What Is Thiamine?
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Medically reviewed by Kristie Reed, PharmD
Thiamine (vitamin B1) is an essential nutrient involved in energy metabolism and cellular function. The body can't produce thiamine on its own, but the vitamin is found in several foods and can also be taken as a dietary supplement.
Most people in the United States consume enough thiamine through diet to meet their needs. However, some populations, such as people with alcohol dependence, older adults, and people with certain medical conditions, may require thiamine supplements to maintain optimal levels.
Thiamine supplements can offer health benefits for these groups, and are generally safe to take. However, the B1 supplements may have some side effects.
Benefits of Thiamine
Thiamine plays a critical role in energy metabolism and is necessary for growth, cellular function, and development. Some people may have low or deficient levels of thiamine because they lack the ability to properly absorb the thiamine found in foods, have a medical condition that increases thiamine excretion, or don't consume enough thiamine in their diet. For these groups, taking thiamine supplements can benefit health in several ways.
May Benefit People With Diabetes
People with diabetes are more likely to have low levels of thiamine due to increased thiamine excretion through the kidneys. Studies show renal clearance of thiamine increases by 24-fold in people with type 1 diabetes and by 16-fold in people with type 2 diabetes. This is why people with diabetes have significantly lower thiamine levels compared to people without diabetes.
Thiamine is necessary for carbohydrate metabolism, so having low thiamine levels could lead to high blood sugar and diabetes-related complications, such as diabetic neuropathy or nerve damage caused by high blood sugar.
Evidence suggests thiamine supplements may benefit people with diabetes in several ways when taken as a standalone supplement or when combined with other nutrients.
A study that included 82 people with obesity and type 2 diabetes found supplementation of α-lipoic acid (ALA), carnosine, and thiamine for eight weeks reduced blood sugar levels by 7% and reduced the long term blood sugar control marker hemoglobin A1c (HbA1c) by 28% compared to a placebo.
Another review found taking thiamine supplements in doses of 100–900 mg per day for up to three months led to small, yet significant improvements in blood sugar control, increased heart-protective HDL cholesterol, and reduced triglyceride levels in people with type 2 diabetes. However, the researchers noted larger studies lasting for one to two years are needed to fully understand how thiamine supplements may improve the health of people with diabetes.
Findings from older research suggest Benfotiamine, a specific fat-soluble form of supplemental thiamine, may improve diabetes-related nerve damage and its symptoms. However, not all studies have found a benefit, and evidence is limited at this time.
May Help Protect Older Adults from Deficiency and Cognitive Decline
Older adults are more likely to develop low or deficient thiamine levels due to decreased ability to properly absorb thiamine from food, and a low dietary intake of this nutrient. They may also use medications that deplete thiamine or interfere with its absorption. Studies show up to 30% of older adults have thiamine deficiency.
Thiamine deficiency can negatively impact health in many ways and could increase the risk of cognitive decline. Thiamine deficiency is associated with oxidative stress, mitochondrial dysfunction, a buildup of acid in the brain, amyloid plaque deposition, and abnormal brain function, all of which are features of Alzheimer’s disease.
Some evidence suggests supplementing older adults who have early signs of Alzheimer’s disease may help prevent disease progression and protect brain health.
A study that included 70 older adults with mild cognitive impairment or mild dementia due to Alzheimer’s disease found dementia rating scores were 43% and 77% lower in the group supplemented with 600 mg of benfotiamine per day for 12 months compared to the placebo group. Benfotiamine also prevented increases of advanced glycation end products (AGEs), toxic compounds implicated in Alzheimer's disease.
Necessary for People With Certain Medical Conditions
People with alcohol dependence and people with certain medical conditions, such as inflammatory bowel disease (IBD) and HIV, lack the ability to maintain healthy thiamine levels.
For example, up to 80% of people with alcohol dependence develop thiamine deficiency due to decreased intestinal absorption, poor dietary intake, liver damage, and decreased ability to convert thiamine into its active form.
People with IBD, such as Crohn’s disease, and people with HIV/AIDS, are also more at risk for developing a thiamine deficiency due to poor dietary intake and absorption issues. People with heart failure are also at risk for thiamine deficiency.
Studies show supplementation with thiamine may help reduce fatigue in people with Crohn's disease.
A small study in 40 people with Crohn’s disease found supplementation with 600 to 1,800 mg of thiamine per day for four weeks significantly reduced symptoms of fatigue compared to a placebo. Participants who received the thiamine treatment had an average reduction of 4.5 points in fatigue after treatment compared with an average increase of 0.75 points in fatigue for the placebo group.
Additionally, people who’ve undergone bariatric surgery are required to take dietary supplements, including thiamine, in order to prevent deficiency.
If you have a medical condition that impacts your ability to maintain healthy thiamine levels, your healthcare provider will recommend an appropriate supplement.
Good Sources of Thiamine
Thiamine is naturally concentrated in several foods and is also added to popular products, like breakfast cereals, through fortification.
The main sources of thiamine in the U.S. diet are fortified breakfast cereals and bread, though it's also found in animal-based foods, such as milk, meat, and seafood.
Here are the top food sources of thiamine:
Fortified breakfast cereal: 1.2 milligrams (mg) per serving, or 100% of your daily value (DV)
Enriched egg noodles: 0.5 mg per cup, or 42% DV
Pork chop: 0.4 mg per 3-ounce serving, or 33% DV
Trout: 0.4 mg per 3-ounce serving, or 33% DV
Black beans: 0.4 mg per ½ cup serving, or 33% DV
Enriched English muffin: 0.3 mg per muffin, or 25% DV
Mussels: 0.3 mg per 3-ounce serving, or 25% DV
Acorn squash: 0.2 mg per ½ cup serving, or 17% DV
Enriched pasta, brown rice, sunflower seeds, yogurt, oatmeal, and milk also contain smaller amounts of thiamine.
How to Take Thiamine
Thiamine can be taken on its own as a supplement in a pill or liquid form, and it can also be found in B-complex products and multivitamins.
Thiamine is water-soluble, so it can be taken at any time of day, with or without food. Benfotiamine is a fat-soluble form of thiamine, so it may be better absorbed with a meal or snack containing fat.
However, it’s best to follow instructions on supplement labels as some products, such as those containing multiple nutrients, may be better absorbed when taken on an empty stomach.
Dosage
Most thiamine supplements contain around 1.5 mg of thiamine, but some can contain much higher doses. For example, most B-complex vitamins provide around 100 mg of thiamine per serving, which covers over 8,000% of the DV.
People with thiamine deficiency need much higher doses of supplemental thiamine than what's found in most supplements. For example, people with severe thiamine deficiency require 200 mg of intravenous (IV) or oral thiamine up to three times daily until symptoms resolve, followed by 10mg of oral thiamine per day until normal thiamine levels are obtained.
If you are taking thiamine to treat a deficiency or other medical condition, make sure to talk to your healthcare provider about the appropriate dose.
Is Thiamine Safe?
Like other water-soluble vitamins, thiamine is safe to take, even in high doses. This is because the body excretes any extra thiamine it doesn’t need.
For this reason, the Food and Nutrition Board (FNB) has not established a Tolerable Upper Intake Level (UL) for thiamine supplements. The UL is the maximum amount a nutrient a person can ingest daily without causing harm.
Benfotiamine, which is a fat-soluble form of thiamine, has also been shown to be safe in high doses. One study found doses of benfotiamine ranging from 150 to 1,200 mg were safe and well-tolerated.
Potential Drug Interactions
Thiamine isn’t known to interact with medications. However, some medications can deplete levels of thiamine in the body.
For example, diuretics, such as Lasix, can increase urinary excretion of thiamine.
The chemotherapy drug Fluorouracil may also cause low thiamine levels, possibly by increasing thiamine breakdown and blocking the conversion of thiamine into its active form.
People taking these medications may need to supplement with thiamine in order to maintain healthy levels.
What to Look For
It’s best to purchase thiamine supplements from companies that hire independent third-party laboratories to test their supplements for quality and purity. Many supplement companies are certified by third-party organizations like U.S. Pharmacopeia and NSF International, which help ensure supplement safety and quality.
It’s also important to choose a form of thiamine that you can tolerate. People who have difficulty swallowing capsules may want to choose a liquid or chewable thiamine supplement.
Lastly, if you have sensitivities or allergies, you’ll want to purchase a thiamine supplement that’s free from potential allergens like soy, gluten, tree nuts, and dairy.
Can You Take Too Much Thiamine?
Due to its low level of toxicity, thiamin is considered safe even when taken in high doses. The FNB has not set an upper intake limit for thiamin.
However, you should avoid taking very large doses of thiamine unless it’s recommended and monitored by a healthcare provider to treat a specific medical condition.
Side Effects of Thiamine
Thiamine supplements may cause the following side effects:
Flushing
Hives
Itching
Sweating
Nausea
Weakness
Restlessness
If you experience any of these symptoms while taking a thiamine supplement, stop taking the supplement and contact your healthcare provider for advice.
Thiamine is often combined with other nutrients in dietary supplements, such as multivitamin supplements. Other nutrients and common ingredients found in dietary supplements, such as herbs, may cause additional side effects. Make sure to read the entire label on dietary supplements.
A Quick Review
Thiamine is a B vitamin involved in energy metabolism. Most healthy people obtain enough thiamine through their diets, though some people, such as older adults, people with diabetes, and people with alcohol dependence, may require thiamine supplements in order to maintain healthy levels.
Some research shows thiamine may help protect against cognitive decline in older adults and may offer some health benefits to people with diabetes.
If you need a thiamine supplement, your healthcare provider can help you pick out a high-quality product and recommend an appropriate dose to take to promote optimal health.
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Read the original article on Health.
