Calcium Intake & Grapefruit Juice

Calcium is essential for bone and tooth health. It also plays a crucial role in nerve transmission, muscle function and blood clotting. Regular grapefruit juice provides some calcium, and calcium-fortified grapefruit juice provides enough to help you meet your daily calcium intake requirement. Combining calcium channel blocker medications for high blood pressure with grapefruit juice, however, could be fatal.

Calcium Recommendations

A single cup of grapefruit juice contains approximately 22 mg of calcium. According to the National Academy of Sciences, if you are between the ages of 19 and 50, your calcium intake should be 1,000 mg per day. If you are 50 years old and up, your calcium intake should be 1,200 mg per day. Pregnant or lactating women should make sure to consume 1,000 mg of calcium per day. While grapefruit juice does provide calcium, the amount of calcium in a cup of regular grapefruit juice is only a small percentage of what should be your total calcium intake for a day.

Calcium-Fortified Grapefruit Juice

Some types of commercial grapefruit juice contain added calcium. Grapefruit juice that is calcium-fortified may contain 200 mg or more of calcium per cup. Check product labels. The nutrition label on the can or bottle of grapefruit juice will reveal the amount of calcium it contains. Consuming calcium-fortified grapefruit juice could provide you with more than nine times the amount of calcium in regular grapefruit juice.

Grapefruit Juice and Calcium Channel Blockers

Although calcium protects your bones and helps prevent osteoporosis, calcium that doesn’t get absorbed by your bones stays in your bloodstream. Sometimes calcium, like cholesterol and triglycerides, gets trapped in your arteries. These calcium blockages can lead to high blood pressure and heart attacks. Doctors sometimes prescribe calcium channel blockers to keep calcium away from your heart. If you take calcium channel blockers, do not combine them with grapefruit juice. Grapefruit juice increases the effectiveness of calcium channel blockers, meaning your blood pressure could drop to dangerously low levels. In extreme cases, your heart could stop beating.

Other Sources of Calcium

Besides calcium-fortified grapefruit juice, you can find also find a significant amount of calcium in dairy products. An 8-oz. container of plain yogurt for instance, contains 450 mg of calcium, which is 45 percent of your daily recommended calcium requirement. An 8-oz. glass of skim milk contains 302 mg of calcium, while 1 oz. of American cheese contains 202 mg of calcium; 30 percent and 20 percent of your daily calcium requirements, respectively. Non-dairy sources of calcium include broccoli, canned salmon with bones, and raw, firm tofu. Half a cup of cooked broccoli contains 47 mg of calcium, 3 oz. of canned salmon with bones contains 203 mg of calcium, and 1/2 cup of raw, firm tofu contains 258 mg of calcium.