Phosphorus and magnesium and their relationship with parathyroid hormone and calcium metabolism.
The parathyroid (parathyroid) glands are located on the posterior surface of the thyroid gland. They have an oval shape, small size, and the number is usually 4, but it is possible to vary both in their number and location. The so-called parathyroid hormone, which is involved in the regulation of calcium and phosphorus metabolism, is secreted by the parathyroid glands.
The balance between the amount of calcium in the blood and bone structures is maintained by the complex involvement of the hormone of the parathyroid glands, vitamin D , calcitonin (thyroid hormone) and nutrition.
Vitamin D is a fat-soluble vitamin, whose main function is to ensure the absorption of calcium from food ingested through the lining of the small intestine. This function is performed by its metabolically active form - 1,25-dihydroxy vitamin D . Rich in vitamins are fish oil, some fish - carp, salmon, mackerel, as well as eggs, liver and mushrooms.
The supply of vitamin D with food alone is not enough, as its main function for the absorption of calcium from food is performed by the active form of the vitamin, which is obtained under the action of a specific enzyme in the kidneys. In turn, the stimulation of this enzyme is under the control of the parathyroid hormone secreted by the parathyroid glands.
When taken in excess of the daily dose of water-soluble vitamins (B, C), the excess is excreted in the urine. In contrast, excess amounts of fat-soluble vitamins cannot be eliminated from the body and toxicity occurs with prolonged overdose. The group of fat-soluble vitamins includes vitamins A, D, E and K.
Overloading the body with excessive supply of vitamin A and / or D can cause an increase in the level of calcium in the blood and the appearance of the corresponding symptoms - headache, constipation, fatigue and irritability, loss of appetite and others. The overdose is mainly due to excessive intake and non-compliance with the daily dose of the respective vitamins.
When reduced amounts of calcium in the blood leads to the secretion of parathyroid hormone , which leads to release of calcium from bones into blood, decreasing the release of calcium in the urine and increase calcium absorption from the mucous membrane of the gastrointestinal tract.
Changes in the amount of magnesium in the blood can also affect the secretion of parathyroid hormone. Even with a minimal decrease in the element in the blood, stimulation of the release of parathyroid hormone occurs. Nuts, seeds, green leafy vegetables, some types of fish - mackerel, tuna, avocado, bananas, dates, cocoa and others are rich in magnesium.
The increased amount of phosphates (phosphorus compounds) in the blood is also a reason to stimulate the secretion of parathyroid hormone. Phosphorus is found in almost all foods, which is why acute deficiencies are rare in a varied diet. In contrast, the intake of increased and excessive amounts of phosphorus in the body can lead to changes in calcium levels as a compensatory reaction to restore the disturbed mineral balance.
Foods rich in phosphorus, such as oat bran, sunflower, cheese, sesame and sesame tahini, soy, should be consumed in moderation, especially in patients with kidney disease (with difficulty clearing excess phosphate in the urine). It is important to keep in mind that the absorption of phosphorus from meat products is much easier than vegetable.
Research has shown an association between changes in normal parathyroid hormone levels and elevated cholesterol and triglyceride levels in some patients. This gives grounds for monitoring the level of the components of the lipid profile in patients with hypo- or hyperfunction of the parathyroid glands. 3733