Scientists are pretty sure that one mineral--potassium--can be used to help lower blood pressure. Exactly what role the other two--calcium and magnesium--play in the treatment of high blood pressure remains to be determined.
Pass the Potassium, Please
It's very simple: If your body is low in potassium, your blood pressure is likely to go up. Recent studies have also shown that eating a potassium-rich diet--or taking potassium supplements--can reduce blood pressure. The potassium appears to lower blood pressure by creating a healthy balance of sodium in your cells. In fact, potassium is the third most abundant mineral in the body after calcium and phosphorus; almost all of the potassium in the body is found inside the cells.
A coming-out party. The spotlight shone on potassium as a potential aid in treating high blood pressure in 1997, when a group of scientists analyzed the findings of 33 different randomized studies. This meta-analysis found that people with high blood pressure who took potassium supplements had an average drop in systolic pressure of 4.4 mm Hg and in diastolic pressure of 2.5 mm Hg. People with normal blood pressure had an average drop of 2 mm Hg in systolic pressure and 1 point in diastolic. These small changes reduce the chance of developing hypertension by 25 percent.
In general, aim to consume about 3,500 milligrams of potassium a day. Your best bet is simply to eat more potassium-rich foods, especially fruits, vegetables, and low-fat dairy products. If you're following the DASH diet, eating these foods shouldn't be much of a problem. Have a cup of orange juice with breakfast, half an avocado in a salad at lunch, and half a cup of cooked spinach or a baked potato with dinner. For snacks, try a banana, 8 ounces of low-fat yogurt, or five dried prunes.
You might also want to consider taking potassium supplements, particularly if you're having trouble limiting the salt in your diet; the supplements seem to help mediate the bad effects of too much salt in the body. (But don't think that by adding potassium to your diet you can reinstate the salt-shaker to your dinner table!) If you're taking a class of blood pressure drugs called diuretics, your doctor may recommend potassium supplements. Diuretics flush extra salt and water from the body, and sometimes potassium goes along for the ride.
Below you will find foods that contain plentiful amounts of potassium (starting with those that contain the greatest amounts of the mineral). Don't just home in on the best sources of the mineral; eating a wide range of foods provides healthy benefits, like phytochemicals and fiber.
- Apricots, dried: 1 cup, 1,567 mg
- Avocado: 1 medium, 1,097 mg
- Potato (baked with skin): 1 medium, 844 mg
- Pinto beans: 3 oz. cooked, 646 mg
- Yogurt: 8 oz., 579 mg
- Orange juice: 1 cup, 550 mg
- Cantaloupe: 1 cup, 482 mg
- Banana: 1 medium, 467 mg
- Winter squash: 1/2 cup cooked, 448 mg
Can You Count on Calcium?
Here's what we know for sure (sort of) about calcium: Having too little of the mineral in our bodies seems to increase our risk for high blood pressure. Take the findings from the study of 80,000-plus American nurses, known as the Nurses' Health Study. Women in that study who consumed at least 800 milligrams of calcium daily had a 23 percent lower risk for high blood pressure than women who ingested less than 400 milligrams of calcium.
You would think, therefore, that popping calcium supplements every day would help reduce blood pressure. But, unfortunately, studies have shown that not to be true. Calcium supplements have little, if any, impact on blood pressure.
Still, given that a deficiency of calcium has been linked to high blood pressure, don't take chances. Make sure you get enough of the mineral. If you're under age 50, you should be taking in at least 1,000 milligrams of calcium a day; if you're over age 50, bump that amount up to 1,200 milligrams (for men) or 1,500 (for women).
Foods first. Try to get most of your calcium from food sources rather than supplements. Dairy products are particularly high in calcium--an 8-ounce glass of milk, for example, contains about 300 milligrams of the mineral--but they can also be loaded with fat. So be sure to follow the DASH dictum: Always choose fat-free or low-fat milk, cheese, and yogurt. And go very easy on the butter.
Below you will find the foods that are most plentiful in the mineral calcium. Once again, try to eat all of the foods rather than focusing on just the richest sources.
- Yogurt (plain, fat-free): 1 cup, 400 mg
- Collard greens (cooked): 1 cup, 357 mg
- Ricotta cheese (part skim): 1/2 cup, 337 mg
- Milk (fat-free or low-fat): 1 cup, 300 mg
- Orange juice (with added calcium): 1 cup, 300 mg
- Tofu (processed with calcium sulfate): 1¼2 cup, 260 mg
- Broccoli (cooked): 1 cup, 118 mg
- Almonds (dry roasted): 1/2 cup, 100 mg
Magnesium Is a Maybe
As with calcium, having to little magnesium has been linked to high blood pressure. Some studies have also shown that taking magnesium supplements can lower blood pressure slightly, particularly in people whose blood pressure is over 140/90 mm Hg. But findings haven't been consistent, and most experts remain unconvinced of the value of prescribing magnesium willy-nilly to people with high blood pressure.
Mining magnesium. Still, you might as well make sure you're getting enough of this important mineral. After all, one of magnesium's many duties in the body in increasing the width of blood vessels, a task that many explain how it helps knock down blood pressure.
The recommended daily dose of magnesium is 400 milligrams. Once again, remember that nature is best--and cheaper. Try to get the nutrient naturally through foods rather than through supplements.
Below you will find foods that are rich in magnesium. Try all of the foods rather than focusing on just the richest sources of the mineral.
- Almonds or hazelnuts: 2 oz., 170 mg
- Spinach (cooked): 1 cup, 155 mg
- Swiss chard (cooked): 1 cup, 150 mg
- Sunflower seeds (dried): 1/2 cup, 130 mg
- Halibut or mackerel (cooked): 4 oz., 120mg
- Tofu: 4 oz., 120 mg
- Brown rice (cooked): 1 cup, 85 mg
- Avocado: 6 oz., 70 mg
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