Also known as vitamin B1, thiamin (or thiamine) is one of the B group of vitamins. Essentially, the B vitamins are heavily involved in various metabolic pathways and energy production. That being said, each individual B vitamin has its own role to play. Likewise, there are various differences between each, both in terms of availability and stability. Today, we'll look at the specifics of vitamin B1 - thiamin.
What is thiamin?
In its pure form, thiamin consists of white crystals which dissolve in water. These crystals smell and taste a little like yeast.
Thiamin is chemically stable up to 100°C when dry - for example, baking in an oven. Conversely, in a wet environment with water present, thiamin is broken down quickly and easily.
In your body, thiamin combines with phosphoric acid. In doing so, it creates thiamin pyrophosphate - a coenzyme crucial in several energy production biochemical pathways.
Why do I need vitamin B1?
Your body uses thiamin to release energy from carbohydrates continuously and steadily. Additionally, it's involved in releasing energy from fat and protein.
Thiamin intake is also important to keep your nervous system healthy. It's involved in acetylcholine production, which is an important neurotransmitter.
How much thiamin do I need from my diet each day?
Since thiamin assists energy release from food, your actual daily requirement is linked to the amount of food you eat. Higher calorie consumption results in increased thiamin needs.
The beauty of nature is that unprocessed, whole foods tend to supply plenty of thiamine. Therefore, if we eat more of these foods, we automatically get more thiamin. Diets high in junk food, refined and fatty foods or alcohol can cause a problem. These types of food contain very little thiamin, but your body still needs it to metabolise the food properly.
In the UK, the British Nutrition Foundation lists the Reference Nutrient Intake (RNI) for thiamin as 0.9mg/day for males aged 11-14. The 15-18 age group has an RNI of 1.1mg/day while 1.0mg/day is advised for those over 18. For females, the RNIs are 0.7mg/day for 11-14-year-olds and 0.8mg/day for women over 15.
In the United States, the National Institutes for Health's Recommended Daily Allowances for thiamin are slightly different. They are 1.2mg/day for adult men and 1.1mg/day for adult women.
Meanwhile, in Australia, the government sets its Recommended Daily Intake (RDI) for thiamin at the same levels as in the US.
Dietary Guidelines for vitamin B1 | thiamin intake in the UK, USA and Australia
Reference Nutrient Intake (RNI)
Recommended Dietary Allowance (RDA)
Recommended Dietary Intake (RDI)
What foods do I get thiamin from?
The germ and bran of cereals and grains are rich sources of thiamin. As a result, wholegrain foods provide good amounts of vitamin B1 while refined versions are often poor sources. However, white flours are often enriched with added thiamin - particularly in countries where wheat is a staple food.
Other good sources of vitamin B1 include pork, milk, liver, eggs, fruit and vegetables. However, cooking in water can reduce the thiamin content quite considerably.
Thiamin | Vitamin B1 Content of Various Foods
Thiamin Content (milligrams)
per 100 grams of edible portion
Breakfast cereal, mixed grain, fortified
Simmer sauce, for chicken, commercial
Bread, from white flour, toasted
Muesli, toasted, added dried fruit & nuts, unfortified
Cashews, raw, unsalted
Tuna, yellowfin, baked
Bread, from wholemeal flour
Sausage roll, commercial
Potato chips or crisps, plain, salted
Basa fillet, raw
Lamb chop, grilled
Egg, chicken poached
Apple, granny smith
Beer, full strength
Figures supplied by the Australian Food Composition Database and AusFoods 2019
What happens if I don't get enough thiamin?
Vitamin B1 deficiency results in a disease known as beriberi. Symptoms include fatigue, weight loss, confusion, depression, dulled reflexes and memory, and even heart problems and peripheral paralysis.
Full-blown deficiencies are rare in developed countries though. More commonly, less severe deficiencies cause unexplained fatigue, appetite loss, irritability and mood swings.
Who should take the most care to regulate their vitamin B1 intake?
As we mentioned earlier, foods high in sugar, processed fats and refined white grains contain virtually no thiamin. Therefore, anyone with a poor diet who eats little in the way of whole foods is potentially at risk of a lower-than-ideal intake.
Of course, being a B vitamin, thiamin is water-soluble too. As a result, it can't be stored in the body significantly. Thiamin can be excreted in urine so mild symptoms of deficiency can occur quite quickly once the diet quality deteriorates.
Additionally, some population groups are more susceptible to thiamin deficiency:
People with alcohol addiction may have lower vitamin B1 levels
In the Western world, chronic alcoholism tends to be the most common cause of thiamin deficiency. The ethanol reduces the amount of thiamin that your body can absorb. Furthermore, it can deplete thiamin levels within the liver as well as lead to further breakdown.
Also, people with alcohol addiction tend to lack the basics of a healthy diet, further restricting their vitamin B1 intake.
The elderly may be more at risk of low thiamin levels
Up to a quarter of older adults may test low on thiamin levels. There are a few reasons why this could be the case. The older people get, the more likely they are to eat less each day. Additionally, they are more likely to suffer from one or more chronic diseases as well as take multiple medications which may interfere with vitamin absorption.
Lastly, the body may naturally absorb less vitamin B1 due to growing older.
Weight loss surgery patients
Some of the risks of bariatric surgery include malabsorption of key vitamins. Often, patients have to heavily modify their diet and may consume far less varied diets.
In general, dietitians and clinicians may monitor thiamin levels after surgery and often recommend micronutrient supplements.
Can I get too much thiamin?
To clarify, being water-soluble, thiamine is relatively non-toxic. According to Australia's national 'Eat for Health' guidelines, "There are no reports of adverse effects from consumption of excess thiamin by ingestion of food."
However, supplementing solely with vitamin B1 may be unwise. Instead, since thiamin is one of several b vitamins which work in conjunction with each other, a multivitamin or B-complex supplement may be better. That is, if you are even looking to supplement.