Final answer:
Niacin (vitamin B3) interferes with the metabolism of blood glucose.
Step-by-step explanation:
The vitamin-B supplement that interferes with the metabolism of blood glucose is niacin (E).
Niacin, also known as vitamin B3, plays a crucial role in energy metabolism and can affect the way our body converts glucose into energy. It is involved in the breakdown of carbohydrates, fats, and protein, and helps regulate blood sugar levels.
When niacin is taken in high doses, it can cause an increase in blood sugar levels and interfere with glucose metabolism. This is particularly important for individuals with diabetes, as it can potentially worsen their condition.