There has been a lot of media attention of late to calcium and to some extent Vitamin D. An article in the New York Times suggested that we may be overdoing calcium supplementation and that calcium can cause calcification of the coronary arteries as well as renal stones. I’ve been asked about this by several of my patients. It’s somewhat complicated… It’s true that you’re not going to reverse underlying osteoporosis by simply piling on calcium and Vitamin D. It’s also true that too much calcium can cause renal stones and calcification of coronary arteries (indeed I covered that in an article I wrote for my website more than a year ago). Calcium citrate, however, seems less likely to cause kidney stones than calcium carbonate. Like every essential vitamin and mineral, the best way to get it into your body is not with pills but through your food. Dairy products are of course rich in calcium and do have some Vitamin D. You will of course get vitamin D through sunlight which is quite ubiquitous in Southern California. (Although as winter approaches and dermatologist issue warnings about skin cancer we are less likely to expose our skin in order to achieve appropriate sunlight conversion of the cholesterol to Vitamin D in our system.) The current recommendation is that you should have at least 400 units of Vitamin D a day, but I tell most patients to get between 1000 and 2000 units. I might be overdoing this recommendation but I don’t think it will cause harm.
When it comes to calcium, you’re getting a lot in your food. Even without milk products you get about 300 mg in your diet. You “use up” approximately one thousand milligrams every day through sweat, urine and feces. So you might want to make sure you get an additional 600 mg . Now if you drink milk or have yogurt you may indeed get that amount (just look on the container and see what’s there). If not, then if you supplement, don’t take more than that 600 mg.
The topic of calcium and Vitamin D was just addressed again in a recent article in the October 15th New England Journal of Medicine which reported on a trial of calcium and Vitamin D for the prevention of colorectal adenomas. (Remember these are usually the precursors of colon cancer).
The researchers recruited patients with recently diagnosed adenoma and randomly assigned 2259 participants to receive daily vitamin D3 at a dose of 1000 units as well as calcium carbonate 1200 mg. Follow up colonoscopy was performed 3 to 5 years after the baseline examination. They found that there was no difference in adjusted rate risk ratios for recurrent adenomas in those who took vitamin D versus no vitamin D, with calcium versus no calcium, with both agents versus neither agents. The conclusion was that daily supplements with vitamin D and calcium or both did not significantly reduce the risk of recurrent colorectal adenomas after 3 to 5 years. Does this mean it has no impact on colon cancer? Probably….
Once more…mega vitamins are not a cure-all. Just continue (or start) the prevention of disease through nutrition, exercise and in the case of colon cancer, appropriate colorectal testing.