AS I SAY
In this case, we are reffering to the general sentiment that in general doctors are currently offering this sort of advice.
This is from news, and SAYS instead of SAID is used even when the act of saying is past because this thing has just happened. (if this is not the reason, please correct me)
What makes the backshifting rule even more difficult is that there are exceptions in use - a fact to which most descriptive and ESL/EFL grammar books are sensitive, and one which calls the "rule" into question. ...
State-event remains true. Thompson (1994:109ff), drawing on a corpus database, suggests that present tense is retained in reported clauses when the author wishes to emphasize that the state or event in question holds true at the time of reporting and/or is not presented as something temporary.
The Grammar Book - An ESL/EFL Teacher's Course Celce-Murcia & Larsen-Freeman 2nd edition; page 690
But at university professors sometimes say AS I SAY, sometimes AS I SAID; is there any difference? Does it mean SAY, the present tense, is used in the same way as the above to show something that has just happened (words having been just said); or SAY is used to refer to a habit, just as I DO EXERCISES EVERY DAY?
can mean past, present and future.
2.You say it can be used of the future, but can you give me an example? I can't for the life of me think of one.