For fat-soluble vitamins A, D, E, K I prefer to eat cod liver from time to time..... It's not only healthy but also very delicious.....
The trouble is the ratios of vitamins in cod liver oil.
And different brands will have different ratios.
To get enough vitamin D to bring blood levels up to optimal levels then too much vitamin A will be taken.
The form of vitamin A in cod liver oil is active meaning it doesn't have to be converted.
Beta carotene is better in that it will be converted to active vitamin A as the body needs it.
But a little cod liver oil now and then will help some.
The vitamin K in cod liver oil is K1.
K2 (MK-4, MK-7) is what's needed.
K2 takes calcium out of the body and into the bone after carboxylating proteins.
The MK-7 form is preferred as it stays in the body for some time to do it's work but the MK-4 is gone with a short half life of hours.
The minimum of K2(MK-7 form) needed is 200 mcg, a very small amount and more doesn't hurt as it's non toxic.
The vitamin E is good but the form most people need is called gamma E and should get about 500-1000 mg a day. Cod liver oil has natural vitamin e which helps some.
So if you take it now and then it WILL help some especially if you are running low in one of those vitamins.
People get in trouble by taking too much all the time, getting too much vitamin A.
Never tried it myself. But from what I've heard.
I guess it's a acquired taste.