What is vitamin D?
It is one of the fat-soluble vitamins and is produced by the skin when exposed to the sun. It is a nutrient that must be supplemented with a diet due to insufficient body production.
How vitamin D works
Regulates the concentration of calcium in the body and keeps it constant.
Helps absorb calcium and phosphorus and promotes bone formation.
It has also been advertised to be effective in boosting immunity and preventing cancer, but the details are unknown.
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In case of shortage
The shortage of babies increases the risk of dysgenesis and rickets.
In adults, bone formation is not normal and there is an increased risk of joint deformity and brittle bones. Older people are at higher risk of developing osteoporosis.
If you drink too much
It is said that there is little risk of overdose on a normal diet, but overdosing on supplements unnaturally causes hypervitaminosis. When hypervitaminosis occurs, hypercalcemia occurs due to excessive absorption of calcium, leading to kidney dysfunction.
Vitamin D absorption and function
In mammals, including humans, vitamin D2 and vitamin D3 have roughly the same physiological potency. Vitamin D is converted into active vitamin D through the liver and kidneys, and exerts various actions mainly by activating the functions of functional proteins in the body. The main physiological effect of vitamin D is to promote normal growth of the skeleton and teeth. It also has the function of normalizing nerve transmission and muscle contraction by promoting intestinal absorption of calcium and phosphorus in the small intestine and adjusting the concentration of calcium in the blood to a constant level.
Standard daily intake of vitamin D
According to the Japanese Dietary Intake Standards (2015 edition), the recommended daily intake for men and women over 18 years of age is 5.5 ㎍ (micrograms), with a maximum allowable amount of 100 ㎍.
According to the 2015 National Health and Nutrition Examination Survey, the average vitamin D intake in Japanese is 7.5 ㎍, which can be said to meet the standard intake on average. Of this, the intake of seafood is overwhelmingly 5.8㎍, which represents 77.3% of the total.
Due to the blessings of sunlight, vitamin D is unlikely to be deficient if a healthy person leads a normal life in moderate sunlight. However, older people consume more vitamin D from their diet than usual because their skin's ability to produce vitamin D is reduced, outdoor activity is reduced, and their potential for exposure to sunlight is reduced ... It has been pointed out that it is necessary. People who feel less exposed to the sun on a daily basis will find it important to consciously get vitamin D from their diet.
What if I am deficient in vitamin D 1)?
Vitamin D deficiency reduces calcium absorption from the intestinal tract and calcium reabsorption by the kidneys, leading to calcium deficiency and hypocalcemia. The result is softening of the bones, resulting in osteocalcin in adults, especially pregnant and lactating women. In children, bone growth retardation occurs, posture deteriorates, the leg bones bend, and rickets develops. Older people with low bone mass are more likely to develop osteoporosis and are at higher risk of bed-ridden due to fractures.
Vitamin D overdose problem
Vitamin D is also a fat-soluble vitamin and is known to cause health problems in overdose. Excessive intake of vitamin D causes hypercalcemia, which deposits large amounts of calcium on the walls of blood vessels, kidneys, heart muscle, and lungs. The result is symptoms such as kidney dysfunction, loss of appetite, vomiting, and increased nervous excitability.
Foods rich in vitamin D
Vitamin D is abundant in mushrooms, shellfish, eggs, and milk.
Foods that can be bought in familiar places, such as general supermarkets, are easy to cook and eat on a daily basis and are high in vitamin D.
Vitamin D is fat soluble, which makes it easier to absorb from animal foods that contain lipids, but you can increase the rate of absorption by taking mushrooms in stir-fries or oil-fried foods.