Thiamin, Riboflavin, Niacin, Vitamin B6, Pantothenic Acid and Biotin...continued #1.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim. (Chapter 3)

Biochemical Indicators

Indicators used to estimate thiamin requirements are urinary excretion, erythrocyte transketolase activity coefficient, erythrocyte thiamin, blood pyruvate and lactate, and neurologic changes. The excretion rate of the vitamin and its metabolites reflects intake, and the validity of the assessment of thiamin nutriture is improved with load test. 

Erythrocyte transketolase activity co-efficient reflects TPP levels and can indicate rare genetic defects. Erythrocyte thiamin is mainly a direct measure of TPP but also is a measure of thiamin and thiamin monophosphate by high performance liquid chromatography (HPLC) separation.

6. Food and Nutrition Board, Institute of Medicine/National Academy of Sciences- National Research Council. 1998. Dietary Reference Intake: Folate, Other B Vitamins, and Choline. Washington, D.C., National Academy Press. 

9. McCormick, D.B & Greene, H.L. 1994. Vitamins. In: Tietz Textbook of Clin Chem., 2nd edition. Burtis, V.A., Ashwood, E.R., eds. Philadelphia: W.B. Saunders, p. 1275-1316.

12. Bayliss, R.M., Brookes, R., McCulloch, J., Kuyl, J.M. & Metz, J. 1984. Urinary
thiamine excretion after oral physiological doses of the vitamin. Int. J. Vit. Nutr. Res., 54:
161-4.

Thiamin status has been assessed by measuring urinary thiamin excretion under basal conditions or after thiamin loading, transketolase activity, and free and phosphorylated forms in blood or serum (6, 9). Although overlap with baseline values for urinary thiamin was found with oral doses below 1 mg, a correlation of 0.86 between oral and excreted amounts was found by Bayliss et al. (12).

9. McCormick, D.B & Greene, H.L. 1994. Vitamins. In: Tietz Textbook of Clin Chem., 2nd edition. Burtis, V.A., Ashwood, E.R., eds. Philadelphia: W.B. Saunders, p. 1275-1316. 

13. Gans, D.A. & Harper, A.E. 1991. Thiamin status of incarcerated and nonincarcerated adolescent males: dietary intake and thiamin pyrophosphate response. Am. J. Clin. Nutr., 1991; 53: 1471-5.

14. Schrijver, J. Biochemical markers for micronutrient status and their interpretation. In: Modern Lifestyles, Lower Energy Intake and Micronutrient Status. Pietrzik, K., ed. Heidelberg: Springer-Verlag, p. 55-85.

The erythrocyte transketolase assay, in which an activity coefficient based on a TPP stimulation of the basal level is given, continues to be a main functional indicator (9), but some problems have been encountered. Gans and Harper (13) found a wide range of TPP effect when thiamin intakes were adequate above 1.5 mg/day over a 3-day period. In some cases the activity coefficient may appear normal after prolonged deficiency (14).

15. Bailey, A.L., Finglas, P.M., Wright, A.J. & Southon, S. 1994. Thiamin intake, erythrocyte transketolase (EC 2.2.1.1) activity and total erythrocyte thiamin in adolescents. Br. J. Nutr., 72: 111-25.

16. Singleton, C.K., Pekovich, S.R., McCool, B.A. & Martin, P.R. 1995. The thiaminedependent hysteretic behavior of Human transketolase: implications for thiamine deficiency. J. Nutr., 125: 189-194.

17. Baines, M. & Davies, G. 1988. The evaluation of erythrocyte thiamin diphosphate as an indicator of thiamin status in man, and its comparison with erythrocyte transketolase activity measurements. Annals Clin. Biochem., 1988; 25 (Part 6): 698-705.

18. Gerrits, J., Eidhof, H., Brunnekreeft, J.W. & Hessels, J. Determination of thiamin and thiamin phosphates in whole blood by reversed-phase liquid chromatography with precolumn derivatization. In: Methods in Enzymology. Vitamins and Co-enzymes. McCormick, D.B., Suttie, J.W., Wagner, C., eds. San Diego: Academic Press, 279: 74-82.

This measure seemed poorly correlated with dietary intakes estimated for a group of English adolescents (15). Certainly, there are both inter-individual and genetic factors affecting the transketolase (16). Baines and Davies (17) suggested that it is useful to determine erythrocyte TPP directly because the co-enzyme is less susceptible to factors that influence enzyme activity; however, there are also methods for determining thiamin and its phosphate esters in whole blood (18).

Factors affecting requirements

19. Fogelholm, M., Rehunen, S., Gref, C.G., Laakso, J.I., Lehto, J., Ruskonen, I. & Himberg, J.J. 1992. Dietary intake and thiamin, iron, and zinc status in elite Nordic skiers during different training periods. Int. J. Sport Nutr., 2: 351-65.

20. van der Beek, E.J., van Dokkum, W., Wedel, M., Schrijver & van den Berg, H. 1994. Thiamin, riboflavin and vitamin B6: impact of restricted intake on physical performance in man. J. Am. Coll. Nutr., 13: 629-40.

9. McCormick, D.B & Greene, H.L. 1994. Vitamins. In: Tietz Textbook of Clin Chem., 2nd edition. Burtis, V.A., Ashwood, E.R., eds. Philadelphia: W.B. Saunders, p. 1275-1316.

Because thiamin facilitates energy utilisation, its requirements have traditionally been expressed on the basis of energy intake, which can vary depending on activity levels. However, Fogeholm et al. (19) found no difference in activation coefficients for erythrocyte transketolase from a small group of skiers and from less physically active control subjects. 

Also, a study with thiamin-restricted Dutch males whose intake averaged 0.43 mg/day for 11 weeks did not reveal an association between short bouts of intense exercise and the decreases in indicators of thiamin status (20). Alcohol consumption may interfere with thiamin absorption (9).

Findings by age and life stage

21. Committee on Nutrition. 1985. Composition of Human milk: normative data. In: Pediatric Nutrition Handbook, 2nd Edition. Elk Grove Village, IL: Am. Acad. Pediatr., p.363-368.

22. Wyatt, D.T., Nelson, D. & Hillman, R.E. 1991. Age-dependent changes in thiamin concentrations in whole blood and cerebrospinal fluid in infants and children. Am. J. Clin. Nutr., 53: 530-6.

Recommendations for infants are based on adequate food intake. Mean thiamin content of human milk is 0.21 mg/l (0.62 μmol/l) (21), which corresponds to 0.16 mg (0.49μmol) thiamin per 0.75 l of secreted milk per day. The blood concentration for total thiamin averages 210 ± 53 nmol/l for infants up to 6 months but decreases over the first 12–18 months of life (22).

15. Bailey, A.L., Finglas, P.M., Wright, A.J. & Southon, S. 1994. Thiamin intake, erythrocyte transketolase (EC 2.2.1.1) activity and total erythrocyte thiamin in adolescents. Br. J. Nutr., 72: 111-25. 

23. Sauberlich, H.E., Herman, Y.F., Stevens, C.O. & Herman, R.H. 1979. Thiamin requirement of the adult Human. Am. J. Clin. Nutr., 32: 2237-48.

24. Wood, B., Gijsbers, A., Goode, A., Davis, S., Mulholland, J. & Breen, K. 1980. A study of partial thiamin restriction in Human volunteers. Am. J. Clin. Nutr., 33: 848-61.

25. Anderson, S. H., Charles, T.J. & Nicol, A.D. 1985. Thiamine deficiency at a district general hospital: report of five cases. Q. J. Med., 55: 15-32.

A study of 13–14-year-old children related dietary intake of thiamin to several indicators of thiamin status (15). Sauberlich et al. (23) concluded from a carefully controlled depletion-repletion study of seven healthy young men that 0.3 mg thiamin per 4184 kJ met their requirements. Intakes below this amount lead to irritability and other symptoms and signs of deficiency (24). Anderson et al. (25) reported thiamin intakes of 1.0 and 1.2 mg/day as minimal for women and men, respectively.

26. Hoorn, R.K., Flikweert, J.P. & Westerink, D. 1975. Vitamin B1, B2 and B6 deficiencies in geriatric patients, measured by co-enzyme stimulation of enzyme activities. Clinica Chimica Acta, 61: 151-62.

27. Nichols, H.K. & Basu, T.K. 1994. Thiamin status of the elderly: dietary intake and thiamin pyrophosphate response. J. Am. Coll. Nutr., 13: 57-61.

Hoorn et al. (26) reported that 23 percent of 153 patients aged 65–93 years were deemed deficient based on a transketolase activation coefficient greater than 1.27, which was normalised after thiamin administration. Nichols and Basu (27) found that only 57 percent of 60 adults aged 65–74 years had TPP effects of less than 14 percent and suggested that ageing may increase thiamin requirements.

28. Food and Nutrition Board, Institute of Medicine/National Academy of Sciences-National Research Council. 1990. Nutrition During Pregnancy. Part I Weight Gain. Part II Nutrient Supplements. Washington, D.C, National Academy Press. 

6. Food and Nutrition Board, Institute of Medicine/National Academy of Sciences-National Research Council. 1998. Dietary Reference Intake: Folate, Other B Vitamins, and Choline. Washington, D.C., National Academy Press.

An average total energy cost of 230 MJ has been estimated for pregnancy (28). With an intake of 0.4 mg thiamin/4184 kJ, this amounts to 22 mg total, or 0.12 mg/day for an additional thiamin need for the second and third trimesters (180 days). Taking into account an increased growth in maternal and foetal compartments, an overall additional requirement of0.3 mg/day is adequate (6). Lactating women are estimated to transfer 0.2 mg thiamin in their milk each day, and an additional 0.2 mg is estimated as a need for the increased energy cost of lactation of about 2092 kJ/day.

Recommendations

The recommendations for thiamin are given in Table 6.