RDA of thiamine per 1000 kcal energy per day is
**Core Concept**
Thiamine, also known as Vitamin B1, is an essential nutrient required for various bodily functions, including energy metabolism and nerve function. The Recommended Dietary Allowance (RDA) of thiamine is crucial for maintaining optimal health, and it is often expressed in relation to energy intake.
**Why the Correct Answer is Right**
The RDA of thiamine is typically expressed in micrograms (mcg) per 1000 kcal of energy intake per day. This is because thiamine is an energy-dependent nutrient, and its requirements vary based on the body's energy expenditure. The recommended intake is designed to meet the needs of individuals with average energy requirements. Thiamine plays a critical role in the decarboxylation of alpha-keto acids in the Krebs cycle, which is essential for energy production.
**Why Each Wrong Option is Incorrect**
**Option A:** This value is too low to meet the energy-dependent requirements of thiamine.
**Option B:** This value is higher than the established RDA for thiamine.
**Option C:** This value is not specific to thiamine, as it is a general recommendation for energy intake.
**Clinical Pearl / High-Yield Fact**
The RDA of thiamine is 1.1-1.2 mg per 1000 kcal of energy intake per day, which is essential for maintaining optimal energy metabolism and preventing conditions like beriberi and Wernicke-Korsakoff syndrome.
**Correct Answer: D. 1.2 mg**