Being vegan, I make sure to take either flaxseed or hempseed oil every day to make sure my milk has everything DD needs (the only other supplement I take is B12 - we get vitamin D from the sun and everything else from food.) The omega-3's and 6's are present in most other vegetble oils, but not in the amount found in flaxseed and hempseed. As far as I know the only other rich source is fatty fish and maybe liver (not sure on that, I may be confusing myself since liver is the only rich natural food source of vitamin D) but we don't eat those so flax oil it is! I mix it in a smoothie so it isn't gross like taking straight oil. Or you can use it as salad dressing.