The association between estimated hepatic SCD-1 enzyme activity and overweight and obesity.
Abstract
Stearoyl Co-A desaturase (SCD-1) has an essential role in the human fatty acid metabolism as a rate limiting enzyme that ensures the synthesis of monounsaturated fatty acids from saturated fatty acids. Changes in fatty acid composition and hepatic SCD-1 activity have been found to be associated with overweight and obesity as well as disproportionate and abnormal body fat accumulation. The aim of this thesis was to perform a literature review of human studies investigating these associations.
Methods: A literature search was performed in PubMed to identify relevant studies. A set of predefined selection criteria were used to determine inclusion.
Results: Variations in estimated SCD-1 activity were found to be associated with BMI in most of the included studies, but also varied in response to anthropometric indicators reflecting body fat distribution. Differences in SCD-1 estimates were found despite similar BMI and similar estimates were found despite different BMI. The SCD-1 enzyme’s activity was also found to be associated with other variables measuring metabolic health, especially insulin regulation.
Conclusion: Data on SCD-1 activity in overweight and obesity need to be interpreted and understood in a larger context than the influence of excess body mass. Alterations in SCD-1 activity, and especially a high SCD16 index, may be a symptom of chronic overnutrition and high hepatic lipogenesis as well as central obesity, excessive liver fat and/or metabolic stress. However, a high SCD-1 activity has also been found to be conducive in the preservation of metabolic health. When considering a possible association between SCD-1 estimates and BMI it appears necessary to consider additional anthropometric and metabolic health indicators. Due to the large variation in thematic orientation, study design and subject characteristics of the included articles it was difficult to compare results. No firm conclusions regarding the SCD-1 enzyme’s role and influence in excessive and abnormal body fat storage may be drawn, and more research is necessary.