Lemon

Lemon is considered a staple seasoning in kitchens everywhere, thanks to its zesty aroma and flavor.  Its nutritional value cannot be underestimated.

Quick Facts
General Information
  • Common name(s)Lemon
  • Scientific nameCitrus limon
  • Plant typeTree
  • Native regionAsia
  • Main producer(s)India
  • Main Economic UseFood industry, Culinary
Lemon

Lemon is believed to be native to the subtropical and tropical regions of Asia. The citrus fruit made its way to Europe via southern Italy during the 1st century CE, even though ancient Romans did not cultivate it widely. Afterwards, it traveled through Persian and Arabian societies, where it gained esteem. Christopher Columbus is credited with completing the lemon's global tour, as he brought it with him to America in 1493, and a few centuries later, in 1747, James Lind used it to cure scurvy in vitamin C-deficient sailors, though information about lemon and its nutritious properties were still misunderstood.

Medicinal and Nutritional Information

Quick Facts (Medicinal and Nutritional Information)
  • Medicinal actionAntibacterial, Immune stimulant
  • Key constituentsVitamin C, citric acid, 8-geranyloxypsolaren, d-limonene
  • Ways to useCold infusions, Decoctions, Hot infusions/tisanes, Liquid extracts, Food, Freshly ground, Juiced, Syrup
  • Medicinal rating(3) Reasonably useful plant
  • Safety rankingSafe
Lemon

Health Benefits of Lemon

The antibacterial and immune stimulant properties of lemon have led to fruit to many medicinal uses. Lemon has been traditionally used for:

  • Treating scurvy (vitamin C deficiency). Lemon's high vitamin C content made it ideal for staving off scurvy on long sea voyages.

  • Preventing colds and flu. The high antioxidant content in lemon can help it stave off sickness and increase white blood cell count.

  • Relieving stress and fatigue. A traditional aromatherapy, lemon is thought to relax the body. 

In addition, many recent studies have shown lemon can be used for:

  • Treating anemia. Lemon can help improve iron absorption, which can help people with anemia.

  • Alleviating canker sores and oral bacterial infections. Lemon is often found in mouthwash because of this ability. The antioxidants in it enhance the immune system and stimulate white blood cell production, which can help fight infections.

How It Works

Lemon contains high amounts of vitamin C (ascorbic acid), around 37 mg per fruit. This antioxidant vitamin is responsible for most of lemon's medicinal properties. Vitamin C has been shown to enhance the immune system in several ways, including the stimulation of white blood cell production, which helps the body to fight infections. The ascorbic acid also plays an essential role in regenerating vitamin E from its oxidized form, and improving iron absorption.

The oil from lemon peel contains certain antibacterial compounds, such as 8-geranyloxypsolaren.

An important terpene contained in lemons, as well as in other citrus fruits, is d-limonene, which is a natural solvent of cholesterol and has been used clinically to dissolve cholesterol-containing gallstones. Because of its gastric acid neutralizing effect and its support of normal peristalsis, it has also been used for relief of heartburn and gastroesophageal reflux (GERD).

Lemons' citric acid is an important compound in fuel metabolism. It plays a role in turning carbohydrates into energy that cells can use. For this reason, citric acid can help reduce feelings of fatigue and mitigate stress. In terms of nutritional value, lemons are a good source of simple carbohydrates, which give the body energy.

Sesquiterpenes are what give lemons their distinct citrus aroma.

Lemon Side Effects

Lemon has no real side effects other than those associated with citrus allergies. However, in such cases, lemon consumption can be very dangerous, since repeated consumption may trigger a potentially lethal anaphylactic shock. Nevertheless, citrus allergies are fairly rare and, because of cross contamination, often mistaken for other allergies, such as nuts or dairy.

How to Consume Lemon

Remedies

A way of concentrating the antibacterial benefits of lemon is consuming it as a remedy.

Main preparations: Cold infusions, decoctions, tea, liquid extracts, capsules

Lemon has a variety of medicinal applications, and most of lemon remedies involve the use of the peel, since it is the source of lemon oil, pectin and citric acid. Both peel and flesh of lemon boast antibacterial, antiinflamatory, and antipyretic properties. Lemon peel extract can also be applied topically to the mouth and gums. A very popular remedy to relieve the symptoms of cold, as well as scurvy, is to drink the fresh juice a lemon mixed it with honey. The ascorbic acid of lemons can also be found in many dietary supplements.

Foods

The best way to take advantage of both immune stimulant and nutritional benefits of lemons is consuming them in their fresh form.

Main ways: freshly ground, juice

To make the most of lemon's rich content of vitamin C (ascorbic acid), as well as its anti-scurvy and energizing effects, is better to use it fresh and consume it immediately. Lemon can used as an ingredient for salad dressings and refreshing beverages. Although it loses its antioxidant properties when cooked, lemon can be used to marinate seafood dishes, pasta, and all kind of meats, where it will provide its beneficial, aromatic oils.

Buying

Quick Facts (Buying)
  • Where to buySupermarkets, Online herb stores

Fresh lemon is an everyday commodity found throughout the year in most supermarkets and grocery stores. Regions that boast the right growing climate may have access to fresher forms of the fruit via local farmers' markets. Though primarily bought fresh, lemon juice and oil are also available commercially.

Fresh lemon, usually of the Eureka variety, is available to most consumers year-round in generic food markets as well as more specialized stores, provided there is a produce section. They are pre-picked and normally grouped together in a crate so that consumers may pick whatever individual fruit they prefer. Lemon juice is also widely sold in supermarkets, though it can be homemade using fresh fruit. Lemon oil is somewhat harder to find, though health stores and online sources both carry the product.

As stated above, strictly lemon supplements are not in great supply, though vitamin C supplements that contain lemon flavoring can be found in many department stores, supermarkets, and pharmacies. Online retailers are also a great option when looking for specialized products.

Growing

Quick Facts (Growing)
  • Life cyclePerennial
  • Harvested partsFruit
  • SoilLoamy sand
  • Soil pH6.6 – 7.3 (Neutral)
  • Growing habitatSubtropical regions
  • USDA Plant Hardiness Zones9a (From −6.7 °C (20 °F) to −3.9 °C (25 °F)), 9b (From −3.9 °C (25 °F) to −1.1 °C (30 °F)), 10a (From −1.1 °C (30 °F) to +1.7 °C (35 °F)), 10b (From +1.7 °C (35 °F) to +4.4 °C (40 °F)), 11a (From +4.4 °C (40 °F) to +7.2 °C (45 °F)), 11b (From +7.2 °C (45 °F) to +10 °C (50 °F))
  • Plant spacing average5 m (16.4 ft)
  • Potential insect pestsAphids, Moths
  • Potential diseasesPhytophthora spp.

Growing Guidelines

  • Lemons grow best in tropical, semitropical and temperate climates. Leaves will fall at 22 - 24°F (-6 to -4°C), and at 20°F (-7°C) the trunk will be severely damaged. Flowers and young fruits die around 29°F (-2°C), and nearly mature fruits will be badly damaged below 28°F (-2°C).
  • Thanks to a shallow root system, lemon trees have prospered year-round all over the world in all types of soil, as long the range of pH is 5.5 - 6.5. If acidity is high, it is necessary to apply lime to achieve the optimum level.
  • Lemon trees require very good water drainage and adequate irrigation.
  • Lemon trees are widely grown from seed, although some varieties are propagated by root cuttings.
  • Lemon trees should be spaced 25 feet (8 m) apart each way. If crowded or "hedged", production declines.
  • The trees must be pruned when young and kept below 10 - 12 feet (3 - 4 m) in height.
  • Lemon trees are very sensitive to herbicides, so weeds need to be carefully controlled.
  • Most common pests of lemon trees are scales and mites. In California, young lemon trees sometimes requires protection from wild rabbits.
  • Lemon trees are also susceptible to a variety of diseases, such as branch knot, damping-off, leaf spot, green scurf, tar spot, felt fungus, root rot, and a variety of molds.

Additional Information

Plant Biology

Lemon tree is a perennial than can reach 10 - 20 feet (3 - 6 m) in height and usually has sharp thorns on the twigs. Its glossy leaves are reddish when young and become dark green, 2.5 - 4.5 inches (6 - 11 cm) long. The white and purplish, mildly fragrant flowers of lemon can bloom solitary or more clustered in the leaf axils, have four to five petals approximately one inch (2 cm) long, and around 20 - 40 united stamens with yellow anthers.

Lemon fruit is round shaped with a nipple-like protuberance at the apex, and is 2 - 4 inches (5 -10 cm) long. Lemon fruit color can go from light yellow to bright and dark green.

  • Classification
    Scientifically known as Citrus limon, the lemon is part of the Rutaceae or citrus family, and it is thought to be a hybrid between the sour orange and citron fruits. Lemon trees range in form and size from herbs and shrubs to full-grown trees, and their flowers are white tinged with purple before ripening into fruit form. Several varieties exist, though some are more commercially produced than others. The lemon's fruit and peel are the most useful and harvested parts.
  • Varieties and Subspecies of Lemon

    There is a myriad of varieties of lemon, many of which are considered hybrids with other citrus fruits. Only in the U.S., there are more than  21 commercial cultivars of lemon, but the most commonly grown type is the 'Eureka' lemon, also known as "four seasons" because it grows year-round. Another particularly famous strain is the 'Sorrento', an Italian lemon that is used to make the liqueur limoncello.

Economic Data

Economic Importance of Lemon
Approximately 16% of the global yield of lemon comes from India.

These days, lemon is a worldwide staple and one of the most important crops currently grown. It's primarily used in food and beverage preparation, as a garnish, or as the main ingredient featured in several ethnic cuisines, but other important industries such as perfumery, personal care, and cleaning also utilize the fruit. In addition, herbal medicine lauds lemon as an additive in nutritional supplements for its vitamin C and other antioxidants. Around 16% of the world's lemon production comes from India, though Spain and South America also benefit from its cultivation.

Other Uses of Lemon

  • Cleaning. Besides its physical benefits, lemon is also a great cleaning agent. The fruit's juice can brighten cookware, deodorize, remove grease, disinfect, and dissolve grime, making it an ideal component in sanitary products as well as home remedies.
  • Perfume. Perfumes are sometimes scented with its aroma, as it is associated with cleanliness and freshness.
  • Timber. The wood is fine-grained, compact, and easy to work. In Mexico, it is carved into chessmen, toys, small spoons, and other articles.
  • Power. Scientific studies reveal that lemon can be a possible source of electricity by attaching it to electrodes.

Bibliography

  • Encyclopedia of Herbal Medicine, p. 85
  • Medicinal Plants of the World, p. 107
  • USDA Nutrient Database, Basic Report: 09150, Lemons, raw, without peel
  • A Treatise on the Scurvy
  • Journal of Endourology, Quantitative Assessment of Citric Acid in Lemon Juice, Lime Juice, and Commercially-Available Fruit Juice Products, 2008
  • The Plant Journal, Citrus fruit flavor and aroma biosynthesis: isolation, functional characterization, and developmental regulation of Cstps1, a key gene in the production of the sesquiterpene aroma compound valencene, 2003
  • Drugs Under Experimental and Clinical Research, Oxidative stress and antioxidants at skin biosurface: a novel antioxidant from lemon oil capable of inhibiting oxidative damage to the skin, 1999
  • Fruits of Warm Climates, Lemon, pp. 160–168
  • Journal of Food Science and Technology, Isolation and extraction of antimicrobial substances against oral bacteria from lemon peel, 2011
  • Linus Pauling Institute, Vitamin C
  • Journal of Clinical Biochemistry and Nutrition, Effects of Citric Acid and l-Carnitine on Physical Fatigue, 2007
  • Alternative Medicine Review, D-Limonene: safety and clinical applications, 2007