(NBC News Channel) -- You may be taking dietary supplements that have no added health benefits.
Researchers studied data from roughly 300 nutritional studies involving nearly a million people.
Reducing salt intake was associated with a lowered risk of suffering an early death in people who have a normal blood pressure.
Omega-3 fatty acids offered protections against heart disease and heart attacks, while folic acid helped protect against strokes.
But, calcium plus vitamin d intake was linked to an increased risk for stroke.
Taking multivitamins, selenium and vitamins A, B6, C, E, Or D, as well as calcium, folic acid or iron, had no added benefit when it comes to the heart.
Following a Mediterranean diet, reducing fat intake and taking fish oil supplements also had no significant effect when it comes to the heart or preventing an early death.