Can bananas help to lower blood pressure?

Not directly: Many foods have been given health benefits and have been occasionally validated. Bananas are a healthful food, but also are a source of calories and carbohydrates (sugars) if consumed in excess (plus the loose stools that may result). Because of their potassium content, they may be useful for patients on some diuretics (for BP rx) that deplete potassium. No reliable data for benefit. Sorry.

Maybe: Diets rich in potassium, calcium and low in sodium (i.e. Dash type diet) have been shown to lower the blood pressure by as much as 10 mmhg in those with hypertension and 6 mmhg in those with prehypertension. Bananas are rich in potassium, so if they are part of a healthy diet with plenty of fruits and vegetables, they can contribute to lowering of the blood pressure.