Evidence

These uses have been tested in humans or animals.  Safety and effectiveness have not always been proven.  Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Key to grades

A
Strong scientific evidence for this use
B
Good scientific evidence for this use
C
Unclear scientific evidence for this use
D
Fair scientific evidence against this use (it may not work)
F
Strong scientific evidence against this use (it likely does not work)

Grading rationale

Evidence gradeCondition to which grade level applies
A

Metabolic disorders

Taking thiamine by mouth may help some complications of metabolic disorders associated with genetic diseases. These include: Leigh's disease (a nervous system disorder causing movement problems), maple syrup urine disease (protein breakdown disorder in which urine smells like maple syrup), pyruvate carboxylase deficiency (rare disorder causing developmental problems in babies), and high blood levels of alanine, an amino acid. Long-term management should be under strict medical supervision.
A

Thiamin deficiency

Humans depend on diet for their thiamine needs. Very little thiamine is stored in the body and depletion can occur within 14 days. Severe thiamine deficiency may lead to serious complications involving the nervous system, brain, muscles, heart, and stomach and intestines. Thiamine deficiency can be associated with alcoholism, poor nutrition, cancer, vomiting associated with pregnancy, bariatric surgery, and hemodialysis. Some people may be more at risk of thiamine deficiency. Those with thiamine deficiency or related conditions should receive supplemental thiamine under medical supervision.
B

Alcoholism

Alcoholics or those experiencing alcohol withdrawal are at risk of thiamine deficiency and its associated complications. Thiamine has been injected into the vein with other nutrients. Further research is needed on the impact of thiamine on alcoholism.
B

Total parenteral nutrition (TPN)

Thiamine has been added to total parenteral nutrition (TPN, nutrition given through the veins) for people who cannot receive thiamine by mouth, such as a multivitamin.
C

Alzheimer's disease

Thiamine deficiency can result in a form of dementia. The relationship of thiamine to Alzheimer's disease and other forms of dementia has been studied. However, there is still controversy over whether thiamine supplementation may benefit people with Alzheimer's disease. More research is needed before a firm conclusion can be made.
C

Anemia

Thiamine-responsive megablastic anemia (TRMA) is a genetic disorder that affects thiamine transport and conversion in the body. Thiamine has been studied for heart problems associated with TRMA, as well as other TRMA symptoms. More information is needed in this area.
C

Athletic performance

Active people who reduce food intake may have a higher risk of vitamin deficiency, including thiamine deficiency. More research is needed in this area.
C

Blood vessel clots

B vitamins have been studied for the treatment of clots in blood vessels. Further research is needed in order to form conclusions.
C

Cancer

Thiamine deficiency has been seen in some people with cancer, possibly due to medication use or poor nutrition. Currently, it remains unclear whether thiamine supplementation may benefit any particular types of cancer. Supplementation may be needed in people with cancer who have or are at risk of thiamine deficiency.
C

Cataract prevention

Early evidence suggests that high dietary thiamine intake may help reduce the risk of cataracts. Further study is needed before a firm conclusion can be made.
C

Cerebellar ataxia (movement disorder due to brain cell damage)

Early research suggests that thiamine supplementation may benefit people with cerebellar ataxia after an illness involving fever. Further research is needed.
C

Clogged arteries

Blood sugar imbalances may increase the risk of clogged arteries. Thiamine has been studied as a way to help widen narrowed arteries. Regular thiamine intake may improve blood vessel function and slow the progression of clogged arteries in people with blood sugar imbalances. Further study is needed.
C

Coma/hypothermia of unknown origin

Thiamine is often recommended in people with coma or hypothermia (dangerously low body temperature) of unknown origin. Thiamine has been studied in people with reduced consciousness due to poisoning. More research is needed.
C

Crohn's disease

Low thiamine levels have been reported in people with Crohn's disease (a form of inflammatory bowel disease). It is not clear whether regular thiamine intake may benefit people with this disease in general.
C

Diabetic complications

Thiamine has been studied for complications associated with diabetes, involving the nervous system, eyes, blood vessels, and kidneys. Thiamine may improve complications such as increased urination, high levels of glucose in the urine, and high blood cholesterol levels. Regular thiamine intake may also help slow the progression of clogged arteries in some diabetics. More research is needed in this field.
C

Epilepsy

Early research suggests that thiamine may improve attention and mental function in people who have epilepsy. Further research is needed.
C

Heart failure

Long-term thiamine deficiency may cause heart failure, which requires thiamine supplementation. It is unclear whether thiamine supplementation may benefit people who have heart failure due to other causes. However, it is reasonable for those with heart failure to take a daily multivitamin including thiamine. More evidence is needed before a firm conclusion can be made.
C

Kidney dysfunction

Vitamin deficiency, including thiamine deficiency, has been linked to long-term kidney dysfunction. Taking a multivitamin is often suggested. However, further research is needed in this field.
C

Leg cramps

Vitamin B supplements have been used to treat leg cramps during pregnancy. However, more studies are needed to determine if this is effective.
C

Menstrual cramps

Early evidence suggests that thiamine may be effective for menstrual cramps. Further research is needed to confirm these results.
C

Mitochondrial disorders

Thiamine has been studied as a treatment for mitochondrial disorders, which occur when there are defects in the mitochondria (a part of the cell that produces energy). More research is needed before conclusions can be made.
C

Pyruvate dehydrogenase deficiency (PDH)

PDH is a disorder caused by the buildup of lactic acid, which may be life-threatening and cause nervous system problems. Early evidence suggests that thiamine supplementation may benefit children with PDH. Further evidence is needed before a firm conclusion can be reached.
C

Rheumatism (joint problems)

Early evidence suggests that B vitamins may reduce pain. Further research is needed to determine the effectiveness of thiamine in rheumatism and related disorders.
C

Temporomandibular joint disorder (TMJ)

TMJ is a disorder of the chewing muscles and joints. A combination of indomethacin and thiamine has been studied for this condition, but was found to be less effective than acupuncture. More research is needed in this field.
C

Thiamin deficiency (elderly people)

Thiamine levels may be lower in elderly people, although there is typically a lack of symptoms. There is limited evidence that thiamine supplementation may benefit people who have low thiamine blood levels. However, general multivitamin use has been suggested in elderly people. More research is needed before a firm conclusion can be made.
D

Hip fractures

Early evidence shows that thiamine lacks benefit for hip fractures. However, research is limited and further study is needed.

Uses based on tradition or theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Abnormal heart rhythms, aging, AIDS/HIV, amnesia, antioxidant, arthritis, Bell's palsy (disorder of nerve that controls face muscles), bladder control, brain damage, canker sores, circulation improvement, death and dying, delirium, Down's syndrome, drug withdrawal, encephalopathy (brain disease), erectile dysfunction, eye disorders, fibromyalgia (long-term body-wide pain), Guillain-Barre syndrome (disorder in which immune system attacks nervous system), hair loss, hepatic encephalopathy (confused thinking due to liver disorders), high blood pressure, insect repellant, kidney failure, lactic acidosis (lactic acid build up), learning, liver damage from drugs or toxins, liver disease, loss of appetite, low back pain, lung disorders, malaria, memory enhancement, menstrual problems, migraine, mood, motion sickness, multiple sclerosis, muscle weakness, myelodysplastic syndrome (disorder of blood cells in the bone marrow), nervous system disorders, neuropathy (nerve damage), optic nerve dysfunction, pain, parasites, poisoning, radiation side effects, refeeding syndrome prevention (metabolic disorders caused by feeding after starvation or poor nutrition), stomach disorders, stress, sudden infant death syndrome (SIDS), tetanus (bacterial infection of the nervous system), tissue healing after surgery, vitamin and nutrient deficiency, weight loss.

This evidence-based monograph was prepared by The Natural Standard Research Collaboration

www.naturalstandard.com