Vitamin B1 Thiamin - Information and Sources

Thiamin is a water soluble vitamin which is a coenzyme involved in the metabolism of glucose into energy or to other sugars, and it works synergistically with other B vitamins. Requirements for thiamin are related to the carbohydrate and energy content of the diet. Adults should aim for 0.4mg of thiamin per 1,000kcal energy intake per day. Therefore an average sedentary female should aim for around 0.8mg and a male 1.1mg thiamin per day.

Deficiency of thiamin is called beriberi and occurs where intake of thiamin is low and carbohydrate intake is high, eg in developing countries where only one starchy staple food is primarily consumed. Thiamin deficiency also occurs in chronic alcoholism where it is called Wernicke-Korsakov syndrome. Mild thiamin deficiency can result in difficulty in concentration, irritability, depression, muscle weakness and poor coordination. Severe thiamin deficiency, as in beriberi, is characterised by mental confusion and peripheral neuropathy; oedema characterizes the 'wet' form of beriberi, and muscular atrophy, tachycardia and cardiomegaly are characteristics of the 'dry' form.

Thiamin can be lost in cooking both through high temperatures and leeching out in water. It can also be lost during milling of grains, thus some white flours may be fortified with thiamin.

Thiamin is found in good amounts in the following dietary sources:

  • Brewer's yeast (2 tblsp) - 2.3mg
  • Shreddies (55g) – 0.66mg
  • Fruit 'n' Fibre (50g) – 0.5mg
  • Muesli (95g) – 0.48mg
  • All-bran (45g) – 0.45mg
  • Bran Flakes (45g) – 0.45mg
  • Crunchy Nut Corn Flakes (45g) – 0.45mg
  • Frosties (45g) – 0.45mg
  • Special K (35g) – 0.42mg
  • Rice Krispies (35g) – 0.35mg
  • Coco Pops (35g) – 0.35mg
  • Weetabix (2 biscuits) – 0.28mg
  • Corn Flakes (25g) – 0.25mg
  • Wheatgerm (15g) – 0.3mg
  • Wholemeal bread (1 slice) – 0.24mg
  • Bagel, white enriched (60g) - 0.4mg
  • Pasta, wholewheat boiled (150g) – 0.3mg
  • Brown rice, cooked (165g) - 0.23mg
  • Cashews (40g) – 0.17mg
  • Peanuts (30g) – 0.27mg
  • Brazil nuts (30g) – 0.3mg
  • Hazel nuts (25mg) – 0.1mg
  • Sunflower seeds (25g) - 0.6mg
  • Sesame seeds (15mg) – 0.11mg
  • Pork (100g) - 0.9mg
  • Ham (100g) - 0.7mg
  • Kidney (75g) – 0.42mg
  • Liver (90g) – 0.23mg
  • Plaice (120g) – 0.36mg
  • Salmon (135g) – 0.22mg
  • Soya milk (250ml) - 0.4mg
  • Baked beans (200g) – 0.2mg
  • Green peas (75g) – 0.18mg
  • Potato, baked (140g) – 0.14mg
  • Potato, boiled (150g) – 0.12mg
  • Chips (250mg) – 0.27mg
  • Sweet potato, boiled (150g) – 0.12mg
  • Orange juice (250ml) - 0.2mg