Which vitamin appears to be the most powerful regulator of cell growth and seems to keep cells from becoming malignant?

Ans.

The vitamin, which is considered as the most powerful growth regulator is vitamin D (calcitriol). It regulates various biological processes that affect cell growth, such as apoptosis and cell proliferation.

Vitamin D inhibits proliferation of cancer cells and keeps them from becoming malignant by increasing the activity of proteins that inhibit cell division and proteins that promote apoptosis.

Thus, the correct answer is 'vitamin D.'