Are grapes good for weight loss?
Do you want to know that whether grapes are helpful for weight loss or not? If so, then you need to check out this article as it will tell you all about grapes, the substances they contain, their benefits for weight loss and other benefits.
What are grapes?
Grapes are actually a part of the Vitis genus. It is actually a fruit berry, which can be eaten in raw form. For different purposes, grapes can be used, for example, they can be used for making raisins, grape seeds extract, grape seed oil, vinegar, jam, juice and wine. Generally, in the form of clusters, grapes are found. Also, grapes are non-climacteric fruits. This basically means that they can be grown in any kind of conditions and don’t require a specific climate or condition.
History of grapes
About 6,000 to 8,000 years ago, in the Near East, the grapes were first cultivated. When the wine was first formed, the grapes were first cultivated. First of all, in Georgia, around 8,000 years ago, the wine was made. The wine was made from the grapes due to the presence of yeast on the grapes. Yeast are naturally found on the grapes. First of all, wine making started in Georgia around 8,000 years from now. This was confirmed in a recent research made by some well-known archeologists. The archeologists found out more than 110 grapes cultivators and concluded that all these cultivators basically originated from Georgia. In Georgia, the archeologists found the remains of wine, in 8,000 years old jars. According to the researchers, the oldest wine shop was found around 4,000 B.C. in the Armenia. The oldest wine in the Middle East was found in the city of Shiraz around 9th century A.D. According to some researchers, the Shiraz gave birth to the name Syrah red wine. Actually, a popular place in Middle East, known for making wines, is Shiraz.
The origin of purple grapes has also been sought by some scientists. According to the Ancient Egyptian Hieroglyphics, there was not one place of origin of purple grapes, but three places of origin. These three places are Rome, Phoenicians, and Greece. In these places, grapes were used both for producing wine and for eating purposes. From these places, the wine growth business moved into North Africa and Europe and then after that, to North America. By many Native Americans, grapes were eaten. However, according to some European colonists, these grapes were unfit for making wine. For the purpose of cultivation of wine, vitis vinifera, a popular variety of grapes, was used.
Description of the grape fruit
Now that you know a bit about the history of grapes, it is a good idea to know about the description of the grape fruit. In clusters of 15 to 250, grapes are generally found. In color, the grapes have their own variety. The color of grapes ranges from black and dark blue to green, yellow, and pink. The color of white grapes is green and their place of origin are the purple grapes. The color of purple grapes is obtained from anthocyanins, which is actually the mutation of two genes. Other than anthocyanins, many other color pigments are also present. The shady color of red wines is due to the presence of these chemical pigments. In their shape, the grapes are just like prolate spheroid (an ellipsoid formed when an ellipse is revolved around its axis).
Now let us look at some grapevines. From Mediterrancean and Centra Asia, most grape cultivators of Vitis vinifera are obtained. From the Asian and American species, some minor fruits and wines are obtained. One of the popular Asian species is Vitis Labrusca. In the Eastern Canada and United States, this grape juice grapevines and the North American table are generally found. Another popular species of grape vines is Vitis riparia. In the North America, for making wine and jam, this species is generally found. In the north of Quebec and Eastern U.S., this species is generally found. One other species of grapevines is Vitis rotundifolia. In the Gulf of Mexico and South Eastern United States, this species is generally found. Generally for making wine and jam, this species is used. Another popular Asian species is Vitis Amurensis.
Grape is cultivated widely around the world. According to recent reports, for the cultivation of grapes, about 75,866 square kilometers are allocated. Now the division is such that 2% of this area is allocated for the production of dry grape fruit, 27% of the area is allocated to the production of Fresh fruit, and about 71% of this area is dedicated to the production of wine. Grape juice is formed from grapes. This juice doesn’t contain any added ingredients and is 100% natural. At the rate of 2% per year, the area of vineyards is increasing. Currently, there is no reliable source according to which the production of the grapes with each variety can be known. Sultana is one of the most popular planted variety of grapes known so far. It is cultivated around an area of 3600 km2. Another popular grape variety is Airen. Chardonnay, Cabernet Franc, Riesling, Tempranillo, Sauvignon Blanc and Cabernet Sauvignon are some other popular varieties of grapes.
Before we move forward, you should know something about seedless grapes. Now-a-days, the main number of the planting of grapes are the seedless cultivators. You might be thinking that if there is no seed, it might pose a problem in the reproduction process. However, this isn’t so. It can, however, pose a problem for the grape breeders. The reason behind this is that breeders need the seeded variety of grapes to try different tissue culture techniques.
Of the seedlessness trait, there are several varieties. The main cultivators of Vitis vinifera are Russian Seedless, Black Monukka, and Thompson seedless. Almost more than a dozen of seedless grapes are currently available. In cold climates of southern Ohio, the Venus and Reliance are cultivated. Eating seedless varieties of grapes poses a risk that the various health benefits provided by the seed variety aren’t present in the seedless variety.
Substances contained in grapes that are beneficial for weight loss
Grapes are especially beneficial for losing weight. Just 67 calories are present in 100 grams of grapes. Also, water is present in grapes, which makes you satisfied for longer periods of time. The high water content makes the energy density of the grapes low. According to the Centers for Disease Control and Prevention, lower density foods are beneficial for weight loss. Also, another thing is important to consider here. The grapes aren’t high caloric food. Due to their low caloric content, you won’t gain weight if you eat them in excess. The main factor which determines weight loss is the caloric content in the body. If you burn more calories than you consume, you will lose weight.
Now let us look at the substances present in grapes. In grapes, dissolved solid is present and 70% water is present. Many organic and inorganic compounds are present in these soluble solids. Some of the compounds present in grapes include organic acids, sugar, aroma compounds, minerals, pectic substances, mineral and nitrogenous compounds. Each of these compounds is described below:
In grapes, organic acids are present. For making wine and grape juice, organic acids are quite important. The taste of the wine is given by these organic acids. Also, for the pH and wine color, this type of wine is quite important. Malic, tartaric and citric are mostly the organic acids present in grapes. In the wines and juices, many other organic acids are also present, like amino acids. However, the majority of the space is filled by malic and tartaric acid; they account for 90% of the amino acids present in grapes. The production of the acids in the fruit increases during the growth period of the grapes. However, when the time of maturation comes, the concentration of the acid decreases. At the time of ripening, the concentration of the malic acid, in particular, decreases. Therefore, we can say that the concentration of malic acid in grapes is less as compared to the concentration of tartaric acid.
Among fruits, grape is quite a unique one in the sense that it contains tartaric acid in it. Tartaric acid is generally present in sodium bitartrate. Bitartrate is very important in the sense that it controls the coldness in the wine. Many factors are responsible for composition of the acids in the grapes. These include cultural practices, varieties and the climatic regions. In warm areas, generally the levels of the acid is lower in comparison to cold areas. Titratable acidity is the parameter generally used for acidity. The use of a parameter is really important, because it helps experts to determine the quality of wine or grape juice.
The pH of wine is generally determined by the acid content present in it. In general, H+ ions are given by acids when they lose their stability, which are generally known through their pH levels. Here, we can say that there is a relationship between acidity and pH. However, the relation isn’t simple. The relationship is quite complex due to the presence of different acids and salts present in the grapes. For making good quality wines, it is essential that one knows about the role of pH in the making of wine.
Research has shown that organic acids are quite beneficial for weight loss. For example, a recent research showed that the balance between the organic acids and different bases present in the body is essential for weight loss (1). Therefore if there is acid base balance in the body, the weight loss is facilitated.
Different sugars are also present in wine. Sugars are the major part of the soluble solid. In juice, the main sugars present are glucose and fructose. About 150 to 250 g/L of grapes contain sugar. The main sugar present in unripened grapes is glucose. In equal amounts, glucose and fructose are present when the ripening stage is close. They are present in 1:1 ratio. The concentration of glucose is lower in overripe grapes. Nothing can be said in ripe grapes, because the ratios of glucose and fructose fluctuate in ripened grapes. The high glucose varieties are Zinfandel and Chenin Blanc whereas the high fructose varieties are Pinot blanc and Chardonnay.
The sweetness of all three, namely fructose, sucrose and glucose is quite different from each other. In general, glucose is the least sweet of the three. Sucrose is sweeter than glucose but less sweet than fructose. If 100 is the sweetness of fructose, then the sweetness of sucrose will be 84 and the sweetness of glucose will be 66. You might consider this information as unimportant. However, to a wine maker, this information is quite important. A wine maker balances the three ratios while making wine.
In the class of fermentable sugar, glucose and fructose are present. These sugars are converted into carbon dioxide and alcohol by the yeasts. This is known as the fermentation process. There is a relation between the sugar amount and alcohol amount. If one can control the amount of sugar in the wine, he can definitely control the amount of alcohol in the wine. However, the relation between alcohol and sugar shouldn’t be exaggerated. Brix is the term used for measuring the sugar content in juices.
Now let us see whether the sugar in grapes is beneficial for weight loss. Research has shown that if one can control the blood sugar levels in the body, then the glucose in the body can also be controlled (2). In general, this means that if a person can improve the blood sugar level in his body, by consuming more amounts of sugar from different sources, such as grapes, then the weight loss process is facilitated.
An important component of grapes are the phenolic compounds. They are the most abundantly found compounds in the grapes, after organic acids and sugars. In different amounts, phenolic acids are present and they are also quite diverse in structure. The color and flavor of the wine is determined by phenolic compounds. In different browning reactions (conversion into brown color without the use of enzymes), phenolic compounds play an important role.
In the grapes, the phenolic compounds are present in the seeds. In grape juices, only a small amount of phenolic compounds is present. From juices with little seed contact, white wine is produced. White wines have lower amount of phenolic compounds present in them, ranging from 100 to 250 mg/L. With seed contact, red wines are generally produced. Anywhere between 1000 and 3500 mg/L, the phenolic content of the red wines is present.
Tannins and anthocyanins are the major substances present in phenolic compounds. Generally, the red and purple color of the wines are formed by anthocyanins. In both colored and colorless forms, these compounds are present. The anthocyanins, in red wines are present in colored form. The anthocyanins work with other compounds, when the red wines become older. This compound is also responsible for stabilizing the color of the wine. On the other hand, tannins aren’t simple compounds but are quite complex. Over 500 is the molecular weight of these compounds. They vary in color, ranging from yellow to red color and are quite bitter. When the grapes become older, the tannins undergo a polymerization process. The molecular size is increased as a result of polymerization. The bitter taste is due to the smaller molecules. When the molecular size increases, the bitter taste vanishes slowly and is replaced by a sharp taste. These molecules become insoluble when the molecular size increases.
Phenol is quite beneficial for weight loss. Numerous studies have shown that phenol plays a role in weight loss. Breathing in an air full of phenol can certainly lead to weight loss (3). Although in different researches, the weight loss of phenol is considered as a side effect, however, it can be considered as a benefit.
Different nitrogenous compounds are present in grapes. Ammonium cations and organic compounds are generally the nitrogenous compounds present in grapes. These include peptides, proteins and amino acids. According to the cultural practices and climate, the amount of nitrogen in grapes varies. During the ripening phase of grapes, the amount of nitrogen in the fruit increases. For yeast and lactic acid bacteria, the nitrogen compounds act as nutrients. The different qualities of wine are controlled by these nitrogenous compounds. The production of by products and the biomass formation is controlled by these nitrogenous compounds. The wine is made stable due to the presence of proteins. When there is insufficient nitrogen, the odor of the nitrogenous compounds become just like rotten egg. Diammonium phosphate is generally used to counter this problem.
Nitrogen containing compounds are quite beneficial for weight loss. Several researches have been done on amino acids and their beneficial effects have been known. An alpha amino acid, L-histidine has been found to be especially beneficial for weight loss (4). The study was done on rats. In the study, the rats were exposed to L-histidine for a period of 3 to 4 weeks. After 3-4 weeks, it was observed that the weight of the rats was significantly reduced. When more high proteins were added, the weight loss effect became a bit less.
In grapes and wines, different aroma compounds are also present. Mainly from grapes, these aroma compounds are obtained. However, they can also be obtained from fermentation and the ripening process of the grapes. Many flavored compounds are present in grapes. Different characters are given due to these compounds. The major aroma compound present in grapes is 2-methoxy-3-isobutyl pyrazine. These are the most abundantly found aroma compounds in grapes. They give a pepper-like odor to different grape varieties. The other major aroma compound is 4-vinylguaiacol and 4-vinylphenol. They give spicy and medicinal odor to the grapes. Another popular aroma compound is Terpenes.
Distinct odor is present in many varieties of grapes such as Chardonnay and Seyval Blanc. One or two compounds are responsible for this distinct odor. In these compounds, the flavor is enhanced. In the skin and layers beneath them, the aroma compounds are present. During the process of ripening, the concentration of these compounds increases. When the flavor of grapes are dominant, the grapes should be harvested. The aroma compound concentration in grapes is affected by many reasons. For achieving the desired flavor, it is essential to monitor the concentration of aroma compounds.
In grapes, minerals are also present. About 0.2 to 0.6% of the weight in grapes can be attributed to minerals. Some of the important minerals present in grapes include sulfate, chloride, sodium, potassium, phosphates and iron. Potassium is the most important mineral among all the minerals present in grapes. The potassium constitutes about 70% of the cations in the minerals. The potassium in grapes increases during the ripening process. Potassium bitartrate is formed when potassium is present in the grapes. The wine instability problems are generally caused by the tartaric acid salt of potassium. Research has shown that magnesium is quite beneficial for weight loss (5).
In the cell wall, the different agents which help in cementing are known as pectin. Actually the pectin substances are the complex polysaccharides which are formed when the galacturonic acids are grouped together. By different enzymes, the pectin is passed through the process of hydrolysis (break down through chemical reaction with water). Due to this, the grapes become softer. The fruit pulp is suspended in juices, due to which a clouded atmosphere develops. Usually, the commercially prepared pectolytic enzymes are used.
Other benefits of grapes
Now let us look at some other benefits of grapes. Grapes are beneficial for the prevention of heart disease. The development of heart diseases is stopped due to the presence of flavonoids and polyphenols in grapes. Also, different anti-oxidants are present in grapes. These antioxidants give the grapes anti-inflammatory properties. Grapes are also beneficial for the eyes. The antioxidants, lutein and zeaxanthin present in grapes make them beneficial for eye. Also, grapes are helpful against diabetes. The reason is that they have a low glycemic index (GI = 46). In general, the lower the glycemic index, the more suitable a fruit is for diabetic patients. Another main benefit of grapes is that it improves memory. Different animal studies have shown that due to grapes, the memory decline with age reduces. Also, due to high water content in grapes, different toxins are removed.
Grapes contain lots of substances, which are beneficial for weight loss. However, if you really want to lose weight you need to remember that eating grapes (or any other so called weight loss foods) is only a part of your journey. In addition to eating habits you will also have to be more active and do some physical activity as well. Also do not eat just grapes but try to eat a variety of good foods.
|Written by:||Michal Vilímovský (EN)|
|Education:||Medical student, 3rd Faculty of Medicine, Charles University, Prague, Czech Republic|
|Article resources:||See numbered scientific references within the article.|
|Published:||May 29, 2015 7:05 AM|
|Next scheduled update:||May 29, 2017 7:05 AM|