Health of pregnant women
Vladimir Spirichev Head of the Laboratory of Vitamins and Mineral Substances of the Institute of Nutrition of the Russian Academy of Medical Sciences, Honored Scientist of the Russian Federation, Corresponding Member of the ATN, Professor, D.Sc.
Why is it needed?
Phosphorus is one of the most important elements in the biological sense. It is a part of a large number of various organic compounds involved in the construction of living body structures and the implementation of the most important metabolic processes.
An important role in the processes of vital activity belongs to inorganic phosphate - the residue of phosphoric acid - and its salts. Inorganic phosphate, together with calcium, is part of the basic mineral component of bone tissue - oxyapatite. A similar function is performed by phospholipids, which are the building material of cell membranes.
Being part of nucleotides and nucleic acids (DNA, RNA), phosphate takes part in the processes of coding, storage and use of genetic information, the synthesis of nucleic acids, proteins, growth and cell division.
No less great is the role of organic phosphorus compounds in the energy supply of life processes. So, in the form of adenosine triphosphate (ATP) and creatine phosphate in the body, energy is stored and used.
The importance of phosphorus in energy metabolism is due not only to the central role of ATP, but also to the fact that all the glucose changes in the body occur with its participation.
With the participation of the rest of phosphoric acid, vitamins begin to function.
Particular mention should be made of the role of cyclic adenosine monophosphoric acid (CAMP), the central link in the hormonal regulation system, a substance that transmits to regulatory cells a number of hormones.
The multifaceted functions of phosphorus compounds predetermine their important role for such leading physiological processes as conduction of a nerve impulse and muscle contraction. Phosphorus compounds are involved in the formation of myelin, which forms an insulating coat of nerve fibers.
Inorganic phosphate also plays a significant role in maintaining acid-base balance. A necessary condition for the absorption of phosphorus from organic compounds is their cleavage by intestinal alkaline phosphatase, an enzyme that is produced in the intestine.
The absence of phytase in the intestine (the enzyme processing the phytin) makes it impossible to absorb phosphorus phytic (inositophosphoric) acid, in the form of which there is a significant part of the phosphorus of plant products. The processing of phytin by yeast containing phytase, for example in the process of baking bread, promotes the assimilation of phosphorus.
The effectiveness of absorption of phosphorus depends on the ratio of calcium and phosphorus. Optimum for absorption of both elements is a ratio of 1: 1.
Maintenance of phosphorus in the body and regulation of its metabolism is carried out with the participation of vitamin D and the hormone of the parathyroid glands.
How much phosphorus do we need?
The exact human need for phosphorus is not established. The current norm in Russia for adults is 1200 to 1600 mg.
Most food is rich in phosphorus, and a normal diet easily provides up to 1500 mg of phosphorus per day. In this regard, the lack of phosphorus, due to its lack of food, almost never occurs. A more serious problem is preventing the excessive intake of phosphorus in the body. In this regard, it becomes important to ensure the optimal ratio of calcium and phosphorus in the human diet. In real conditions, achieving this goal is difficult, since in a ratio close to optimal, calcium and phosphorus are found only in milk and dairy products, as well as in certain vegetables, berries and fruits. In all other products, this ratio is strongly shifted toward an excess of phosphorus. So, in bread and potatoes the phosphorus content exceeds the level of calcium 5 times, and in fish and meat - at 10 and even 20 (!) Times.
In this regard, in the diet of modern man, especially with the predominance of meat products and bread, the ratio of calcium and phosphorus can be very different from optimal in the direction of excessive consumption of phosphorus. This unfavorable ratio is further shifted towards phosphorus excess due to the widespread use of phosphate-containing food additives, in particular polyphosphates added to sausage products as a humectant.
The adverse effects of excessive phosphorus intake for humans are indicated by a number of observations, in particular, information on lower bone density in persons consuming phosphate-rich meat food, compared with vegetarians, the ratio of calcium and phosphorus in the diet of which is close to optimal. Thus, excessive consumption of phosphorus leads to osteoporosis - thinning of bone tissue.
Experiments carried out on laboratory rats have shown that, with vitamin D deficiency, even a moderate excess of phosphorus in the diet increases such manifestations of insufficiency of this vitamin as growth retardation, increased deposition of calcium salts in tissues and organs, including in the placenta during pregnancy, that can lead to poor blood supply to the fetus.
Since the reduction of phosphorus in the diet by selection of natural products is practically unattainable, it is recommended that future mothers use specialized dietary products with low phosphorus content and high calcium content based on milk and dairy products, flour and cereal products, as well as the corresponding protein products.