D-Limonene: Citrus Treatment for Heartburn, Tumors and Gallstones
D-limonene
a major constituent of several citrus oils (orange, lemon, mandarin, lime, and
grapefruit), and is listed in the Code of Federal Regulations as generally recognized
as safe (GRAS) for a flavoring agent that can be found in common food items
such as fruit juices, soft drinks, baked goods, ice cream, and pudding [1-2].
In addition, d-limonene has some specific medicinal properties for human
health, including natural heartburn protectant, slowing tumor progression and
helping to dissolve gallstones.
Natural Heartburn Protectant
D-limonene has been shown to be effective in relieving
occasional heartburn. In one study, 19 adults used d-limonene to relieve their symptoms.
Participants took one capsule containing 1,000 mg d-limonene every day or every
other day. On the second day of taking d-limonene, 32% of participants
experienced a significant relief of symptoms; this relief rate improved
gradually during the regimen. By day fourteen, 89% of participants achieved
complete relief of symptoms [3].
In a double-blind, placebo-controlled study, 13
participants suffering from mild/moderate to severe heartburn received 1,000 mg
d-limonene daily or every other day, or a placebo. On day four, 29% of
participants in the d-limonene group experienced significant relief of
symptoms, compared to no relief of symptoms in the placebo group. By day fourteen,
86% of participants achieved complete relief of symptoms, compared to 29
percent of participants in the placebo group [3].
Results from these two studies suggest the beneficial
effects of d-limonene appear to develop over time, with the best results
attained after following a 10-capsule regimen. Research suggests d-limonene may
neutralize the effect of gastric acid by coating the stomach wall and
protecting the mucosal and esophageal lining from gastric acid exposure [3].
Some researchers believe d-limonene may support healthy peristalsis (movement
of food and waste through the gastrointestinal tracts), which may also help [4].
Slows Tumor Progression
Research
on cancer cells indicates that limonene may prevent lymphoma, breast, skin,
liver, lung, colon, and gastric cancer. In fact, D-limonene taken orally in
21-day cycles concentrated in tumor tissue in patients with advanced cancer and
may slowed disease progression [5]. Limonene might help reduce the risk of
cancer by inducing phase I and phase II detoxification enzymes in the liver
that metabolize carcinogens into harmless products. Limonene may also prevent
tumor cell proliferation [6]. In addition, preliminary research suggests that
limonene stimulates immune system activity [7].
Helps Dissolve
Gallstones
During in-vitro laboratory experiements, d-limonene
dissolved human gallstones within two hours [8]. In patients who had recently
had gallstone surgery, infusion of 20 mL d-limonene every other day dissolved
gallstones overlooked during surgery. In some patients gallstone dissolution
occurred after only three infusions [8]. A study with 200 patients reported a
direct infusion of 20-30 mL d-limonene (97% solution) completely or partially
dissolved gallstones in 141 patients. The duration of the treatment ranged from
three weeks to four months [9]. Although these studies all used direct infusion
of d-limonene into the gallbladder, researchers have also suggested that
systemic or "oral dissolution" may also be effective [10].
References
1. Anonymous. Limonene monograph. Cri Rev Food Sci Nutr 1999;39:260-265.
2. The United States Code of the Federal Regulations, Title 21, Part
182.60.
3.
Sun J. D-Limonene: Safety and Clinical Applications. Altern
Med Rev 2007;12(3):259-264.
4.
Lis-Balchin M, Ochocka RJ, Deans SG, et al. Bioactivity
of the enantiomers of limonene. Med Sci Res 1996;24:309-310.
5.
Vigushin DM, Poon GK, Boddy A, et al. Phase I and
pharmacokinetic study of D-limonene in patients with advanced cancer. Cancer
Research Campaign Phase I/II Clinical Trials Committee. Cancer Chemother
Pharmacol 1998;42:111-7.
6.
Crowell PL. Prevention and therapy of cancer by dietary
monoterpenes. J Nutr 1999;129:775S-778S.
7.
Raphael TJ, Kuttan G. Immunomodulatory activity of
naturally occurring monoterpenes carvone, limonene, and perillic acid. Immunopharmacol
Immunotoxicol 2003;25:285-94.
8.
Igimi H, Hisatsugu T, Nishimura M. The use of
d-limonene preparation as a dissolving agent of gallstones. Am J Dig Dis 1976;21:926-939.
9.
Igimi H, Tamura R, Toraishi K, et al. Medical
dissolution of gallstones. Clinical experience of d-limonene as a simple, safe,
and effective solvent. Dig Dis Sci 1991;36:200-208.
10. Plaisier
PW, Vergunst H, Terpstra OT. Dissolution of gallstones. Dig Dis
1993;11(3):181-8.