Aspartame is the most controversial food additive in history, and its approval for use in food was the most contested in FDA history. In the end, the artificial sweetener was approved, not on scientific grounds, but rather because of strong political and financial pressure.
The arterioles then divide further into capillaries. Capillaries are the smallest blood vessels and their walls are only one cell thick which allows diffusion between the blood and cells to occur. Nutrients and oxygen from the blood diffuses through the capillary walls into the tissues that need it. This is aided by the relatively high blood pressure that also squeezes the oxygen and nutrients through the capillary wall and into the cells of the tissue.
The blood vessels are responsible for transporting blood throughout the body. There are three major types of blood vessels: arteries, veins, and capillaries. Oxygen is the most important nutrient carried by the blood. Arteries carry oxygenated blood from the heart to all the structures of the body. Capillaries are very small, permeable vessels at which the exchange of water and chemicals between the blood and body tissues takes place.