Quick Answer. The effects of caffeine start within 10 minutes after it is consumed, according to ScienceDaily. However, caffeine requires 45 minutes to reach its maximum concentration in the blood. Continue Reading.
The heart, blood, and blood vessels are the three structural elements that ... These nutrients enter the bloodstream by passing through the walls of the intestine.he heart, blood, and blood vessels are the three structural elements that ... These nutrients enter the bloodstream by passing through the walls of the intestine.
Rather than slipping easily into the bloodstream like most water-soluble vitamins, fat-soluble vitamins gain entry to the blood via lymph channels in the intestinal wall. Many fat-soluble vitamins travel through the body only under escort by proteins that act as carriers. The following describes how fat-soluble vitamins are absorbed by the body: