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.
Once these materials have been broken down, nutrient absorption can occur. As food is processed along the digestive tract, most of the nutrients are absorbed through the walls of the small intestines. The nutrients are carried into the bloodstream where they can travel to all parts of the body. Other substances that are absorbed during digestion include vitamins, water, and salt. Learn more about digestion: 1  Digestive System. 2  Pregastric Digestion. 3  The Esophagus.