Symptoms Vitamin B1 Deficiency?



Vitamin B1 (also known as Thiamine) helps provide our cells with energy and protects our nerves by producing myelin. It’s absorbed in the small intestine. The body can store up to 20 days of vitamin B1 (13).

Vitamin B1 is a important vitamin to the human body. Since our body is unable to create this vitamin itself, we need to get vitamin B1 from our foods. This includes pork, seeds, nuts, beens, grean peas, tofu, brown rice, asparagus, fish, seafood and plankton.

While a deficiency in vitamin B1 does not occur very often, there are certain groups of people that have a higher risk of creating a B1 deficiency. Those people may benefit from using vitamin B1 supplements next to their daily meals. It is, however, important to note that if you suspect you have a shortage of thiamine, you should always consult a doctor before taking any supplements.

People with a higher risk of obtaining an vitamin B1 deficiency are:

  • Persons with diabetes,
  • Humans with HIV or AIDS,
  • Kidney patients undergoing dialysis treatment,
  • People with a stomach disorder (stomach operation or gastric bypass),
  • Seniors.

A shortage of vitamin B1 can be recognized by the following symptoms. If you experience one or more of these symptoms, it may be wise to consult a physician.


Since vitamin B1 is used to support nerves, a lack of vitamin B1 can result in negative effects on the motor nerves.

This is seen a lot in younger people with a deficiency, especially children. The nerves in their knees and ankles have troubles functioning, causing troubles with walking and even just moving their joints.

In short: vitamin B1 is used to support nerves. A lack of it causes the body to lose function in its joint, making moving harder (1)(2).


Fatigue is a common symptom and overall complaint of people with a lot going on in their lives. It can, however, also be a sign of a deficiency of thiamine. Many studies have linked a thiamine deficiency to a reduced energy level and fatigue (3)(4)(5)(6).

The thiamine isn’t transported from the blood to the mitochondria, causing less energy to be moved towards the cells. And since our body is made up of cells, we will feel that energy deficiency as well.

In short: a lack of thiamine prevents the mitochondria from functioning properly, causing us to feel fatigued.


A deficiency in vitamin B1 damages the optic nerve, causing it to swell. This swelling induces a phenomenon called “Optic Neuropathy”.

Optic Neuropathy can cause your vision to become blurred and colours distorted. A severe case of optic neuropathy can even lead to complete loss of vision. There are multiple studies that have found a connection between a deficiency of vitamin B1 and blurry vision (7)(8)(9)(10).

In short: a deficiency in vitamin B1 can cause blurry vision, or even vision loss.


Your heart decides how much blood is pumped through your body based on its beats per minute (BPM).

When your body lacks vitamin B1, there is not enough energy to get your BPM to increase. This results in a slower than normal heartbeat, which may lead to even more fatigue and dizziness (11)(12).

In short: a lack of vitamin B1 causes the heart to pump slower, resulting in fatigue.


When your body runs out of thiamine, you will be able to notice the deficiency within a few days already. Your body will become weaker and show symptoms of a disease called ‘Beriberi’, which stands for severe weakness.

Beriberi is also responsible for psychological symptoms like irritability. Especially infants suffer from this symptom as they can’t communicate how they are feeling (2)(13)(14)(15).

In short: a thiamine deficiency can cause both physical and psychological symptoms, one of which being irritability. This is especially noticeable in infants.


Vitamin B1 usually works like a satiety regulator, meaning that you know when you are hungry and when you are full.

A lack of vitamin B1 stops the feeling of feeling peckish or hungry, causing you to lose your appetite. In the long term, this can lead to weight loss or even anorexia (17)(18).

In short: : a deficiency of vitamin B1 stops the feeling of being hungry, causing you to eat less.


According to multiple studies, patients with a vitamin B1 deficiency have noted that they felt weakness in their muscles as one of the symptoms.

While short term muscle weakness can happen to anyone, long-term muscle weakness without clear cause may point to a vitamin B1 deficiency. A daily dose of thiamine supplements helps to regain the strength again (19)(20).

In short: a vitamin B1 deficiency can lead to muscle weakness in the long term.


Since a lack of vitamin B1 causes nerves to get damaged, this can also lead to tingling sensations in ones arms and legs. This phenomenon is also often called 'Paresthesia'.

People often notice this symptom at the beginning of their deficiency. Going undiagnosed for a longer period of time may also lead to loss of muscle strength, like named above (21)(22).

In short: when first noticing a deficiency in vitamin B1, a person may notice tingling limbs. This is described as Paraesthesia.


While it has not yet been discovered as to why people experience issues with their digestion system in case of a thiamine deficiency, their problems were resolved after taking thiamine supplements (23).

However, infants with a thiamine deficiency will vomit more often. This mostly occurred in infants who were fed a soy-based milk, which may point to the fact that vegans and vegetarians need to be cautious of their thiamine intake as well (14).

In short: a deficiency in thiamine may lead to vomiting, nausea and problems with the digestive system.


Because a deficiency in vitamin B1 causes your heart to beat slower, it may also induce problems with breathing.

Mainly: shortness of breath. When the heart pumps too slowly, it may accumulate fluids in the lungs, leading to troubles with breathing (24). However, shortness of breath can have many causes and if you experience only this symptom, it doesn’t necessarily have to be a thiamine deficiency.

In short: because of a decreased BPM, a deficiency in vitamin B1 may lead to shortness of breath.

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