I understand that for your body to absorb Vitamin D-3, it requires an oil. Is a quality flax seed oil supplement sufficient?
You had a wide variety of choices and you picked one of the few ones that does not work for this purpose. Flaxseed Oil, when taken in sufficient doses, does not get absorbed well. Flax oil forms what is called an oil-water partition in the gut.
If you are going to use an oil, your best bet is fish oil, followed by olive oil, followed by evening primrose oil, and maybe borage oil. Flaxseed and castor oil are the two things you should not use for this.
It is a good question. The absorption of Vitamin D-3 is an important subject– 5,000 IUs daily cuts your risk of cancer in half.