The bone mass of human body reaches its peak around the age of 35, and then gradually loses in the next few decades. The bone mass of the elderly gradually decreases with the increase of age, and men will show a linear decline, while women lose bone mass faster in the first five years after menopause and are more prone to osteoporosis symptoms.
Studies have shown that 43% of fracture patients over 50 years old are short of calcium and vitamin D. Dietary intervention studies have found that reasonable intake or supplementation of vitamin D and calcium can help reduce the risk of fracture in the elderly.
So, what are the functions of calcium and vitamin D, and how should they be supplemented reasonably?
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The role of calcium and vitamin d
Calcium is the most abundant mineral element in human body and has many physiological functions.
Calcium is the main component of bones and teeth. More than 99% of calcium in the body exists in bones and teeth. The remaining 65,438+0% calcium exists in the internal environment and other tissues and cells, which is involved in regulating the excitability of neuromuscular, the integrity and permeability of biofilm, maintaining the normal function of cells, the activation of enzymes, the release of various hormones and neurotransmitters, the process of blood coagulation, and the physiological functions such as regulating blood pressure and transmembrane transport of iron.
Vitamin D is metabolized to 25-(OH)D in liver, and converted to active 1, 25-(OH)2D, 1, 25-(OH)2D in kidney, which combines with parathyroid hormone to maintain blood calcium stability, and 1, 25-(OH)2D mainly promotes calcium.
The deficiency of calcium and vitamin D can lead to the decrease of the basic unit of bone, the thinning of bone cortex and the thinning and reduction of bone trabecula, thus reducing the bearing capacity of bone and increasing the risk of osteoporotic fracture.
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Supplement of calcium and vitamin d
Insufficient intake of calcium and vitamin D is common among residents in China. According to the survey, the dietary calcium intake of the elderly in China is less than half of the recommended amount. Therefore, the elderly need to take enough vitamin D and calcium, and also need to do appropriate outdoor sports activities to achieve the purpose of strengthening bone strength.
Suggestions on Dietary Nutrient Reference Intake of China Residents (20 13);
The recommended daily intakes of calcium and vitamin D for middle-aged and elderly people over 50 years old are 1000 mg and 10 μ g respectively.
The recommended daily intake of vitamin D for the elderly over 65 years old is 15 micrograms.
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Which foods are rich in calcium?
Milk and dairy products contain high calcium content, and the ratio of calcium to phosphorus is appropriate. They also contain factors that contribute to calcium absorption, such as vitamin D, lactose, amino acids, etc., which have high absorption and utilization rate and are the main sources of high-quality calcium in diet. The elderly should consume 300 grams of milk or dairy products every day, such as drinking a box of milk (about 220 ml) and a box of yogurt (about 120 ml) every day, or replacing it with cheese.
In addition to milk and dairy products, there are also bean products (such as tofu), seafood (such as kelp, shrimp, shells), sesame seeds, black fungus and so on. It is also a food rich in calcium. In addition, oxalic acid and phytic acid in the diet can precipitate with calcium, reducing the absorption of calcium. It is suggested to choose vegetables with high calcium and low oxalic acid, such as celery, rape and alfalfa.
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Where does vitamin D come from?
Vitamin D helps to promote the absorption of calcium. The source of vitamin D in human body is mainly through skin contact with sunlight or from diet. It is suggested that the elderly should increase outdoor activities and sunshine time while supplementing calcium.
It is recommended to bask in the sun twice a week for 15-30 minutes each time. Foods with high vitamin D content include fatty marine fish, animal liver, egg yolk, cream and so on.
If you can't get enough calcium and vitamin D from food, you should supplement it reasonably under the guidance of professionals.
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Author | Dr. Ma Health Group Dr. Zhang Na
Picture | selfie net and network
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Reprint cooperation | faye.feng@ignitehealth-gp.com
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