Voluntary fortification is ineffective to maintain the vitamin B12 and folate status of older Irish adults: evidence from the Irish Longitudinal Study on Ageing (TILDA)

Br J Nutr. 2018 Jul;120(1):111-120. doi: 10.1017/S0007114518001356.


Mandatory fortification of staple grains with folic acid and/or vitamin B12 (B12) is under debate in many countries including Ireland, which has a liberal, but voluntary, fortification policy. Older adults can be at risk of both deficiency and high folate status, although little is known on the actual prevalence and the major predictors. Population prevalence estimates from older adults (n 5290 ≥50 years) from the Irish Longitudinal Study on Ageing (TILDA) (Wave 1) are presented here. Measures included plasma total vitamin B12 and folate, whereas predictors included detailed demographic, socio-economic, geographic, seasonal and health/lifestyle data. The prevalence of deficient or low B12 status (45 nmol/l) was observed in 8·9 %, whereas high B12 status was observed in 3·1 % (>601 pmol/l). The largest positive predictor of B12 concentration was self-reported B12 injection and/or supplement use (coefficient 51·5 pmol/; 95 % CI 9·4, 93·6; P=0·016) followed by sex and geographic location. The largest negative predictor was metformin use (-33·6; 95 % CI -51·9, -15·4; P<0·0001). The largest positive predictor of folate concentration was folic acid supplement use (6·0; 95 % CI 3·0, 9·0 nmol/l; P<0·001) followed by being female and statin medications. The largest negative predictor was geographic location (-5·7; 95 % CI -6·7, -4·6; P<0·0001) followed by seasonality and smoking. B-vitamin status in older adults is affected by health and lifestyle, medication, sampling period and geographic location. We observed a high prevalence of low B12 and folate status, indicating that the current policy of voluntary fortification is ineffective for older adults.

Keywords: B12 vitamin B12; FA folic acid; NANA National Adult Nutrition Study; NHANES National Health and Nutritional Examination Survey; TILDA Irish Longitudinal Study on Ageing; B-vitamins; Biomarkers; Folate; Fortification; Supplements; Vitamin B12.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Aging*
  • Biomarkers / blood
  • Cluster Analysis
  • Cohort Studies
  • Dietary Supplements*
  • Female
  • Folic Acid / blood*
  • Folic Acid Deficiency / blood
  • Folic Acid Deficiency / prevention & control*
  • Food, Fortified
  • Geography
  • Humans
  • Ireland
  • Life Style
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Nutritional Status
  • Prevalence
  • Regression Analysis
  • Risk
  • Seasons
  • Smoking
  • Vitamin B 12 / blood*
  • Vitamin B 12 Deficiency / blood
  • Vitamin B 12 Deficiency / prevention & control*
  • Vitamins


  • Biomarkers
  • Vitamins
  • Folic Acid
  • Vitamin B 12