Vitamin B12 and Homocysteine Levels in Patients With Nafld: A Systematic Review and Metanalysis

Abstract

BACKGROUND: The vitamin B12 absorption can be affected in patients with nonalcoholic fatty liver disease (NAFLD), and low serum vitamin B12 levels has been related to the high homocysteine (HCY) levels and to the degree of NAFLD. OBJECTIVE: To carry out a systematic review and metanalysis of serum vitamin B12 and HCY levels in patients with NAFLD. METHODS: Original studies including serum vitamin B12 and HCY levels in humans with NAFLD were included. The searches were performed in four databases. RESULTS: 159 studies were identified, and after excluding the duplicates and non-eligible titles, eight original articles were included. Six out of eight showed higher B12 levels in NAFLD patients (404.9±136.2 pg/mL in relation to controls 353.91±117.3 pg/mL). Seven of the eight studies also showed higher HCY levels in NAFLD patients (14.2±3.44 umol/L in relation to controls 11.05±3.6 umol/L). The results for serum vitamin B12 and HCY levels were submitted to metanalysis, showing no difference in the vitamin B12 levels between patients with NAFLD and controls. However, the levels of Hcy were higher in NAFLD patients than in controls. CONCLUSION: There was no relashionship between the vitamin B12 levels and NAFLD. The levels of HCY were significantly higher in patients with NAFLD, suggesting this could be a potential marker for liver damage.

The Association between Non-Alcoholic Fatty Liver Disease (NAFLD) and Advanced Fibrosis with Serological Vitamin B12 Markers: Results from the NHANES 1999–2004

“…Serum vitamin B12 and folate levels were not associated with NAFLD or advanced fibrosis. Consistently, a meta-analysis showed that vitamin B12 levels were similar between participants with and without NAFLD [6]. Serum vitamin B12 and folate were affected by many factors, such as age, dietary habits, and lifestyle.…”

“…Our study suggested that HCY was independently associated with the risk of advanced fibrosis in NAFLD. It was demonstrated that HCY was increased in participants with histology-confirmed NAFLD [ 6 , 10 ]. In a sizeable Chinese epidemiological study, HCY was associated with NAFLD diagnosed by ultrasound [ 25 ].…”

“…A few studies had found that levels of vitamin B12 and its related biomarkers were altered in participants with NAFLD; however, a meta-analysis suggested that compared with non-NAFLD participants, levels of vitamin B12 itself were unchanged [ 6 ]. Since vitamin B12 levels and folate were affected by many factors, such as age, dietary habits, and lifestyle, appropriate intermediary compounds such as homocysteine (HCY) and methylmalonic acid (MMA) were more sensitive markers than serum vitamin B12 and folate in reflecting vitamin B12 homeostasis [ 7 ].…”

“…Red blood cell (RBC) folate represented the average folate levels in the preceding 120 days (the half-life of a RBC), and therefore it was used as an index for accurate tissue folate level [ 7 ]. It was found that HCY levels were increased in participants with NAFLD [ 6 ]; however, the change in serum HCY in participants with NASH is controversial [ 8 , 9 , 10 ]. Previous studies had limited sample sizes since the primary diagnostic tool for NASH was liver biopsy, which was less accepted than non-invasive diagnostic tools in patients.…”

Vitamins and Non Alcoholic Fatty Liver Disease

“…Bazı çalışmalarda NAYKH hastalarında kontrollere kıyasla serum B12 seviyelerinin azaldığı (47,49), düşük vitamin seviyelerinin ise daha yüksek fibrozis derecesi ile ilişkili olduğu bulunmuştur (45). Meta analiz ve sistematik derleme çalışmasında ise B12 vitamini seviyelerinin NAYKH ile ilişkili olmadığı, ancak vakalarda homosistein seviyelerinin anlamlı şekilde daha yüksek olduğu bildirilmiştir (52). Bu çelişkili sonuçlara rağmen NAYKH'nin daha iyi yönetimi için hastaların B12 vitamin seviyelerinin takip edilip eksiklik olduğunda düzeltilmesi önerilmektedir (49).…”