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 .
Cystatin C levels in plasma and peripheral blood mononuclear cells among hyperhomocysteinaemic subjects: effect of treatment with B-vitamins.
Homocysteine has been related to increased risk of CVD . Matrix degradation and inflammation may be involved in this link between hyperhomocysteinaemia and CVD . Recent studies suggest that cystatin C can modulate matrix degradation and inflammation . The present study measured cystatin C at protein ( plasma ) and mRNA levels ( peripheral blood mononuclear cells ( P BMC ) ) in hyperhomocysteinaemic individuals ( n 37 , female seven and male thirty , aged 20 - 70 years ) before and after B-vitamin supplementation for 3 months in a r and omised , placebo-controlled double-blind trial . In a cross-sectional study , seventeen of the hyperhomocysteinaemic subjects were age- and sex-matched to healthy controls ( n 17 ) . Our main findings were : ( i ) as compared with controls , hyperhomocysteinaemic subjects tended to have higher plasma concentrations of cystatin C and lower mRNA levels of cystatin C in P BMC ; ( ii ) compared with placebo , treatment of hyperhomocysteinaemic individuals with B-vitamins significantly increased plasma levels of cystatin C and mRNA levels of cystatin C in P BMC ; ( iii ) while plasma levels of cystatin C were positively correlated with plasma levels of TNF receptor-1 , mRNA levels of cystatin C in P BMC were inversely correlated with this TNF parameter . Taken together , our findings suggest that disturbed cystatin C levels may be a characteristic of hyperhomocysteinaemic individuals , potentially related to low- grade systemic inflammation in hyperhomocysteinaemic subjects , and that B-vitamins may modulate cystatin C levels in these individuals
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 .