Food and mood are so intricately connected that they've inspired a new area of brain study: Nutritional psychiatry, which examines how what we eat impacts how we feel.

As a dietitian and nutritionist who has researched and experienced this connection firsthand, I find it infinitely fascinating that we can empower ourselves to feel partly — or sometimes entirely — better based on our dietary habits.

The foods you eat can make or break everything from your work and productivity to your mental state and physical health. To boost your mood and brain energy levels, put these 35 foods on your grocery list:

Complex carbs

1. Pumpkin seeds
2. Apples
3. Chickpeas
4. Strawberries
5. Oatmeal

Complex carbs pack in more nutrients than simple carbs and, due to their higher fiber content, take longer to break down.

They also help stabilize blood sugar levels, which can stabilize your mood. Fluctuations in blood glucose can cause your mood to change rapidly, leaving you irritable, low on energy and feeling downright dreadful.

Lean protein

6. Eggs
7. Salmon
8. Lentils
9. Chicken
10. Lean beef

Protein is necessary for healthy energy levels. It takes longer to digest than carbs, keeping your blood sugar balanced and providing lasting energy.

It also affects hormones that control satiety, so when you eat enough of it, you can ward off "hanger."

Amino acids, which are the building blocks of protein, help repair and replenish tissue — and your body needs them to make certain neurotransmitters.

Healthy fats

11. Avocados
12. Olives
13. Tofu
14. Dark chocolate
15. Sardines

Omega-3 fatty acids are part of cell membranes, particularly in the brain, and eating foods like salmon and sardines has been shown to ease depression and boost mood.

Beyond omega-3s, the unsaturated fats found in foods like avocados, olives and nuts may help keep inflammation at bay and reduce blood pressure, which are important for brain health.

Eating enough healthy fats helps your immune system, too.

Folate

16. Spinach
17. Asparagus
18. Brussel sprouts
19. Pomegranates
20. Shellfish

Folate plays a role in the production of dopamine and impacts other mood-related neurotransmitters, helping you keep calm and carry on.

It has also been shown to help prevent neural tube defects, support cell growth and repair, and regulate sleep patterns, especially as you age.

A deficiency in folate levels has been linked to a number of brain issues, including dementia and depression.

Iron

21. Potatoes
22. Turkey
23. Cashews
24. Kidney beans
25. Quinoa

Low iron can cause fatigue and depression. The proteins found in iron also help maintain healthy brain function and development.

Consuming too much or not enough of this mineral can impact both your innate and adaptive immune functions. When you have healthy levels of iron and use it effectively, harmful bacteria can't use the mineral for growth.

And certain white blood cells fight off infection by carefully managing their iron levels.

Vitamin C

26. Oranges
27. Lemons
28. Kiwi
29. Bell peppers
30. Tomatoes

Vitamin C is an antioxidant that assists the body's ability to make neurotransmitters, including dopamine and serotonin, which both work to stabilize mood.

Your body needs vitamin C to maintain and repair all tissues, so it helps wounds and cuts heal. Plus, your adrenal glands require vitamin C to make stress hormones, including cortisol. The more stressed you are, the more cortisol you produce — and the more vitamin C you need.

Melatonin

31. Tart cherries
32. Grapes
33. Barley
34. Broccoli
35. Pistachios

Tryptophan, as well as nutrients like calcium and vitamin B6, help you produce melatonin, but you can also get this "sleep hormone" from the foods listed above.

Melatonin doesn't have a soporific effect. Instead, it shifts you into a state that helps you ease your way toward sleep. Eating foods rich in melatonin before bedtime can help you take full advantage of the natural increase in this hormone that happens in the evening.

Patricia Bannan, MS, RDN, is a dietitian, nutritionist, chef and author of "From Burnout to Balance: 60+ Healing Recipes and Simple Strategies to Boost Mood, Immunity, Focus and Sleep." She has been featured in The Oprah Magazine, Shape, Health, Parenting and Good Housekeeping. Patricia received her master's degree in nutrition from the Friedman School of Nutrition Science and Policy at Tufts University. Follow her on Twitter and Instagram.

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