Here’s a link to a fish oil study, which includes a brief 5-minute video.
They looked at vitamin D as well as fish oil.
They did not find much benefit (re heart disease or cancer) after people took vitamin D for 5 years.
But the issue could be that the people were taking just 2000 iu per day. Those researchers think that’s a lot, but we know that 2000 iu/day will often never bring your 25-hydroxy D3 blood level up to 60 - 70 ng/mL, which Dr. Davis says is required in order to achieve benefits.
The fish oil study showed a bit of promise for heart disease protection. They used a gram per day, nowhere near the dose that Dr. Davis recommends. Still, they did observe benefits from fish oil.
In the book, The End of Illness, by Dr. David Agus, Dr. Agus says eating real fish is superior to taking fish oil.
He says you would have to consume 20 – 30 fish oil capsules to obtain the same benefit as eating a single 3 – 4 oz. serving of fish. [Not sure how he figured that out].
He feels eating real fish is the better way to go and you then don’t have to worry whether the fish oil supplement you are taking really has what it says it has in it.
In a recent video by Dr. Paul Mason, https://www.youtube.com/watch?v=4lJPjsuftmQ
… He mentions (near the end) that fish oil could be “readily oxidized right out of the bottle.” [Not a good thing]. He too prefers real food over taking supplements.
I was looking back at an old Rodale health book I own (circa 1992).
It says doctors advise caution with fish supplements as they can interfere with the ability of blood to clot, with a risk of excessive bleeding in some people. [Dr. Davis generally disagrees with this]. Again, they recommend eating fish instead, preferably 3 times per week.
I occasionally get spontaneous bruises and I think it may be from taking fish oil, even though I don’t take as high a dose as Dr. Davis recommends.
My platelet count, however, which appears in my CBC blood panel, is always below the reference range. So perhaps for that reason I’m more susceptible to bruising.
In general, I’ve never taken fish oil consistently over the years.
For quite some time, instead of taking fish oil, I’ve been eating canned (wild-caught) salmon. I eat ½ a can 4 times per week.