D2 vsD3 and other stuff about vitamin D

I've posted this before on the RNY board, but I've seen a few posts here on the main board about vitamin D lately so I thought I would share this here too.

There are two types of vitamin D, D2 and D3. It’s important that we know this because one type, D3, is absorbed well and the other type, D2, is not. Unfortunately, many doctors do not know the difference. They may not even realize there are two types of vitamin D, and if they do know there are two types, they may think they are both equally well absorbed or may have no idea what the difference is. I know it seems like a doctor should know these things, but the reality is, many do not.

D2 must be converted to D3 in the body in order for the body to use it. It takes a fair amount of D2 to make a little bit of D3. I’ve seen anywhere from three units of D2 to make one unit of D3 to ten units of D2 to make one unit of D3.

When your vitamin D level is low, doctors often want to give you a prescription for vitamin D. What they prescribe is called Drisdol, and it’s D2. They prescribe it in 50,000 IU soft gels, those little things that look like footballs and have oil inside. The reason they put it in oil is because vitamin D is a fat soluble vitamin. Being in oil is supposed to make it absorb better. That’s true for non-RNY folks, but is not true for RNY-folks because we malabsorb fat. We need dry D3. But some docs don’t know that, either.

OK. So your D is low and they give you 50,000 IU D2 and usually tell you to take it once a week. That’s not enough if your level is really low – and if your doc is prescribing vitamin D, it’s usually because it’s very, very low.

If it takes three units of D2 to make one unit of D3 in your body and you take 50,000 IU of D2, you’re really only getting about 16,666 IU of vitamin D. If it takes ten units of D2 to make one unit of D3, you’re really only getting about 5000 IU of vitamin D.

Now, keep in mind that recent research suggests that folks that have not had WLS and that have normal levels of vitamin D need 1000 – 2000 IU per day just to maintain their levels. If you needed 7000 – 14,000 IU per week just to maintain your level, do you think 5000 – 16,666 IU once a week is going to bring your level up? Not likely.

And if you had RNY, that prescription D2 in oil will help you even less because you won’t absorb much of it at all because you malabsorb fats. But even if you are pre-op, or had lap band or VSG, the D2 is not going to be sufficient for you.

You cannot get D3 by prescription. It is only available over the counter. Even if your doc knows the difference between D2 and D3 and writes a prescription for D3, the pharmacist will give you D2. That’s because there is no D3 available by prescription and legally pharmacists are allowed to make certain substitutions. You have to get your D3 over the counter and if you had RNY, you need to make sure it is dry D3, not in oil.

Many people don’t notice any symptoms of low vitamin D, at least not until it’s super super low.  Then they might get tired easily, feel weak, have muscle pain, feel depressed and get sick easily.  High blood pressure is sometimes a symptom of low vitamin D, too.

Keep in mind that we want our D levels about 80-100.  Lower than that, we are at increased risk for things like osteoporosis, heart disease and some cancers.

Your doc is almost certain to think your vitamin D is OK if it’s a bit lower than 80 and is almost certain to freak out if you tell him/her that you are taking big doses of D3, like 50,000 IU a day.  All I can say is, that’s how much many of us post-ops have taken for periods of time in order to get our level up above 80.  I currently take 50,000 IU D3 three to four times a week just to maintain a good level.