A cup of cooked black beans contains about 15 grams of fiber, 610 mg of potassium, 240 mg of phosphorus, 120 mg of magnesium, more than 46 mg of calcium, and many other important nutrients. Black beans also contain phytochemicals and amino acids that help improve blood vessel function and sleep, according to the medical information site Medicine Net (USA).

All of these effects can help improve blood pressure in people with high blood pressure. High blood pressure is a condition in which the blood circulation creates pressure on the artery walls. When this pressure exceeds the normal level, it leads to high blood pressure.

Normal blood pressure will fluctuate around 120/80 mmHg. However, for people with high blood pressure, this index can reach 130/80 mmHg or higher.

In a study conducted on rats published in the journal Nutrients , scientists looked at the effects of black beans and white beans on blood vessel function in rats with high blood pressure.

The results showed that black beans help blood vessels become more elastic, thereby reducing blood pressure. However, this was not found for white beans. The study also found that the blood pressure-lowering benefits of black beans were only maintained when eaten regularly. This means that to reap the benefits of black beans, people should include this vegetable in their daily diet.

Not only does black beans help improve blood pressure, they also help you sleep better thanks to their rich content of tryptophan. This is an amino acid that is essential for the synthesis of two sleep-promoting hormones: melatonin and serotonin.

Many research evidences also show that not only black beans but also other types of beans rich in tryptophan have the effect of improving sleep quality and sleep time, while reducing the condition of light sleep and the number of times waking up during the night. In addition, tryptophan is also essential for muscle activity, neurotransmitter balance and many other functions, according to Medicine Net.