RESULTS The meta- analysis of observational studies showed a weaker slope of dose-response relations than the meta- analysis of RCTs .
The obtained dose-response estimate between vitamin B-12 intake and status provides complementary evidence to underpin recommendations for a vitamin B-12 intake of population
BACKGROUND Many r and omized controlled trials ( RCTs ) and observational studies have provided information on the association between vitamin B-12 intake and biomarkers .
The use of these data to estimate dose-response relations provides a useful means to summarize the body of evidence .
OBJECTIVE We systematic ally review ed studies that investigated vitamin B-12 intake and biomarkers of vitamin B-12  status and estimated dose-response relations with the use of a meta- analysis .
Iron, folate and vitamin B12 status of an elderly South African population
Objectives : To determine the prevalence of anaemia and the haemopoietic nutrient status of older mixed ancestry ( coloured ) South Africans . Design : A cross-sectional analytic study . Subjects : A r and om sample of 200 non-institutionalized subjects aged ≥65 y of age , resident in urban Cape Town , was drawn using a two-stage cluster design . Methods : Trained fieldworkers interviewed subjects to obtain demographic and lifestyle data .  Dietary intake was assessed using a vali date d food frequency question naire . Fasting blood sample s were drawn for the determination of haematological parameters , serum vitamin B12 , serum folate , RBC folate and a full blood count . Results : The prevalence of anaemia was 13.9 % . Eight of the 26 cases of anaemia ( 31 % ) were associated with suboptimal haemopoietic nutrient status ; 2(25 ) and 3(38 ) cases of these 8 anaemic subjects had suboptimal vitamin B12 and folate status , respectively . Iron deficiency anaemia accounted for 5(63)% of the subjects with nutrition-related anaemia . Ten men and two women ( 6.5 % of subjects ) had raised serum ferritin concentrations , half of whom had abnormal biochemical parameters indicative of alcohol abuse . Conclusions : Older coloured South Africans , particularly women , should be encouraged to eat diets with a high nutrient density and to consume adequate amounts of foods high in iron , folate and vitamin B12 . Further investigation regarding the high prevalence of hyperferritinaemia found in the men in this population is indicated . Sponsorship : Financial assistance from the HSRC/UCT Centre for Gerontology , the South African Sugar Association , the Zerilda Steyn Memorial Trust and the Medical Research Council ( DL ) for this project is acknowledged
RESULTS The meta- analysis of observational studies showed a weaker slope of dose-response relations than the meta- analysis of RCTs .
The obtained dose-response estimate between vitamin B-12 intake and status provides complementary evidence to underpin recommendations for a vitamin B-12 intake of population
BACKGROUND Many r and omized controlled trials ( RCTs ) and observational studies have provided information on the association between vitamin B-12 intake and biomarkers .
The use of these data to estimate dose-response relations provides a useful means to summarize the body of evidence .
OBJECTIVE We systematic ally review ed studies that investigated vitamin B-12 intake and biomarkers of vitamin B-12  status and estimated dose-response relations with the use of a meta- analysis .