A seaweed (Ascophylum nodosum) which is often taken as a dietary supplement for its high iodine content (about 500 mcg per gram). It is also a good source of other minerals.

Ketone bodies

A term used for the three substances acetoacetic acid, beta-hydroxybutyric acid and acetone, which are products of incomplete fatty acid oxidation and are formed when fat is used as an energy source by the body. Being water-soluble, ketones can be used by most cells as an alternative to glucose.

An abnormal accumulation of ketone bodies is known as ketosis. When severe, ketosis is known as ketoacidosis, because the body becomes over-acidified due to the acidity of two of the ketone bodies.

Conditions leading to ketosis are fasting or starvation, a shortage of carbohydrate, or uncontrolled diabetes mellitus which results in the body's inability to utilize carbohydrate as an energy source. In all these cases the body is forced to use fat as an alternative energy source, and free fatty acids in the circulation are converted to ketone bodies in the liver. Ketone production increases gradually during fasting or carbohydrate deprivation, reaching its maximum by about 10 days.

Ketosis (see Ketone bodies)

Kidneys

The kidneys consist of small funnel-like units called nephrons which filter blood under high pressure, removing water, urea, salts and other soluble wastes from blood plasma, and eliminating them as urine. All the blood in the body passes through the kidneys about 20 times every hour.

The kidneys also play an important role in the activation of vitamin D.