Eating Enough Vegetables Promotes Well-Being and Happiness, Study Says

Vegetables and fruits
Vegetables and fruits.

Monticello / Getty Images

Key Takeaways

  • The USDA Dietary Guidelines recommend that adults eat fruits and vegetables daily.
  • A new study found that adults who eat at least three servings of vegetables per day score better on the Subjective Happiness Scale.
  • The research suggests that following the USDA Dietary Guidelines for vegetables may help promote happiness and psychological well-being.

Vegetables contain a variety of nutrients that support overall physical health. A new study published in the Journal of the Academy of Nutrition and Dietetics suggests that beyond physical health, vegetables can promote good mental health as well.

"Vegetables contain myriad micronutrients such as zinc, magnesium, folate, and iron, which are critical for optimal mental function," says Isa Kujawski, MPH, RDN, a dietitian in DC. "They also contain antioxidants that protect the body against oxidative stress, which has been associated with depression and anxiety."

About the Study

In the new study, researchers wanted to see if they could detect an impact on happiness and psychological well-being based on the number of vegetables that people consume. To test this, researchers recruited 75 participants between the ages of 18 and 65, who habitually had low vegetable intake. They were split into test and control groups.

For 8 weeks, the test participants were given a selection of fresh or frozen vegetables, and were guided to consume the amounts recommended in the Dietary Guidelines—about two to four servings per day, based on their usual calorie levels. This intake was more than they habitually consumed while the control group ate their usual diet.

The researchers used the Subjective Happiness Scale (SHS) to assess happiness both before and after the 8-week study. The SHS uses four questions for participants to self-report their happiness level based on questions to measure their level of happy versus depressive symptoms.

Elizabeth Barnes, MS, RDN, LDN

It is not surprising that eating more vegetables might make you feel happier. Vegetables provide your body with needed vitamins, and nutrients, fiber. 

— Elizabeth Barnes, MS, RDN, LDN

The study results showed that increasing vegetable consumption to meet recommendations in the USDA Dietary Guidelines can improve mean SHS scores.

"SHS scores increased when the amount and type of vegetables recommended by the Dietary Guidelines were consumed," says Shanon Casperson, PhD, DTR, a research biologist at the Grand Forks Human Nutrition Research Center, USDA-Agricultural Research Services, and one of the researchers on this study.

The participants were given a selection of more than 30 vegetables to choose from, and Dr. Casperson explains that the researchers were unable to identify if one vegetable is better than any other based on this research. It was recommended that participants select green, red, and orange vegetables daily, per USDA Dietary Guidelines.

"Each participant in this study ate two to three servings of vegetables every day," says Dr. Casperson. "They were given the freedom to pick the vegetables they wanted to eat from each of the required vegetable subgroups. It is important to eat a wide variety of vegetables from all the colors of the rainbow each week."

These results confirm what many food and nutrition experts have suspected—that nutritious eating can have a broad impact on a person.

"It is not surprising that eating more vegetables might make you feel happier," says Elizabeth Barnes, MS, RDN, LDN, a dietitian and the owner of Weight Neutral Wellness. "Vegetables provide your body with necessary vitamins and fiber. "

Why Vegetables Promote Happiness

Dr. Casperson's research paper notes that the vitamins and phytochemicals in vegetables have antioxidant and anti-inflammatory effects, which can positively impact psychological well-being. However, she notes that more research is needed to fully understand the impact of eating vegetables on psychological well-being.

"There are some nutrients as well as behavioral mechanisms that may help explain the effect of vegetables on psychological well-being," says Dr. Casperson.

Isa Kujawski, MPH, RDN

Vegetables contain myriad micronutrients such as zinc, magnesium, folate, and iron, which are critical for optimal mental function. They also contain antioxidants that protect the body against oxidative stress, which has been associated with depression and anxiety.

— Isa Kujawski, MPH, RDN

Barnes also gives a nod to the antioxidant effect, citing vitamin C as one beneficial nutrient that may help regulate neurotransmitters like serotonin and dopamine, which are involved in mood regulation. Barnes also says that the B-vitamins in some vegetables may play a role in your mood. 

"The folate that dark green leafy vegetables contain is necessary for making serotonin and dopamine, which act as mood stabilizers," says Barnes.

And Kujawski suggests that some of the helpful mechanisms that connect vegetables with happiness may be due to fiber.

"When you eat vegetables, you're supplying your body with dietary fiber, which feeds beneficial gut bacteria that works to strengthen the lining of the gut," says Kujawski. "A strong gut lining is important, as increased intestinal permeability may trigger the immune system and promote
depressive symptoms."

Fiber also may help lower inflammation, which may influence neurotransmitter concentrations and lower depressive symptoms, Kujawski explains.

Barnes adds that beyond the nutrients in vegetables, doing things that you know are good for your body makes you feel better. It's well-known that vegetables promote wellness, so the simple act of choosing a healthy habit may improve well-being.

Do Fruits Also Promote Happiness?

The present study only looked at the association between vegetables and happiness but did not assess the effects of fruits. Is it possible that fruit may have the same impact?

"This is an interesting question and one that researchers are beginning to ask," says Dr. Casperson. "There is currently not enough research in this area to fully understand the differential impact of vegetables and fruits on psychological well-being or subjective happiness in particular."

Kujawski believes it is possible that fruits could have the same impact.

"Fruits, although higher in sugar than vegetables, are also very high in beneficial nutrients, antioxidants, and fiber," she says. "A good rule of thumb is to stick to 75% veggies and 25% fruits."

Happiness is Multi-Faceted

Your overall nutrition and meal plan also matter. While studies like this one show that eating more vegetables is beneficial for your mental health, it is also important to limit foods that may be detrimental to your well-being.

"Adding vegetables to your 'feel better' strategy is a great idea," says Barnes. "Just don't make it the only component."

Barnes advises her clients to improve their happiness by getting enough sleep, practicing mindfulness, and performing deep breathing or meditation to reduce stress. Exercise can help boost mood as well.

Studies also show that eating a lot of ultra-processed foods, which are high in sugar, salt, fat, additives, and preservatives, is associated with a greater risk of depression. Eating more vegetables may reduce consumption of ultra-processed foods, thus reducing depressive symptoms.

What This Means For You

The USDA Dietary Guidelines recommend consuming 2 to 4 servings of vegetables a day. Eating more vegetables may help you consume fewer ultra-processed foods, plus the vegetables provide fiber, vitamins, and antioxidants that may help promote happiness and help combat some depressive symptoms. If you need help incorporating more vegetables into your eating plan, talk to a healthcare provider or a registered dietitian.

5 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. De Leon A, Jahns L, Roemmich JN, Duke SE, Casperson SL. Consumption of Dietary Guidelines for Americans types and amounts of vegetables increases mean Subjective Happiness Scale scores: A randomized controlled trialJournal of the Academy of Nutrition and Dietetics. Published online November 2021:S2212267221014866. doi:10.1016/j.jand.2021.11.009

  2. USDA and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025.

  3. Pullar JM, Carr AC, Bozonet SM, Vissers MCM. High vitamin C status is associated with elevated mood in male tertiary students. Antioxidants (Basel). 2018 Jul 16;7(7):91. doi: 10.3390/antiox7070091

  4. Swann OG, Kilpatrick M, Breslin M, Oddy WH. Dietary fiber and its associations with depression and inflammation. Nutr Rev. 2020 May 1;78(5):394-411. doi: 10.1093/nutrit/nuz072

  5. Pagliai G, Dinu M, Madarena MP, Bonaccio M, Iacoviello L, Sofi F. Consumption of ultra-processed foods and health status: a systematic review and meta-analysisBr J Nutr. 2021;125(3):308-318. doi:10.1017/S0007114520002688

By Cara Rosenbloom, RD
 Cara Rosenbloom RD is a dietitian, journalist, book author, and the founder of Words to Eat By, a nutrition communications company in Toronto, ON.