Dear Dietitian: Calcium and Vegetables
I read your last column on calcium where you recommended that we get the mineral in our diet rather than pills. Is it better to get calcium from plant foods or dairy products?
Calcium is the most abundant mineral in the body, accounting for 39 percent total body minerals. Most of us know that calcium is needed for strong bones and teeth, but did you know it is also needed for blood clotting? Calcium initiates the release of blood-clotting agents from your platelets. Other functions include regulation of heartbeat and nerve function.
While there are many calcium-rich foods including tofu, navy beans, and fortified juices and plant milks, this column will focus on dairy and green vegetables. For adults, the Recommended Daily Allowance (RDA) for calcium is 1,000 mg up to age 50. That amount increases to 1,200 mg per day for women over 50 and men older than 70.
Dairy sources of calcium include milk, yogurt, and cheese. The calcium in these foods has a high bioavailability, meaning it is easily absorbed by the body. There are many delicious-tasting yogurts on the market today, some of which are in my refrigerator. I was surprised to learn that a 5.3 oz portion (about a half-cup) only provides 15 percent (150 mg) of the Daily Value (DV) for calcium. In comparison, 1 cup of plain, non-fat yogurt contains 45 percent DV (450 mg). In order to maximize your calcium intake, start with a plain, fat-free yogurt, then sweeten it with your favorite fruit. Or simply eat two cartons of the smaller, pre-packaged yogurts.
Dark, green leafy vegetables, such as kale, collards, turnip greens, mustard greens, and broccoli are good sources of calcium. The calcium in these foods is just as good as the calcium in dairy products, but you will need to consume larger portions of these vegetables compared to dairy. This is a good thing since these veggies are also rich in folic acid and fiber. For example, two cups cooked broccoli provides 360 mg calcium, or 36 percent DV. It is important to note that the presence of oxalic acid limits the availability of calcium in rhubarb, spinach, chard, and beet greens. This simply means your body doesn't absorb as much of the calcium in these foods as it does in the aforementioned group of vegetables.
The bottom line is to keep it simple. Choose calcium-rich foods that you like. Be sure to get these products in your diet every single day. And don’t forget about vitamin D because it is needed for calcium absorption. This mighty vitamin can be made from sunlight exposure, and it is also found in fortified milk, juice, and some cereals.
Good health to you!
Leanne McCrate, RD, LD, CNSC, is an award-winning dietitian based in Missouri. Her mission is to educate consumers on sound, scientifically-based nutrition. Do you have a nutrition question? Email her today at DearDietitian411@gmail.com.