Grapes are round or oval berries that grow on woody vines in clusters ranging from about fifteen to nearly three hundred. Grapes feature semi-translucent juicy flesh encased in a smooth skin and may contain edible seeds.
Categorized as either “white” (green in color) or “black” (crimson, dark blue, deep purple, and reddish pink) grapes are more commonly referred to as green and red. Mutations in the green grapes, has turned off the gene that accounts for the purple color found in red grapes.
Grapes are also classified as either table or wine grapes, depending on their respective uses. Wine grapes tend to be smaller, seeded, sweeter with thick skins while table grapes are larger, seedless with thinner skins.
The characteristic whitish bloom found on grape skins is from a type of yeast that naturally occurs on the fruit. It is this yeast that led to the innovation of fermented grapes or wine.
Although grapes are traditionally thought of as a Mediterranean fruit, they are actually native to many different parts of the world. Grapes are extremely hearty and thrive in a variety of climates. Grapes have grown wild across Europe, Asia, Africa and North America since prehistoric times. Grapes are famously mentioned in the Bible, referred to as “the fruit of the vine”, depicted in hieroglyphics in the Egyptian pyramids and revered in ancient Greek and Roman culture for their wine making ability. Cultivation of grapes seems to have begun as early as 8,000 years ago in Asia. By the second century A.D., over 90 varieties of grapes had been cultivated. Today, over 8,000 varieties of grapes are grown worldwide.
Annually about 30,000 square miles of land worldwide are planted with grapes, resulting in the production of 150 trillion pounds of grapes. Major grape producing countries include Italy, China, Spain, and France. About one-third of all world vineyards are found in the three countries of Italy, Spain, and France. Other important grape-producing countries include Turkey, Chile, Argentina, Iran, South Africa, and Australia. In the United States, 97% of table grapes are grown in the temperate central coastal region of California.
Common varieties of grapes include Thompson, Flame, Ruby, Perlette and Tokay.
Compared with other fruits, grapes are naturally quite sweet. A cup of grapes (about a handful) contains 104 calories of which 23 grams are from sugars and 1 gram from fiber.
Although grapes are not as nutritionally dense as other fruits, they are a good source of several vitamins and minerals. Grapes are a very good source of vitamin C and vitamin K, providing about 27% of daily values for both vitamins. A cup of grapes is also a good source of potassium, providing 288 mg or 8% of daily values. Grapes are also a source of thiamin, vitamin B6, riboflavin, copper and manganese.
Instead of grapes, raisins are often eaten as a snack. While the dried fruit is a good source of potassium, many of the nutrients like vitamin C and vitamin K are lost in the drying process. Fresh grapes are about 80% water compared with raisins which are 15%. For this reason, a small box of seedless raisins (1.5 oz) is a very concentrated source of calories (129) and sugars (25 grams).
On a health awareness note – the 2011 edition of the Shopper’s Guide to Pesticides by the Environmental Working Group has identified imported grapes as one of the most problematic fruits in terms of pesticide residues. For those wary about pesticide intake, organically grown grapes are a good option.
Grapes contain a wide variety of phytonutrients including stilbenes, flavanols, flavonols, phenolic acids and carotenoids. Anthocyanins tend to be the main phenolic acid in purple grapes whereas catechins are the main flavanols in white varieties. The phytonutrient compounds found in grapes are associated with powerful antioxidant and anti-inflammatory benefits.
These phytonutrients are concentrated in the seeds and skins of the fruit (not the flesh), so table grapes tend to be lower in these beneficial compounds. Red wine may offer greater health benefits than white wine because red wine is fermented with the skins. In white wine production, the skins are removed before the fermentation process.
Resveratrol, a phytonutrient found in the skin of purple grapes, has received considerable attention and notoriety. Animal studies have shown that resveratrol has anti-aging benefits. The mechanism is similar to that of caloric restriction – the only dietary & lifestyle modification that has demonstrated to slow the aging process – where longevity genes are activated.
The substantial cardiovascular benefits of grapes have often been thought to be the reason for the “French Paradox”. Despite eating fairly large amounts of saturated fat in their overall diet, the French population as a whole has been observed to have much lower levels of heart disease than would be expected with their high saturated fat intake. One of the reasons might be the anti-inflammatory (and antioxidant) support provided to their cardiovascular system by their regular consumption of red wine.
Selection & Storage
Different varieties of table grapes can be found throughout the year. From January to April, grapes are imported from South American countries like Chile. In May through June, grapes typically are imported from Mexico. After June, grapes comes from California.
When selecting grapes, pay attention to their color as this is usually a good indication of the sweetness of the fruit. Green grapes should have a slightly yellowish hue while red or black grapes should be deep and rich in color.
For the highest concentration of antioxidants, select grapes that are fully ripe. Because grapes are harvested when they are ripe, simply look for plump clusters that are firmly attached to a healthy looking stem. Grapes should be free of wrinkles and should not be leaking juices.
Grapes tend to spoil quickly and ferment when left at room temperate and should always be stored in the refrigerator. Wrap unwashed grapes loosely in a paper towel and place in an airtight container or plastic bag. They will keep this way for up to 5 days.
Rinse grapes immediately before serving. Table grapes are best served slightly chilled, as it enhances their crisp flavor. If you are enjoying just a few grapes, use scissors to cut a cluster from the stem. Pulling just a few individual grapes off can cause the stem to dry out.
Grapes are used to make raisins, jam, juice, vinegar, wine, grape seed extract and grape seed oil.
Grapes are more than just a convenient, healthy snack option – they can be enjoyed at any point during the day. Add fresh grapes to your yogurt in the morning. Chop grapes and mix them into your chicken salad at lunch. Serve a fruit salad for dessert that includes colorful green and red grapes.
Barbecue Chicken and Grape Salad is reminiscent of a Waldorf salad. This dish replaces granny smith apples with grapes. The spice rub on the chicken provides a bite. Roasted Pork with Honeyed Grape Sauce is deliciously rich and using red grapes makes the sauce a vibrant, deep color.
Grapes are easily frozen and can serve as a wonderful snack, especially for kids.
David H. Rahm, M.D. is the founder and medical director of The Wellness Center, a medical clinic located in Long Beach, CA. Dr. Rahm is also president and medical director of VitaMedica. Dr. Rahm is one of a select group of conventional medical doctors who have education and expertise in functional medicine and nutritional science. Over the past 20 years, Dr. Rahm has published articles in the plastic surgery literature and educated physicians about the importance of good peri-operative nutrition.