Lemon

Scientific Name(s): Citrus limon (L.) Burm. f. [ medica × aurantifolia ] Family: Rutaceae

Common Name(s): Lemon

Uses

Pharmacologically, lemon is primarily important for its vitamin C nutritional value and for its potassium content. Epidemiological studies associate the intake of citrus fruit with a reduction in the risk of various diseases. Antioxidant and anticancer actions are being investigated, and a role in hypocitraturic calcium nephrolithiasis has been suggested. Lemon also shows some antimicrobial activity.

Dosing

Clinical information is limited. To increase citrate levels, 120 mL of lemon juice, containing citric acid 5.9 g, was diluted and consumed daily.

Contraindications

Contraindications have not been identified.

Pregnancy/Lactation

Generally recognized as safe when used as food. Avoid dosages above those found in food because safety and efficacy are unproven.

Interactions

Chloroquine plasma concentrations may be reduced; iron absorption may be increased.

Adverse Reactions

Erosive effects on tooth enamel and anaphylactic allergy to lemon soap have been reported. Citrus juice is often implicated in the worsening of gastroesophageal reflux disease symptoms.

Toxicology

Research reveals little or no information regarding toxicology.

Botany

The lemon tree is an evergreen, growing to over 6 m in height. Its toothed leaves are light green and the citrus fruit (lemon) is oval, small, and green to yellow. Unlike other citrus varieties, the lemon tree bears fruit continuously. The plant is cultivated in Mediterranean and subtropical climates worldwide. 1 , 2 , 3

History

The lemon originated in Southeast Asia, probably in India or southern China. Its history is sometimes unclear because of the confusion with the similarly appearing citron, a closely related species. The lemon may have been depicted in Roman artwork as early as the first century AD. 3

In the 1600s, physicians became aware that daily intake of lemon juice would prevent outbreaks of scurvy among sailors on long sea voyages. English ships were required by law to carry enough lemon or lime juice for each sailor to get 1 ounce daily, earning them the nickname “limeys.” 4

The California lemon industry became established after the gold rush of 1849. From 1940 to 1965, production increased and the United States became a major provider of lemons. More than 50% of the US lemon crop is processed into juice and other drink products. The peel, pulp, and seeds are used to make oils, pectin, or other products. 3

Lemon juice has long been used as an astringent, diaphoretic, diuretic, gargle, lotion, and tonic. 3 Application of lemon juice in conjunction with exposure to sunlight was once thought to fade tattoos, but this theory was disproven. 5 Lemon has also been used externally for acne, fungus (ringworm and athlete's foot), sunburn, and warts. 2

Chemistry

Citrus fruits in general contain sugars, polysaccharides, organic acids, lipids, carotenoid (pigment), vitamins, minerals, flavonoids, bitter limonoids, and volatile components. 6 , 7 The lemon is a good source of potassium (145 mg per 100 g fruit), bioflavonoids, and vitamin C (40 to 50 mg per 100 g, twice as much as oranges). 2 , 3 The isolation of vitamin C from lemon juice has been performed. 8 Calcium (61 mg) is also present, along with vitamins A, B 1 , B 2 , and B 3 . The fruit is also low in calories, containing 27 Kcal per 100 g. 2 , 3 , 9 Other constituents of lemon include volatile oil (2.5% of the peel), limonene, alpha-terpinene, alpha-pinene, citral, coumarins, mucilage, pectins, and bioflavonoids (mostly from pith and peel). 2 , 10 , 11 , 12 , 13 Flavonoids eriocitrin and hesperidin have been evaluated. 10 , 14 When purchasing supplements for bioflavonoid benefits, note that content varies. Low-cost powdered lemon (and other citrus fruit) peel contains only 1% to 2% flavonoids; however, standardized products contain 10% to 90% flavonoids. 15

Uses and Pharmacology

Pharmacologically, the lemon is primarily important for its vitamin C and potassium content. Epidemiological studies associate the intake of citrus fruit with a reduction in the risk of various diseases. 13 , 16 , 17

Antioxidant effects

German studies in the late 1980s related this effect to the peel. 4 The pectin fiber and lemon oil also possess antioxidant properties. 18

One group of researchers, having identified eriocitrin, hesperidin, and coumarins as antioxidants, pursued experiments in diabetic rats, 14 and venous endothelial cells, 10 as well as in activated Epstein-Barr virus models. 11 Antioxidant mechanisms include the inhibition of radical formation and radical scavenging. 10 , 11 , 13 Clinical trials are lacking.

Cancer

In an experiment with the flavonoid eriocitrin and its metabolites 19 and with coumarins extracted from lemon fruit, 11 apoptosis has been demonstrated in acute myelomonocytic leukemia cells.

A meta-analysis of epidemiological studies associates the consumption of citrus fruit with a larger protective effect against oral cancer (odds ratio [per doc] 0.38; 95% confidence interval 0.26 to 0.56) than with overall fruit consumption. 17 The structure of various chemical constituents of lemon and their relationship to cancer prevention has been investigated. 13 , 20

Nephrolithiasis

Lemon juice has been shown to increase citrate levels in patients with hypocitraturic calcium nephrolithiasis in a small, long-term trial (mean duration, 44.4 months); 120 mL diluted lemon juice containing 5.9 g consumed daily resulted in a clinically important reduction in stone formation. 21 , 22

Other uses

Lemon juice and lemon oil have been evaluated for antimicrobial action. The oil shows some bacteriostatic and antiviral action thought to be due to citral and linalool content. 12 , 13 Lemon has been shown to inhibit the growth of Aspergillus mold, 23 and has been used to disinfect drinking water 24 and to inactivate rabies virus. 25

The sperm-immobilizing properties of lemon juice have been investigated as a potential topical vaginal contraceptive. 26 Lemon juice accelerated the transit of tetrofosmin through the liver parenchyma and improved myocardial imaging in a small study. 27

Dosage

Clinical information is limited. To increase citrate levels, 120 mL of lemon juice, containing citric acid 5.9 g, was diluted and consumed daily. 21

Pregnancy/Lactation

Generally recognized as safe when used as food. Avoid dosages above those found in food because safety and efficacy are unproven.

Interactions

Chloroquine plasma concentrations may be reduced, decreasing the therapeutic effect. 28 Lemon juice may increase iron absorption. 23

Adverse Reactions

Lemon juice may cause loss of gloss, alteration in enamel color, and irregular dental tissue on tooth enamel. 29 , 30 , 31 , 32

Anaphylactic allergy to lemon soap has been reported resulting from a possible cross sensitivity of citrus seed to peanut allergen. 33

Citrus juice is often implicated in the worsening of gastroesophageal reflux disease symptoms. However, no effect on lower esophageal sphincter pressure was demonstrated in a small study, and the effects are not considered to be related to fruit juice acidity. 34

Toxicology

Research reveals little or no information regarding toxicology with the use of lemon.

Bibliography

1. Citrus × Limon (L.) Burm. f. (pro sp.) [ medica × aurantifolia ]. USDA, NRCS. 2008. The PLANTS Database ( http://plants.usda.gov , 8 September 2008). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
2. Chevallier A. Encyclopedia of Medicinal Plants . New York, NY: DK Publishing, 1996:81.
3. Ensminger A, et. al. Foods & Nutrition Encyclopedia . 2nd ed. Boca Raton, FL: CRC Press; 1994:1299-1302.
4. Carper J. The Food Pharmacy . New York, NY: Bantam Publishing; 1988:222-223.
5. Chapel JL, Leonard MW, Millikan LE. Lemon juice, sunlight, and tattoos. Int J Dermatol . 1983;22(7):434-435.
6. Ranganna S, Govindarajan VS, Ramana KV. Citrus fruits—varieties, chemistry, technology, and quality evaluation. Part II. Chemistry, technology, and quality evaluation. A. Chemistry. Crit Rev Food Sci Nutr . 1983;18(4):313-386.
7. Ranganna S, Govindarajan VS, Ramana KV. Citrus fruits. Part II. Chemistry, technology, and quality evaluation. B. Technology. Crit Rev Food Sci Nutr . 1983;19(1):1-98.
8. King CG. The isolation of vitamin C from lemon juice. Fed Proc . 1979;38(13):2681-2683.
9. Murray, M. The Healing Power of Herbs . Rocklin, CA: Prima Publishing Co; 1993:143,366.
10. Miyake Y, Mochizuki M, Okada M, Hiramitsu M, Morimitsu Y, Osawa T. Isolation of antioxidative phenolic glucosides from lemon juice and their suppressive effect on the expression of blood adhesion molecules. Biosci Biotechnol Biochem . 2007;71(8):1911-1919.
11. Miyake Y, Murakami A, Sugiyama Y, Isobe M, Koshimizu K, Ohigashi H. Identification of coumarins from lemon fruit (Citrus limon) as inhibitors of in vitro tumor promotion and superoxide and nitric oxide generation. J Agric Food Chem . 1999;47(8):3151-3157.
12. Fisher K, Phillips CA. The effect of lemon, orange and bergamot essential oils and their components on the survival of Campylobacter jejuni , Escherichia coli O157, Listeria monocytogenes , Bacillus cereus and Staphylococcus aureus in vitro and in food systems. J Appl Microbiol. 2006;101(6):1232-1240.
13. Manners GD. Citrus limonoids: analysis, bioactivity, and biomedical prospects. J Agric Food Chem . 2007;55(21):8285-8294.
14. Miyake Y, Yamamoto K, Tsujihara N, Osawa T. Protective effects of lemon flavonoids on oxidative stress in diabetic rats. Lipids . 1998;33(7):689-695.
15. Liva E. Quality of nutritional supplements, Part II: The good news, the bad news. Nat Pharm . 1999;3(1):18.
16. Johnsen SP, Overvad K, Stripp C, Tjønneland A, Husted SE, Sørensen HT. Intake of fruit and vegetables and the risk of ischemic stroke in a cohort of Danish men and women. Am J Clin Nutr . 2003;78(1):57-64.
17. Pavia M, Pileggi C, Nobile CG, Angelillo IF. Association between fruit and vegetable consumption and oral cancer: a meta-analysis of observational studies. Am J Clin Nutr . 2006;83(5):1126-1134.
18. Polunin, M. Healing Foods . New York, NY: DK Publishing; 1997:64-65.
19. Ogata S, Miyake Y, Yamamoto K, Okumura K, Taguchi H. Apoptosis induced by the flavonoid from lemon fruit (Citrus limon BURM. f.) and its metabolites in HL-60 cells. Biosci Biotechnol Biochem . 2000 64(5):1075-1078.
20. Benavente-García O, Castillo J, Alcaraz M, Vicente V, Del Río JA, Ortuño A. Beneficial action of Citrus flavonoids on multiple cancer-related biological pathways. Curr Cancer Drug Targets . 2007;7(8):795-809.
21. Kang DE, Sur RL, Haleblian GE, Fitzsimons NJ, Borawski KM, Preminger GM. Long-term lemonade based dietary manipulation in patients with hypocitraturic nephrolithiasis. J Urol . 2007;177(4):1358-1362.
22. Seltzer MA, Low RK, McDonald M, Shami GS, Stoller ML. Dietary manipulation with lemonade to treat hypocitraturic calcium nephrolithiasis. J Urol . 1996;156(3):907-909.
23. Ballot D, Baynes RD, Bothwell TH, et. al.The effects of fruit juices and fruits on the absorption of iron from a rice meal. Br J Nutr . 1987;57(3):331-343.
24. Alderman GG, Marth EH. Inhibition of growth and aflatoxin production of Aspergillus parasiticus by citrus oils. Z Lebensm Unters Forsch . 1976;160(4):353-358.
25. D'Aquino M, Teves SA. Lemon juice as a natural biocide for disinfecting drinking water. Bull Pan Am Health Organ . 1994;28(4):324-330.
26. Clarke GN, McCoombe SG, Short RV. Sperm immobilizing properties of lemon juice. Fertil Steril . 2006 85(5):1529-1530.
27. Cherng SC, Chen YH, Lee MS, Yang SP, Huang WS, Cheng CY. Acceleration of hepatobiliary excretion by lemon juice on 99mTc-tetrofosmin cardiac SPECT. Nucl Med Commun . 2006;27(11):859-864.
28. Mahmoud BM, Ali HM, Homeida MM, Bennett JL. Significant reduction in chloroquine bioavailability following coadministration with the Sudanese beverages Aradaib, Karkadi and Lemon. J Antimicrob Chemother . 1994;33(5):1005-1009.
29. Allan DN. Enamel erosion with lemon juice. Br Dent J . 1967;122(7):300-302.
30. Takaoka S, Okada N, Tsugawa K, Morimoto M. Initial changes in human enamel surface caused by the topical application of fresh lemon juice [in Japanese]. Koku Eisei Gakkai Zasshi . 1971;21(1):6-11.
31. Pias MJ. The effects of lemon juice (citric acid) on the surfaces of teeth. Chronicle . 1972;35(8):217-218.
32. Grando LJ, Tames DR, Cardoso AC, Gabilan NH. In vitro study of enamel erosion caused by soft drinks and lemon juice in deciduous teeth analysed by stereomicroscopy and scanning electron microscopy. Caries Res . 1996;30(5):373-378.
33. Glaspole IN, de Leon MP, Rolland JM, O'Hehir RE. Anaphylaxis to lemon soap: citrus seed and peanut allergen cross-reactivity. Ann Allergy Asthma Immunol . 2007;98(3):286-289.
34. Kaltenbach T, Crockett S, Gerson LB. Are lifestyle measures effective in patients with gastroesophageal reflux disease? An evidence-based approach. Arch Intern Med . 2006 8;166(9):965-971.

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