A recent study published in the American Journal of Clinical Nutrition revealed that 25 percent of Americans are vitamin B6 deficient.

This vitamin is essential for a healthy heart and immune system, as well as optimal brain function, says a recent Women's Health article. To get the RDA of 1.3 milligrams, the folks at Women's Health suggest adding the following foods to your diet:

• 4 oz yellowfin tuna = 1.18mg
• 1 banana = .68mg
• 4 oz roasted chicken breast = .64mg
• 4 oz salmon or cod = .52mg
• 1 cup cooked spinach = .44mg
• 1 cup avocado = .41mg

If none of these foods appeal to you (no pun intended with the banana), you may also want to try popping a multi-vitamin each day, as most contain about two milligrams of B6.