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 .
The effect of 7 to 8 months of vitamin/mineral supplementation on the vitamin and mineral status of athletes.
Blood indicators of eight vitamins ( B1 , B2 , B6 , C , E , A , B12 , folate ) and six minerals ( Cu , Mg , Zn , Ca , P , Al ) were measured in 86 athletes before and after a 7- to 8-month period of training . During this period half consumed a multivitamin/mineral supplement and a matched group took a placebo . Following the supplementation period , blood biochemical indicators of B1 , B6 , B12 , and folate status all increased but there were no significant effects of supplementation on B2 , C , E , and A , or on the blood levels of any of the minerals . The supplementation had no effect on red or white cell counts or on hemoglobin levels . Irrespective of the supplementation , some blood measures varied according to sex , females evidencing significantly higher values than males for vitamins C , E , copper , magnesium , and aluminium , with B2 being higher in males . It is concluded that 7 to 8 months of multivitamin/mineral supplementation increased the blood nutritional status of some vitamins but did not affect any blood mineral levels , and that some blood nutritional indicators may vary according to sex
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 .