**Core Concept**
PUFAs (Polyunsaturated Fatty Acids) are essential fatty acids that cannot be synthesized by the human body and must be obtained through the diet. They are crucial for various physiological processes, including membrane structure, energy storage, and inflammation regulation. The metabolism of PUFAs requires certain vitamins and enzymes to facilitate their breakdown and utilization.

**Why the Correct Answer is Right**
The increased intake of PUFAs requires an increased amount of vitamin E (alpha-tocopherol) to prevent lipid peroxidation. Vitamin E acts as an antioxidant, protecting cell membranes from the oxidative damage caused by free radicals generated during the breakdown of PUFAs. The vitamin E-PUFA complex is crucial for maintaining membrane integrity and preventing the formation of pro-inflammatory mediators. The enzyme glutathione peroxidase, which is dependent on vitamin E, plays a key role in reducing lipid peroxides and maintaining the balance of PUFA metabolism.

**Why Each Wrong Option is Incorrect**
**Option A:** Vitamin C is essential for collagen synthesis and iron absorption, but it is not directly involved in PUFA metabolism.
**Option B:** Vitamin K is necessary for blood clotting and bone health, but it does not play a significant role in PUFA metabolism.
**Option C:** Vitamin B12 is crucial for DNA synthesis, fatty acid synthesis, and energy production, but it is not specifically required for PUFA metabolism.

**Clinical Pearl / High-Yield Fact**
A diet rich in PUFAs may increase the risk of lipid peroxidation and oxidative stress, especially in individuals with inadequate vitamin E levels. This can lead to the development of chronic diseases, such as atherosclerosis, and exacerbate existing conditions, such as diabetes and cancer.

**Correct Answer:** D.