Grapes' Role In Age-Related Memory Support

Introduction

Grapes are a small but mighty fruit with many health benefits. Have you ever wondered how they can boost your brain health? We have all heard the term ‘brain food’, but are grapes one of them? 

Grapes contain several antioxidants, vitamins and minerals that contribute to healthy ageing through their beneficial effects on brain health and cognitive performance. Research has shown that the antioxidants found in grapes can aid age-related memory support (helping to prevent the decline in our memory as we get older). These findings are important as they show that grapes can be beneficial in preventing a range of diseases, including neurodegeneration, diabetes, and cancer.

This article outlines the nutritional composition of grapes, how to include them in your diet, and the benefits they can give you, such as cognitive health, anti-inflammatory and anti-cancer properties and memory support. Read on to discover how.

Nutritional composition of grapes

Antioxidants in grapes

Antioxidants are chemicals that prevent the oxidation of food when it is broken down in our bodies. Oxidation is a chemical reaction that produces compounds called free radicals (highly reactive molecules). Free radicals damage our cells, and a buildup of free radicals causes oxidative stress in the body, leading to diseases such as Alzheimer’s, heart disease and cancer.^{1, 2, 3}

Diseases caused by free radicals:³

1. Nervous system: Alzheimer’s, stroke, depression 
2. Cardiovascular system: high blood pressure, atherosclerosis (thickening or hardening of arteries, often caused by high cholesterol), cardiomyopathy (when the heart muscle struggles to pump blood around the body, which can lead to heart failure).⁴ 
3. Respiratory system: asthma 
4. Excretory system (kidneys): kidney failure
5. Skeletal system: arthritis
6. Metabolic system: diabetes
7. Other: cancer, inflammation, ageing

Grapes contain several antioxidants, with resveratrol and quercetin being most notable for their health benefits. Resveratrol is an antioxidant found in the skin and seeds of grapes. It has many health benefits, including protection against ageing, diseases associated with ageing, and neurodegeneration. It has also been shown to prevent the growth of cancer cells and reduce inflammation in several parts of the body.

Quercetin is a type of antioxidant known as a flavonoid. Flavonoids are natural substances found in many plants and plant products such as fruits, vegetables, grains, flowers, tea and wine, which have antioxidant, anti-inflammatory and anti-cancer effects. Flavonoids are also responsible for the pigment and aroma of the plants they are found in. Quercetin gives red grapes (and red wine) their colour.⁵

Vitamins and minerals

Grapes are also rich in vitamins and minerals, especially vitamins C, K, and potassium. 

Vitamin C is known for its immune-boosting effects. Consuming grapes can help protect against viruses that are damaging to the brain and could impair our memory. Vitamin C is also important in aiding iron absorption. Iron is involved in many processes in the brain, including oxygen transportation and the production and maintenance of neurotransmitters (the chemicals that communicate messages in the brain). Therefore, consuming grapes contributes to iron levels, which helps keep the brain and our memory functioning normally.⁶

Vitamin K supports bone health and blood clotting.⁷ Blood clots can lead to strokes, which are common in elderly people and can damage any area of the brain, including the area responsible for memory. Eating grapes can help defend against this by preventing blood clot formation.  

Additionally, their high potassium and low sodium content means that grapes help keep blood pressure low and protect against heart disease.⁸ A lower blood pressure also helps to prevent strokes. 

Grapes and cognitive health

Impact of antioxidants on brain health

As previously discussed, antioxidants help reduce oxidative stress. Diseases such as Parkinson’s and Alzheimer’s indicate oxidative stress, and thus, the powerful antioxidant effects of resveratrol reduce oxidative stress and, therefore, the chances of developing cognitive disorders.⁸ Additionally, resveratrol has been linked to increased lifespan due to its stimulation of a specific gene, the SirT1 gene, known as an evolutionary mediator of longevity. This gene is expressed in most body parts, helping to prevent metabolic diseases, cardiovascular diseases and cancer. Most notably, when expressed in the brain, SirT1 regulates neurodegeneration.⁹

There is evidence that quercetin protects the brain against neurotoxins (toxic substances that alter the structure or function of the nervous system) and damage to neurons (the cells of the brain). Neurons can be damaged when the brain suffers an injury, such as a stroke. Damaged neurons can lead to dementia, thus the protective effect of quercetin may help to reduce this risk. 

Anti-inflammatory effects

Inflammation can cause a range of health issues throughout the body, including the brain. Inflammation in the brain damages neurons and speeds up the onset and progression of neurodegenerative diseases. For example, Alzheimer’s is thought to be caused by inflammation in the brain, thus quercetin can help prevent the memory loss associated with Alzheimer’s. 

Studies and research

The Mediterranean diet

Due to the natural occurrence of grapes in Mediterranean countries such as Italy, France and Spain, grapes are a key part of the Mediterranean diet. Many people follow this diet due to its wide-ranging health benefits. This diet has been famed for reducing the risk of Alzheimer’s disease and other dementias due to its positive effects on cholesterol levels, blood sugar levels and overall blood vessel health. In a study on healthy people aged over 40 years old in the USA, it was found that people who consumed more foods in line with the Mediterranean diet had a slower decline in cognitive function, which is a hallmark sign of dementia.¹⁰

Data gathered from over 34,000 participants revealed that people with a more Mediterranean-based diet had a 20% lower risk of developing a cognitive disorder compared to those with a less Mediterranean-based diet.¹¹

Cognitive benefits of consuming grapes

A study on the effect of grapes on human cognition in people with mild cognitive decline found that the compounds found in grapes prevented any further decline in cognition after 6 months, compared to a group who didn’t consume grapes. The grapes group showed a higher metabolic rate in certain brain regions, resulting in improved attention and working memory. The placebo group showed a decline in regions of the brain involved in the early stages of Alzheimer’s.¹² This shows that eating grapes can protect against early stages of cognitive decline. 

Another clinical trial investigated the effect of grape seed extract on cognitive function in older people with cognitive impairment by comparing the effect of 6 months of taking a supplement with a placebo group. The 60-70 year olds with mild cognitive decline who were otherwise healthy showed improvements in their episodic memory (long-term memory of events or experiences).¹³

Mouse models have been used to take a deeper look at the mechanisms of antioxidants against cognitive decline. One study showed that quercetin has an anti-amnesic effect on mice by counteracting a neurotoxin called TMT, which causes severe learning and memory deficits. 

This same study found that quercetin may be effective against Alzheimer’s disease; oxidative stress and a reduced level of the neurotransmitter acetylcholine are both thought to contribute to the onset of Alzheimer’s. Quercetin not only reduced oxidative stress but was shown to boost levels of acetylcholine in the mice.¹⁴

Mechanisms of memory support

Grapes help to protect neurons against oxidative stress, which can cause cell death. Neuronal cell death can cause memory decline and even amnesia. Additionally, resveratrol can enhance synaptic plasticity,15 the ability of the brain to adapt by increasing or decreasing communication between neurons in response to more or less activity in that brain region. This is important in brain development and recovering after damage or injury to the brain. This means that eating grapes can protect our brains as we age and prevent memory deterioration.

Blood flow to the brain is also vital for keeping neurons functioning; the greater the blood flow to the brain, the more likely it is that our memory will remain intact. Grapes can help to reduce the build-up of cholesterol in arteries, which help to maintain  good blood flow to the brain. 

Other health benefits of grapes

Cardiovascular health 

Nutrients found in grapes can help lower cholesterol, preventing atherosclerosis.3 Epidemiological studies show that consuming grapes and grape products, including wine, is associated with a decreased risk of cardiovascular disease.¹⁶

Anti-inflammatory properties 

As already discussed, inflammation causes damage to the brain and can cause neurodegeneration. It also contributes to a range of other diseases throughout the body. The anti-inflammatory effects of consuming grapes regularly can help to reduce the risk of diseases such as arthritis, heart disease, high blood pressure, asthma, Crohn’s, irritable bowel syndrome and even depression.¹⁷

Anti-cancer potential

Another important health benefit of the antioxidants in grapes is their potential to reduce the growth of cancer cells. This is due to antioxidants clearing free radicals in our body, which are known to cause cancer cell growth. However, this does not mean that eating grapes can cancel out the effects of other carcinogenic lifestyle factors like eating lots of processed foods and smoking. A healthy and balanced diet and lifestyle are the main ways to reduce your risk of cancer.

Healthy skin 

Studies have also shown that grapes help keep skin cells young due to their high antioxidant and vitamin C content. The antioxidants also help protect the skin from ultraviolet radiation, which can cause skin cancer. Grapes are often used in homemade skin remedies and face masks to help reduce wrinkles and dark pigmentation.¹⁸

Incorporating grapes into the diet

Grapes are ideal for people with diabetes and also to prevent diabetes. They have a low score on the glycemic index, which means they do not cause a spike in blood sugar levels when consumed. This is due to a compound found in grapes which prevents glucose uptake in our bodies. Additionally, stimulation of the SirT1 gene causes increased insulin sensitivity, helping the body to use up glucose. As we age, insulin sensitivity decreases, making grapes an ideal food choice for both diabetics and older people.¹⁹

Grapes are also high in melatonin, the hormone that makes you sleepy.⁸ Based on this, and their low-calorie content, grapes are a good choice for an evening snack; getting a good night's sleep contributes greatly to brain health and memory consolidation, thus further contributing to the prevention of memory degeneration.

Meal Ideas

Grapes are delicious on their own and, therefore, easy to incorporate into the diet. Along with the key antioxidants and vitamins, they have a high water content, contributing to hydration, which is vital for brain health and cognitive function. They can also be added to smoothies or frozen to enjoy as a sweet treat while preserving their nutritional content. Grapes can also be made into jam or cooked into cakes, but be mindful when cooking grapes, as with all fruits and vegetables, this can reduce their nutritional value.  

Raisins are also great to incorporate into the diet, and many people find it easier to eat raisins as they are easy to pack for an on-the-go snack or to be added to cereal and salads. Some research suggests they can be more beneficial to your health than raw grapes; despite having lower vitamin levels than non-dried grapes, raisins are higher in antioxidants, having almost three times the antioxidant capacity than grapes^[18]. Raisins are also much higher in fibre than their non-dried form.²⁰ Fibre contributes to good gut health and can help lower cholesterol. 

Grape juice is also a good option - red grape juice contains a similar amount of calories to raw grapes and remains rich in antioxidants and vitamin C, while boosting hydration.

Considerations and precautions

Interactions with medications 

Grapes and grape juice can interact with certain medications processed by the liver, as they affect the speed at which the liver metabolises drugs. This can alter the effect of the drug and, therefore, its side effects. Additionally, grapes can slow down the speed of blood clot formation, so when consumed alongside medications that inhibit blood clotting, there is a higher risk of bruising and bleeding. There has recently been misleading information spread online that eating grapes after some medications could be fatal, however there is no evidence to support this, and this claim has been dismissed by medical experts. It is thought that these claims may have arisen from confusion with grapefruits, which can interact with certain drugs to delay, increase or decrease their absorption into the body.²¹

Moderation in consumption 

As always, a balanced diet is the key to leading a healthy life. Grapes should be consumed in moderation as they are highly acidic, meaning they can wear down the enamel on our teeth, increasing the risk of developing cavities. The acid in grapes can also irritate sores in the mouth, so it should be avoided if you are prone to mouth ulcers.²²

Allergies and sensitivities

Flavonoid supplements are available for people allergic to grapes, which can provide many of the benefits gained from grapes.²³

Summary

Grapes are rich in antioxidants and vitamins, which contribute to brain and body healthy by preventing cell damage and boosting immunity. Red grapes, in particular, are rich in quercetin, which has anti-inflammatory and anti-ageing effects and helps preserve memory function. Resveratrol is another key antioxidant found in grapes. It is known for its memory-boosting, anti-ageing and neuroprotective abilities. 

Grapes are a good choice for preventing diabetes (and for people who already have diabetes) and for maintaining good brain health. Despite this, they should be consumed in moderation as part of a healthy and balanced diet to avoid acid erosion of the teeth. 

Extracts from grape seeds and skin could be used as a therapeutic agent for neurological disorders, including neurodegenerative diseases, which are detrimental to memory, and also to improve synaptic plasticity, which is important for learning and memory.