|Title||B-vitamins and body composition: integrating observational and experimental evidence from the B-PROOF study|
|Author(s)||Oliai Araghi, Sadaf; Braun, Kim V.E.; Velde, Nathalie van der; Dijk, Suzanne C. van; Schoor, Natasja M. van; Zillikens, M.C.; Groot, Lisette C.P.G.M. de; Uitterlinden, Andre G.; Stricker, Bruno H.; Voortman, Trudy; Kiefte-de Jong, Jessica C.|
|Source||European Journal of Nutrition (2019). - ISSN 1436-6207 - 10 p.|
Nutritional Biology and Health
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||BMI - Body composition - Effect of vitamin B12 and folic acid on obesity - Fat (Free) mass - Vitamin B12 and folic acid|
Purpose: Higher folate and vitamin-B12 have been linked to lower risk of overweight. However, whether this is a causal effect of these B-vitamins on obesity risk remains unclear and evidence in older individuals is scarce. This study aimed to assess the role of B-vitamin supplementation and levels on body composition in older individuals. Methods: A double-blind, randomized controlled trial in 2919 participants aged ≥ 65 years with elevated homocysteine levels. The intervention comprised a 2-year supplementation with a combination of folic acid (400 µg) and vitamin B12 (500 µg), or with placebo. Serum folate, vitamin-B12, active vitamin-B12 (HoloTC), methylmalonic acid (MMA), and anthropometrics were measured at baseline and after 2 years of follow-up. Dietary intake of folate and vitamin-B12 was measured at baseline in a subsample (n = 603) using a validated food-frequency questionnaire. Fat mass index (FMI) and fat-free mass index (FFMI) were assessed with Dual Energy X-ray absorptiometry (DXA). Results: Cross-sectional analyses showed that a 1 nmol/L higher serum folate was associated with a 0.021 kg/m 2 lower BMI (95% CI − 0.039; − 0.004). Higher HoloTC (per pmol/L log-transformed) was associated with a 0.955 kg/m 2 higher FMI (95% CI 0.262; 1.647), and higher MMA (per μgmol/L) was associated with a 1.108 kg/m 2 lower FMI (95% CI − 1.899; − 0.316). However, random allocation of B-vitamins did not have a significant effect on changes in BMI, FMI or FFMI during 2 years of intervention. Conclusions: Although observational data suggested that folate and vitamin B12 status are associated with body composition, random allocation of a supplement with both B-vitamins combined versus placebo did not confirm an effect on BMI or body composition.