Interviewer: Dr. James Dowd with us today, author of The Vitamin D Cure. When people think of Vitamin D, I think they automatically think of the immune system. If you've got a cold, you've got to have vitamin D.Doctor, can you talk about its relationship with our immune system, first of all, and then we'll a couple of other certain issues.
Dr. Dowd: I recently wrote a white paper for a company that measures vitamin D, and it was on this exact topic of what is the importance of vitamin D in our immune system, and so it's a timely summary. Early on, when our immune system is developing, during fetal development and early childhood. The placenta is this organ... and, I really think of the placenta as an endocrine gland, and its secreted product is a new human being. Because the placenta makes so many different hormones.One of them is Vitamin D. It has the ability to take the active substrate and turn it in to active hormone. But, the placenta is this engineered, immunosuppressed environment, so that the mother doesn't reject the fetus. Because the fetus is made of her husband, and it is foreign protein, and so theoretically her immune system should reject this foreign thing. But it doesn't, and it doesn't because of the cortisol, and DHEA, and Vitamin D,and all of these are immunosuppressive hormones, that protect the fetus during its development in the womb.Vitamin D is playing an additional role at suppressing the immune system to prevent reject of the fetus. At the same time, the fetal immune system is developing what we call "central tolerance". Which is, it's learning who it is, what itself is. It's learning self. It gets introduced to proteins in its muscle, in its liver, its kidney, its brain, its heart, and it says, "This is me. I'm this new human being,"let's call it Joe, "and I'm being introduced to every little part of Joe. And, it's okay, so I'm not going to have an immune response to myself." Okay? Then, the hormones of pregnancy, and Vitamin D, and the hormones the fetus makes all contribute to suppressing the immune system and allowing it a chance to develop recognition of self. Then, after birth, it has to develop recognition of some key things in its environment. It has to develop recognition of food, it has to develop recognition of the bacteria that is growing in its gut.Because there's a difference between getting the flu, and the bugs that are in your gut all the time. And you don't want your immune system to attack the bugs in your gut all the time because there's a symbiotic relationship there.
Dr. Dowd: They're helping you grow and digest your nutrients for you. By the same token, you want to be able to fight off a virus that you might bet infected with. So, the immune system has to learn the difference between bugs that are friendly and bugs that are not so friendly. And Vitamin D plays a key role in the immune system being able to make that distinction. And so, Vitamin D, in general, helps with tolerance, adapting to these things... self, and the environment. And then after the child is relieved from the mother's protection, because after birth the child is protected by the mother's breast milk. There's lots of antibodies there, and the mother's immune system is still doing most of the work. Once the breast feeding stops, then the immune system takes on a much more defensive posture. Which is why newborn babies who are still breast feeding rarely get sick, and they don't get sick until they stop breastfeeding, because now the immune system is in defense mode. Everything changes complexion. And now Vitamin D is no longer suppressing the immune system to develop tolerance as much as it's alerting the immune system to protect it, in defense mode from microorganisms like viruses, bacteria and fungi that come along later in childhood. So, Vitamin D is important for central tolerance, learning who you are, self tolerance. it's important for peripheral tolerance, learning what foods are okay and what bugs are okay. And then after that stage of developing tolerance, Vitamin D becomes critical in managing and preventing infections. There are studies looking at children and influenza. This study was done in Japan. And they said, "Well, lets put one group of kids on Vitamin D and the other group not on Vitamin D, and follow them through a flu season and see what the rate of contraction of the flu is between these two groups. And what they found is the Vitamin D group had 30% or 40% lower risk of developing the flu that the kids who are not getting Vitamin D. So, it works with viruses... we have lots of animal studies and lots of human data, looking at its relationship with diseases like Tuberculosis, and Vitamin D seems to be critical in helping your immune system attack, isolate and kill Tuberculosis. So, it seems to be very important, and there's lots of research going on now with HIV, and we're wondering, "Why is Africa the country that's plagued with it?" Well, there're clearly issues with poverty and malnutrition, but when you think of the malnutrition you think, "What about Vitamin D deficiency? Actually, despite being a country bathed in sunlight, because of severe malnutrition these people are also Vitamin D deficient. Because, you need enough fat and cholesterol in your diet to make Vitamin D, and if you don't have enough fat and cholesterol from malnutrition you can't even make Vitamin D from sunlight. And that's what we're seeing in a lot of areas of Africa and India, is that the equatorial populations are suffering from Vitamin D deficiency because of the malnutrition. The general malnutrition is not giving the fat they need to make Vitamin D from. And they have many more infectious diseases there. Yes, there are public health issues there too, but Vitamin D may be playing another role in why these infection rates are so much higher in these areas.
Vitamin D plays an integral role in developing and sustaining our immune system. Dr. James Dowd talks about how vitamin D does this from fetal development on to early years as well as adulthood.
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