This irks me every time I read about it. Breastmilk is deficient in vitamin D. Infants are at risk. Come on people!! This is sooo easy to fix. Get your but outside and get some sun on your skin!! Studies show you only need 5 to 10 minutes of sunlight (without sunscreen) 2 to 3 times a week for your body to make enough vitamin D. You also only need filtered sunlight. Darker skinned folks may need more sun to absorb enough vitamin D.
Another option to ensure your breastfed baby is getting enough vitamin D is to offer supplement drops. Don’t wait for your pediatrician to recommend them –ask about them and do so early on. A breast feeding mother also needs to ensure she is getting enough vitamin D to up the amount in her milk — get in the sun, eat foods rich in vitamin D such as salmon, drink your milk fortified with vitamin D. Those in areas where there is limited sunlight or can’t be in sunlight should talk to their doctor about supplements. Do be careful with supplements, as taking 2 multivitamins contain too much vitamin A which can be toxic.
Vitamin D deficiency is thought to lead to certain cancers, diabetes and other diseases. So this is certainly not an issue that is isolated to infants. Everyone needs to ensure they are getting the appropriate amount of vitaman D each day.
Mininmum daily vitamin day intakes, which are set by the Institute of Medicine are: 200 IU daily for children and young adults, 400 IU for those ages 51 to 70 and 600 IU for those 71 and older. And some proponents recommend 1,000 IU per day.
Studies also show the BEST time for an infant to get vitamin D is in the womb. Children whose mothers get plenty of vitamin D during pregnancy have bigger, stronger bones at age 9. In fact, maternal vitamin D matters more than all the milk children drink in those first nine years.
I am so tired of hearing that breast feeding causes vitamin D deficiency I could scream. Yes, there are some very real side effects of vitamin D deficiency, such as rickets, but this is prevantable by ensuring the infant and mother get their recommended intake of vitamin D. Throughout history babies were breastfed, and before the invention of TV and fear of skin cancer, vitamin D deficiency was not an issue because people spent most of the day outdoors.
Everyone needs to take this issue seriously, not just mothers with breastfed infants.
Natural families and lifestyle 
This synthetic Vitamin D3 in Milk will cause your body to not properly absorb magnesium which helps with stress. As Americans we are always stressed, anxious or depressed and we don’t know why?!? We’re not getting enough magnesium, because we aren’t using the sun for natural Vitamin D! We lather up with sunscreen thinking we’re being good,
Go outside, take magnisuim (especially new moms, Mama Calm is a great brand and yummy!) and hold off on that sunscreen for just a few minutes. Great article, I am so grateful to you!