Grapes And Their Role In Liver Detoxification

Background

The liver is one of the largest organs in the human body, accounting for approximately 2% of body weight. Metabolically active, it performs several functions, including converting food into energy and aiding in blood clotting and detoxification. However, when the liver undergoes stress, detoxification can become compromised, further straining the body. This is when nutritional strategies are recommended to patients. In this article, we will explore what liver detoxification is, why grapes, in particular, may assist this process, and the best way to incorporate grapes and their many benefits into your lifestyle. 

The liver

The liver has several metabolic functions, playing a crucial role in converting glucose into glycogen, a vital energy stored in tissues. Aminos and fatty acids function both vitally by acting as a sorting centre by redirecting substances to different parts of the body and releasing them into circulation to reach the required tissues.¹ Furthermore, the liver is responsible for producing bile, clotting factors, and proteins while also serving as a purification plant - acting as the primary site of detoxification, a crucial function for protecting the body against toxins.  

The liver detoxification process

Detoxification is a complex process that converts potentially harmful substances into non-toxic forms, facilitating their excretion from the body as waste products. This process comprises two main phases, each relying highly on enzyme activity. Phase I is the initial line of defence in the liver and uses cytochrome P450 mixed-function enzymes to modify toxins. These enzymes use three chemical reactions to alter the chemical structure of toxins: hydrolysis, which uses water to break chemical bonds; oxidation, which donates oxygen to another substance; and reduction, which removes electrons. This process results in the production of biotransformed intermediates, which can often have deleterious side effects and require further treatment.² 

Sometimes, biotransformed intermediates produced from phase I can be particularly harmful. For example, carcinogenic (also known as cancer-causing) compounds illustrate this point, which is where phase II comes into play. The second phase in the detoxification process involves conjugation, where two or more substances are bound together. This step is essential for converting phase I products into safer, water-soluble metabolites, which are then excreted from the body in the urine.³ 

Phase II can effectively repackage toxic intermediates into safer versions, while Phase I activity produces oxygen-free radicals. These radicals are unstable and reactive bioproducts. The presence of free radicals puts the liver at risk of oxidative stress, subjecting the body to insults such as tissue damage. However, a healthy diet rich in antioxidants can greatly help protect the liver.⁴

Health benefits of grapes

The grape, or Vitis vinifera, is a popular vine-growing berry native to the Mediterranean and Central Asia. They can be consumed fresh, dried, or crushed in the form of grape juice and wine, the latter requiring fermentation. Historically, grapes made frequent appearances at Greek, Roman, and Egyptian banquets and, for some cultures, signified wealth and luxury. This delicious fruit provides a multitude of health benefits, including the following:

• Packed full of antioxidants, which help repair cells damaged by free radicals
• Source of fibre, which aids the digestive system
• May lower cholesterol
• Can lower blood pressure
• Assist in eye health
• Provide a source of water and hydration 

Nutritional value of grapes

A healthy, balanced diet high in fibre, vitamins, and minerals and composed of fruits, vegetables, grains, legumes, and lean protein is highly beneficial to all. For patients with liver conditions, nutritional strategies can support liver function, alleviating some strain off the liver. For others, adopting a healthy lifestyle can prevent liver disease, which is becoming more prevalent in today's population, and improve overall liver health and efficiency. Grapes are high in antioxidants and will greatly benefit the body and cellular health. Below are some of the key antioxidants present in grapes and the benefits they yield.

Resveratrol

Grapes provide a good source of resveratrol, a polyphenol with antioxidant and anti-inflammatory properties. Studies have shown that resveratrol can inhibit oxidative stress through the activation of several anti-inflammatory pathways.⁵ Resveratrol has been found to improve antioxidant enzyme activity and promote the production of antioxidant molecules. Additionally, resveratrol inhibits the Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway, which is implicated in several diseases, and the inflammation-promoting small proteins (known as cytokines) associated with this pathway.⁶

Anthocyanins

Anthocyanins are water-soluble pigments that can produce a blue, black, or purple hue in foods that contain high quantities, including blueberries, red cabbage, and red and purple grapes. Research has highlighted that anthocyanins can contribute to a reduction in both lipid retention in the liver and oxidative stress.⁷

Carotenoids

Carotenoids are a group of naturally occurring organic pigments found in fruits, vegetables, and plants that appear red, yellow, and orange, such as carrots and peppers. Humans do not synthesise carotenoids,  so we obtain our supply from fruit and vegetables. Grapes are known to contain carotenoids; lutein and β-carotene are two carotenoids established as the main ones in grapes, with studies revealing distinct differences in the carotenoid profiles amongst varieties.⁸ White grapes contain a higher proportion of carotenoids, while blue-black varieties contain more total polyphenols, which are plant compounds renowned for their purported health benefits. Epidemiological studies have shown that, in addition to having antioxidant properties, carotenoids also have a positive effect on patients with non-alcoholic fatty liver disease and alcoholic liver disease due to β-carotene regulation of liver signalling pathways.⁹

Introducing grapes to your diet

If you have not consumed grapes already, you can easily introduce them into your lifestyle as they are widely available and easy to enjoy. The recommended daily intake of grapes varies according to factors such as gender, age, and health. An 80 g portion of grapes is the equivalent to 1 of your 5-a-day, however eating up to 2 cups daily is often promoted to reap maximum benefits. Grapes can be enjoyed in the form of dried fruit, but they contain more sugar compared to fresh fruit.

Consuming red wine over other alcoholic alternatives is often favoured due to its antioxidant properties and associated health benefits. However, it is important to note that guidelines recommend not exceeding 14 units weekly, with 1 unit being the equivalent of 10 ml of alcohol. By opting for grapes in fruit form, you can receive the health benefits without the risk of negative side effects.

FAQs

What is liver detoxification?

Liver detoxification is an important two-phase process that occurs in the liver and is mediated by enzymes. Its role is to convert toxins into non-toxic forms by modifying the substances through a range of chemical reactions, which are then removed from the body via the urine.

Are there any differences in the nutritional values of grapes?

The nutritional value of grapes can change depending on the variety. For example, white grapes contain a high polyphenol content compared to blue-black grapes. Nutritional value can also differ depending on the pigments present; for example, red grapes will typically contain more carotenoids, which help to give them their red colour.

How do grapes aid the liver?

The high level of antioxidants in grapes supplement liver function and prevent it from being damaged by oxidative stress. They can also be used to help prevent liver disease.

Summary

Liver detoxification is a crucial process which prevents potentially dangerous toxins from causing damage to the body. Reactive intermediates and free radicals produced as a result of phase I of detoxification subject the liver to a great deal of oxidative stress, which is known to cause harm to tissues and is linked to several diseases.

To help protect the liver and facilitate its many functions, nutritional strategies are often recommended, which include a wide range of antioxidant-rich foods. Antioxidants are chemicals that directly scavenge free radicals and activate anti-inflammatory pathways in the body, thus dampening inflammation and reducing the risk of injury to tissues. Grapes are particularly rich in antioxidants, namely resveratrol, anthocyanins, and carotenoids, which can aid liver function and detoxification. 

Supplementing your diet with grapes can also provide hydration, vitamins, minerals, and has been linked to a wealth of other health benefits, including eye health and general well-being, and so enjoying them is encouraged.