Vitamin D is the key to the immune system.
People living up north with a long, dark winter, have traditionally got their vitamin D from fish, especially cod liver oil. Vitamin D is essential for absorption of calcium and phosphorus for teeth and bones. It is also important for fighting cancer. Recent research shows that we need 5 times more D- vit. than previously recommended. Children and old people need twice as much vitamin D as adults. Sunscreen with SPF prevents conversion of sunlight to vitamin D through the skin. Therefore, this is one of the reasons to take cod liver oil the whole yearthrough, not only for months starting with the letter R.