British Journal of Nutrition

Dietary Surveys and Nutritional Epidemiology

Lifestyle and genetic determinants of folate and vitamin B12 levels in a general adult population

Betina H. Thuesena1 c1, Lise Lotte N. Husemoena1, Lars Ovesena2, Torben Jørgensena1, Mogens Fengera3 and Allan Linneberga1

a1 Research Centre for Prevention and Health, Glostrup University Hospital, The Capital Region of Denmark, DK-2600 Glostrup, Denmark

a2 Department of Gastroenterology, Slagelse Hospital, DK-4200 Slagelse, Denmark

a3 Department of Clinical Biochemistry and Molecular Biology, Hvidovre Hospital, DK-2650 Hvidovre, Denmark


Danish legislation regarding food fortification has been very restrictive resulting in few fortified food items on the Danish market. Folate and vitamin B12 deficiency is thought to be common due to inadequate intakes but little is known about the actual prevalence of low serum folate and vitamin B12 in the general population. The aim of the present study was to evaluate the folate and vitamin B12 status of Danish adults and to investigate associations between vitamin status and distinct lifestyle and genetic factors. The study included a random sample of 6784 individuals aged 30–60 years. Information on lifestyle factors was obtained by questionnaires and blood samples were analysed for serum folate and vitamin B12 concentrations and several genetic polymorphisms. The overall prevalence of low serum folate ( < 6·8 nmol/l) was 31·4 %. Low serum folate was more common among men than women and the prevalence was lower with increasing age. Low serum folate was associated with smoking, low alcohol intake, high coffee intake, unhealthy diet, and the TT genotype of the methylenetetrahydrofolate reductase (MTHFR)-C677T polymorphism. The overall prevalence of low serum vitamin B12 ( < 148 pmol/l) was 4·7 %. Low serum vitamin B12 was significantly associated with female sex, high coffee intake, low folate status, and the TT genotype of the MTHFR-C677T polymorphism. In conclusion, low serum folate was present in almost a third of the adult population in the present study and was associated with several lifestyle factors whereas low serum concentrations of vitamin B12 were less common and only found to be associated with a few lifestyle factors.

(Received May 18 2009)

(Revised September 16 2009)

(Accepted September 29 2009)

(Online publication December 08 2009)


c1 Corresponding author: Dr Betina H. Thuesen, fax +45 43233977, email


Abbreviations: MTHFR, methylenetetrahydrofolate reductase; SNP, single nucleotide polymorphism; TCN, transcobalamin gene