Health Benefits Of Eggplants

Introduction

The World Health Organization (WHO) recommends the intake of 400g of fruits and vegetables daily to reduce the risk of developing chronic diseases and cancer.¹ This formed the basis of the NHS 5-a-day campaign which promotes the consumption of 5 portions of fruits and vegetables a day.¹

Just like the tomato, eggplant is also classified as a fruit.² The origin of this fruit appears to be multiple, genetic studies indicate that eggplant originated from India, Southern China, and the Malay Islands.³ Eggplant is known by many names, brinjal in South Asia, aubergine in Europe, melongene in the West Indies, Guinea squash in America, and Patlican in Turkey.³

The eggplant (Solanum melongena) is a fleshy fruit with numerous seeds that comes in a variety of shapes (ovoid, slender, elongated) and colours ( deep purple, black, white, green, and yellow) and can grow up to 40 cm in size. (2,4)

Colourful fruits and vegetables like eggplant have been shown to contain beneficial compounds that are of immense health benefits. Examples of these beneficial compounds found in eggplants are an anthocyanin called nasunin which is found in high concentrations in the peel and a phenolic compound called chlorogenic acid, which is concentrated in the flesh.⁵ Both compounds have high antioxidant properties, which are beneficial to health and the prevention of diseases.⁵

Antioxidants are compounds that help the body mop up reactive species called free radicals. Free radicals are by-products of the metabolic processes of the body which, if left unchecked, can cause damage to the organs of the body, speed up the ageing process and increase the risk of developing several chronic diseases.⁶

Generally, people are making the conscious decision to eat healthier due to evidence provided by numerous studies which show that eating healthier can reduce the risk of developing certain chronic diseases, cancer and supports healthy ageing. The culinary versatility of eggplant and its associated medicinal and dietary benefits have contributed to its increasing popularity globally.³

Health benefits of eggplants 

Eggplant is a low-calorie, nutrient-dense fruit that contains several beneficial antioxidants both in the flesh and skin. Eggplants are usually prepared or processed before eating. The health benefits of eating eggplants include:^2,6

• Gastrointestinal health: Eggplants are a good source of fibre. A diet high in fibre aids digestion by stimulating the secretion of gastric fluids which makes the digestion and processing of food for absorption by the body easier. In addition, a high-fibre diet results in regular bowel movements, which support optimal gut health
• Weight Loss: Eggplants are the ideal food for individuals who want to shed a bit of weight without compromising on their intake of beneficial nutrients that the body needs. Eggplants have a high water content, are low in fat, have no cholesterol and are high in fibre. The high fibre content allows you to feel fuller for longer; fibre does this by inhibiting the action of a hormone called ghrelin, which acts on the brain to make us think we are hungry. Inhibiting this hormone helps to reduce appetite and allows you to achieve satiety quickly
• Anti-tumour: An extract found in the peel of eggplants named solasodine rhamnosyl glycosides has been shown to have anti-cancer properties when applied directly to the skin for the treatment of non-melanoma skin cancers
• Bone health: The peel of eggplants also contains other phenolic compounds which give the eggplant peel its characteristic colour. These phenolic compounds are of benefit in reducing the signs of osteoporosis and improving bone strength and mineral density. Eggplant is also a good source of iron and calcium, which contribute to bone health
• Anaemia: Is of various forms, each of which is managed by finding out the root cause. Iron deficiency anaemia is the most common type of anaemia and this occurs when there is not enough iron in the body to make new red blood cells (RBC). Eggplant is a good source of iron and may be of benefit in the dietary management of iron deficiency anaemia. Iron is needed by the body to make new RBCs. When iron deficiency anaemia occurs, the number and quality of RBCs which are essential in carrying oxygen and nutrients to vital organs around the body decreases. This leads to the classical signs of iron deficiency anaemia - headaches, fatigue, weakness, and dizziness

• Cognitive function: Eggplants are a good source of phytonutrients, which is a fancy name for nutrients that are found in plants. These phytonutrients exhibit excellent antioxidant properties, which boost cognitive function. In addition, eggplants are also a good source of potassium, which can improve blood flow to the brain. This increase in blood flow improves the supply of oxygen and beneficial nutrients to the brain. The chemical nasunin found in eggplants helps to prevent damage to the neural cells of the brain, which are responsible for sending messages from the brain to the body and back
• Heart health: High cholesterol is often referred to as a silent killer as it can lead to heart attacks, and stroke, and contributes to the development of atherosclerosis. A diet high in fibre is of benefit in reducing the levels of bad cholesterol. Soluble fibre is said to act like a sponge that soaks up the bad cholesterol in the blood (LDL), reducing its levels and the risk of heart-related events and stroke
• Diabetes: Dietary management of type 2 diabetes (T2DM) usually involves the consumption of food that does not lead to spikes in blood sugar. A high fibre and low/medium glycaemic index food is usually recommended as these are better for achieving good blood sugar control. Thus, the high fibre and low glycaemic index of eggplant make it an ideal addition to the diet of individuals with T2DM
• Birth defects: Folate deficiency is one of the contributory factors to the development of Neural tube defects (NTDs). NTDs are congenital defects that affect a growing baby while it is still in its mother’s womb, The most common NTD is spina bifida. Eggplants are a rich source of folate, which may be beneficial to pregnant women as studies have shown that folic acid supplementation and a high folate diet during pregnancy reduce the risk of NTDs
• Anti-microbial properties: Nasunin and chlorogenic acid found in eggplants exhibit antiviral and antibacterial qualities, which may offer some protection against some viruses and bacteria

Nutrients we can get from eggplants

The following nutrients are in ONE  unpeeled, raw eggplant, which is estimated to weigh approximately 548g.⁷

Source: U.S. Department of Agriculture (USDA)

Ways to include eggplants in our health

Eggplant is such a versatile fruit that is easy to cook and can be prepared using a variety of methods prior to eating. The different methods of cooking eggplant and suggested recipes for each method include:²

• Baking 
• Stuffed 
• In curries
• As a sauce with pasta 
• Mashed to form a dip
• Juiced
• Fried - This is the least healthy way to prepare eggplants because the frying process increases the fat content of the eggplant. Thus this is not recommended for individuals who consume eggplant as part of the dietary management of a chronic disease condition (e.g. T2DM) or to lose weight.

How much is enough?

Eggplant belongs to the Solanaceae family or more commonly known as the nightshade family, which also includes other fruits like tomatoes, bell peppers, the potato, which is classified as a vegetable, and the deathly belladonna plant.⁸ The belladonna (belladonna means beautiful woman in Italian) plant was used during the middle ages for beautification purposes but was later found to be extremely toxic when ingested.⁸

Coincidentally, some varieties of eggplant, the dark purple and black varieties have similar colouring to the belladonna plant, which has violet flowers and dark shiny black berries. This similarity between the two earlier made people cautious about whether the deep purple and black varieties of eggplants are safe to consume given the toxicity of the belladonna berries.^8,9

Fortunately, the eggplant is safe to consume with only one caveat. Have you ever wondered why eggplants have a slightly bitter taste? Or why do recipes recommend sprinkling a bit of salt on raw eggplants to prevent them from getting bitter? This is due to the presence of a bitter-tasting  chemical found in eggplants and other members of the Solanaceae family, called solanine.⁸

In eggplants, solanine is usually found in the peel of eggplants and can be toxic when consumed in high doses. A ripe eggplant is said to contain about 75 micrograms of Solanine.⁸

So how high is too high when it comes to how many eggplants you can safely consume without ingesting toxic levels of solanine? Again,  fortunately, the amount of eggplants one needs to consume to reach toxic levels of solanine is above the consumption capacity of humans.⁸

It is estimated that a 68 kg adult would need to eat 1000 eggplants in one sitting to attain toxic levels of solanine in the body. This is an impossible feat for any human because you will recall earlier that the high fibre content of eggplant reduces appetite through the action of the hormone ghrelin and allows you to achieve satiety quickly.^2,8

Side effects and how much to consume and other information¹⁰

As with all things, moderation is key when it comes to the consumption of eggplants. Likely negative side effects documented following the consumption of eggplant include

• Food-drug interaction
• Shortness of breath
• Headache
• Allergic reactions 
• The development of oxalate-based kidney stones-eggplant contains oxalates

In addition, ayurvedic practices suggest that although eggplants are rich in folate, which is beneficial for reducing the risk of having a baby with NTDs, eggplants should not be consumed by pregnant women as it can abort a fetus and may result in skin reactions in the fetus.¹⁰ More research is needed to confirm this, perhaps moderation is also key when it comes to eating eggplants whilst pregnant. 

Summary

The eggplant is such a versatile fruit, with only the potato surpassing it in culinary versatility. The high water and fibre content and its low-fat content make it an ideal addition to your diet especially as various studies have shown proven benefits of eating healthy for the prevention and management of chronic disease conditions and for living longer healthier lives.

As with things that are consumed, be it food, supplements, or medicines, side effects can occur following consumption. Despite this, the amount of eggplant that needs to be consumed to achieve toxic levels of the chemical solanine is way beyond the consumption capacity of humans.

Caution is still advised for individuals that experience signs of an allergic or anaphylactic reaction following the consumption of eggplants and in individuals with certain conditions where research suggests that the consumption of eggplant should be limited or avoided.