Blood oranges
It's a good thing this produce pick is in season during the winter: with more vitamin C than their bloodless counterpart, they're a perfect quick defense against drama. In a study published in the journal Psychopharmacology, German researchers attempted to stress out 120 people by asking them to give a speech and then answer difficult math problems. Researchers found that those participants who had been given high doses of vitamin C before the stress-fest had lower blood pressure levels and concentrations of the stress hormone cortisol. (Here are 12 more foods with more vitamin C than oranges.)
Oatmeal
A perky disposition depends on carbohydrates. Serotonin, your brain's primary mood-boosting neurotransmitter, comes from the amino acid tryptophan, which needs carbohydrates to reach the brain, according to Judith Wurtman, PhD, former MIT research scientist and co-author of The Serotonin Power Diet. Problem is, as cute as Christmas cookies are, their refined carbs spur an overproduction of insulin that's not only linked to sugar crashes but spikes in stress hormones as well. Reach for warm and gooey oatmeal instead, suggests Wurtman. It contains the healthy carbohydrates and fiber needed to boost your serotonin levels for a full three hours.