Fasting glucose 115
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Understanding Fasting Glucose Levels of 115 mg/dL
Fasting Glucose and Insulin Secretion
Fasting glucose levels are a critical marker for assessing metabolic health. Research indicates that an acute insulin response is present in individuals with fasting glucose levels below 115 mg/dL but is absent in those with levels above this threshold 1. This suggests that 115 mg/dL may be an upper limit of normal for fasting plasma glucose levels. Additionally, the glucose disappearance rate, which measures how quickly glucose is cleared from the bloodstream, is related to the acute insulin response in individuals with fasting glucose below 115 mg/dL. In contrast, for those with fasting glucose levels above 115 mg/dL, the total insulin response becomes more relevant 1.
Genetic Factors Influencing Fasting Glucose
Genetic studies have identified several loci associated with fasting glucose levels and insulin regulation. For instance, loci near genes such as ADCY5, MADD, and ADRA2A have been linked to fasting glucose levels 2. These genetic factors can influence various biological processes, including signal transduction, cell proliferation, and glucose sensing. Notably, some of these loci are also associated with an increased risk of type 2 diabetes, highlighting the genetic overlap between elevated fasting glucose levels and diabetes risk 2.
Impact of Fasting and Energy-Restricting Diets
Dietary interventions, particularly fasting and energy-restricting diets, have been shown to significantly impact markers of glucose and insulin control. A systematic review and meta-analysis of randomized controlled trials found that such diets lead to significant reductions in fasting blood sugar (FBS), insulin levels, and insulin resistance (HOMA-IR) 3. Specifically, fasting or energy-restricting diets resulted in a weighted mean difference (WMD) of -3.376 mg/dL for FBS, -1.288 μU/ml for insulin, and -0.41 mg/dL for HOMA-IR 3. However, these diets did not significantly affect hemoglobin A1c (HbA1c) levels, which is a longer-term marker of blood glucose control 3.
Conclusion
A fasting glucose level of 115 mg/dL is a critical threshold for normal insulin response and glucose metabolism. Genetic factors play a significant role in determining fasting glucose levels and the risk of type 2 diabetes. Additionally, dietary interventions such as fasting and energy-restricting diets can effectively reduce fasting glucose and insulin levels, although their impact on long-term glucose control markers like HbA1c may be limited. Understanding these factors can help in managing and potentially preventing metabolic disorders.
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Most relevant research papers on this topic
Relationships between fasting plasma glucose levels and insulin secretion during intravenous glucose tolerance tests.
The acute insulin response plays a crucial role in determining glucose disappearance rates during intravenous glucose tolerance tests, with 115 mg/dl as the upper limit of normal fasting plasma glucose levels and 1.06 per cent per minute as the lower limit of normal glucose disappearance rate.
Observational Study
Highly CitedNew genetic loci implicated in fasting glucose homeostasis and their impact on type 2 diabetes risk
New genetic loci have been identified influencing fasting glucose and type 2 diabetes risk, highlighting the potential of genetic studies of glycemic traits to identify risk factors and modest elevations in glucose levels.
Meta-Analysis
Rigorous JournalHighly CitedThe effect of fasting and energy restricting diets on markers of glucose and insulin controls: a systematic review and meta-analysis of randomized controlled trials
Fasting or energy-restricting diets significantly reduce fasting blood sugars, insulin, and HOMA-IR levels, but have modest, non-significant effects on HbA1c levels.
Meta-AnalysisVariants in MTNR1B influence fasting glucose levels
Variants in MTNR1B gene are associated with fasting glucose levels and an increased risk of type 2 diabetes.
Meta-AnalysisHighly CitedHigh fat diets for weight loss among subjects with elevated fasting glucose levels: The PREDIMED study
Participants with elevated fasting glucose levels lost more weight on moderate to high-fat diets than those with lower fasting glucose levels.
RCT
Large Human TrialA common haplotype of the glucokinase gene alters fasting glucose and birth weight: association in six studies and population-genetics analyses.
Common variation in the glucokinase gene is associated with fasting glucose and fetal growth, but no strong evidence of positive selection exists.
Meta-AnalysisHighly CitedDiabetes mellitus, fasting blood glucose concentration, and risk of vascular disease: a collaborative meta-analysis of 102 prospective studies.
Diabetes mellitus increases the risk of various vascular diseases by about two-fold, while fasting blood glucose concentration is modestly and non-linearly associated with vascular disease risk in people without diabetes.
Meta-AnalysisRigorous JournalHighly CitedEffects of fasting on insulin binding, glucose transport, and glucose oxidation in isolated rat adipocytes: relationships between insulin receptors and insulin action.
Fasting increases insulin binding in adipocytes, but glucose oxidation is severely impaired, glucose transport decreases, and insulin receptor-glucose transport system coupling is normal after 24 hours but impaired after 48 and 72 hours.
Non-RCT
Animal StudyHighly CitedIs fasting glucose sufficient to define diabetes? Epidemiological data from 20 European studies
Fasting glucose alone is insufficient to diagnose diabetes, as it excludes 31% of diabetic subjects with non-diabetic fasting glucose but diabetic 2-h glucose levels, and the risk profile of impaired fasting glycaemia depends on 2-h glucose concentrations.
Meta-AnalysisHighly CitedImpact of intermittent fasting on glucose homeostasis
Intermittent fasting may not effectively regulate glucose homeostasis, with no effect observed in alternate day fasting and Ramadan fasting in healthy individuals with mild weight loss.
Systematic Review