Vitamin D is essential for immune support and bone and cardiac health—and that’s even before we get to the fertility and pregnancy benefits. Unfortunately, about half of North Americans are deficient in the vitamin, and it’s hard to get what you need from sun or food alone. That’s where supplementing comes in. The Calcium + Magnesium + Vitamin D Boost has 1,000 IU of Vitamin D, covering the official doc-recommended daily value. And because many doctors and studies recommend daily doses up to 2,500 IU to benefit reproductive health and correct the deficiency many of us have, we recommend taking this product plus any of our preconception, prenatal, or postpartum supplements, which also contain 1,000 IU. That way, you can get a total of 2,000 IU daily, which is an effective dose yet safely within both the U.S. National Institute of Health’s and Health Canada’s tolerable upper intake level of 4,000 IU.