While conversations about depression tend to center on the brain, the gastrointestinal system has a strong effect on our mental health. Within our gut is a massive ecosystem made up of thousands of distinct microbiotic species.

When the microbiome is in balance, it helps the body by supporting the immune system and extracting important nutrients from food. Stress, illness, and eating the wrong foods can kill off beneficial microbes and feed unhelpful ones.

Researchers are still learning about the connection between the gut biome, the brain, and depression. However, there is increasing evidence that an overabundance of inflammatory microbes is linked to depression.

When the GI tract is in distress, it sends out pain signals to the brain and triggers anxiety. Likewise, emotional stress can interfere with digestion and cause systemic inflammation.

Gut inflammation is also a side effect of our dietary choices. Eating high-fat and processed foods disrupts the natural gut flora and increases inflammation throughout the GI tract. This can amplify the distress signal fired off to the brain and worsen depressive symptoms.

Components of the Mediterranean diet, which includes fresh fruits, vegetables, and lean proteins, can reverse this inflammation.

One reason why the Mediterranean diet is so powerful is that it contains multiple superfoods, which are ingredients that are rich in anti-inflammatory nutrients and vitamins.

Switching to a completely Mediterranean diet is the most effective way to reduce depressive symptoms. Still, changing your eating habits all at once is not easy. You can start by adding more nutrient-rich foods to your diet. Here are ten of the best depression-fighting ingredients you can incorporate into any meal of the day.

1. Whole grains

whole grain toast

Whole grain products, like cereals and breads, retain all parts of the grain, including the nutrient-dense bran. As a result, whole grains contain higher levels of dietary fiber than refined grains.

Dietary fiber makes the gut biome more hospitable for anti-inflammatory microbes, like Lactobacillus. Studies suggest that these changes can modulate the stress response and lower the risk of depression.

Most people don’t eat enough dietary fiber. One study found that boosting fiber intake to 50g per day can positively change the gut biome within a couple of weeks.

Replacing refined products like white bread and white rice with 100% whole-grain options is one way to increase intake. Other sources of dietary fiber include:

  • Whole wheat bulgur
  • Couscous
  • Millet
  • Steel-cut oats
  • Whole cornmeal
  • 100% whole-grain versions of breakfast cereals
  • Flax, sourdough, oat, and rye bread

Bulgur wheat and millet can be boiled and served with steamed mixed vegetables. You can also eat bulgur and couscous cold as a salad.

2. Berries

berries blueberries raspberries on spoon

These fruits of the forest are exceptionally rich sources of brain-boosting nutrients given their small size. Berries are packed with inulin, a type of dietary fiber that doubles as a prebiotic. This means that it supports the growth of healthy gut microbes.

Berries also contain polyphenols, which are active antioxidants. They boost gut function and help foster a diverse microbiome. While all berries, fresh or frozen, offer impressive health benefits, blueberries stand out for their antidepressant properties.

Nutritional psychiatrist Dr. Uma Naidoo notes that the anthocyanins that give blueberries their deep color also reduce inflammation in the brain. She recommends eating at least half a cup of blueberries every day to reap the most benefits.

Here are a few ways to add berries to your meals:

  • Blend fresh or frozen berries with yogurt, low-fat milk, and a banana into a smoothie
  • Sprinkle fresh blueberries on top of whole-grain oatmeal or cereal
  • Mix chopped berries with coconut milk and freeze in an ice cube tray

3. Fermented foods

fermented food

While processed foods are usually a no-no for gut health, fermented foods are an exception to this rule.

Fermentation is a natural process that uses microbes to transform macronutrients like sugars into other components. During this process, some foods generate pre-and-probiotics, which can help balance the gut microbiome.

Here are some fermented foods you can add to your diet:

  • Kimchi
  • Sauerkraut
  • Yogurt
  • Sugar-free kombucha
  • Tempeh

Researchers are investigating the link between eating fermented foods and depression symptoms. A 2019 study tracking more than 25,000 people found that higher fermented vegetable consumption was linked to fewer depressive symptoms.

You can find pre-made fermented products at the store, or pickle your own vegetables at home.

  1. Chop up your favorite veggies and put them in a jar.
  2. Add seasoning to your taste and then fill the jar with a 1:1 ratio of boiling vinegar and water.
  3. Sprinkle in a tablespoon of sugar and close the lid tightly.
  4. After the jar cools down, place it in the fridge.
  5. Home-made fermented vegetables can last up to two months.

4. Nuts

nuts

Due to their high fiber and polyphenol content, nuts are one of the most gut-friendly snacks. Some types of nuts also have high concentrations of important vitamins.

  • Walnuts: Fatty acids such as alpha-linolenic acid and polyunsaturated fatty acids
  • Almonds: High levels of vitamin E, protein, and dietary fiber
  • Cashews: Rich source of zinc
  • Peanuts: Contain resveratrol, an anti-inflammatory and antioxidant compound
  • Hazelnuts: Packed with folate, which supports intestinal health

Eating all types of nuts can promote a healthy gut. However, a 2019 study found that nut mixes with walnuts are the most effective at reducing depressive symptoms.

Still, with nuts, there can be too much of a good thing. Nuts are calorie dense, so eating too many can cause weight gain. Store-bought nuts with added sugars and salt can also have a negative effect on health. It’s best to eat a variety of natural nuts and limit portion sizes to under 40g per day.

5. Cruciferous vegetables

cruciferous vegetables

Cruciferous vegetables are part of the large Brassicaceae plant family. These delicious veggies fall under three main categories:

Cabbages

  • Bok choy
  • Cauliflower
  • Savoy Cabbage
  • Broccoli
  • Kale

Green leafy vegetables

  • Collard greens
  • Watercress
  • Arugula

Root fruits

  • Rutabaga
  • Turnip

Cruciferous vegetables contain glucosinolates that produce an anti-inflammatory byproduct when ingested. Several studies have noted glucosinolates' neuroprotective and antidepressant effects. Unfortunately, when cruciferous vegetables are boiled, it can remove some of the glucosinolates and make them more difficult for the body to absorb.

Steaming or roasting vegetables like broccoli, cauliflower, and root fruits keep the powerful glucosinolates intact.

6. Fatty fish

salmon fatty fish

Protein in the Mediterranean diet comes primarily from fish and seafood. Fatty fish species, like salmon, herring, and tuna, are especially beneficial for brain health.

Unlike beef, fatty fish are a rich source of omega-3s, a type of fatty acid that the body needs, but cannot produce itself. Omega-3 fatty acids contain the building blocks for important hormones that regulate the cardiovascular system.

Omega-3 can also cross the blood-brain barrier and modulate neurotransmitter release and function. For this reason, increased omega-3 consumption can reduce and prevent anxiety and depression symptoms.

Most adults need between 1 to 1.6g of alpha-linolenic acid (ALA), a special type of omega-3, per day. Experts recommend eating at least two 110g servings of fatty fish per week combined with other brain foods like walnuts and flaxseed to obtain optimum ALA levels.

Here are a few low-effort ways to consume fatty fish:

  • Breakfast: Smoked salmon and cottage cheese on toast
  • Lunch: Chunk light tuna fish and lettuce wrap
  • Dinner: Mackerel seasoned with lemon and dill baked in aluminum foil

7. Sweet potato

sweet potato

While the sweet potato is not a traditionally Mediterranean ingredient, it is a more nutritious replacement for the starchy, white potatoes that are staples of the typical Western diet. Sweet potatoes are a more significant source of Vitamin A due to the presence of beta-carotene.

Sweet potatoes also contain a special type of carbohydrate known as oligosaccharides that promote healthy gut flora. While the body cannot digest these sugars, they serve as a food source for helpful GI bacteria.

Sweet potatoes also contain vitamin B6, which helps the brain synthesize serotonin. Purple sweet potatoes, a variety originating from Indonesia, contain amino acids that can act as antidepressants.

Sweet potatoes can be used instead of white potatoes in the following ways:

  • Mashed
  • Cut up into fries and oven roasted
  • Baked

8. Citrus fruits

citrus fruits

The citrus family contains many popular fruits, including oranges, grapefruits, lemons, and mandarins. What sets them apart from other fruits is the presence of chemical compounds known as flavonoids.

The flavonoids in citrus fruits have prebiotic properties. By feeding helpful bacteria and reducing less helpful ones, citrus fruits can keep the gut microbiome in balance. Citrus fruits also contain antioxidants that protect cells against oxidative stress and reduce inflammation.

Neuroscientist Dr. Lisa Mosconi, author of the book Brain Food, recommends fortifying water with citrus fruit slices to reap the nutritious benefits without consuming too much sugar or calories. Freshly peeled mandarins or tangerines can also serve as a tasty, mood-boosting, snack.

9. Legumes

legumes

Legumes, which include lentils and beans, are one of the most varied categories in the Mediterranean diet. They taste great as a side dish for brown rice or blended into dips and stews. Legumes contain several important nutrients, including protein, potassium, and magnesium.

In relation to brain health, legumes have a notable effect on depression susceptibility. One study found that in people with healthy diets, legume consumption had the largest effect on preventing depression. Researchers believe this effect comes from the high levels of tryptophan, a precursor to serotonin, and dietary fiber in legumes.

Legumes are also packed with bioactive peptides, which help the digestive system function properly and protect the intestinal tract against irritating toxins.

Legumes can come canned or dried. While both are beneficial, the canning process removes some of the nutrients and can add sodium. Draining and rinsing canned legumes under cold running water can wash away up to a third of the sodium content.

10. Low-fat dairy

low fat dairy

When it comes to dairy, monitoring the fat content is key. Low-fat options like cottage cheese, yogurt, and the fermented milk product kefir, offer a high level of nutrients without excessive levels of saturated fats.

Many low-fat dairy products are probiotics, which means they contain live bacteria cultures that can benefit the gut microbiome. This includes strains of Lactobacillus and Bifidobacterium. At the same time, dairy products help keep levels of pathogenic microbes low.

In addition to supporting GI health, low-fat dairy may also mitigate depression. A study of more than 20,000 adults found that people who consumed low-fat milk experienced fewer depressive symptoms than people who drank whole-fat products.

The Mediterranean diet incorporates several different types of low-fat dairy products including:

  • Unsweetened Greek yogurt
  • Feta cheese
  • Mozzarella
  • Parmesan
  • Ricotta

Hard, low-fat cheeses can top salads, open-faced sandwiches, and whole-grain pasta dishes. However, servings should be under 40g and limited to 2 to 4 times per week.

Eating your way to mental health

It’s easy to overlook the connection between our moods and our diets. Choosing foods that support a healthy gut ecosystem can make a notable impact on your stress levels and depressive symptoms.

If you need more inspiration, check out the brain food meal plan, complete with recipes, in our post Brain foods for depression.

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