Don't waste your money on bags of old lettuce, green salad has hardly any vitamins in it at all. Good for fibre if you need it and it looks tasty but don't buy it for the vitamins.
Better a banana or an orange or a carrot. I only buy organic carrots, but other veg is OK.
I am on my third life! Antibiotics saved me from death by pneumonia and later by bloodpoisoning. ( a rescue cat bit me) Looking at it realistically it is better to eat well, eat what you like, don't drink too much, don't smoke but RELAX. Stress is what kills people. There is not much left to learn about living longer in good health, but the papers will carry on about it.
My daughter is a microbiologist and they are always doing tests and half of the papers disappear in the bottom drawer because they couldn't prove anything. Doesn't stop the media from publishing them though.
Now she is researching stem cells and when they have cracked that nut, then we shall all live forever.