Opt for fat-packed protein
"A good diet equals a good mood," says Julia Ross, MA, director of Recovery Systems, a holistic clinic in Mill Valley, California, and author of The Mood Cure (Penguin, 2004). Composed of 22 amino acids, protein is the only nutrient that replenishes serotonin, the brain's primary mood- and sleep-enhancing chemical, which helps regulate depression, aggression, and anxiety. It's also crucial for the production of endorphins—neurotransmitters that convey feelings of pleasure. Terrific protein sources, wild salmon and sardines pack omega-3 essential fatty acids, which help boost your brain's production of the antidepressant dopamine, says Ross. In a 2005 study at Israel's Bar Ilan University, a mixture of omega-3 and omega-6 was associated with lowered levels of cortisol, a stress-coping hormone that can go into overdrive when you're under prolonged pressure, causing you—ironically—to feel more anxious ( Nutritional Neuroscience, 2005, vol. 8, no. 4).

Bolster your Bs
Your brain needs B6 to produce serotonin, and B5 is crucial to maintaining your adrenals—triangular glands above the kidneys that manage the stress response by producing cortisol and adrenaline. When you're under pressure, your body burns through these vitamins, leaving you susceptible to symptoms of adrenal fatigue, including lethargy, mild depression, and scatterbrained concentration. If you're stressed out, chances are you're chronically deficient in vitamin Bs. So staff your dietary team with star players, such as avocados, bananas, sunflower seeds, oats, and turkey. Eat in moderation, though: Too many bananas can cause your blood sugar to spike and your good mood to crash.

Maximize your minerals
Your brain and bones need ample amounts of calming minerals, such as magnesium and calcium, which cortisol leaches from your bone matrix during chronic stress, says Ross. Your food fix: figs, which are high in calcium and offer blood pressure–regulating potassium. Or eat cottage cheese to benefit from dairy's high calcium content and endorphin-boosting proteins.