Better Fed on the Med?

It has been reported that it is not too late to switch to a Mediterranean diet, even for old fogeys (https://www.theguardian.com/science/2018/aug/31/mediterranean-diet-old-age-longer-life-study). Trading up, as a mature adult, to a diet rich in fresh vegetables and fruit along with fish and olive oil as a cooking agent, reportedly results in people living longer (but, pretty obviously, going easy on the alcohol and certainly not smoking). Perhaps, in some geographical areas nearer the poles, you would still have to supplement vitamin D?