Thiamine mononitrate, or vitamin B1, is available as part of a B-vitamin complex vitamin or sold separately. B vitamins help the body convert fat to energy and often are advertised for weight loss. The University of Maryland Medical Center indicates that B vitamins are all required for optimal health of the liver, skin, eyes, hair and nervous system. Since thiamine is water-soluble, the body typically expels any excess to prevent most side effects. However, thiamine mononitrate is fat-soluble, meaning the body has more difficulty expelling any excess. Anyone with a pre-existing condition has the risk of retaining excess thiamine, which may cause potential side effects.
Thiamine mononitrate is synthetic and has the potential to illicit mild to severe allergic reactions. If you experience trouble breathing, a rash or itchy skin, you should see a doctor quickly. Impurities present in synthetic vitamins are more probable than in the natural sources available for B vitamins. The "Journal of Nutrition" reported in 1985 that diets fortified with thiamine mononitrate do not compensate for lower thiamine levels in rats that were thiamine deficient. Therefore, you may want to seek a more natural source of thiamine.
Thiamine mononitrate is the synthetic form of vitamin B1. Although excess vitamin B1 is excreted from the body efficiently, the fat-soluble synthetic version may accumulate in the liver and other fatty tissues. Accumulation of any vitamin, including thiamine mononitrate, will eventually cause cellular toxicity and can lead to severe liver damage. Since thiamine mononitrate is stored in fat cells, simply stopping ingestion will not reverse the effects of chronic exposure to this synthetic vitamin. If you have any history of liver disease, you should be cautious in taking any supplements that contain thiamine mononitrate. Buying your vitamin B1 supplements from a reputable supplier may help you avoid the more dangerous form of vitamin B1, thiamine mononitrate.
Low levels of thiamine mononitrate are unlikely to cause any severe kidney problems. However, if you have a history of reduced kidney function or kidney disease, you may have an increased chance of kidney failure. The nitrates present in thiamine mononitrate may accumulate in the kidneys and induce kidney stones or cellular death. MedlinePlus indicates that anyone with impaired kidney function may have difficulty filtering nitrates out of their system and should avoid taking thiamine mononitrate. You should talk to your doctor about alternate methods to ensure that you have the proper amount of vitamin B1 in your system.