Thiamine Deficiency and its Prevention and Control in Major Emergencies

Review in progress

WHO are finalising a report on Thiamine Deficiency and its Prevention and Control in Major Emergencies This is a comprehensive review which is unique in that its focus is on thiamine deficiency in an emergency context. Furthermore, the document tackles subject areas which until now have not been properly addressed in the literature, e.g. guidelines on how to assess whether there is a public health problem, and prevention strategies geared specifically to emergency situations.

 

The review documents recent outbreaks of the deficiency disease amongst emergency affected populations e.g. Cambodian refugees in Thailand and Bhutanese refugees in Nepal and then examines risk factors associated with these outbreaks for example:

• dependence on milled rice, or
• the presence of thiaminases in the diet.

The review then moves on to describe the symptoms and various syndromes of thiamine deficiency in adults and infants. The document also identifies risk factors for sub-clinical deficiency and symptoms, i.e. anorexia.

There is a section on biochemical methods of detecting thiamine deficiency:

• measuring blood thiamine or urinary thiamine excretion,
• estimation of blood pyruvate and lactate, and
• measuring the activity of thiamine requiring enzymes.

There is also a table which suggests guidelines for differentiating levels of risk for thiamine deficiency in a population. The table defines mild, moderate and severe public health problems in terms of percentages of a population with clinical or biochemical signs of deficiency, e.g. percentage of the population with urinary thiamine levels below a certain amount. Such guidelines have been absent from the literature and are long overdue.

The review also sets out the thiamine content of certain foods and discusses the factors influencing content and utilisation of thiamine in food, i.e. interaction with other micronutrients. There is also a section on recommendations to reduce losses of thiamine during food preparation, some of which are summarised below.

• using minimum amounts of water for vegetable preparation and cooking for minimum amounts of time,
• covering pots to shorten cooking time, washing vegetables before cutting them, and
• not cooking rice with excess water that needs to be discarded.
• using parboiled rice where available.

The paper holds that nutrition education messages based on the above could contribute enormously to keeping losses of thiamine at a minimum. There is a very useful section on anti-thiamine factors which are present in food, or are produced as a result of microbial or other action, e.g. polyphenols which may be found in coffee and tea. This section concludes with recommendations for decreasing the influence of anti-thiamine factors, e.g. heating products containing thiaminase before consumption.

The final part of the review deals with strategies to prevent thiamine deficiency in large populations affected by emergencies. This section raises awareness about thiamine deficiency risks in populations heavily dependant on milled rice and starchy staple foods

A list of the main ways to increase intake of thiamine in emergency affected populations is given

• diversify the diet to include enough pulses and vegetables
• promote parboiled rice instead of polished rice
• reduce losses of thiamine during preparation and cooking of meal
• reduce intake of thiaminases
• fortify commonly consumed food commodity with thiamine, e.g. wheat flour, corn meal, salt
• add thiamine-rich commodities to the food basket, e.g. fortified cereal legume blend
• supplement the population with regular thiamine/ vitamin tablets (correct dosages are given in the report).

Further information contact Zita Weise Prinzo, WHO, Avenue Appia 1211 Geneva 27, Switzerland. E-mail: weiseprinzoz@who.ch