First, the misunderstanding in daily diet
& ltI > Although the daily diet is rich in nutrition, it will be harmful to health if you eat it carelessly. For example:
1 milk can't be drunk on an empty stomach, which makes milk enter the intestine before it is fully digested, which is not conducive to nutrient absorption. At the same time, the hypnotic ingredients such as monochloramine in milk enter the body, which will make your work or study at a low tide.
2 don't eat frogs. Frogs feed on pests in the field, and pests are often contaminated by pesticides and remain in frogs.
Don't drink tea after meals: Because tannic acid in tea can be combined with food protein, which not only hinders the absorption of protein, but also tends to constipation.
It is not advisable to use strong tea to sober up after drinking, because the alcohol in the wine is converted into acetaldehyde, then into acetic acid, and then into water and CO2, which is excreted through the stomach. Two. Food pollution in daily life
< second > the sources of chemical pollutants in food.
2. 1 Chemical fertilizer pollution in food
In agricultural production, rational and scientific application of chemical fertilizers can not only improve soil structure, but also increase crop yield. In recent years, due to the long-term indiscriminate application of chemical fertilizers, the physical and chemical properties of soil have deteriorated, the fertility has declined, and the agricultural environment has been polluted, which in turn has brought pollution to food. In the production and consumption of chemical fertilizers in China, nitrogen fertilizer accounts for about 80% of the total output and 70% of the total consumption. In vegetable production, excessive application of nitrogen fertilizer and vegetable being a plant food rich in nitrate have the greatest influence on nitrate content in leafy vegetables.
2.2 pesticide pollution in food
Organochlorine pesticides have been used in China for more than 30 years. Although 1983 stopped the production of organochlorine pesticides, its residue problem can not be ignored. For example, the residue period of DDT and HCH is as long as 50 years. Organochlorine pesticides have low volatility, strong fat solubility and stable chemical properties, and are easy to accumulate in fat-rich tissues of animals and plants and fat-rich parts of grain shells. Because of its stable chemical properties, it is less decomposed by sunlight and microorganisms and slowly degraded in the environment, so it has strong residues in food and belongs to highly toxic pesticides. For example, the half-life of bhc in soil is 2 years, while that of DDT is 3 ~ 10 years. Long-term intake of food containing organochlorine pesticides mainly causes acute and chronic poisoning, which is harmful to liver, kidney and nervous system, and also has certain damage to endocrine and reproductive systems. According to the investigation results of human fat accumulation in a city in recent years, the average value of DDT is 6.09mg/kg, and the average value of HCH is 1 1.2mg/kg. It is worth noting that the detection rate of DDT and HCH in placenta and human milk is as high as 60%.
3. Reasonable dietary balance
& ltI > dietary balance
From the perspective of modern chemistry, the human body is a huge and exquisite chemical reactor. The speed and control of biochemical reaction is the core to prevent this "human machine" from failing, and it is also an important content of macro-preventive health care, and dietary balance is its key joint.
The requirements for nutrition vary with age, sex, physique, weight and type of work. According to the calories provided by sugar, protein and fat per unit weight and their proportions in the total calories, the basic daily requirements of an adult are roughly as follows: 300-400g of carbohydrates, of which 1/3 is sugar and 2/3 is starch, accounting for 34-45% of the total energy; Protein 80 ~ 120g, equivalent to 400g lean meat or 4 eggs, accounting for 20 ~ 35% of the total energy; Fat needs about 84 ~ 100g, accounting for 30 ~ 35% of the total energy.
< second >, dietary methods and dietary composition
Scientific catering is the central topic of nutrition research. The "four dishes" of well-off families in China (one meat, one vegetarian and one appetizer) and the combination of thick and thin recipes coincide with the new trend of modern diet reform.
1. Guiding principles
Mainly should follow the principle of "light, punctual, multi-meal, diverse and safe". Eating too greasy dishes, especially greasy dishes, consumes a lot of blood for digestion, which leads to insufficient blood supply to the brain, fatigue after meals, and decreased body temperature, blood sugar and work efficiency. Eating regularly and quantitatively can maintain a reasonable calorie distribution during the day and at night. A rich breakfast can improve the mental reaction speed of the whole morning, and can also improve physical labor. Eating less and eating more is more efficient than eating more and eating less. Try to avoid overeating at all times. Overeating can lead to obesity, diabetes, mental retardation of children, Alzheimer's disease and other diseases. A rich and varied diet is easier to meet the needs of multiple nutrients than a fixed single diet. "Safety" means not eating spoiled, toxic and harmful substances.
2. Dietary ingredients
According to the characteristics of food nutrients, the composition of modern balanced diet must include the following four aspects of food:
1) cereals, potatoes and miscellaneous grains. Collectively called grain, it is the traditional staple food in China. Rice is dominant in the south, and wheat, corn and miscellaneous grains are dominant in the north. Grain is the main source of carbohydrate, and carbohydrate is the heat source of heat energy. Protein is also found in grains. Although the content is not high, it is also the main source of protein due to its high consumption, accounting for about half of the protein needed by human body. It also contains B vitamins and inorganic salts. How much food a person eats every day depends on the need of heat energy, which is related to factors such as age, labor intensity and the supply of non-staple food. Therefore, the consumption of food should be adapted to the consumption of the body. Adults engaged in moderate manual labor need 500-600g of grain every day, accounting for 5 1% of the total diet.
2) Animal meat and beans. Such as pigs, cattle, sheep, rabbits, viscera, chickens, ducks, geese, aquatic products, eggs, milk, soybeans, bean products and so on. This kind of food is mainly supplied to protein, and it is a high-quality protein with high physiological value to make up for the shortage of protein in the staple food. Adults engaged in moderate manual labor should provide 50 ~ 100g lean meat, 50g eggs, 50g soybeans or corresponding bean products every day.
3) Vegetables and fruits. Among them, fresh vegetables are the main ones. Fruit is a supplementary food. The reason why it is an auxiliary food does not mean the quantity, quality and variety of nutrients it contains, but because of its source and price factors, it cannot be the food of every meal or day on the table of the masses in China. .
References:
1. Li Shumei Influence of agricultural environmental pollution on human health. Agriculture and Science and Technology, 1999, (6): 19.
2. Wei Environmental pollution caused by chemical fertilizer and its control measures. Shandong Environment, 1999, (4):67.
3. An Wenjing, etc. Preliminary study on water pollution caused by chemical fertilizers and pesticides. Henan Chemical Industry, 2000, (9):33.
4. wear silver, etc. Lectures on food hygiene. Beijing: China Light Industry Press,1992,83.
5. Zhou Shunan. Lecture on Food Hygiene, Nanjing: Jiangsu Science and Technology Press,1995,28.