Q.37
Which of the following metabolite(s) accumulate(s) in the blood of a human adult
consuming a ketogenic diet?
(A) D--hydroxybutyrate
(B) Acetoacetate
(C) Pyruvate
(D) Oxaloacetate
Ketogenic Diet Blood Metabolites: D-β-Hydroxybutyrate and Acetoacetate Accumulation Explained
Ketogenic diets induce ketosis by limiting carbohydrates, leading to ketone body production. D-β-hydroxybutyrate and acetoacetate accumulate in the blood as primary metabolites during this state.
Correct Answer
The correct options are (A) D-β-hydroxybutyrate and (B) Acetoacetate. These ketone bodies rise significantly in blood on a ketogenic diet, serving as alternative energy sources when glucose is scarce.
Ketogenic Diet Mechanism
A ketogenic diet shifts metabolism from glucose to fat oxidation, producing acetyl-CoA in the liver. Low oxaloacetate levels from gluconeogenesis divert acetyl-CoA to ketone body synthesis via HMG-CoA pathway, causing D-β-hydroxybutyrate and acetoacetate to accumulate in blood for use by brain, heart, and muscles.
Option Analysis
| Option | Metabolite | Accumulates on Ketogenic Diet? | Explanation |
|---|---|---|---|
| (A) | D-β-hydroxybutyrate | Yes | Major ketone body formed by reduction of acetoacetate; blood levels rise to 1-3 mM in nutritional ketosis, avidly used by extrahepatic tissues. |
| | |||
| (B) | Acetoacetate | Yes | Precursor ketone body synthesized from acetoacetyl-CoA; equilibrates with D-β-hydroxybutyrate and spills into blood during ketogenesis. |
| | |||
| (C) | Pyruvate | No | Central glycolytic intermediate; decreases due to low carbohydrate intake, as pyruvate dehydrogenase is inhibited and pyruvate funneled to gluconeogenesis. |
| | |||
| (D) | Oxaloacetate | No | Depleted in liver mitochondria for gluconeogenesis, blocking TCA cycle entry of acetyl-CoA and promoting ketogenesis instead of accumulation. |
1 Comment
Vanshika Sharma
December 26, 2025opt A AND B is correct