The Healthy Bean That Can Lower Blood Pressure And Help You Sleep

Beans go with just about anything: a heart-healthy stew, a smoked barbecue platter, or as the perfect chip dip side. Black beans, in particular, are one healthy bean that may benefit you if you're trying to lower your blood pressure, as well as those of us attempting to get a good night's sleep (via CBS News).

One cup of cooked, salt-free black beans contains 15 grams (g) of fiber, 611 milligrams (mg) of potassium, 241 mg of phosphorus, 120 mg of magnesium, and over 46 mg of calcium, according to the U.S. Department of Agriculture (USDA). Black beans also contain phytochemicals and amino acids that have been linked with improvements in blood vessel function as well as sleep, per a 2021 article in the Annual Review of Nutrition. Let's start with the positive effects that black beans appear to have on blood pressure, which may benefit the nearly 50% of adults in the U.S. living with hypertension, or high blood pressure (via the American Heart Association).

When blood flow places increased pressure on the artery walls, the result is hypertension (via National Heart, Lung, and Blood Institute). A healthy blood pressure measurement reads as 120/80 mm Hg. People with high blood pressure, however, have a blood pressure measurement of 130/80 millimeters of mercury (mmHg) or above.

In a 2020 rodent study published in the scientific journal Nutrients, researchers looked at the effects of black beans and white beans on vascular functioning in rats with high blood pressure. The study findings showed that eating black beans was associated with greater vascular compliance (how blood vessel volume changes in response to pressure fluctuations), greater arterial flexibility, and more. Yet these improvements were not seen in connection with white bean consumption. The researchers also found that these effects persisted only as long as black bean consumption continued. This means we may be better off making black beans a regular, ongoing part of our diet to maintain benefits in the long run.

While black beans are busy working their magic on blood pressure, they may also help lull us to sleep at night. This is because black beans are rich in tryptophan (via MedicineNet). Essential to the health of our muscles, neurotransmitters, and more, tryptophan is an amino acid that we can only get from the foods we eat, explains MedlinePlus. Tryptophan is one piece of the puzzle in the body's production of two sleep-promoting hormones: melatonin and serotonin. Both of these chemicals help regulate our natural circadian rhythm, allowing our body to be in sync with the rising and setting of the sun (via the National Institute of General Medical Sciences).

In a 2022 scientific review published in the Annual Review of Nutrition, researchers note that legumes are one of several foods that may help your sleep. Experts point to the melatonin and tryptophan content in many of these foods as a contributing factor to this relationship. In the article, the researchers cite different studies that have shown tryptophan consumption to boost sleep quality and sleep duration, as well as reduce sleep fragmentation and the number of wake-ups experienced throughout the night.