Citrus fruits are known to be rich sources of vitamins. Even long people scientists started tracking nutrients, the benefits of this juicy produce were celebrated. Sailors in the 1800s carried barrels of lemon or lime juice to prevent scurvy on long voyages, and many Asian cultures used citrus in traditional medicine. We now know that citrus fruits are packed with nutrients and bioactive compounds.
The abundance of Citrus Fruits
Between 144 and 150 citrus varieties, or cultivars, are grown around the world. Producers grow approximately 108 million tons of citrus fruit annually, ranging in flavors, with colors from pale yellow to brilliant reds, oranges, and greens. Most citrus fruits have similar nutrient profiles, although concentrations of specific nutrients vary.
Vitamin C, or ascorbic acid, is the star of the citrus world. The water-soluble vitamin is necessary for wound healing and a strong immune system. It is also a potent antioxidant that can help protect against cardiovascular disease, cancer, and eye disorders. Many bodily processes, such as synthesizing neurotransmitters and metabolizing proteins, require vitamin C. Our bodies can’t make vitamin C or store water-soluble vitamins, so this essential nutrient must come from dietary sources on a regular basis.
Folate is vital during pregnancy because it is necessary for DNA production and fetal development. Insufficient amounts can lead to birth defects. Adults with insufficient folate are at risk of cardiovascular disease and may experience seizures. Citrus fruit is a rich source of folate. One European study finds that drinking 750 milliliters of orange juice daily over four weeks increased folate concentrations in the blood of adult subjects by up to 18%.
Flavonoids are a type of phytonutrient in citrus fruits. The highest concentrations are in orange or red fruits, such as tangelos, oranges, blood oranges, tangerines, and red grapefruit. Phytonutrients are antioxidants with protective effects on the cardiovascular system. Flavonoids are also associated with lower cholesterol levels and may help stabilize blood glucose levels.
Carotenoids are yellow and orange pigments found in fruits and vegetables. Human consumption of carotenoids is important for vitamin A production, which is necessary for healthy eyes, a strong immune system, and many other bodily processes. Brightly colored citrus fruits, such as lemons, oranges, and tangerines, are rich sources of carotenoids.
Although vitamin C is an important antioxidant, citrus fruits also contain several types of phenolic acids. Phenolics have anti-inflammatory properties that may reduce or relieve allergy symptoms. Some phenolic acids act as indirect antioxidants that influence protective enzymes, enhance metabolic functions of the liver, and regulate platelet production to reduce the risk of blood clots. Many phenolic acids also have protective effects against cardiovascular disease, cancer, and diabetes.
All citrus fruits contain citric acid. Although not a nutrient, this compound has some antioxidant and anti-inflammatory properties. The citric acid in urine inhibits kidney stone formation. It can also coat surfaces of existing stones. The coating blocks the attachment of new material so stones don’t get any bigger.
Citrus fruits are often overlooked as rich sources of minerals like phosphorus, calcium, copper, zinc, manganese, selenium, magnesium, and iron. Most mineral content is in the citrus peels, which also contain vitamins and fiber. Citrus peels can be eaten as candied strips or grated into zest to flavor salads and baking.
Many citrus essential oils contain limonene, an antioxidant with antimicrobial properties. Mandarin and bitter orange essential oils are especially well known as broad-spectrum antibacterial and antifungal agents. Citrus oils are occasionally used as topical treatments for acne and fungal infections. Limonene prepared for oral consumption may relieve an upset stomach or help with weight loss.
Make the Most of Citrus Fruit
Nutrients are distributed throughout citrus peels, pulp, and juice. Peels and pulp have the highest nutrient density, while juice has the lowest density. Many vitamins and phytochemicals in citrus fruit deteriorate after exposure to light, which leads to nutrient loss through storage, transport, and processing. Citrus products, such as juice or canned segments, contain only a fraction of the nutrients available from whole fruits. Consume whole, fresh citrus fruits whenever possible to fully benefit from their nutritional content.