Oranges 101: A Complete Guide

Oranges are a distinctively bright, common fruit you’re likely to find year-round in your local grocery store. These fruits can be eaten raw or juiced, and can be added to a variety of dishes for a touch of sweetness.

But there’s more to oranges than their delicious taste. They also contain important nutrients that can help keep your immune system strong, protect against certain chronic illnesses, and benefit your health overall. Here’s what you need to know about oranges, including how they can help you stay healthy, easy ways to incorporate them into a healthy diet, and what to know to make sure you’re not getting too much of a good thing.

“Oranges are a nutritious fruit with a variety of vitamins, minerals, and antioxidants,” says Natalie Rizzo, RD, founder of Greenletes, a plant-based nutrition blog for athletes, and author of the cookbook Planted Performance. “Not only are they beneficial for the immune system and heart, they also play a role in regulating inflammation in the body. Plus, oranges are 86 percent water, so they help keep you hydrated.”

Oranges are a member of the citrus family and are known for their orange-colored, leathery rinds, which can be peeled to reveal the edible sweet, juicy flesh inside. According to Britannica, oranges are indigenous to tropical areas of Asia, where farming then spread them to the Mediterranean and eastern portions of Africa. Today, they are also an important crop in the United States.

As much as 84 percent of the oranges harvested in the United States are used in juice, with the majority of the rest sold to be consumed fresh, according to the American Farm Bureau Federation. Other products made from this fruit include marmalade, pectin, and essential oils.

You may have seen a few types of oranges at your local grocery store or farmers market, but hundreds of varieties have been cultivated throughout the centuries, according to research. Oranges are the product of two types of citrus trees: pummelo and mandarin. (Interestingly, mandarin oranges, despite the name, are not technically oranges, since they don’t have the pummelo strain, nor are tangerines, which are a type of mandarin.)

Oranges are classified into two categories: sour and sweet. Sour oranges, such bergamot and Seville, are typically not eaten because they are very bitter. They are commonly used to make products such as perfume, liqueur, and marmalade, according to The University of Arizona Cooperative Extension. Sweet oranges are typically eaten fresh or juiced. There are many popular types, including navel, Valencia, and blood oranges, which also have their own subvarieties:

Parent Washington

This variety of navel orange is extremely popular and likely to be what you pick up when you see an orange simply labeled “navel orange” at the store, according to The University of Arizona Cooperative Extension. Like other navel oranges, Washington parent oranges are deliciously sweet, easy to peel, and seedless.

Cara Cara

Another type of navel orange, this variety is known for its pretty pink color and complex berry flavor.

Valencia Oranges

These oranges are commonly used for juicing due to their high sugar content, rich flavor, and vibrant orange color, according to The University of Arizona Cooperative Extension. The University of California in Riverside Givaudan Citrus Variety Collection lists dozens of varieties, but these types of oranges are typically sold as Valencia or juice oranges.

Blood Oranges

These oranges are characterized by a deep red color (hence the name), which indicates a high level of antioxidants called anthocyanins. According to a review, research shows that ingesting this powerful compound in blood oranges may be beneficial in reducing the risk of chronic conditions such as cardiovascular disease and cancer. There are several types of blood oranges, including moro and sanguinelli.

Oranges are high in vitamin C, with 109 percent of your daily value found in just one large orange, says Kelsey Lorencz, RD, nutrition advisor for Fin vs. Fin, a website that reviews wellness platforms. “They're also a good source of folate and thiamine, two B vitamins important for keeping your nervous system healthy. One large orange has 4.5 grams of fiber, making it a high fiber food.”

According to the U.S. Department of Agriculture, 1 cup of oranges contains:

• 84.6 calories
• 1.69 grams (g) protein
• 0.2 g fat
• 21.2 g carbohydrates
• 4.32 g fiber
• 16.8 g sugars
• 2 milligrams (mg) calcium
• 0.18 mg iron
• 326 mg potassium
• 0 mg sodium

Oranges also contain an antioxidant called hesperidin, which is a bioflavonoid that research suggests may help protect against diseases that stem from inflammation, such as arthritis and neurodegenerative disorders, notes Rizzo.

Perhaps best known for their vitamin C content, oranges have a lot of nutritional perks. When eaten as part of a balanced diet, these citrus fruits may benefit your overall health in the following ways.

Help Boost Your Immune System

Oranges may boost your immune system, thanks to their vitamin C content. Research shows that vitamin C helps your immune system form antibodies and get them where they need to go to fight infections. Vitamin C can also help protect the body from damage caused by environmental factors and unhealthy habits such as tobacco smoke, ultraviolet rays, and fatty, fried foods.

Reduce Inflammation

Vitamin C is an antioxidant that may help prevent chronic inflammation in the body, which is linked to heart disease and diabetes, according to the Academy of Nutrition and Dietetics. Fruits such as oranges also contain phytochemicals that help protect your body against the long-term inflammation that’s associated with chronic illnesses.

One review found that orange juice was helpful in reducing the inflammation that occurs in the body after eating a high-fat, high-carbohydrate meal, which has been linked to increased risk of cardiovascular disease.

Support Heart Health

According to the National Institute of Health’s Office of Dietary Supplements, people who tend to eat more foods that are rich in vitamin C seem to have a lower risk of developing heart disease. However, it’s not clear whether vitamin C in supplemental form could help prevent oxidative effects on the heart or if such effects may be gained only by eating antioxidant-rich foods such as oranges and other fruits and vegetables.

One small but interesting study of healthy adults found that taking a supplement of citrus fruit extracts (grapefruit and bitter orange) and olive leaf extract for eight weeks was associated with reduced blood pressure, improved inflammation and total cholesterol levels, and other signs that suggested such supplements may play a role in decreasing risk of cardiovascular disease.

Help Manage Diabetes

Despite the bad reputation that fruits may have due to sugar content, oranges aren’t considered off-limits for people with diabetes. In fact, the American Diabetes Association includes citrus fruits such as oranges on its list of superstar foods that are good for diabetes, taking particular note of the fact that these fruits are rich sources of vitamin C, fiber, potassium, and folate.

What’s more, citrus flavonoids may have potential anti-diabetic effects in the body, such as better glycemic control, insulin sensitivity, and lipid profiles, according to a review of studies on animals and cells. These preliminary findings show that further studies are needed to confirm whether oranges and other citrus fruits can indeed have these effects on humans.

Promote Eye Health

According to the American Academy of Ophthalmology (AAO), vitamin C is critically important for eye health, and this and other antioxidants may help reduce your risk of developing or slowing the progression of eye conditions such as cataracts and age-related macular degeneration (AMD).

For people who have early to moderate forms of AMD, nutritional supplements, which include vitamin C, along with a healthy diet, may help reduce the risk of the disease getting worse and developing into advanced AMD, according to the AAO.

“Oranges can definitely be part of a weight loss diet, since they are low in calories,” says Rizzo. “That said, weight loss comes down to maintaining a small calorie deficit over a period of time. If you’re eating oranges and consuming more calories than you are burning off, then you won’t be able to lose weight.”

Despite any claims you have heard or read online, there isn’t such a thing as an orange diet. However, oranges plus a variety of other fruits and vegetables can be incorporated into a weight-loss promoting diet. According to the Centers for Disease Control and Prevention, most fruits and vegetables are lower in fat and calories than other foods and contain a lot of water and fiber. This means you’re more likely to feel fuller on fewer calories, which may promote weight loss.

“Being a high-fiber food, oranges have the superpower of filling you up while not adding a lot of calories to your diet,” explains Lorencz. “You can get over 10 percent of your daily fiber needs from just one orange.”

Whether you’re purchasing oranges from a store or picking them straight from a tree, here are some key tips to help you select them at their peak ripeness — and some strategies to keep them fresh for as long as possible.

Selection

While oranges are typically available year-round in grocery stores, thanks to worldwide cultivation, citrus fruits are usually in season in the United States between November and March, according to the Center for Nutrition in Schools at the University of California in Davis.

When selecting oranges, look for ones that are heavy for their size, have vibrant rinds that are firm and smooth, and smell aromatic, advises The Foundation for Fresh Produce, an organization that works to increase Americans’ consumption of fruits and vegetables for better health. Dully colored, lightweight, and odorless oranges are likely unripe. Furthermore, you’ll want to avoid citrus fruits that have signs of rotting, such as soft spots or wrinkly rinds.

Storage

Once you’ve found the perfect oranges to purchase and take home, you have a few options for storage depending on how soon you want to use them. Oranges may be left at room temperature on your kitchen counter for one to two days or refrigerated in a produce drawer for one to two weeks, according to The Foundation for Fresh Produce.

Oranges are perhaps most often eaten whole in raw, peeled form. You can also make homemade orange juice without the added sugars you may find in concentrated store-bought versions.

“Oranges are in season in the winter, so I like to add them to my morning oatmeal for some natural sweetness,” says Rizzo. “They also add sweetness and hydration to a smoothie. And they pair nicely with savory flavors, like those in this beet salad.”

And of course, oranges are a perfect, portable healthy snack you can eat anytime. “I love snacking on oranges along with a handful of almonds for a filling and satisfying snack,” adds Lorencz.

Some other delicious ideas to incorporate oranges into your diet suggested by The Foundation for Fresh Produce:

• Add orange slices to a fruit salad with yogurt.
• Combine orange juice with fresh lemon juice to make orange lemonade.
• Add to a bed of salad greens for a touch of sweetness and zest.
• Make an orange salsa to use with fish or chicken by combining orange peel, chopped oranges, tomatoes, green onions, cilantro, and lime juice.
• Saute chicken, bell peppers, onion, garlic, and ginger with a bit of lemon juice, brown sugar, sesame oil, and soy sauce; then stir in chopped orange pieces and serve in lettuce leaves to make a healthy wrap.

While there are few known health risks associated with eating oranges, it’s important to take precautions so that you don’t get too much of a good thing. “It is safe to eat oranges every day,” says Lorencz, but “you may want to consider how much you're eating at once because the natural sugars and acid in oranges can lead to stomach upset in some people.”

For instance, people who have gastroesophageal reflux disease, a chronic digestive condition that can cause frequent heartburn (a painful, burning discomfort in the middle of the chest), may find that certain foods, including citrus fruits, may trigger or worsen their symptoms, according to Johns Hopkins Medicine.

And some people with certain health conditions or those who are taking medications that should not be taken with citrus fruits should speak to their doctor before reaching for oranges.

People who have hemochromatosis (a condition in which iron levels become too high, which could potentially damage your heart, liver, pancreas, and more) or hyperkalemia (abnormally high levels of potassium in the blood, which can lead to dangerous heart rhythms, or arrhythmias) may also be cautioned by their doctor to limit or avoid certain foods, including ones that are high in vitamin C, which may increase levels of potassium and iron.

In addition, if you take certain antibiotics, chemotherapy drugs, or beta-blockers, talk with a doctor about whether it’s safe to eat oranges, as research suggests that certain medications may interact with orange juice.

Finally, be aware that some side effects are associated with oranges, as well as the potential for an allergic reaction in some individuals.

Side Effects

According to Lorencz and Rizzo, potential side effects from oranges include:

• Diarrhea, nausea, and stomach cramps from too much vitamin C
• Itchy mouth or throat, which may be a sign of an allergy
• Worsened acid reflux, due to the potential of oranges aggravating the stomach lining
• High blood potassium if you have kidney issues

Is It Possible to Be Allergic to Oranges?

While an allergy to oranges isn’t considered common, any food can cause an adverse reaction, according to the American College of Allergy, Asthma & Immunology (ACAAI). An allergic reaction to food occurs when your immune system overreacts to something you’ve eaten, triggering symptoms such as hives, swelling of the tongue, shortness of breath, and even anaphylaxis (a life-threatening condition that can cause you to go into shock and stop breathing).

One study published in PLoS One found that people who have grass pollen allergies may have an increased risk for citrus allergies. And according to the American Academy of Allergy, Asthma & Immunology, oral allergy symptoms (OAS) from eating oranges are most common in people who are allergic to Timothy and orchard grasses, which pollinate during the summer months. OAS can include itchiness and swelling of the mouth, face, lip, tongue, and throat.

But testing positive for sensitivity to citrus doesn’t always mean someone will experience an allergic reaction to the food. According to the ACAAI, not everyone with a pollen allergy experiences OAS after eating oranges.

And the researchers of the PLoS One study noted that many people who tested as having a sensitivity to citrus fruits did not experience OAS after eating the fruit.

If you experience possible symptoms of OAS when you eat oranges, talk to your doctor right away or seek emergency help if the symptoms seem serious.

While historically exclusive to tropical and subtropical climates, the Almanac notes that citrus fruits such as oranges may be grown in almost any region if you take the right steps. To grow your own orange trees, it recommends the following:

• First determine the right time to plan your orange trees. Spring is best in most parts of North America, while oranges may be planted any time of year in Southern California, Florida, and other parts of the so-called Citrus Belt.
• Plant citrus trees 12 to 25 feet apart in a warm, sunny area of your yard that’s protected against wind.
• If your orange tree is in a pot, be sure to use well-draining soil and don’t overwater it.
• Oranges may ripen between 8 to 15 months, depending on the type and size.