The role of calcium
It has been used as lime (calcium carbonate) in various fields since ancient times, and its manufacturing method, properties, and usage are described in books from BC. The chemical symbol for calcium is "Ca".
In adults, 30 to 40% of dietary calcium is absorbed through the small intestine.
However, the absorption rate of calcium is affected by factors such as nutritional status, age, and amount of activity.
Calcium is the most abundant mineral in the body, accounting for 1-2% of body weight.
Next, let's take a look at the function of calcium. Calcium contained in food is absorbed from the intestinal tract, with 1% distributed in blood and 99% distributed in bones and teeth.
Calcium contained in blood and other sources plays an important role in nerve excitation, release of neurotransmitters, muscle contraction, maintenance of membrane integrity, and blood coagulation.
Calcium, a constituent of bones and teeth, provides structural support for the body.
Calcium plays an important role in the body, and blood calcium levels are tightly regulated to keep them constant.
One of the mechanisms for this regulation is that when the calcium concentration in the blood decreases, the amount of calcium solute (bone resorption) from the bones increases and the concentration is kept constant.
In other words, calcium is stored in bones in preparation for when it is insufficient, just like saving in a bank.
Calcium deficiency and intake balance
Calcium is stored in bones, so acute deficiency symptoms do not appear immediately. may appear.
Continued calcium deficiency leads to insufficient bone formation, which can lead to rickets in children and osteoporosis and osteomalacia in adults.
In addition, it is said that long-term calcium deficiency can cause hypertension and arteriosclerosis.
Next, let's look at what happens when you take in too much calcium.
Calcium absorption from the intestinal tract is regulated to maintain blood calcium levels. Therefore, even if a healthy person takes a large amount of calcium temporarily from a normal diet, it is rare to develop health problems. However, excessive intake from supplements can cause problems such as urinary stones.
Also, it is important to keep in mind that it is important to balance calcium intake with other minerals.
Excessive intake of calcium may interfere with the absorption of magnesium and phosphate.
The ideal intake ratio is considered to be 2:1 calcium:magnesium and 1:1 calcium:phosphorus.
The recommended daily intake of calcium is 650 to 800 mg for adult men and 650 mg for adult women.
Pregnant women and lactating winds are 650 mg, the same as adult women. The upper limit is 2500 mg for both adult males and females.
Examples of people who should consider calcium supplementation include those who do not like dairy products, growing children, and middle-aged and elderly women.
Calcium-rich animal foods such as sakura shrimp, cheese, dried whitebait, milk and yogurt, and vegetable foods such as peas, roasted sesame, dried hijiki, frozen tofu, dried daikon radish, etc. I have.
Calcium absorption rate is particularly high during infancy, puberty, and late pregnancy.In order to prevent osteoporosis, it is important to take calcium well from a young age and maximize maximum bone mass in the late teens.
It is important to keep
In addition, absorption of calcium from the intestinal tract is known to be affected by various physiological factors such as intake, dietary components, aging, menopause, and physical activity.
Vitamin D is an ingredient that enhances the absorption of calcium.
It undergoes two-step hydroxylation in the liver and kidneys, is converted to active vitamin D, and promotes calcium absorption from the small intestine.
The action of vitamin D is due to this active form of vitamin D, which is one of the calcium absorption regulators, and vitamin D is abundantly contained in fish, liver, shiitake mushrooms and wood ear mushrooms. Others include lactose, casein, and lysine.
Calcium is absorbed differently depending on the food, about 50% in milk and dairy products, about 30% in small fish, and about 17% in vegetables. Among them, the absorption rate of milk is high, and it is thought that the papillae, protein called casein, and amino acids contained in milk enhance the absorption of calcium.
Conversely, dietary fiber, unrefined grains (brown rice and whole grains), and fuchinsan phytic acid contained in legumes can inhibit calcium absorption if taken in too much.
Dietary fiber has the property of inhibiting the absorption of minerals by its cation exchange ability, and phytic acid by its chelating action.
Oxalic acid, which is abundant in vegetables, has binding properties with calcium, and when combined with calcium, it becomes calcium oxalate.
Calcium oxalate is poorly soluble in water and inhibits calcium absorption.
On the other hand, since oxalic acid is water-soluble, it is important to devise cooking methods such as using a large amount of water to dissolve it in the juice that has been boiled and avoiding eating it raw.
It is also known that excessive intake of protein increases the amount of calcium excreted in the urine.
Phosphorus is next, and the ideal intake ratio is said to be calcium:phosphorus = 1:1.
If this balance is disrupted, it can lead to excess on the one hand and deficiency on the other.
Phosphate is added to instant foods and processed foods to improve storage stability and quality, or to improve taste.
In addition, it is said that the absorption of calcium is suppressed by taking too much alcohol and fat.
Calcium and drug interactions
Finally, we will look at interactions between calcium and pharmaceuticals.
Drugs that have descriptions of interactions with calcium preparations in package inserts have been summarized.
Tetracycline antibiotics, quinolone antibacterial drugs, bisphosphonate-type preparations and estracyte, etc., are drugs that may form chelates, inhibit absorption, and attenuate their effects when used in combination with calcium preparations.
Similarly, there are drugs such as polyflu, kayexalate, and calimate that may weaken the effect.
In addition, since polyflu contains calcium in the main component, there is also a risk of high calcium crystals.
Active vitamin D3 preparations such as Localtrol promote the absorption of calcium in the intestinal tract, and there is a risk of high calcium crystals, so they should be used with caution.
Similarly, medicines that may cause high calcium crystals include antacids such as magnesium oxide and sodium bicarbonate, rhubarb, and senna compounds. Concomitant use with digosine and ranirapid, which are cardiac glycosides, is cautioned because calcium enhances the myocardial contractility.