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When an infant suckles the breast, there are receptors on the nipple which sends a "message" to the hypothalamus and posterior pituitary causing prolactin production. It is the prolactin produced in this manner that stimulates the breast to produce milk. Nursing mothers should have and additional 600 calories to their diet 20g of which should be protein. An additional 400-500 mg of calicium is a good idea as well. Other vitamin supplements have been helpful as well (including prenatal vitamins).
It is possible to breastfeed. Prolactin levels could also be checked with a blood test. It is possible that you may not have given the baby enough "suckling" time. Most hospitals will have what is called a "lactation specialist". I would encourage you and your wife to consult with this person to learn different breastfeeding techniques and ways to improve milk "letdown".
I hope this helps and I wish you and your wife all the best with your new baby boy!