we could ingest two (or more) harmless food items which then combine within the digestive tract to form a harmful one! We just don't know - and with there being millions of combinations, nor does anyone.
The only way to solve this conundrum is to go for it and enjoy what you want (only eliminating things you know are obviously harmful). My personal view is get to 70 and we have had a fair share and everything after that is a bonus. Worrying too much about research telling us what foods are healthy or unhealthy just decreases our enjoyment of life. All of us have a good idea by now of what constitutes a balanced diet (I think it means to drink our own body weight in alcohol every week so it balances, but I might be wrong) and all 'extras' are perks.