Low Vitamin D May Increase Risk of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the buildup of extra fat in the liver that isn’t caused by alcohol abuse.

Up to 25% of individuals in the United States are affected by NAFLD. Risk factors include being overweight or obese; having diabetes, high cholesterol, or high triglycerides; experiencing rapid weight loss; and having poor eating habits. However, patients can also develop NAFLD without these risk factors.

NAFLD is often a silent, asymptomatic disease. If left undiagnosed, this condition can lead to further complications, such as steatohepatitis and cirrhosis. There’s no approved treatment for NAFLD. with the exception of a healthy diet and regular exercise.

The journal

Medicine

recently published a cross-sectional study that shows a relationship between patients with NAFLD and levels of vitamin D and sex hormone-binding globulin (SHBG) in men and postmenopausal women. The researchers investigated the documented role of SHBG in metabolic diseases alone and in relation to vitamin D levels.

Patients with NAFLD often have 25-hydroxy-vitamin D (25(OH)D) deficiency. This deficiency is associated with suboptimal bone health and immune system function. SHBG is a serum-steroid transporting protein produced in the liver. Lower levels can affect sex hormone activity throughout the body. Data suggest SHBG levels can impact inflammation, diabetes, obesity, and the risk for cardiovascular disease.

The researchers enrolled patients from 16 sites and measured 25(OH)D and SHBG levels. Each patient also had a liver ultrasound, which is the best way to confirm the presence of NAFLD.

Patients who had low 25(OH)D or low SHBG had a higher risk of mild and moderate-severe NAFLD when compared with patients with normal levels. The combined association of low 25(OH)D and low SHBG was more significant for patients with moderate-severe NAFLD and was independent of age, total testosterone, abdominal obesity, diabetes, and lipid profile.

No recommendation is made for 25(OH)D supplementation in the effort of preventing NAFLD. The study authors recommended further studies to explore the relationship between 25(OH)D and SHBG levels and NAFLD.