OK, we’ve all heard the adage “an apple a day keeps the doctor away.” But a study by the American Journal of Public Health has found that eating fruits and veggies can actually help improve your mental health, too. Subjects reported increased happiness for each additional serving they ate in a day. So the next time you’re feeling down, reach for one of these 11 foods.

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SPINACH

Dark green veggies are rich in folate, a B vitamin that affects the mood-controlling neurotransmitters in your brain. Yay, science.

CITRUS

Mandarins, clementines, navel oranges, grapefruit, you name it. They’re all packed with folate, a B vitamin that's an instant mood booster.

BANANAS

Three reasons to make this ingredient a smoothie staple: potassium (improves brain function), B6 (increases serotonin, which calms the body) and tryptophan (the happy amino acid that regulates mood).

RELATED: Why You Should Always Eat Those Weird Strings on Your Banana

SWISS CHARD

Magnesium gives you an instant shot of energy and also staves off depression. Plus, it’s one of the nutrients lacking in the average diet, so sauté some up as a regular side dish.

BERRIES

Say hello to the best carbs ever. Berries provide a boost of glucose, which can decrease irritability.

BLUE POTATOES

Look for these pretty spuds the next time you’re at the farmers' market. They’re packed with antioxidants that reduce inflammation (a known mood killer) and are loaded with iodine, which helps regulate your thyroid (aka the mood master).

ASPARAGUS

Load up on the triple threat when it’s in season this spring: It’s a source of serotonin, folate and enzymes that break down alcohol. (Yep, that means it's a natural hangover remedy, too.)

CHERRY TOMATOES

It’s all about the lycopene, a fat-soluble phytonutrient that can actually stop the buildup of pro-inflammatory compounds linked to depression.

SWEET POTATOES

Complex carbs (like these tasty baked fries) increase serotonin levels, which have a calming effect on the body.

AVOCADOS

The combo of B vitamins and potassium increases serotonin levels and lowers blood pressure, both of which keep you calm and collected. Pass the avo toast, please.

RELATED: How to Quickly Ripen an Avocado in 4 Easy Ways

PEPPERS

Foods rich in vitamin C can help stop the production of the stress hormone cortisol. Yellow peppers have the most, followed by red and green. Slice these guys and pack them in a snack baggie for a mid-afternoon pick-me-up. 

RELATED: 6 Breakfasts That Are Scientifically Proven to Put You in a Good Mood