Sublingual vitamin B-12 refers to preparations of the vitamin as tablets or lozenges that are placed under the tongue for direct absorption into the tissues. Some sublingual B-12 products may claim to promote better absorption than other oral supplements, but no evidence exists to support this claim, notes the National Institutes of Health Office of Dietary Supplements. Doctors may prescribe oral or sublingual vitamin B-12 supplements to treat B-12 deficiency or pernicious anemia.
Effectiveness for Treating Elevated Homocysteine Levels
Vitamin B-12 deficiency can cause increased levels of homocysteine, an amino acid in the blood. Increased homocysteine levels have been associated with an increased risk for cardiovascular disease. A study by researchers at the University of Bridgeport College of Naturopathic Medicine and published in November 2006 in the "Journal of Alternative and Complementary Medicine" investigated the relative efficacy of sublingual and oral vitamin B-complex in treating elevated homocysteine levels over a 6-week period. Both treatments significantly reduced homocysteine levels. The study found no significant difference in the effectiveness of the two treatments.
Effectiveness for Treating Vitamin B-12 Deficiency
A study published in December 2003 in the "British Journal of Clinical Pharmacology" investigated the efficacy of sublingual and oral vitamin B-12 in treating vitamin B-12 deficiency. The study found that 500 microgram doses of sublingual and oral vitamin B-12 were equally effective at correcting deficiency.
Significance
Data from the Framingham Offspring Study suggests that people who take vitamin B-12 supplements or eat fortified cereals more than four times each week are less likely to have vitamin B-12 deficiency, notes the National Institutes of Health Office of Dietary Supplements. Individuals at high risk for vitamin B-12 deficiency should consider taking an oral or sublingual supplement. High-risk individuals include older adults, vegetarians, vegans, people who have had gastrointestinal surgery and people with atrophic gastritis, pernicious anemia, Crohn's disease or celiac disease.
Dose and Absorption
The body absorbs only a small percentage of vitamin B-12 from food and supplements. For example, healthy people may absorb only 10 micrograms of a 500 micrograms oral B-12 supplement, according to the National Institutes of Health Office of Dietary Supplements. Doctors may recommend doses of 300 to 10,000 micrograms of oral or sublingual vitamin B-12 to treat vitamin B-12 deficiency or pernicious anemia, notes MedlinePlus. Doses of 500 micrograms in combination with folic acid and pyridoxine may be used to treat elevated homocysteine levels.
References
- National Institutes of Health Office of Dietary Supplements: Vitamin B-12 Quick Facts
- "Journal of Alternative and Complementary Medicine"; A single-center, double-blinded, randomized controlled study to evaluate the relative efficacy of sublingual and oral vitamin B-complex; Y Yazaki, et al.; November 2006
- "British Journal of Clinical Pharmacology"; Replacement Therapy for Vitamin B12 Deficiency: Comparison Between the Sublingual and Oral Route; A Sharabi, et al.; December 2003
- MedlinePlus; Vitamin B-12; April 4, 2011
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