This year’s double eleven, the sales of health care products ranked first in the rankings. "Eat the most expensive health care products and stay up the deepest night." It is a common problem of many people at present. These people regard health care products as a good medicine for health.
Among many health care products, vitamins are favored because of their relatively cheap prices and their non-negligible effects on anti-aging and prevention of chronic diseases. Recently, however, a new case report in the Journal of Vitreoretinal Diseases suggests that excessive use of nicotinic acid (vitamin B3) can damage specific cells in the eyes, so that an old man loses his vision seriously and becomes blind.
It does not provide energy for the human body, but it is indispensable.
"Vitamins, as the name implies, are elements that maintain life. They are a kind of trace organic substances that people and animals must obtain from food in order to maintain normal physiological functions." Zhang Ming, deputy director of the Nutrition Department of Tianjin Third Central Hospital, said that vitamins neither participate in the formation of human cells nor provide energy for the human body, but play an important regulatory role in the process of human growth, metabolism and development. Although the dosage of each vitamin required by the human body is not very large, each vitamin can not be lacking, otherwise it will lead to the occurrence of corresponding diseases.
The vitamin family is huge, and we often pay attention to more than a dozen vitamins every day. Among them, vitamins B1, B2, B6, B12, nicotinic acid, folic acid, choline biotin, etc. in the vitamin B family belong to water-soluble vitamins, while vitamins A, D, E and K belong to fat-soluble vitamins.
"Nicotinic acid mentioned in the above case report was originally called vitamin B3, which is an indispensable nutrient in the human body. Nicotinic acid deficiency may cause furuncle. " Zhang Ming said.
When the dosage of nicotinic acid exceeds its dosage as a vitamin, it can obviously reduce blood lipid. "Clinically, nicotinic acid was previously used as an adjuvant treatment for hypercholesterolemia." Yuan Ruyu, director of the Department of Cardiology, Second Hospital of Tianjin Medical University, said that nicotinic acid was used as a lipid-regulating drug in the mid-1950s, but its clinical application was limited due to its great side effects.
In the above-mentioned cases, the patient suffered from severe hypertension and hyperlipidemia, but took too much nicotinic acid for several months, resulting in a rare toxic reaction called nicotinic acid-induced cystic macular disease, which led to retinal swelling and eventually lost vision.
Cases of excessive intake of nicotinic acid are rare. Zhang Ming said that nicotinic acid, as a water-soluble vitamin, can be regulated by the human body. If excessive intake occurs, most of it can be excreted through urine metabolism. The situation of the above cases may be that patients take nicotinic acid in a short period of time, which exceeds the body’s metabolic regulation ability, thus causing rare toxic reactions.
"Family members" have different functions and usages.
Members of the vitamin family perform their duties and participate in ensuring the normal operation of various functions of the human body. For example, vitamin B1 can maintain the normal metabolism of the human body and the normal physiological function of the nervous system, which is the cause of annoying beriberi. Vitamin B2 contributes to the health of skin, mucous membrane and hair follicle system, and without it, it will lead to many skin and mucous membrane problems such as angular stomatitis, cheilitis and oral ulcer. Vitamin D can help the human body absorb phosphorus and calcium, which is an essential substance to ensure the health of bones. Without vitamin D, it may lead to rickets or osteoporosis.
There is also the most popular vitamin C. After entering winter, many people take it every day to prevent colds. In this regard, Zhang Ming said that vitamin C can promote the synthesis of collagen and maintain the elasticity of skin. At the same time, this characteristic can also soften blood vessels and prevent arteriosclerosis and osteoporosis. Vitamin C also plays a certain role in resisting viral colds, mainly promoting the production of immune antibodies in human bodies, thus preventing the occurrence of colds.
However, Zhang Ming reminded that although many people’s health will be affected by insufficient vitamin intake at present, the harm caused by excessive vitamin supplementation is sometimes far more serious than vitamin deficiency. For example, the human body’s demand for vitamin C is very small, and a daily intake of 100 mg can meet the human body’s needs. Taking it in large quantities will lead to a decrease in the pH of uric acid in the body and an increase in the contents of oxalate and urate in urine, which may lead to diseases such as gallstones and kidney calculi’s disease. There may also be gastrointestinal adverse reactions; After taking a large amount of vitamin C, it is easier to have various symptoms of vitamin C deficiency, such as increased vascular fragility, gingival bleeding and even scurvy.
Compared with water-soluble vitamins, taking too much fat-soluble vitamins is more likely to lead to human poisoning. Zhang Ming explained that fat-soluble vitamins will dissolve in fat and accumulate in fat, and the body will not excrete them by itself, so taking them in excess will cause poisoning. For example, vitamin A, if you take 100,000 IU every day (IU is the international unit of vitamin and antibiotic content), it is usually stipulated according to the characteristics of the drug that 1IU is equal to how much mass. In Pharmacopoeia, taking pure 1000IU for more than 6 months can cause chronic poisoning symptoms such as loss of appetite, vomiting, diarrhea, itchy skin, dryness and desquamation, increased intracranial pressure, and some people can also cause acute poisoning symptoms such as abnormal excitement, drowsiness and diplopia.
In addition to not taking too much vitamins, when taking vitamins, we should also pay attention to avoid taking them with certain drugs or foods at the same time, resulting in adverse side effects. When taking vitamin A, it is necessary to avoid alcohol. The main function of vitamin A is to convert retinol into retinol, and ethanol will inhibit the production of retinol during metabolism, which will seriously affect the visual circulation and the production function of male sperm. High-fat diet will increase the requirement of vitamin B2, thus aggravating the deficiency of vitamin B2; Previous studies have found that vitamin E supplements may conflict with cholesterol-lowering drugs.
A balanced and normal diet can meet the needs.
"As long as a balanced intake of a normal diet is enough to meet the normal needs of the human body for vitamins." Zhang Ming said that it is not recommended that healthy people supplement vitamins in large quantities, because the human body has its own regulatory function. For example, if the content of vitamin C in the body is too small, the absorption capacity of vitamin C will be enhanced to meet the needs of the body. Clinically, corresponding vitamin supplements are generally only given to patients suffering from vitamin deficiency caused by certain diseases. Like patients with liver disease, because vitamin B12 and vitamin A are stored in the liver, and the liver is a "synthetic chemical plant" of the human body, many vitamins will be transformed in the liver, and if there is a problem with the liver, a certain vitamin will be lacking. Therefore, patients with liver disease need vitamin supplements.
Generally speaking, vitamins are over-the-counter drugs, and some large-dose vitamins are prescription drugs, such as nicotinic acid sustained-release capsules. Clinicians sometimes use certain vitamins in large doses to treat certain diseases. Vitamin B1, as an auxiliary medicine for heart and cardiovascular and cerebrovascular diseases, is often used by doctors in clinic.
"Although most vitamins are over-the-counter drugs, since 2000, the nutrition community has reached a consensus that the intake of vitamins should refer to the recommended dosage standard for safe intake, that is, each vitamin has a maximum intake limit and a low limit without lack, which can neither be excessive, cause side effects, but also be higher than the low limit to ensure the effect." Zhang Ming said that as for how to judge whether you lack a certain vitamin and whether you need to supplement it, you should judge it through professional examination and doctor’s diagnosis, from whether the dietary intake is reasonable, whether there is vitamin deficiency, and blood biochemical tests.
In order to achieve the goal of losing weight, some women don’t eat or eat very few meals, and rely on vitamin supplements to maintain their health. In this regard, Zhang Ming also expressed disapproval of this practice: "On the one hand, weight loss should follow scientific principles and be planned and reasonable in combination with physical conditions, especially scientific arrangements for dietary intake; On the other hand, most vitamins in the market are synthesized by industrial chemistry, and the composition is single, which is far less than the rich and varied daily diet. Long-term excessive supplementation is more prone to imbalance and even side effects.
Zhang Ming suggested that according to the China Nutrition Society’s Balanced Diet Pagoda for China residents, we should eat grains, vegetables, fruits, meat, aquatic products, eggs, beans, milk and other foods every day, and learn to mix them to form rich table contents, so that we can ensure all kinds of vitamins needed by the human body every day, and there is no need to supplement them. It is not only useless, but even counterproductive to take supplements with expensive health care products such as vitamins while staying up late.