Grapes have been cultivated for many centuries and have long been enjoyed as a fruit, in winemaking and many other products. Grapes are rich in health-protective compounds in the polyphenol family, such as flavonoids and resveratrol, which can reap many health benefits.¹ This includes improving your mental health and having relaxing effects on body.

Grapes and health

The grape (scientifically termed Vitis spp.) is grown primarily in temperate regions, with warm weather, rain, and gentle winters.¹ As a result of changing climates, the UK now has several hundred vineyards. 

 Grapes are rich in flavonoids, which make them rich in antioxidants helping us protect our hearts, reduce inflammation, stave off disease and even reduce the chances of developing cancer.¹ It is thought that the high consumption of red wine, rich in these flavonoid compounds, reduces the rate of cardiovascular disease in the Mediterranean region.¹

Specific types of grape flavonoids, called anthocyanins, have been found to have a considerable beneficial effect on the brain and central nervous system, reducing inflammation and oxidative stress (i.e. a state that leads to cell and tissue damage), and preventing neurodegeneration.¹ Flavonoid consumption can also improve memory function, particularly in older adults.¹

Flavonoids belong to a group of plant compounds called polyphenols, which are associated with many health benefits. Along with flavonoids, the polyphenol resveratrol is found in abundance in the skin of dark grapes. Resveratrol has been found to confer many benefits on the body. In animal models, resveratrol was found to alleviate symptoms of depression.² But what about in humans? Let's explore a bit more about this.

Grapes for mood enhancement and relaxation

In one study, healthy young adults given purple grape juice had significantly improved mood as well as cognitive performance, compared to a group of healthy young adults given a low polyphenol drink.³ Ratings of calmness increased considerably from before and after the experiment, as did speed on tasks testing their levels of attention.³

In another study comparing fresh and fermented varieties of grape skins, it was found that the fermented extracts (as are created during the production of wine) were very rich in polyphenol products. The fermented extracts created more of a ‘vasorelaxant effect’ (a reduction in the tension of blood vessel walls, causing them to widen) compared to the non-fermented extracts.⁴ This effect can increase the delivery of oxygen and nutrients to the cells and tissues of the body. However, further research is needed to verify this and the exact effects of fermented grape skin extracts on mood enhancement and relaxation. 

A 2022 systematic review amalgamated the evidence for the impact of interventions involving grapes on mental performance and cognition, comparing healthy individuals to those with mild cognitive impairment.⁵ Seven studies were found to assess mood, depression and anxiety related outcomes. Only two of these studies showed significant improvements, one in mood (including reduced symptoms of depression and anxiety) after supplements of grape, and the second in increasing levels of calmness. This again highlights the need for more research in the area. 

Mechanism of action

Many models have been proposed to explain exactly how the powerful compounds in grapes confer such benefits to health and mood. Some of the prevailing theories are listed below but further research is required to elucidate the exact processes:³

• Increased cerebral blood flow – in other words, a higher volume of blood flowing to the brain in a unit of time
• Inhibition of the activity of an enzyme called monoamine oxidase type B (MAO-B), which breaks down a neurotransmitter called dopamine responsible for feelings of pleasure, motivation and satisfaction. By inhibiting the breakdown of MAO-B, resveratrol may be having positive effects on mood and cognition 
• Creating an anti-inflammatory effect, inhibiting factors involved in the cycle of inflammation (known as pro-inflammatory markers), such as nitric oxide (NO) and interleukins (ILs)⁶

Research limitations

To understand the underlying biological mechanisms of grapes and be able to measure the mental health outcomes of grape consumption, further investigation into correct dosing of polyphenol compounds (for example, from dietary supplements) is important to consider.⁷

Robust clinical trials are needed to understand how and to what extent polyphenols enhance mood and reduce the symptoms of common mental health conditions like depression and anxiety. These trials need to specify the exact concentrations of polyphenols being provided in the intervention (for example, the concentration of flavonoid), to be able to produce more accurate results. 

There is no conclusion as to how long the grape intervention needs to be to produce positive effects on mood, mental health and relaxation. There is also no clear view of how the interventions may affect different subpopulations (different sexes, ages, and ethnicities, for example).⁵

FAQs

Do grapes improve mood?

Grapes contain compounds (such as resveratrol) that are neuro-protective and can boost brain health. These compounds can reduce inflammation and confer many other health benefits that can improve overall mood. 

Which colour grape is the healthiest?

Generally, the darker the grape, the more antioxidants it has to fight off diseases and improve cellular and tissue health. Black grapes are the richest course of health-boosting compounds, called polyphenols, but the skin of red grapes is another rich source.

Are grapes good for stress?

Grapes contain polyphenol compounds that have been associated with reduced levels of stress, anxiety and depression, and better cognitive function and synaptic plasticity (adaptive changes that occur at the connections – or synapses – between neurons/brain cells).

What do grapes do for your brain?

The polyphenols in grapes could increase the circulation of blood to the brain and reduce oxidative stress. They could also reduce inflammation and relax blood vessels.

Summary

Grapes have been grown and harvested for many centuries in many places across the world. Many grape-containing products have been produced, from wine to juices, jellies, and nutritional supplements. There is a high concentration of plant compounds called polyphenols, including resveratrol and flavonoids, particularly in the skin of darker grape varieties. These confer many health benefits, including enhancing cognition, mood, and cardiovascular health. Grape interventions have been found to increase levels of calmness, in one study. Whilst there are promising results so far, few studies provide statistically significant results on the impact of grape compounds on mood and relaxation levels. Further research is needed to clarify this link, and to understand the exact mechanisms of action in the body.