Is it easy to be knocked down by viruses and mycoplasma recently？ May be the lack of these two vitamins.
Since the beginning of November, the season has turned into winter, and the temperature is getting lower and lower. Winter is the season of high incidence of respiratory infectious diseases. If it is cold late this year and it may be a warm winter, respiratory infectious diseases will be more popular, which will be a severe test for everyone.
The best way to deal with the endless stream of pathogenic bacteria is to strengthen the body’s own resistance. Improving nutritional status is one of the important measures.
Many studies have found that the lack of vitamin A and vitamin D is related to poor resistance to various infectious diseases. People who lack these two vitamins will have a greater risk of severe mycoplasma pneumonia, and the risk of severe illness in Covid-19 will also increase. Especially for children and the elderly, the resistance is relatively low, so we should be more careful about the insufficient intake of these nutrients.
Vitamin A is an important anti-inflammatory vitamin.
Vitamin A is beneficial to improve the mechanism of resisting virus infection, including strengthening immune response, inhibiting inflammatory response and promoting mucosal repair.
Several studies have found that in patients infected with Covid-19, the plasma vitamin A level will be significantly reduced (viral infection consumes vitamin A in the body), and this lack of vitamin A will promote the release of more pro-inflammatory factors, including IL-6 and IL-1β And TNF-α And so on, thus increasing inflammatory indexes such as C-reactive protein.
Studies have found that vitamin A supplementation has effectively improved Covid-19’s infection, and fever, body pain, weakness and fatigue are not so serious, and the white blood cell count and the level of C- reactive protein have also decreased.
Some studies have also found that patients with low levels of vitamin A have a heavier disease score and a greater risk of hospitalization.
Poor vitamin A will increase the risk of severe mycoplasma pneumonia in children.
In addition, it has been found from previous studies that vitamin A malnutrition will increase the risk of severe mycoplasma pneumonia in children. Children with low serum vitamin A levels are more likely to suffer from severe mycoplasma pneumonia. Vitamin A supplementation can effectively reduce the risk of severe mycoplasma pneumonia. In a word, vitamin A has an important contribution to fight infection.
The risk of pneumonia and tracheitis will also increase when vitamin D is deficient.
Numerous studies have confirmed that vitamin D deficiency is associated with higher risk of infection, severe illness and death in Covid-19. Recently, it has been suggested that the level of serum 25- hydroxyvitamin D is related to the severity of mycoplasma pneumonia and the level of inflammatory factors, and to the risk of bronchial mucus embolism.
A variety of acute respiratory diseases are related to viruses, including coronavirus, influenza virus, respiratory syncytial virus, adenovirus, enterovirus, etc. In children lacking vitamin D, the infection rate of these diseases will increase. In addition, when vitamin D is deficient, the risk of severe pneumonia and tracheitis will also increase. The summary analysis of 25 studies supports the correlation between vitamin D deficiency and acute respiratory infectious diseases.
How to check whether vitamin A and vitamin D are insufficient?
Think about it. Is it possible for you and your family to have insufficient vitamin A and vitamin D?
Check vitamin a first.
If you and your family seldom eat:
— — Orange vegetables (carrots, pumpkins, etc.)
— — Orange-yellow fruits (such as papaya, mango, citrus, etc.)
— — Orange-yellow potatoes (sweet potatoes with orange flesh)
— — Dark green vegetables (such as spinach, broccoli, kale, rape, etc.)
— — Whole milk (including whole yogurt and cheese) or butter.
— — Egg yolk (including egg yolk of eggs, duck eggs, quail eggs, goose eggs, etc.)
— — Various animal livers (chicken liver, duck liver, goose liver, pig liver, sheep liver, etc.)
— — Fatty marine fish (such as saury, sardine, salmon, etc.)
Then it is easier to lack vitamin A, because they are all sources of vitamin A. Even if you eat 1 egg yolk and 1 cup of whole milk every day, the vitamin A you get is still far from reaching the standard. If there are symptoms that the skin and eyes are easy to dry, or you can’t see things clearly at night, it is more likely that there is a lack of vitamin A.
Check vitamin d again.
If you and your family:
— — You can’t wear short sleeves and exercise in the sun for half an hour every day.
— — The exposed parts of the skin are covered with sunscreen.
— — Wear sun protection clothes, hats or umbrellas whenever you see the sun.
Then you can’t get vitamin D from sunlight, which is the most natural and main source of vitamin D.
If you and your family:
— — Do not eat animal liver and kidney.
— — Don’t eat much egg yolk, whole milk and cream.
— — Fatty marine fish are seldom eaten.
Then food-derived vitamin D is also difficult to obtain, because they are the main sources of vitamin D. Even if you eat 1 egg yolk and 1 cup of whole milk every day, the vitamin D you get is still far from reaching the standard.
How to eat three meals to increase the intake of these two vitamins?
How to eat enough of these two vitamins? It’s very simple. Just follow the food suggested by the above self-examination.
Here is a suggestion for three meals that can increase the supply of vitamin A and vitamin D:
breakfast
Have a cup of whole milk and an egg with yolk. It is best to add 100 grams of small oranges, oranges, mangoes, papaya and other orange fruits. If people are not fat and their triglyceride and cholesterol levels are normal, two slices of cheese can be used instead of whole milk.
lunch
Eat animal liver twice a week, fried, boiled or marinated. For example, salted duck liver, stewed pig liver and fried chicken liver are all delicious. Add at least 100 grams of dark green vegetables, such as broccoli and Chinese cabbage.
dinner
Eat a piece of steamed pumpkin, or steamed sweet potato with red hearts, or a dish with fried carrots, and add at least 100 grams of dark green vegetables. Eat fatty marine fish twice a week, such as saury, spring fish and sardines.
Although there may be excessive problems after taking multivitamin A supplements, it is very safe to eat more orange and green fruits and vegetables and take carotene. Even if you eat too much carrots and your skin turns a little yellow, it will gradually fade if you stop.
However, increasing vitamin D mainly depends on sun exposure. If you make up from food, you may consume too much cholesterol, which is more difficult for people with hyperlipidemia.
In winter, the simple way to increase vitamin D is to bask in the back: when the sun is fine and there is no wind, open the window and let the sun shine directly on the bare back skin (it won’t be cold, and the whole body will start to heat up after a few minutes of sunbathing).
Because the area of the back is relatively large, drying the back can effectively increase vitamin D, and there is no need to worry about tanning the face or increasing wrinkles. Sunbathing won’t cause vitamin D poisoning.
How to avoid excessive poisoning by supplementing vitamin A and vitamin D?
The best way is to ask a nutritionist or registered dietitian to help you confirm whether the dose is appropriate.
However, we have to know the basic knowledge ourselves. Vitamin A in human body includes three forms: retinol, retinaldehyde and retinoic acid. Retinol can be converted into retinaldehyde (maintaining normal vision in dark light) and retinoic acid (maintaining normal immunity and children’s growth and development), but retinoic acid cannot be converted back to retinol.
Generally speaking, vitamin A in supplements is retinol, or retinol ester. At the same time, there are also carotene supplements, which can be turned into vitamin A in the body. However, for infants and some people with weak digestive ability, the conversion efficiency of carotene is relatively low, and the effect of vitamin A supplementation is not good.
Therefore, the source of vitamin A = retinol (ester)+carotene. In order to unify the two sources, "retinol equivalent" is often used to represent the total amount in food.
According to China’s nutrient reference intake standard, the daily vitamin A supplement should not exceed 3000 retinol equivalents (10000 international units), and the vitamin D supplement should not exceed 50 micrograms (2000 international units). Unless there is a doctor’s prescription, a larger dose can be used for treatment. The amount of vitamin supplements usually does not exceed the limit, but if you take more than one vitamin supplement at the same time, you need to look carefully to see if the combined amount will be too much.
In short, we must take good care of ourselves and our families when respiratory infectious diseases are high at the end of the year. It is important not to stay up late, go to bed early, keep a good mood, exercise moderately and eat enough nutrition. In addition to vitamin C, which people pay more attention to, vitamin A and vitamin D, two easily overlooked anti-infective nutrients, must also eat enough!
Text/Fan Zhihong (director of China Nutrition Society, chief expert of science communication hired by China Association for Science and Technology)