Another thing we learned...,

[Silverobama]

The paragrpah is from Scientific American.com. I want to write it down for future reference. Since it was in spoken English I'm not sure if it's grammatical and natural. Please help me with it.

Another thing we learned is that vitamin D deficiency is not as big of a problem as we thought. Early in the 2000s studies suggested that vitamin D deficiency was a contributor to cancer, heart disease and many other illnesses and that taking vitamin D supplements might help. But more recent studies have failed to show as much of a benefit as we thought, and most people actually have adequate levels of vitamin D.

 

[PeterCW]

I am not a grammarian but it is perfectly natural spoken English. As an elderly BrE speaker I would probably write "which we learned".

 

[emsr2d2]

The paragraph is from Scientific American.com. I want to write it down for future reference. Since it was in spoken English I'm not sure if it's grammatical and natural. Please help me with it.

Another thing we learned is that vitamin D deficiency is not as big of* a problem as we thought. Early in the 2000s, studies suggested that vitamin D deficiency was a contributor to cancer, heart disease and many other illnesses, and that taking vitamin D supplements might help. But more recent studies have failed to show as much of a benefit as we thought, and most people actually have adequate levels of vitamin D.

See above. The first comma I've added is required. The second is there to indicate that the part after the comma is separate from the list of potential issues caused by vitamin D deficiency.
I've marked "of" with an asterisk in the opening sentence just to point out that this is an indicator that it was written by an AmE speaker. A BrE speaker would omit it.

 

[emsr2d2]

I am not a grammarian but it is perfectly natural spoken English. As an elderly BrE speaker I would probably write "which we learned".

As another definitely-not-young BrE speaker, I might use "that we learned", but I wouldn't use "which".

 

[teechar]

To me, both "which/that we learned/learnt" sound okay.