The role of age on B12 biomarker response to dietary intakes of vitamin B12 and Implications for dietary intake recommendations

Background: Despite having dietary intakes that typically greatly exceed current recommendations, 10–40% elderly population are affected by low vitamin B12 biomarker status as a result of atrophic gastritis (Pfeiffer et al., 2007), leading to an age-related decline in gastric acid secretion necessary for B12 separation from food protein. Despite its mild, non-specific clinical manifestation, this condition may contribute to the development of several diseases of ageing such as cardiovascular disease, dementia and osteoporosis (Hoey et al., 2007). However, B12 dietary intake recommendations remain uniform across adult age groups and there is as yet no evidence to support a revision of the recommendations specifically for older adults who are at increased risk of developing atrophic gastritis. This study aimed to investigate the role of ageing in the relationship between dietary B12 intake and biomarker status, and to provide scientific evidence to support the development of age-specific B12 dietary intake recommendations. Methods: The present research comprised new statistical analysis of a previous cross-sectional study of n250 older (≥60 years) and n191 younger participants who provided a blood sample analysed for B12 biomarkers (holotranscobalamin (holoTC); methylmalonic acid; total homocysteine and serum total B12); and gastric function biomarkers Pepsingonen I:II (Hoey et al., 2007). B12 Dietary intake was assessed using a 4 day food diary completed in conjunction with a semi-quantitative food frequency questionnaire used to identify fortified food consumers. Data were statistically analysed using chi-square, Pearson's correlation and independent samples t-tests as appropriate. Results: Mean dietary B12 intakes were higher amongst elderly participants (4.1 μg day−1 (SD 3.3 μg) versus 3.6 μg day−1 (SD 2.0 μg) amongst those aged