Diets, lead naturally-occurring

Carbohydrates are more plentiful and constant in food supplies throughout the world when compared to other nutrients, such as proteins, vitamin A, folic acid, and iodine. A naturally occurring deficiency specifically in carbohydrates is im-known. However, deliberate omission of carbohydrates from the diet with continued consumption of fat as an energy source can lead to specific problems. Glucose is required as an energy source by the central nervous system. When there is a deficiency of glucose, the body adjusts its metabolism to provide ketone bodies, nutrients derived from fat, which can be utilized by the brain and other parts of the central nervous system. However, excessive production of the ketone bodies can result in acidosis, a lowering of the pH of the blood, which is potentially toxic. 

The nature of the complexes formed between AP+ and citrate is important because even though citrate may not be a substantial binder of AP+ in plasma, it can help AP+ cross membranes. This may occur both for AP+ transport within the body and for AP+ uptake from the gut. For example, citrate in the diet leads to enhanced AP+ levels in the brain and bones of rats 124), and to enhanced blood levels in humans taking Al(OH)3-based antacids together with citrate (125). 

About 40 different fatty acids occur naturally. Palmitic acid (Ci6) and stearic acid (Cis) are the most abundant saturated acids oleic and linoleic acids (both G ) are the most abundant unsaturated ones. Oleic acid is monounsaturated because it has only one double bond, but linoleic and linolenic acids are polyunsaturated fatty acids (called PUFAs) because they have more than one carbon-carbon double bond. Although the reasons are not yet clear, it appears that a diet rich in saturated fats leads to a higher level of blood cholesterol and consequent higher risk of heart attack than a diet rich in unsaturated fats. 

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