Thiamin (Vitamin B1) Levels in Eating Disorder Adolescent Patients
Condition: Eating Disorders
MeSH terms: Feeding and Eating Disorders
Study type: Observational

Summary: 
      Vitamin B1 (Thiamine) is a water soluble essential nutrient; it is synthesized by a variety
      of plants and microorganisms. Since animals usually cannot synthesis it, humans must be
      supplied with exogenous vitamin B1 in the diet. The human storage of thiamine is small- about
      30mg, an intake of 1-2 mg a day is needed to maintain this pool. Deficiency might occur when
      the vitamin is depleted from the diet in a short period. Vitamin B1 has a role in energy
      metabolism and main biosynthetic pathways. Low thiamine causes illnesses in the central and
      peripheral nervous systems as well as affecting the heart and gastrointestinal systems.

      Deficiency may occur from malnutrition of different mechanisms such as alcoholism, lack in
      diet and recently secondary to anti-obesity surgery and few case reports described eating
      disorders as the reason for developing deficiency causing neuropathy, (1,2) and
      encephalopathy (3,4,5).

      One of the presentations of thiamine deficiency is peripheral neuropathy mimicking
      Guillain-Barre syndrome, and administering the lacking vitamin improves the symptoms.

      One study examined the prevalence of vitamin B1 deficiency in adult anorexia nervosa patients
      (6) by measurement of the activation of the enzyme erythrocyte transketolase following
      addition of thiamin pyrophosphate and comparing them to control of blood donors. This study
      found significant lower levels of vitamin B1 in the anorectic patient compared to the
      controls.

      Rational of the study:

      The investigators assume that these few cases described of overt neurologic impairment due to
      vitamin B1 deficiency because of distorted eating are just the "tip of the iceberg" and more
      eating disorders patients lack thiamine, that may have neuropsychiatric effect on the illness
      and identifying and treating the shortage may improve the symptoms of the disorder and maybe
      even the distorted thoughts that are fundamental in eating disorders.
    

Detailed description: 
      Methods:

      In Assaf Harofe medical center over 50 adolescents (mainly girls) aged 10-18 years are
      treated annually for eating disorders by a multidisciplinary team. Their nutritional and
      medical condition is assessed also by blood analysis routinely. The investigators are
      planning to check thiamine status in eating disorders female patients in different stages of
      treatment, comparing them with age and sex matched controls that do not have eating disorders
      problems. The control group will be recruited from patient treated in the outpatient day
      hospital and have blood tested anyhow that don't suffer from eating, metabolic, nutritional
      or gastrointestinal disorders.

      The researchers will look for correlation between different types of eating disorders,
      nutritional state, treatment progress and levels of vitamin B1.

      Thiamin will be determined in whole blood using High-Performance Liquid Chromatography (HPLC)
      that is superior to the previous method as described above, determining thiamin diphosphate;
      the physiologically active form of vitamin B1 accurately.

      Sample size: A previous study on thiamine concentration in 50 healthy French volunteers found
      a standard deviation (SD) of 15 nmol/l (7). 17 patients in each group were required in order
      to detect a 15 nmol/l difference in mean thiamine levels with a power of 80% and Alfa of
      0.05. In order to overcome a possibly higher SD and to allow for subgroup analysis , we
      decided to recruit 30 patients for each group.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        adolescent girls with eating disordes aged 12-18
      
Keywords: B1 adolescents Eating disorders Thaimine