Final answer:
The vitamin produced by the normal flora of the colon in sufficient amounts to meet daily requirements is vitamin K. It plays a vital role in blood clotting, and deficiencies are rare due to synthesis by gut bacteria and dietary sources.
Step-by-step explanation:
The vitamin that is produced by the normal flora of the colon in amounts sufficient to meet a person's daily need is vitamin K. Normal intestinal bacteria, such as Escherichia coli (E. coli), play a crucial role in the synthesis of vitamin K, which is essential for blood clotting and bone health. While the body has a storage capacity for vitamin K in the liver, deficiency is rare due to both dietary intake and microbial synthesis. However, newborns may have a deficiency as they have not yet developed this normal flora.
Other functions of the bacteria in the colon include the absorption of ions, maintaining and training both the infant and adult immune systems, and protecting against pathogens by fostering a healthy intestinal epithelium. While most vitamins need to be obtained through diet, the body and its resident microbiota synthesize certain ones, like vitamins B7, B12, D, and K. It is the role of these microbiota in the large intestine to not only assist in nutrient absorption but also help maintain the body's overall health, including roles in potentially reducing the risk of colon cancer.