Vitamin B1 Thiamine Health Benefits & Why You May Be Running Low

Dr Jess endocrinology, fatigue, Neurology, You

Dr Jess: Like many doctors I was trained to look for severe deficiency of Vitamin B1 – particularly Wernicke’s encephalopathy – but failed to understand the wide range of lesser symptoms like low energy, mood and sleep problems which can be caused by Vitamin B1 deficiency.

Over the years, however, I have improved these symptoms multiple times after finding B1 was low. It is worth considering a multivitamin with good levels of Thiamine to maintain your levels if you think you may be low.

Vitamin B1 also called Thiamin or Thiamine is a water-soluble vitamin (this means it is carried in the bloodstream and eliminated in the urine) that it can be destroyed by heat – cooking and processing.

It is a critical vitamin for the brain and nervous system, and also very important for the heart, muscles and gut…


Thiamine (B1 deficiency) can be very serious…

Although rare in the modern world, very low Vitamin B1 levels can cause a condition called Beri-Beri. This can affect the cardiovascular system (heart and blood vessels) causing heart failure, increased heart rate, shortness of breath and difficulty breathing, swelling of the ankles and legs.

Deficiency also affects the nervous system – creating loss of sensation in the hands and feet, unsteady walking and poor balance, pain in the muscles, eye problems like nystagmus (repeated flicking movement of the eyes). Extreme deficiency worsens into a brain condition called Wernicke’s encephalopathy with memory loss, confusion, psychosis and confabulation (making up words). Low energy, weight loss, depression, fatigue and sleep disorders may be mild signs of deficiency (low levels of B1) which can be corrected with supplements (1).

Patients who drink too much alcohol, have been on an extreme diet or have severe vomiting or diarrhoea can be at risk of Vitamin B1 deficiency…

At risk patients are those with a poor diet or with severe diarrhoea, those who drink to much alcohol regularly, have gut problems affecting absorption of nutrients, hyperemesis gravidarum (severe vomiting in pregnancy) or after stomach surgery or chemotherapy.

Thiamine has an important role in sepsis…

Studies show that your chance of dying from sepsis, a life threatening infection that has dramatically increased in recent years  is higher if your Thiamine levels are low (2) and Thiamine is part of a promising protocol for sepsis showing amazing results alongside IV Vitamin C. Thiamine given in sepsis seems to reduce kidney failure from the infection (3).

It may help in depression…

Thiamine given alongside starting an antidepressant improved symptoms of depression faster, and produced more stability in mood than without it (4). As early Thiamine deficiency can cause symptoms of depression, it is worth considering in low mood.

and for period pain and PMS…

2 trials of female students showed a large significant improvement in the physical and mental symptoms of PMS when taking Vitamin B1 during a menstrual cycle, with no side effects (5)(6).

Period pain (dysmenorrhoea) was significantly improved in high school students taking Thiamine (7)(8).

Thiamine supplements should be considered for diabetes…

Blood sugar and insulin levels of patients with borderline or high blood sugars improved after taking high doses of Thiamine for 6 weeks (9)(10). High doses of Thiamine also reduced high blood pressure in patients with diabetes and so could help prevent heart and circulation complications (11) and kidney complications (12). Giving B1 with B12 improved the nerve pain from diabetes and lessened the amount of painkillers needed in a study (13).

and in patients with fatigue (low energy)…

A trial of Thiamine supplements for 4 weeks given to patients with fatigue, showed a significant improvement in their energy (14). Thiamine has also been shown to help recovery from fatigue after exercise (even if you are not deficient) (15), so may be useful when doing a lot of sport or gym work.

Thiamine supplements may also help with brain function aiding memory loss and reaction time…

Patients given Thiamine supplements had improved reaction speeds and felt more clearheaded and energetic in a study in young adults (16). In patients who had previously been addicted to cocaine Thiamine supplements improved memory accuracy (17).

Other benefits:
  • Alcholism – Giving high doses of Thiamine has been shown to increase the chance of recovery of alcoholics and also reduce emotional symptoms (18).
  • Memory loss/Alzheimer’s – Along with other B vitamins (B6 and B12), B1 has been shown to help reduce blood markers related to mild cognitive impairment (memory loss) and Alzheimer’s (19) and improve symptoms of Alzheimer’s at high dose (20).
  • Autism – A small study of children with Autism showed a clinical improvement in symptoms when given Thiamine supplements for 2 months (21).
  • Copper Coil (IUD) – Thiamine supplements significantly reduced spotting and heavier bleeding side effects from the copper coil when 100mg was taken daily for 3 months (22).
  • Herpes (coldsore) lesions – Itching and pain from Herpes lesions was reduced by injecting Thiamine into them with no side effects (23).
  • Chronic Heart Failure – Patients with heart failure given Thiamine for 4 weeks had a significant improvement in their heart function (24)(25).
  • Dialysis – Patients on dialysis are particularly at risk of Thiamine deficiency and can have serious brain related symptoms due to this (26).
  • Epilepsy – Patients with chronic epilepsy who received Thiamine supplements had a significant improvement in brain function and cognitive ability (27).
  • Biotin Thiamine Responsive Basal Ganglia disease – A genetic disease which causes movement problems in children is significantly helped by giving Thiamine (28).
What is the best way to get my Thiamine checked?

It can be difficult to get the right test for Thiamine levels. It is important to check Thiamine levels by measuring: erythrocyte thiamine pyrophosphate – this is the active form of Vitamin B1, measured inside the blood cells (best test should be >70nmol/L) or by doing an erythrocyte transketolase activity blood test (measuring the activity of Thiamine) should be <1.15, if >1.15, suggests deficiency. Measuring Vitamin B1 in the liquid (plasma) of the blood is not very accurate.

How much Thiamine do I need?

The recommended daily amount of Thiamine is 1.1mg daily (the amount needed to prevent deficiency) however it is very safe at much higher levels and trials use anywhere from 25mg-3g daily. Excess Thiamine is excreted in the urine and many trials have been done using Thiamine supplements in both pregnancy and whilst breastfeeding.

Top 5 sources of Vitamin B1 (Thiamine) in order:
  • Nutritional yeast – 1 tablespoon – 4.8mg (tastes amazing on popcorn, sprinkle it over and shake well – savoury, healthy and delicious)
  • Yeast extract spread (e.g. marmite) – 1 tsp, 0.6mg
  • Macadamia nuts – 1/2 cup, raw, 0.8mg
  • Green garden peas – 1 cup of cooked green peas, 0.4mg
  • Wild Atlantic Salmon – 1 cooked piece, 0.6mg
  • Pistachio nuts – 1/2 cup dried, roasted, 0.6mg
Which supplement is best?

Thiamine Hydrochloride (HCl) is quickly and easily absorbed to increase Thiamine levels (25) if yours are low. Thiamine supplements are regarded as very safe and any excess is easily excreted in the urine (26). Vitamins and minerals work well together and so it is often a good idea to take a high quality multivitamin with a good level of B vitamins like our Ultimate Pro Multivitamin and Mineral Complex or B complex.