In the first half of pregnancy, vomiting occurs mainly due to early pregnancy reactions, and food intake is significantly reduced, which can lead to imbalance of water and electrolytes, significant reduction of minerals and trace elements, protein deficiency, and increased fat oxidation. The ketone bodies produced in pregnant women have an important influence on the early development of the fetus. A balanced diet with high calories, high electrolytes, high vitamins, and easy digestion must be supplemented in large quantities.
Fetal development is accelerated in the second half of pregnancy. Pregnant women need to supplement a lot of nutrients while ensuring their own metabolic needs every day to ensure the high-calorie, high-protein nutrition and a comprehensive and balanced food of multiple vitamins and trace elements required for fetal growth and development.
Below we describe in detail the nutritional needs of each stage of pregnancy:
(1) Early pregnancy
The initial stage of pregnancy is the division and differentiation stage of the fertilized egg. At this time, the embryo is still small and growing slowly. The main form of embryonic development is differentiation into various organs. Therefore, at this time, the requirements for various nutrients are basically the same as before pregnancy or slightly higher than before pregnancy, so the food supply does not change much. If the pregnant woman's body is relatively thin and there is no early pregnancy reaction, the daily heat energy can be increased by about 150 kcal. This is roughly equivalent to the calories produced by nearly one or two staple foods or a bag of milk. Simply put, at this stage of pregnancy, pregnant women can choose some nutritious, meticulously prepared, and high-quality meals without having to pursue an increase in quantity too much. The focus of the diet at this stage should be on food quality and hygiene. If possible, you can choose some pollution-free green foods that do not contain pesticides and fertilizers. Do not contact with toxic and harmful substances and the environment, so that the embryo can develop normally.
(2) Middle and late pregnancy
After the second and third stages of pregnancy, the early pregnancy response has mostly stopped, the growth and development of the fetus has accelerated, and the need for various nutrients has increased. Especially in the third stage of pregnancy, half of the fetus’s weight should increase at this stage, and attention should be paid to various nutrients. Supplement.
◆The need for heat
The recommended supply in China is an increase of 200 kcal per day in the middle and late stages of pregnancy. Since the fetus is very small in the early stage of pregnancy, the pregnant woman's own physiological changes are not obvious, and the weight change is small, so the supply of calories is similar to that of normal women.
There are three types of foods that provide calories: carbohydrates, fats and proteins. You can increase the intake of carbohydrates by increasing the amount of staple food, but do not increase the amount of staple food too much. It is enough to increase the amount of staple food by about 50 grams per day, so as to leave room for protein and other nutrients. The increase in calories is best not to rely too much on fat, so the amount of cooking oil is the same as usual or slightly more than usual. In the late pregnancy, pregnant women's blood lipids are higher than usual. The intake of saturated fatty acids (animal fat) should not be too high, and animal oil should not be used as cooking oil.
In addition, it should be noted that the recommended supply is for the group. The actual heat energy during pregnancy needs to have large individual differences. Each person should adjust at any time according to their own weight growth. Generally, the weight gain in the middle and late stages of pregnancy is every time. It is within the normal range of 0.3 to 0.5 kg per week. If the weight gain is too slow, in addition to appropriately increasing the diet, some nutritional foods specially designed for pregnant women can be added, such as milk powder for pregnant women and other nutritionally comprehensive foods. If the fetus grows slowly in the uterus and is younger than a month old, amino acids can also be injected intravenously to supplement nutrition. If the weight gain during pregnancy is too fast, food intake should be reduced accordingly, especially sweets and fats should be restricted to slow down the weight gain. But you must not lose weight during pregnancy to prevent ketosis from damaging the intelligence of the fetus.
Protein is the material basis of life. Sufficient protein is essential for fetal development and maternal health. During pregnancy, the need for protein increases. The protein stored in the body during pregnancy is about 1 kg, which comes from food. Insufficient protein intake not only affects the health of pregnant women and the physical development of the fetus, but also affects the development and function of the fetal central nervous system, reducing the number of brain cells and thus affecting intelligence. China's recommended supply is increased by 15 grams per day during the second trimester, which is equivalent to 2 eggs or 2 taels of lean pork. Increase by 25 grams per day in the late pregnancy. Animal protein should best account for 2/3 of the total protein intake.
Lipids are not a substance, but a class of substances, which mainly include fat, phospholipids and cholesterol. These types of substances play a very important role in the development of fetal brain nerve cells and nerve fibers. Therefore, fatty foods in the diet of pregnant women should be essential.
Fats exist in many foods. For example, the meat, eggs, milk, nuts (peanuts, melon seeds, walnuts, pistachios, etc.) that we eat every day, soy products, contain different types of fats. The demand for lipids during pregnancy is also greater than before pregnancy. However, as the intake of staple foods and protein foods increases, especially when many people have the habit of eating walnuts and other nuts during pregnancy, the intake of lipids also increases accordingly. Therefore, in general, there is no need to supplement fat. Just follow the principle of normal circumstances to implement it.
The main role of carbohydrates is to produce energy and maintain blood sugar. The brain nerve cells and placenta of mothers and fetuses consume blood sugar for energy. If hypoglycemia occurs due to insufficient carbohydrate intake at this time, the pregnant woman's body will adjust to supplement blood sugar by oxidizing fat and protein. In the process of generating energy through fat oxidation, a substance called "ketone body" is produced. This substance is toxic to the nervous system, so its production should be avoided. This means that it is very undesirable to be hungry or take too little carbohydrates during pregnancy. In order to avoid this situation, pregnant women should eat at least 3 to 4 taels of staple food every day. If there are no special circumstances, it is best to reach 5 to 6 taels.
Dietary fiber is also a carbohydrate, because our body cannot digest and absorb dietary fiber, so it has no nutrition in the general sense. However, dietary fiber has many beneficial physiological effects on the human body, and proper intake should also be paid attention to.
◆Inorganic salts and vitamins
Calcium, iron, zinc, and iodine are inorganic salts that are more important for the growth and development of pregnant women and fetuses, but are more easily deficient during pregnancy.
Calcium and phosphorus are the main components of human bones and teeth. Even in adults, the calcium in the body is constantly being renewed. Calcium intake during pregnancy must be supplied to one's own needs on the one hand, but also for the fetus to grow bones and teeth on the other. Therefore, pregnant women should increase their calcium intake than before pregnancy. Severe calcium deficiency in pregnant women can lead to children's congenital rickets and newborn jawbone and tooth deformities. Pregnant women themselves can also develop diseases such as osteoporosis. China recommends a daily intake of 1000 mg of calcium in the second trimester of pregnancy; daily intake of 1500 mg during the third trimester, which is an increase of 200 mg and 700 mg respectively compared with non-pregnancy. The best sources of calcium in the diet are milk and dairy products.
Phosphorus is very widespread in all kinds of foods, and generally it is not lacking. What needs to be emphasized here is that the ratio of calcium to phosphorus in the diet is best kept within the range of 1:1.2 to 1:1.5.
The trace element iron is a component of blood, and the lack of iron can easily lead to anemia in pregnant women and retarded fetal growth. Many surveys show that the incidence of anemia among pregnant women in China is relatively high. China's recommended iron supply is 28 mg per day from the middle of pregnancy, which is an increase of 10 mg per day from before pregnancy. The absorption rate of iron in food is low, generally not more than 10%. The absorption rate of iron in plant foods is mostly 1% to 3%. Relatively speaking, the absorption rate of iron in animal foods such as lean meat, liver, and blood tofu is relatively high.
In addition to children, pregnant women are also vulnerable to zinc deficiency.
Iodine deficiency during pregnancy can easily cause goiter in pregnant women and affect the physical and intellectual development of the fetus. The daily iodine requirement in the middle and late stages of pregnancy is increased by 25 micrograms than usual. Seaweed, seaweed and other seafood and iodized salt contain higher iodine.
Vitamin A, vitamin D and some water-soluble vitamins should also be supplemented.
The intake of vitamin A must first meet the growth and development needs of the fetus and the storage in the liver, and also meet the mother's own needs and the storage of secreted milk. China recommends a daily supply of 1,000 micrograms of retinol (vitamin A) in the middle and late stages of pregnancy. Excessive intake of vitamin A has teratogenic effects and affects the normal development of fetal bones. Animal livers and egg yolks contain higher vitamin A content. Dark-colored vegetables contain more carotene, which can be converted into vitamin A.
Vitamin D can promote calcium absorption and is extremely important for the formation of bones and teeth. The Chinese Nutrition Society recommends 10 micrograms per day in the middle and late stages of pregnancy. Excessive intake of vitamin D leads to hypercalcemia in infants. Cod liver oil, egg yolk, milk and other animal foods contain a lot of vitamin D. Regular exposure to the sun can make the body produce vitamin D by itself.
Vitamins B1, B2, B6, and niacin in the B vitamins are all involved in the metabolism of the three major nutrients in the form of coenzymes, and the intake in the middle and late pregnancy is higher than before pregnancy. Lean meat, eggs, milk and whole grains contain higher B vitamins.
Insufficient intake of folic acid and vitamin B12 during pregnancy can cause megaloblastic anemia in pregnant women. Especially when folic acid is seriously inadequate in the first trimester, it can cause neural tube defects in the fetus. Animal livers, kidneys, fruits, and vegetables are rich in folic acid.
Vitamin C promotes the normal development of fetal bones and teeth, the soundness of the hematopoietic system and the increase of body resistance. Should increase during pregnancy. Fresh vegetables and fruits contain more vitamin C.
Constipation is prone to occur during pregnancy due to weakened bowel movements and bowel tension, coupled with reduced exercise. In addition, due to the increased abdominal pressure and the compression of the enlarged uterus, the hemorrhoid venous return is blocked, and symptoms such as hemorrhoids are prone to appear. Therefore, during pregnancy, you should eat more vegetables, fruits, kelp, etc. with high fiber, and eat less spicy food.
In short, the needs of various vitamins and inorganic salts in the middle and end of pregnancy have increased compared with those before pregnancy. Some of them cannot be obtained from the diet. They can be taken orally through various inorganic salts and vitamins from the fourth month of pregnancy. Preparations and calcium tablets, etc. to be supplemented.
Children are the future of the motherland and the hope of the family. Every mother has a deep understanding of the hardships of "October Pregnancy". But to get a healthy and smart baby, all the hard work is worth it. Good nutrition during pregnancy is an extremely important part of achieving this goal.