Giving dark chocolate to our sweetheart on Valentine’s Day may be a win-win situation both emotionally and physically. Chocolate with a high cocoa content is quite nutritious. It contains fiber, iron, magnesium, and copper as well as 98% of the manganese you need daily, according to Healthline. But since chocolate is high in calories, and often contains added sugars, it should be consumed in moderation.

Here are some of the key health benefits of chocolate:

• Improves blood flow and blood pressure.  The flavanols in dark chocolate stimulate the lining of the arteries to produce nitric oxide, which helps the vessels relax. This helps improve blood flow and reduce blood pressure according to many controlled studies.
• Increases brain power. A study published in the journal Scientific Reports found that when healthy adults consume flavanol-rich cocoa either in powder form or in dark chocolate — 70% is best — their brain receives increased oxygenation, according to an article by Drs. Mehmet Oz and Michael Roizen. Participants in the study had three times more oxygen delivered to their brains than those who consumed low-flavanol cocoa.
• Boosts the immune system. Dark chocolate is chock full of antioxidants that, according to one study, increases the T-cells, which are the immune markers in your blood, says Sue Van Rues, a functional nutritionist with Boulder Nutrition. The study, published in the journal Frontiers in Pharmacology, says that the polyphenols found in cocoa positively influence the immune system.
• Improves insulin sensitivity. The antioxidants in dark chocolate help the body use its insulin more efficiently to help control blood sugar, says Anna Simos, a certified diabetes care and education specialist at Stanford Health Care’s diabetes care program in Palo Alto, CA. “This in turn helps lower blood sugar levels naturally and actually helps your body use your insulin. As a result, it helps decrease insulin resistance, which we see in Type 2 diabetes.”
• May reduce the risk of heart disease. According to Healthline, the compounds found in dark chocolate impede LDL cholesterol from oxidizing, which causes less dangerous plaque to lodge in the arteries. Research shows that cocoa slashed the risk of heart disease by half. One study found that eating dark chocolate a few times a week lowered the risk of having calcified plaque in the arteries by 32%. 
• Spices up your love life. There is a reason why romance and chocolate are linked, says Van Rues. The famous Aztec leader Montezuma was one of the first to discover the aphrodisiac power of cocoa. A study published in the Indian Journal of Psychiatry called chocolate “the queen of natural aphrodisiacs”, for its abundance of compounds that enhance the sexual experience.

According to Everyday Health, to reap the most health benefits from chocolate, the Harvard T.H. Chan School of Public Health suggests choosing a bar that contains 70% cocoa or more. Often, Simos says, the cocoa content will appear in plain sight on the front of the packaging.