Thiamine (Vitamin B1)

Thiamine, commonly referred to as vitamin B1 is a coenzyme that assists in metabolism and in the release of energy. Discovered in 1937 by R Williams, thiamine was predominantly found to be beneficial in the breakdown of carbohydrate into the energy source adenosine triphosphate (ATP) which is the main energy carrier found within the body's cells. More recently thiamine has also been found to promote normal nerve function, heart function, muscle tone, appetite and digestion.

There are 2 distinct major thiamine deficiency diseases, Beri beri and Wernicke-Korsakoff syndrome. Although the underling cause of both of these diseases is a thiamine deficiency, rarely do they occur together. Beri beri is now rare in the countries where it was originally prevalent (Japan, Indonesia and Malaysia), however in western countries cases of Wernicke-Korsakoff syndrome are still prevalent particularly amongst alcoholics.

It is believed that thiamine is an important component used in the metabolism of alcohol, however alcoholic beverages do not contain it and therefore thiamine stores are used to breakdown the alcohol which can lead to deficiencies. Although we cannot find any evidence to support it, this mechanism in theory, might help to explain why some people claim that taking multivitamins (particularly those containing B complex vitamins) or eating foods such as vegemite (which is high in thiamine) help to cure a hangover.

There are no rich food sources of thiamine, however the best sources are wheat germ, whole wheat and yeast products, vegemite, nuts, oatmeal and fortified breakfast cereals. In many industrial countries (eg. UK, USA) bread flour is enriched with thiamine to help meet daily requirements. In Australia mandatory fortification of bread flour with thiamine was introduced in 1991 with the intention to reduce Australia's relatively high rate of Wernicke-Korsakoff syndrome.

A recent re-evaluation of dietary requirements for all vitamins and minerals was published by the National Health and Medical Research Council in 2006. The dietary recommendations for thiamine from this publication are summarised below.

Recommended Dietary Intakes for Thiamine

Please refer to the following definitions when interpreting these recommendations:

RDI-Recommended Daily Intake
The average daily intake level that is sufficient to meet the nutritional requirements of nearly all (97-98%) health individuals in a particular life stage and gender group.

AI-Adequate Intake (used when an RDI cannot be determined)
The average daily nutrient intake level based on observed or experimentally-determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate.

UL-Upper Limit of Intake
The highest average daily nutrient intake level likely to pose no adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects increases.

Recommendations by Life Stage and Gender - THIAMINE

Infants	AI
0-6 months	0.2 mg/day
7-12 months	0.3 mg/day
Children and Adolescents	RDI
All
1-3 years	0.5 mg/day
4-8 years	0.6 mg/day
Boys
9-13 years	0.9 mg/day
14-18 years	1.2 mg/day
Girls
9-13 years	0.9 mg/day
14-18 years	1.1 mg/day
Adults	RDI
Men
19-30 years	1.2 mg/day
31-50 years	1.2 mg/day
51-70 years	1.2 mg/day
>70 years	1.2 mg/day
Women
19-30 years	1.1 mg/day
31-50 years	1.1 mg/day
51-70 years	1.1 mg/day
>70 years	1.1 mg/day
Pregnancy
14-18 years	1.4 mg/day
19-30 years	1.4 mg/day
31-50 years	1.4 mg/day
Lactation
14-18 years	1.4 mg/day
19-30 years	1.4 mg/day
31-50 years	1.4 mg/day

Source:National Health and Medical Research Council. Nutrient Reference Values for Australia and New Zealand. Department of Health and Ageing, Canberra 2006, copyright Commonwealth of Australia reproduced by permission⁵.

The NHMRC has not set an upper limit for thiamine. Research suggests that there is no toxicity of thiamine when consumed orally which is similar to most water soluble vitamins, where excess levels are normally excreted in urine.

Thiamine back to Vitamins

References
1. Stanton R. Foods that harm, foods that heal: An A-Z guide to safe and healthy eating. Readers Digest; 2006, pp378-382.
2. Mann, J., Truswell, S. Essentials of Human Nutrition. Oxford Medical Publications, New York. 2000.
3. The Merck Manual of Medical Information 2nd Ed. Beers, M.H., Fletcher, A. J., Jones T. J., Porter, R., Berkwits, M., et al., editors. Pocket Books Reference; 2003.
4. Wahlqvist, M.L., et al. Australia and New Zealand: Food and Nutrition. 2nd Ed. Allen and Unwin, Sydney; 2002, pp 251-253.
5. National Health and Medical Research Council. Nutrient Reference Values for Australia and New Zealand. Department of Health and Ageing, Canberra 2006 copyright Commonwealth of Australia reproduced by permission.

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