What is the main function of vitamin D?

The main function is to promote the absorption of calcium and phosphorus by small intestinal mucosa cells, promote the renewal of calcium salt and the formation of new bone, promote the reabsorption of calcium and phosphorus by renal tubule cells, promote the growth of skin cells, and regulate immune function.

What are the consequences of vitamin D deficiency?

Rickets is a disease that affects bone growth due to bone calcification disorder caused by vitamin D deficiency during growth and development. Vitamin D deficiency in infants and young children may be due to too little sunlight exposure, the inability to synthesize vitamin D in the dermal 7-dehydrocholesterol, too little in food, premature birth, congenital deficiency, liver and kidney dysfunction or liver, kidney, digestive tract diseases, or may be due to intake of calcium, phosphorus too little, or phosphorus too little calcium. Loss of appetite, easy crying, hyperhidrosis, occipital alopecia, later softening of the skull, delayed closure of fontanel, a long interval of tooth eruption, irregular dentition, soft rib groove (children under 2 years old due to rib softening, chicken breast, and thoracic depression along the lower margin of the sternum), beaded rib (hypertrophy of rib epiphysis, which can touch the circular ridge), and bangle (hypertrophy of radius epiphysis, which is circular ridge). Type O or X legs are prone to fracture and have low blood calcium. Pregnant, prolific women and the frail elderly may have osteomalacia, bone pain, myasthenia, curvature of the spine, pelvic deformation, bone tenderness, spontaneous fracture, etc. The activity of serum alkaline phosphatase was increased and the product of calcium and phosphorus was <40. Breastfeeding should be encouraged for infants, children should take adequate calcium and vitamin D supplements, and strive for more sun exposure.

What are the consequences of too much vitamin D?

Most common in infants and young children, due to excessive intake of vitamin D. However, each person’s tolerance to vitamin D is different, and children who are allergic to this daily dose of 1500IU (37.5μg) can exhibit toxic symptoms. General adults’ daily intake of 100,000 to 150,000 IU (2500-3750μg), and children’s daily 2000IU/kg (50μg/kg) even for 2 to 3 months can cause poisoning. It is more likely to occur by injection than by mouth. The symptoms of vitamin D poisoning are mainly due to hypercalcemia and the consequent renal impairment and soft tissue calcification. The clinical manifestations include loss of appetite, weakness, atherosclerosis, extensive soft tissue calcification varying degrees of impaired renal function, and in severe cases, death. Excessive maternal intake of vitamin D can cause hypercalcemia in infants. If the fetus develops hypercalcemia, the birth weight is low and the heart has a murmur. In severe cases, there are bradycardia, arrhythmia, nausea, vomiting, polydipsia, constipation, polyuria, and so on. When vitamin D is too high for a long time, hypercalcemia can lead to dysplasia and osteosclerosis. Vitamin D should be stopped immediately and calcium restricted, and if necessary, glucocorticoids should be used to reduce blood calcium or intramuscular calcitonin.

What is the relationship between vitamin D and calcium?

When the body’s intake of vitamin D is normal, calcium intake is also normal, simply put, vitamin D promotes calcium deposition to the bone and promotes bone development.

The complication is that the active component of vitamin D can promote the absorption of calcium from the mucosa of the small intestine, which promotes calcium deposition in the bones. In addition, it can also increase the absorption of calcium by renal tubules, which is conducive to bone calcification.

The active component of vitamin D is the formation of 25-hydroxyvitamin D by the hydroxylase system of vitamin D3 in the liver, which is then hydroxylated to 1, 25-dihydroxyvitamin D in the kidney, which is 50% more active than vitamin D3 and has been shown to be the true active form of vitamin D in the body.

Note: When calcium deficiency is particularly severe, such as when the blood calcium concentration is very low, vitamin D, under the regulation of parathyroid hormone, will transfer calcium from bones to plasma, increasing the plasma calcium concentration and ensuring normal life function.

Which foods are high in vitamin D?

Vitamin D can be obtained in two main ways: through sun exposure and food intake. Sunlight promotes vitamin D production in the skin, and food sources include egg yolks, shiitake mushrooms, maitake mushrooms, and canned tuna. Fortified foods, including orange juice, milk, cereal, and tofu, are important food sources rich in vitamin D.

Which foods are relatively high in calcium content?

The first choice of calcium supplement food is to choose natural foods in the daily diet, such as milk and soy products, its calcium content can definitely meet the needs of a person, especially the calcium content of old tofu is high, and suitable for human absorption; For people with lactose intolerance, yogurt is an option.