Foods Good for Mental Health and Blood Sugar

Making the effort to eat right, exercise and control your blood sugar is much easier when your mental health is thriving. What you eat and drink affects not only your physical health, but your mood as well. Choosing foods scientifically proven to promote good mental health could help get you back on track when you feel low, or just "off," and maintain your progress.

How Can Mental Health Affect Blood Sugar Levels? 

A common side effect of depression is low or irregular appetite. You may skip meals throughout the day, which increases the likelihood of overeating later. It is difficult to maintain stable blood sugar levels if you are swinging between no food and lots of food. 

When you have a low mood and your appetite is sporadic, you may even forget to eat. To mitigate this risk, try using an alarm or reminder on your phone to prompt you to eat at regular intervals. 

Stress and Blood Sugar 

Your stress levels contribute to your mental health. When you are stressed, your body releases stress hormones (just like in a fight-or-flight situation) until the source of your stress goes away. These hormones are epinephrine, cortisol, glucagon, and insulin¹. 

When you experience chronic stress, you experience chronic activation of your fight-or-flight response.² Overexposure to these stress hormones can disrupt digestion, sleep, cognition and your mood³. 

<p class="pro-tip">Read more about stress and blood sugar</p>

Gut Health Is Linked to Mental Health 

The gut and digestive systems are often referred to as the second brain, due to the gut-brain axis⁴. This sophisticated connection is still being studied, but we do know that a well-nourished gut is linked to a happy and healthy brain.⁵

Foods that May Support Mental Health 

Foods that nourish the gut and support a healthy brain also align with a diet plan for blood sugar control. All of these foods are high in fiber, low in added sugars, and can contribute to mental health and stable blood glucose levels.

1. Fatty fish 

Polyunsaturated fats (PUFA) are currently the most researched fats linked to improved mental health⁶. Evidence from studies suggests that the Mediterranean diet (which is rich in PUFAs) supports mental health and can help stabilize blood sugar. 

Fatty fish contain omega-3 fatty acids (a type of PUFA). Salmon, mackerel, herring, and sardines contain DHA and EPA⁷. These forms of omega-3 fatty acids are the most bioavailable and easy to absorb. DHA and EPA omega-3s have also been linked to decreasing inflammation in the body and promoting heart health.  Other sources of healthy fats include olive oil, avocado, seeds, nuts, and nut butters.

2. Unsalted nuts & seeds 

If you’re vegetarian, vegan or just don’t like fish, nuts and seeds also contain PUFAs. Incorporate a variety of seeds, tree nuts, and nut butters into your diet because they all offer different vitamins and minerals. Brazil nuts are rich in selenium, which may reduce your risk of feeling symptoms of depression⁸. You only need  1-3 brazil nuts per day to satisfy your selenium requirements. 

Walnuts and chia seeds are naturally rich in ALA omega-3 fatty acids, another form of PUFAs. ALA is less absorbable than DHA or EPAs, but they should all be included for a balanced diet. Walnuts and chia seeds offer small amounts of protein, but they are rockstars in the fiber department.  Sprinkle them on your oatmeal or on a salad at lunch. 

<p class="pro-tip"><strong>Learn about </strong><a href="/blog/omega-3-fish-oil-weight-loss">omega-3 fish oil and weight loss</a></p>

3. Fresh fruit & vegetables 

Fruits and vegetables are rich in fiber to nourish your gut, possess antioxidants to neutralize harmful free radicals, and many fruits are low on the glycemic index. Citrus fruits contain folate and folic acid, and are low on the GI scale. A folate deficiency may contribute to feelings of depression⁹. More research is required, but studies have shown low levels of folate impair the production of serotonin¹⁰, a neurotransmitter that regulates your mood and more¹¹. Aim to include a variety of colorful produce; the more diversity the better. Learn more about the benefits of eating colorful produce. 

4. Whole grains such as oatmeal, quinoa, barley, and millet  

Whole grains can be served as a side or featured as the star ingredient in your dish. These high-fiber grains can also be prepared in large batches and eaten slowly throughout the week, which relieves you of cooking every day. 

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5. Iron-rich foods 

Symptoms of low iron can include low mood, inability to focus, low tolerance for cold, pale skin, and hair loss¹². If you suspect your iron levels are low, ask your doctor for a blood test. You should include animal or plant-based, iron-rich foods into your diet throughout the week to maintain your iron stores. Foods rich in iron include red meat, poultry, fish, eggs, beans, and dark leafy greens like spinach¹³.

6. Fermented Foods

Naturally fermented foods (that are low in sugar) including yogurt, kombucha, sauerkraut, kimchi, and other pickled vegetables can help stabilize blood glucose levels, which may impact your mood. Fermented foods also have probiotics, helpful bacteria that may contribute to positive mental health through their effect on your gut microbime¹⁴.

7. Dark Chocolate

Dark chocolate (with at least 50-90% cocoa solids) contains ​​cocoa flavanol, an antioxidant molecule shown to have a positive effect on mood and cognitive ability¹⁵. Dark chocolate also has phenylethylamine, a neurotransmitter linked to improved mood and alertness¹⁶.

<p class="pro-tip">Read more about high-fiber low-carb foods</p>

Foods to Avoid for Mental Health 

Your brain thrives on high-quality fuel, such as  complex carbohydrates from whole foods. Refined carbs and highly processed foods can spike your blood sugar, contribute to inflammation, and interfere with quality sleep - all of which can harm your mood and mental health¹⁷.

Foods to limit or avoid include: 

• Caffeine and alcohol can both interfere with quality sleep and neurotransmitter function^18.
• Ultra-processed carbs (candy, chips, french fries, crackers, and baked goods made with white flour)  
• Sugary drinks, including soda, fruit juice, energy drinks, sweetened smoothies, and specialty coffee drinks. 
• Fried foods can be difficult to digest, which may lead to imbalances in your gut microbiome¹⁹.

Food, Mental Health & Blood Glucose: Takeaway

Following the nutrition guidelines above is a great place to start to help stabilize your blood glucose and promote mental health. Incorporating regular physical activity is another way to boost your mood, reduce stress, and control blood sugar. 

If you’re interested to learn more about how blood sugar levels could be impacting your mood, you may benefit from experimenting with a continuous glucose monitor (CGM).

<p class="pro-tip">Learn more about getting started with a CGM from Signos</p>