What is vitamin B1 (Thiamine)?

B vitamins are a group of water-soluble vitamins essential for several important functions in the body, including supporting metabolism and helping the body produce energy. Collectively, this group of B vitamins is often referred to as “vitamin B complex”.

Different kinds of vitamin B

The eight B vitamins are:

  • B1 (thiamin)
  • B2 (riboflavin)
  • B3 (niacin)
  • B5 (pantothenic acid)
  • B6 (pyridoxine)
  • B7 (biotin)
  • B9 (folate)
  • B12 (cobalamin)


B vitamins are water-soluble, so they dissolve quickly in the body. Unlike fat-soluble vitamins (vitamins A, D, E, and K), water-soluble vitamins are absorbed by the body’s tissues and are not stored for long-term use. Therefore, any excess water-soluble vitamins are excreted through urine, faeces and sweat. For this reason, regular intake of each B vitamin is necessary to maintain optimal levels in the body.  

They all have different roles in the body. But overall, they help:

  • release energy from food
  • keep the nervous system healthy
  • make red blood cells
  • keep your skin and eyes healthy
  • act as cofactors (supporters) for many different chemical and metabolic reactions in the body

Health benefits of vitamin B1

Vitamin B1, also known as thiamine, is important for the growth, development, and function of your body’s cells. It’s used by nearly all your cells and responsible for making adenosine triphosphate (ATP), a molecule that transports energy within cells. Vitamin B1 also helps convert food into energy. Since the human body is unable to produce thiamine, it must be consumed through various thiamine-rich foods. 

Animal foods rich in vitamin B1

Foods containing high amounts of thiamine include:

  • Beef liver
  • Pork
  • Salmon
  • Mussels
  • Poultry

Plant-based foods rich in vitamin B1

  • Macadamia nuts
  • Green peas (cooked)
  • Tofu
  • Brown rice
  • Flax seeds
  • Black beans (cooked)
  • Lentils (cooked)
  • Edamame (cooked)
  • Aspragus
  • Fortified breakfast cereal
  • Bread

Many whole grain products are fortified with thiamine, such as:

  • cereal
  • bread
  • rice
  • pasta

Signs & symptoms of a B1 deficiency:

Many people don’t realise that they have a deficiency, as many of the symptoms are subtle and often overlooked. Some signs and symptoms include:

  • Loss of appetite
  • Fatigue
  • Irritability
  • Reduced reflexes
  • Tingling sensation in arms and legs
  • Muscle weakness
  • Blurry vision
  • Nausea and vomiting
  • Changes in heart rate
  • Shortness of breath
  • Delirium

These symptoms are considered quite general and could be a result of other factors going on in the body as well, so it’s important to assess one’s diet to make sure there is a variety of foods containing thiamine. Otherwise, thiamine deficiency can be easily reversed with supplementation as well.

Risk factors for B1 deficiency

Thiamine deficiency is fairly uncommon in developed countries. However, various factors may increase your risk, including:

  • Alcohol dependence
  • Old age
  • Diabetes
  • Bariatric surgery
  • Dialysis
  • High-dose diuretic use


All tissues of our body need thiamine to function properly. Most of us get enough thiamine from food but there are certain medical conditions and dietary practices that may cancel out the body’s usage of thiamine, which can lead to deficiency. In these cases, supplements may be necessary. It’s important to talk to your practitioner before taking any thiamine supplement. It’s key to ensure that you have the right balance of B vitamins in your body.

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