Free radicals are implicated in hypertension, and antioxidants may help reverse it. How do they work? Antioxidants increase the production of nitric oxide (NO). The inner lining of the blood vessels (called the endothelium) uses NO to relax the surrounding smooth muscle. This relaxation widens the artery, thus improving blood flow and blood pressure. Nutrients work best in concert; in other words, the whole is more powerful than the sum of its parts. But let’s examine some of the nutrients that are especially relevant to balanced blood pressure.
Hypertension is rare in populations with low sodium intakes (below 1 teaspoon, or 50 mmol daily). Unfortunately, in developed societies, processed foods add plenty of “invisible” sodium to our diets. But sodium alone isn’t the problem—it’s the combination of too much sodium and too little potassium. When potassium is depleted, the body’s cells gobble up the sodium to make up for the loss. We should be eating about five times more potassium than sodium (5:1). Instead, the typical Western diet includes half as much potassium as sodium (1:2). Isolated societies that eat natural foods—and have virtually no hypertension—consume more than 150 mmol of potassium daily and only 20 to 40 mmol of sodium per day. In contrast, a 1966 report in The New England Journal of Medicine demonstrated that the unhealthy potassium:sodium ratio in Western diets leads to retention of sodium and increased blood pressure.
Salt-sensitive individuals tend to retain sodium and water, which increases blood pressure. Approximately 58 percent of hypertensive individuals are salt-sensitive, says Myron Weinberger, MD, director of the Hypertension Research Clinic at University of Indiana’s School of Medicine. Groups more likely to be salt-sensitive include older adults, African Americans, or anyone related to a salt-sensitive person. Also, people who have more inflammation tend to be more salt-sensitive. To prevent and treat hypertension, the Institute of Medicine recommends a daily intake of 50 to 65 mmol of sodium, and a minimum
of 120 mmol of potassium. Potassium-rich foods include potatoes with skin, bananas, milk, orange juice, tomato juice, cooked spinach, avocados, prunes, raisins, cantaloupe, honeydew melon, and red beans.
Magnesium works with potassium to activate the sodium/potassium pump, which pumps potassium into, and sodium out of, the cells. Magnesium also widens the blood vessels. Several population studies have linked high magnesium intakes with lower blood pressure readings. This mineral, which is at least as important as calcium for bone health, is depleted during stress. Magnesium-rich foods include seafood, tofu, legumes, kelp, wheat bran, wheat germ, almonds, cashews, blackstrap molasses, brewer’s yeast, Brazil nuts, and peanuts. Fruits and fruit juice, leafy green vegetables, and sunflower seeds are also good dietary sources of magnesium.
Researchers have observed that calcium supplementation appears to reverse the blood-pressure-raising impact of salt, especially in salt-sensitive individuals. Dietary sources of calcium include milk, cheese, yogurt, sardines, canned salmon, hulled sesame seeds, sunflower seeds, hazelnuts, garbanzo beans, pinto beans, black beans, tofu, wheat grass, barley grass, parsley, kale, spinach, broccoli, turnip greens, collard greens, mustard greens, kelp, and other green, leafy vegetables.
A shortage of folic acid and vitamins B6 and B12 has been implicated in high homocysteine levels. Homocysteine is a by-product of methionine, an amino acid. Homocysteine is naturally present in the human body. However, several studies suggest that high levels of homocysteine may increase the risk for heart and blood vessel damage—damage that can lead to hypertension. A 2008 study in the European Journal of Medical Research found that hypertensive patients with kidney dysfunction have especially high homocysteine levels.
Folic acid, in particular, relaxes blood vessels, thereby improving blood flow. One study featured in the Journal of the American Medical Association looked at the impact of folic acid on the blood pressure of more than 150,000 women. In one group of women, ages 27 to 46, those who consumed at least 800 mcg of folic acid daily had a 29 percent lower risk of hypertension than other women. In the other group of women, ages 47 to 70, those who got at least 800 mcg of folic acid daily saw a 13 percent lower risk of hypertension. Both groups of women got their folic acid through both diet and supplementation.