Bottom Line/HEALTH: A few years ago, vitamin D was the darling of the supplement world. We were all deficient in it, and if you took vitamin D and plenty of it, you were basically going to be saved from horrible illness and death. Well, unfortunately now the bloom is off that rose, and D also can stand for dangerous. So what do you need to know about vitamin D?

I’m Sarah Hiner, president of Bottom Line Publications, and this is our Conversation With the Experts, where we get the answers to your tough questions from our leading experts.

Today I’m speaking to Dr. Andrew Rubman, a leading naturopathic physician and the medical director of the Southbury Clinic in Southbury, Connecticut. Dr. Rubman is also a contributing medical editor to Bottom Line. Welcome, Dr. Rubman.

Dr. Andrew Rubman: Hi, Sarah.

Bottom Line: All right, so bloom is off this rose. What’s the deal? What does vitamin D do?

Dr. Rubman: Vitamin D primarily helps to move calcium around the body. Vitamin D also has a central role in immunity in the body. Vitamin D also participates in helping the body to modulate inflammation. If you put all of those three things together, you’re talking about virtually every physiological process that goes on in the body, so it’s all over the place, almost like vitamin C.

Bottom Line: Those are all great things.

Dr. Rubman: Right.

Bottom Line: Why is the bloom suddenly off the rose of this beautiful…

Dr. Rubman: We didn’t think it was that important initially. Then we found out it was important. Everybody started taking it. We all know that. Then we found out you can’t just get sun exposure for the most part. You need to really take it. And people started to be aware that D-3 was the active one and D-2 was inactive, and so the D-3 market was encouraged.

Now what we’re finding is that we have to limit the amount of vitamin D-3 that people are taking, either on their own or on the advice of their physicians who may not be as current in the research.

Bottom Line: Is there something that happened culturally—in the old days, did we have vitamin D deficiencies when people were outside? Is there something that changed, that we’re just not outside enough, or in our ability to process the vitamin D from the sun, that we now need to supplement?

Dr. Rubman: It’s partially that. It’s also partially that we have greater life expectancy and that we have access to food that is less seasonal. We can eat fruits and berries in the middle of the winter…we can find things that would only be available in the winter normally in the summer.

So the shift in the diet, and where vitamin D used to be able to be banked adequately during the winter months when people were inside…when the culture was more concerned with agriculture and less in being inside and doing work…then it might’ve worked. Nowadays, the real axiom is that everyone needs to take some level of vitamin D in order to have optimal function.

Bottom Line: And when we say everyone, does that mean everyone adults, or in a world where kids are spending way too much time inside, do we even need to think about supplementing kids with D?

Dr. Rubman: Well, we really do. And again, it depends with the kids on their diet. How open are they going to be to good diet and nutrition, and how resistive will they be? Some kids are impossible to feed good food to. Others are much more interested in doing that.

Bottom Line: Is D available in food? I usually think of it as the sunshine vitamin.

Dr. Rubman: It is available in food. It does show up in meats and fish and fatty tissues in the form of D-3.

Bottom Line: In terms of healthy food and intake for kids and adults, what are the key foods that people need to eat to be able to consume vitamin D in addition to absorbing it from the sun?

Dr. Rubman: Consuming vitamin D-2 so that when they go out in the sun, they can make D-3 – fruits, vegetables. If they’re going to be eating dairy products, that’s going to help as well.

Bottom Line: Let’s talk about vitamin D-2 and vitamin D-3. What’s the difference between the two of them?

Dr. Rubman: D-2 is the precursor. D-2 is found more broadly in foods…needs to be activated by ultraviolet light from sunlight hitting the skin. Then D-2 becomes D-3.

Bottom Line: The basic component is in fruits and vegetables, and then the sunlight actives that.

Dr. Rubman: Correct.

Bottom Line: Can I also just consume what other animal proteins have D-3 in them, and then that’ll automatically supplement it into my body?

Dr. Rubman: Right. Like a nicely marbled steak.

Bottom Line: How does someone know if they’re deficient in vitamin D?

Dr. Rubman: Best way to tell if they’re really out of range is by taking a blood test. It’s simple…it’s inexpensive. Quick turnaround time. It can give us a good idea. If you’re within this rapidly shrinking range, to be honest with you, that’s the best way to tell. A doctor may want to further nuance that by looking at whether or not you have a collection of symptoms that are consistent with an inappropriate D level.

Bottom Line: Let’s flip it the other way. Are there any bellwether symptoms that somebody should be looking out for? Because they may or may not be going to the doctor to be able to get that blood test.

Dr. Rubman: The most important function of vitamin D in the body is moving calcium around. Therefore, we look for symptoms associated with calcium deficiency. Before osteoporosis or osteopenia will show up, we can find functional problems that are associated with functional calcium deficiency going on in the body—bad digestion, issues controlling blood pressure, problems with maintaining mood and temperament, not being able to go to sleep at night.

These are all problems that may very well be remediated by getting adequate calcium levels into the tissue, and that problem may be driven by insufficient vitamin D levels.

Bottom Line: So if somebody wants to supplement, what’s the latest level? What’s the current thinking on the safety level of vitamin D, and how much should somebody be supplementing?

Dr. Rubman: The current thinking on the safe supplemental level is somewhere between 2,000 and 4,500 international units, which is the way that the vitamin D is assessed. How much should one take? Being guided by symptoms and being guided by a blood test is very useful.

Bottom Line: Can somebody decide to supplement vitamin D without going to their doctor?

Dr. Rubman: Generally, yes. If they want to see if it’s going to help them, supplementation between 2,000 and 3,000 international units of vitamin D-3 is generally safe.

Bottom Line: All right, thank you, Dr. Rubman. How do you know if you’re deficient in vitamin D? There are four bellwether symptoms—high blood pressure, a little moody, a little fatigue, or maybe some indigestion. Now, those are very common symptoms, but if you have any of those, a little bit of supplemental vitamin D won’t hurt you as long as you don’t take high levels. This is Sarah Hiner with Bottom Line.