Eating Small Daily Handful of Nuts Linked to Lower Risk of Depression

Thirty grams of nuts is equivalent to about a small handful or 20 walnuts halves, 20 almonds, 30 pistachios or 15 cashews.

“Emerging research is uncovering the profound influence of our dietary habits on our mental health, particularly pointing to a strong gut-brain connection,” says Kelsey Costa, MS, RDN, a registered dietitian and nutrition consultant for the National Coalition on Healthcare.

“These findings underscore the potential of our dietary choices in steering our mental health, highlighting nutrition’s pivotal role in our psychological wellness,” she tells Healthline.

However, it is important to highlight that this is a prospective study that watches for outcomes over a certain period of time.

“As such, results can only establish a correlation (not causation) between factor and outcome,” says Dr. Gabrielle Lyon, a functional medicine practitioner, founder of Muscle Centric Medicine and author of her forthcoming book, “Forever Strong: A New, Science-Based Strategy for Aging Well.”

The cause or etiology of mood disorders is multifactorial and can rarely be reduced to a single factor, she adds.

For example, Dr. Lyon says those individuals who eat more nuts may also engage in other health-promoting behaviors like exercise and good sleep hygiene, which will also decrease their risk for mood disorders.

“While the study does not explore the reasons for the correlation between nut consumption and lower risk for depression, nuts’ anti-inflammatory and antioxidant properties may contribute to the observed benefits,” says Costa.

“The substances in nuts can help our body better manage stress, improve our gut health, and promote brain health,” she explains. “Hence, eating nuts could be a helpful dietary strategy for preventing and managing depression.”

Walnuts and omega-3s

Walnuts, for example, are known for their high omega-3 content and are of notable interest when studying depression.

“Omega-3s, integral to brain function and development, exert anti-inflammatory and antioxidant effects, potentially alleviating depression risk,” explains Costa.

“By influencing the creation and performance of mood-regulating neurotransmitters, such as serotonin and dopamine, regular consumption of omega-3-rich walnuts may aid in mood improvement and decrease depression symptoms,” she adds.

One observational study from 2023 found Omega-3 supplementation was associated with significant improvement in symptoms of depression in people with mild to moderate depression.

Cashews and tryptophan

“Cashews have also gained attention for their potential to alleviate depressive symptoms due to their high tryptophan content,” Costa tells Healthline.

Experts say tryptophan is an amino acid that serves as a precursor to serotonin, which may enhance mood and potentially reduce depression rates as well play a role in sleep regulation.

Studies suggest tryptophan’s antidepressant-like effects may come from its positive impact on neuroinflammation, chronic stress, and dysregulation in the gut microbiota. Lyon adds that beyond tryptophan, there are other amino acids that may have an impact on mood. These include serine, glutamine, and arginine.

Costa adds that more research is needed to fully comprehend the relationship between habitual dietary tryptophan intake and depression.

Almonds and phenolic acids

Almonds are rich in phenolic acids, which have also shown promising results in recent studies for reducing depression-like behaviors. Other nuts with these compounds include walnuts and pistachios.

“These compounds can influence various body systems and functions, including balancing stress responses, aiding in forming nerve cells, and positively affecting gut health—all crucial factors for mental health,” says Costa to Healthline.

Other noteworthy nut nutrients

Lyon says the following nutrients in nuts may also play a role in improving mental and physical health

• Vitamin E: an antioxidant that can help protect brain cells from oxidative stress
• Magnesium: a mineral that plays a role in neurotransmitter function and helps regulate mood
• Monounsaturated and polyunsaturated fats: healthy fat sources that are crucial for maintaining the structural integrity of brain cells and supporting the communication between neurons
• Dietary fiber: supports a healthy gut microbiome

“Both oxidative stress and magnesium deficiency have been implicated in the development of mood disorders, including depression,” she says.

Moreover, in addition to being high in fiber, Lyon explains nuts have a low glycemic index, meaning they don’t cause rapid spikes in blood sugar levels. “Stable blood sugar levels are associated with better mood regulation and lower risk of depressive symptoms,” she says.

However, Costa highlights these nutritional theories are still speculations, showing that our current understanding of exactly how nuts may help reduce depression risk is still in its early stages.

Go for raw

“Often on the shelves we find nuts that are roasted in seed oils, excessively salted, or artificially flavored,” says Lyon. Instead of these highly-processed options, Lyon recommends choosing raw, unprocessed nuts, such as plain almonds, walnuts, macadamia, and brazil nuts to help support brain health.

Consider serving sizes

Nuts are a calorie-dense food choice, so serving size is important, says Lyon. “It is very easy to go over your maintenance level of calories if you enjoy nuts, which may lead to unintentional weight gain,” she tells Healthline.

Costa says a standard serving size is usually one ounce (about 28 grams).

The good news is according to this study, it doesn’t take many nuts to make a difference. Lyons adds that nuts are also relatively high in satiety, meaning they make you feel full and satisfied. “This could potentially help regulate eating behavior and prevent overeating, which might indirectly influence mood as well,” she says.

Get creative

Costa offers plenty of ways to incorporate more nuts into your diet starting today.

• Create a savory nut topping: Rather than traditional breadcrumb toppings to casseroles, baked fish, or roasted vegetables, try a mixture of crushed nuts, herbs, and spices.
• Nut-infused dressings and sauces: Blend nuts with garlic, vinegar, olive oil, and your favorite herbs to create nut-based dressings or sauces for salads and pasta.
• Nutty grain bowls: Add chopped nuts to grain bowls with ingredients like quinoa, brown rice, fresh veggies, and lean proteins to enhance the texture and add a dose of healthy fats and proteins.
• Nuts in homemade granola: Making your own granola with oats, seeds, spices, and a natural sweetener like pure maple syrup or honey gives you control over the ingredients.
• Nuts in stir-fry: Toss a handful of cashews or peanuts into your next stir-fry for a tasty crunch and a boost of heart-healthy fats.
• Add them to your breakfast: Sprinkle nuts over your morning cereal, oatmeal, or yogurt to add a crunchy texture and a dose of healthy fats to your breakfast.
• Blend into smoothies: Add some nuts to your favorite smoothie recipe to get a thick, creamy texture and a boost of protein and healthy fats.
• Include in salads: Nuts can add a satisfying crunch and additional protein to your salads.
• Make a trail mix: Combine your favorite nuts with unsweetened dried fruits, seeds, and dark chocolate for a healthy snack.
• Use nut butter: Nut butter like almond, peanut, or cashew can be spread on whole grain bread, added to smoothies, or used as a dip for fruits and vegetables.

Lastly, Costa says to remember to incorporate a variety of nuts into your diet to benefit from the diverse range of nutrients they offer.

Research suggests eating nuts may help reduce risk of depression in adults. However, it’s not exactly clear the exact reason why. Experts suggest specific nut nutrients may play a role in protecting against depression, although many factors are to be considered in the mental health equation. Incorporating more nuts into your daily diet is one way to support mental wellness.

Nutritional changes are not considered treatment for depression. If you or someone you love is experiencing depression, consider consulting with your healthcare provider or mental health professional.