This transcript has been edited for clarity.
Tricia Ward: Hi. I’m Tricia Ward, from theheart.org/Medscape Cardiology. I’m joined today by Dr Matthew Budoff. He is professor of medicine at UCLA and the endowed chair of preventive cardiology at the Lundquist Institute. Welcome, Dr Budoff.
Matthew J. Budoff, MD: Thank you.
Dietary Calcium vs Coronary Calcium
Ms. Ward: The reason I wanted to talk to you today is because there have been some recent studies linking calcium supplements to an increased risk for cardiovascular disease. I’m old enough to remember when we used to tell people that dietary calcium and coronary calcium weren’t connected and weren’t the same. Were we wrong?
Dr. Budoff: I think there’s a large amount of mixed data out there still. The US Preventive Services Task Force looked into this a number of years ago and said there’s no association between calcium supplementation and increased risk for cardiovascular disease.
As you mentioned, there are a couple of newer studies that point us toward a relationship. I think that we still have a little bit of a mixed bag, but we need to dive a little deeper into that to figure out what’s going on.
Ms. Ward: Does it appear to be connected to calcium in the form of supplements vs calcium from foods?
Dr. Budoff: We looked very carefully at dietary calcium in the MESA study, the multiethnic study of atherosclerosis. There is no relationship between dietary calcium intake and coronary calcium or cardiovascular events. We’re talking mostly about supplements now when we talk about this increased risk that we’re seeing.
Does Vitamin D Exacerbate Risk?
Ms. Ward: Because it’s seen with supplements, is that likely because that’s a much higher concentration of calcium coming in or do you think it’s something inherent in its being in the form of a supplement?
Dr. Budoff: I think there are two things. One, it’s definitely a higher concentration all at once. You get many more milligrams at a time when you take a supplement than if you had a high-calcium food or drink.
Also, most supplements have vitamin D as well. I think vitamin D and calcium work synergistically. When you give them both together simultaneously, I think that may have more of a potentiating effect that might exacerbate any potential risk.
Ms. Ward: Is there any reason to think there might be a difference in type of calcium supplement? I always think of the chalky tablet form vs calcium chews.
Dr. Budoff: I’m not aware of a difference in the supplement type. I think the vitamin D issue is a big problem because we all have patients who take thousands of units of vitamin D — just crazy numbers. People advocate really high numbers and that stays in the system.
Personally, I think part of the explanation is that with very high levels of vitamin D on top of calcium supplementation, you now absorb it better. You now get it into the bone, but maybe also into the coronary arteries. If you’re very high in vitamin D and then are taking a large calcium supplement, it might be the calcium/vitamin D combination that’s giving us some trouble. I think people on vitamin D supplements really need to watch their levels and not get supratherapeutic.
Ms. Ward: With the vitamin D?
Dr. Budoff: With the vitamin D.