Grapes And Their Impact On Digestive Wellness

Grapes are ovular fruits that are nutritious and versatile. They can be eaten fresh or turned into juice, vinegar, wine or raisins. Studies have shown that consuming grapes has a variety of different health benefits including eye health,¹ maintaining blood sugar levels² and providing a source of protective antioxidants.³ Grapes also play a crucial role in the digestive system as it is high in fibre and potassium.^4,5

Here are some of the ways grapes aid in digestive wellness:

Acting as natural pre-biotics:

Due to high fibre and water content, this ensures a healthy digestive system which can promote regular and healthy bowel movements. Grapes can therefore act as a natural pre-biotic.^6,7 Pre-biotics are compounds, often non-digestible, which encourage the growth of healthy microorganisms to incur some sort of health benefit to the individual consuming them.⁸ This is one of the ways pre-biotics modulate the gut microbiome by encouraging the growth of beneficial gut microorganisms. Naturally, gut bacteria play an important role in the fermentation of fibre, which produces short-chain fatty acids, many of which play different roles in health. Furthermore, grapes are high in polyphenols such as resveratrol which also have pre-biotic effects by promoting the growth of beneficial bacteria.⁹ 

Antioxidant and anti-inflammatory effects:

The liver is one of the most important organs in the digestive system. It is responsible for breaking down xenobiotic products which are chemicals that are not naturally found in the human body.¹⁰ Any hepatic injury can lead to severe health complications. Viral infection, metabolic diseases, alcohol, and drug abuse are some common factors which damage the liver. These can lead to the fibrosis of the liver, which can potentially lead to liver cirrhosis which can progressively lead to cancer,¹¹ particularly when the liver is exposed to high levels of toxins from overconsumption of alcohol.¹² Currently, there has been a focus on treating hepatic disorders through medicinal plants due to the adverse side effects of using synthetic drugs on the liver.

Grapes come into play here as certain polyphenol compounds contain anti-oxidant and anti-inflammatory properties.¹³ Resveratrol (RES) in particular, is a polyphenol commonly found in red wine and grapes.^13,14 They can reduce DNA damage through the purification of hydroxyl radicals. The liver metabolises RES using liver phase II enzymes which allows for this polyphenol to be absorbed into the liver and the human body.¹⁵ Soon after, its metabolites are cleared up through urine and bile. RES has also been shown to decrease fibrosis of the liver. Studies have shown that RES administration in cirrhotic mice increased acetylcholine responsiveness and increased endothelial nitric oxide which is linked to a decrease in hepatic fibrosis. Therefore, the consumption of grapes naturally increases levels of RES which have shown to have numerous health benefits related to the liver. 

Increasing gastrointestinal motility

Grape seed powder is extracted from grape seeds and is known to have a variety of health benefits. They contain antioxidant, anti-inflammatory and antimicrobial properties.^{17, 18, 19, 20} They also protect against diabetes, obesity and cancer. Gastrointestinal motility refers to the movement of food throughout the digestive system. This changes depending on the food consumed and is regulated through the relaxation and contraction of smooth muscles²¹ in the digestive system as well as through neurons, hormones and interstitial cells of Cajal (ICC) which are known as pacemakers of the digestive system.²² Grapeseed powder can affect gastrointestinal motility and also interact with ICCs. One study done on mice has shown that grapeseed powder increased the time taken for the ingested food to pass through the intestine and this is also thought to be closely linked to ICC pacemaker activation.²² Not all grapes contain seeds but the variety of different components within the grape can confer many health benefits in the digestive system. 

Increasing microbial diversity of the gut

Studies have shown that the consumption of grapes significantly increases the diversity of gut bacteria. The gut microbiome is the full genetic composition of the bacteria present in the gut. The gut microbiota refers to the microbial species present. These two terms are often used interchangeably but they both show an indication of the bacterial composition present in the gut which in turn, gives an indication of how healthy the gut is. Generally, a diverse microbiome is an indicator of a healthy microbiome. When the body is subjected to different stresses, often the gut is impacted and it can lead to a lack of bacterial diversity. Certain bacteria associated with disease can be present in the gut. When found at high levels, they cause significant damage to the overall health and well-being of the individual. A healthy and balanced diet is one of the key factors which impact the gut microbiome. Although the gut microbiome can be impacted by genetics and environmental factors which cannot always be controlled, the microbiome is often changing with age and this can be altered through diet and exercise. Consumption of fruit and vegetables has a positive impact on the gut. This includes grapes.²³ 

Cholesterol metabolism

Another way in which grapes aid in digestive health is through maintaining cholesterol metabolism. Studies have shown that the consumption of grapes decreases cholesterol levels and bile acids.²⁴ An increase in cholesterol is also linked with high blood pressure and heart health. This suggests that grapes not only play a role in digestive health but also maintain cholesterol levels which can potentially maintain blood pressure and reduce the risk of heart disease by inducing less stress to the heart.²⁵ It is important to ensure a healthy lifestyle through exercise to reduce the risk of heart disease and obesity. Active individuals are significantly less likely to suffer from heart disease. 

Summary

In conclusion, grapes are high in fibre, vitamins and polyphenols which give them many different antioxidant and anti-inflammatory effects. This is because they act as natural free radical scavengers and can also interact with cytokines like IL-6 and C-reactive proteins.²² They boost natural physiological processes. They play a role in improving hyperglycemia which is associated with obesity and have shown to have anti-cancer properties through prevention of tumorigenesis. They play a role in ensuring a healthy liver by reducing the risk of liver fibrosis as the different compounds found in grapes can help down toxic products and decrease hepatic disorders. They also have pre-biotic effects due to high fibre content which further provides an improved gastrointestinal motility as well as promoting a more diverse gut microbiome. The different compounds found in grapes have great many effects on the human body and incorporating them into the diet can help protect against many different diseases and ensure a healthier digestive system.