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

A serving of nuts a day could help keep depression at bay.

According to new research, a serving of nuts (30 grams) per day is associated with a 17% reduced risk of depression.

A small handful of nuts, or 30 grams of nuts, equals about:

The findings of the study were published July 26 in the journal Clinical Nutrition,

For the study, researchers examined data from the UK Biobank cohort, an online database of medical and lifestyle records.

From this database, over 13,500 Britons without self-reported depression or antidepressant use aged 37-73 between 2007 to 2020 were included in a comparison analysis.

People in the study who consumed a serving of nuts daily were less likely at follow-up roughly five years later to have developed depression.

The findings do not clearly indicate why nuts were associated with this reduced risk.

However, researchers and experts speculate protective nutrients in nuts play a role.

Their results also suggest the likelihood of developing depression is also lower among adults in the United Kingdom with healthy weight, healthy lifestyle, and overall general health.

“Emerging research is uncovering the profound influence of our dietary habits on our mental health, particularly pointing to a strong gut-brain connection,” said Kelsey Costa, 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,” said Dr. Gabrielle Lyon, a functional medicine practitioner, founder of Muscle Centric Medicine, and author of the 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,” Costa said.

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

Walnuts 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,” Costa said.

“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 added.

One observational 2023 sudy found that omega-3 supplementation was associated with significant improvement in symptoms of depression in people with mild to moderate depression.

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

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.

Research suggests tryptophan’s antidepressant-like effects may come from its positive impact on neuroinflammation, chronic stress, and dysregulation in the gut microbiota.

Lyon added that beyond tryptophan, there are other amino acids that may have an impact on mood. These include serine, glutamine, and arginine.

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

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,” Costa said.

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

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

Moreover, in addition to being high in fiber, Lyon explained that 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,” Lyon said.Costa also highlighted 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.

Here, our experts share some tips for consuming nuts to give your mental health a boost.

“Often on the shelves we find nuts that are roasted in seed oils, excessively salted, or artificially flavored,” Lyon said.

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.

According to Lyon, “nuts are a calorie-dense food choice, so serving size is important.

“It is very easy to go over your maintenance level of calories if you enjoy nuts, which may lead to unintentional weight gain,” she said.

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 added 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 said.

Costa offered a few ways to incorporate more nuts into your diet each day.

Lastly, Costa said 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.