At present, there exists an unreasonable maternal diet structure in China, which can lead to the occurrence of gestational diabetes mellitus. In this paper, we analyze the importance of diet in the prevention and treatment of diabetes mellitus in China, and propose several key issues in the prevention and treatment of diabetes mellitus in pregnancy: ① how to control energy intake to maintain weight gain during pregnancy; ② the appropriate energy supply ratio of the three macronutrients; ③ the intake of dietary fiber; ④ the glycemic index of food and glycemic control of diabetes mellitus in pregnancy, and focus on recommending the Dietary Guidelines for Chinese Residents Nutrient Intake” to change the dietary structure of pregnant women, reduce maternal insulin resistance, prevent the occurrence of gestational diabetes, effectively control the glycemic level of gestational diabetes, and improve maternal and infant outcomes.
Keywords: diet, gestational diabetes mellitus, insulin resistance
Diabetes mellitus is a clinical syndrome characterized by long-term hyperglycemia due to absolute or relative insulin deficiency and insulin resistance, and is classified into type I diabetes (absolute insulin deficiency due to β-cell destruction), type II diabetes (insulin resistance with relative insulin deficiency or insulin deficiency with insulin resistance), special types of diabetes and gestational diabetes according to the etiology. Gestational Diabetes Mellitus (GDM) refers to the occurrence or first detection of various degrees of abnormal glucose tolerance during pregnancy, accounting for about 80-90% of gestational diabetes mellitus. It is likely to cause metabolic disorders of carbohydrate, protein, fat, water and electrolytes in pregnant women, resulting in adverse pregnancy outcomes for both mother and child. Due to the dietary characteristics of the pregnant population, the prevention and treatment of pregnant women with GDM are different from those of adult diabetic patients, and this paper will discuss the relationship between diet and the prevention and treatment of gestational diabetes.
1. Factors associated with the development of gestational diabetes mellitus
(1) Factors of insulin resistance during pregnancy
Autoimmunity and genetics, changes in hormone levels during pregnancy can lead to a decrease in insulin secretion function and a decrease in insulin sensitivity of the body.
(2) Inflammatory factors and adipokines are related to the development of diabetes
Many studies have found that elevated white blood cells and C-reactive protein in the blood during pregnancy are associated with the development of GDM; leptin and adiponectin may also be associated with the development of GDM.
(3) Dietary factors during pregnancy
High fat, especially high saturated fat diet, high GI and low dietary fiber diet, excessive intake of red meat products, sweet tooth, etc. during pregnancy can lead to weight gain, induce insulin resistance and increase the risk of developing GDM.
2, the prevention and treatment of gestational diabetes several important principles
(1) Diet control
Diet control is the main measure for the prevention and treatment of gestational diabetes. Diet control during pregnancy should not only meet the energy needs of the pregnant woman and the fetus, but also strictly limit the intake of carbohydrates to maintain blood glucose in the normal range, and not to develop starvation ketosis.
(2) Exercise therapy
Exercise therapy is an important measure to treat gestational diabetes in conjunction with medication and diet therapy. Exercise can lower blood glucose levels, reduce the use of insulin, and help treat diabetes.
(3) Insulin therapy
When the effect of diet and exercise therapy is not good, insulin is reasonably applied to control the blood glucose level of gestational diabetes according to the results of blood glucose monitoring, combined with the insulin sensitivity of individual pregnant women.
In summary, the incidence of gestational diabetes mellitus is currently increasing, and diet is related to the onset of gestational diabetes mellitus, and comprehensive prevention and treatment of GDM is needed, of which diet therapy plays a very important position. Currently, most pregnant women with GDM can control their blood glucose levels and improve the prognosis of mothers and infants with gestational diabetes mellitus through reasonable diet therapy.
3, diet prevention and treatment of gestational diabetes focus on the content
(1) Control dietary energy intake and maintain reasonable weight gain during pregnancy.
(2) The relationship between energy intake during pregnancy and the onset of GDM
In addition to meeting the metabolic needs of the pregnant woman, the total energy intake during pregnancy also needs to ensure the supply of fetal growth, and energy consumption increases. Insufficient and excessive energy intake during pregnancy can adversely affect pregnancy outcome and maternal and infant health. Ma Chunling [1] et al. investigated the dietary intake of 2012 pregnant women using the 24-h dietary review method, and the results showed that the average daily total energy intake level was positively correlated with fasting and postpartum glucose during pregnancy, that is, the higher the average daily total energy intake during pregnancy, the higher the fasting and postpartum glucose values, which resulted in weight gain and increased insulin resistance during pregnancy and induced gestational diabetes.
(3) Appropriate energy intake during pregnancy
In 2000, the Nutrient Intakes of the Chinese Dietary Guidelines [2] (referred to as DRIs) recommended that the energy intake (RNI) after mid-pregnancy should be increased by 200 kcal/day from the non-pregnancy period. 2007, the Society of Obstetrics and Gynecology of the Chinese Medical Association formulated the Recommended Guidelines for Clinical Diagnosis and Treatment of Gestational Combined Diabetes [3], which put forward the diagnostic criteria and prevention and treatment of GDM in China for the first time. The recommended total daily energy intake for pregnant women with GDM is 7531-9205 KJ (1800-2200 Kcal/d), and the general daily energy intake is recommended to be no less than 1500 Kcal/d in early pregnancy, no less than 1800 Kcal/d in mid- and late-pregnancy, and controlled at 1800-2200 Kcal/d in mid- and late-pregnancy, and should be combined with pre-pregnancy weight, height, weight gain during pregnancy and medical condition. The diet should be considered in the context of pre-pregnancy weight, height, weight gain during pregnancy and medical condition. Liu Mei [4] and Wang Zhongzhen [5] divided the patients with GDM into a diet therapy group with dieticians and a control group with pregnant women controlling their own diet. The total daily energy intake of pregnant women in the diet therapy group was divided into normal, lean, overweight, and obese according to their ideal weight and variation range, and on this basis, 200 Kcal/d was added in mid-pregnancy and 350 Kcal/d in late pregnancy. The results showed that the glucose level in the treated group decreased significantly (P < 0.01) compared with the pre-treatment level, and the incidence of maternal and perinatal complications was lower than that in the control group, while the glucose level in the control group did not change significantly, suggesting that appropriate total dietary energy can improve maternal and infant outcomes and glucose levels in GDM.
(4) Energy intake during pregnancy and weight gain during pregnancy
At present, obesity is common in pregnant women with GDM, and reducing the energy intake of obese pregnant women can reduce blood glucose levels and plasma triglycerides, but too little energy intake can cause maternal ketosis and maternal and infant undernutrition. Therefore, the total dietary energy intake should be adjusted according to the monitored weight gain during pregnancy and GDM condition. The current weight gain during pregnancy is based on the pre-pregnancy body mass index with reference to the range of singleton pregnancy weight gain recommended by the Institute of Medicine (IOM) in 2009 [6] to evaluate the weight gain during pregnancy, in order to provide reference for the weight management and energy intake assessment during pregnancy in pregnant women with normal glucose metabolism and GDM.
4. Three major macronutrients with appropriate diets can improve maternal and infant outcomes in GDM.
(1) The existence of unreasonable dietary structure during pregnancy
Due to the lack of maternal nutritional health education and counseling services and the overprotection of pregnant women in the society, unreasonable diets such as high sugar, high fat, high saturated fatty acids and animal-based food structure are common before pregnancy or during early and late pregnancy, which can cause abnormal glucolipid metabolism and GDM.
Cheng Juan [7] et al. studied the dietary structure of 96 pregnant women with GDM and 96 healthy pregnant women using food frequency tables and 24-h dietary retrospective survey method, and the results suggested that the protein and fat intake of pregnant women in the GDM group were higher than that of the control group, and the functional ratio of carbohydrates was lower than that of the control group, which confirmed the existence of an irrational dietary structure of pregnant women with GDM. Therefore, the reasonable energy supply ratio of the three major nutrients recommended in the 2007 Recommended Guidelines for Clinical Diagnosis and Treatment of Gestational Combined Diabetes Mellitus is 45%~55% for carbohydrate, 20%~25% for protein and 25%~30% for fat.
(2) The need for appropriate protein intake during pregnancy
Adequate protein intake during pregnancy can ensure the normal development of the fetus, high protein diet can reduce the total energy intake and convert excess protein into fat and blood glucose, causing an increase in blood glucose and blood lipids; too little protein intake is associated with fetal growth restriction and low birth weight babies. The DRIs recommend increasing protein intake by 15g per day from mid-pregnancy and 20g per day in late pregnancy, of which animal protein should account for 1/2, and meeting the need for high-quality protein foods such as meat, eggs, milk and soybeans.
(3) The necessity of appropriate fat intake during pregnancy
Fat in the diet is divided into saturated fat, monounsaturated fat and polyunsaturated fat. A large number of epidemiological studies have shown that excessive saturated fat intake during pregnancy is independently and positively associated with abnormal glucose metabolism during pregnancy, while polyunsaturated fatty acid intake is negatively associated with GDM, and pregnant women with gestational diabetes are often accompanied by hyperlipidemia. Arachidonic acid and docosahexaenoic acid fish are preferred, and olive oil, camellia oil, soybean oil or corn oil with high unsaturated fatty acid content can be used as cooking oil.
(4) The necessity of suitable carbohydrates during pregnancy
Carbohydrates are divided into sugars, oligosaccharides and polysaccharides. Excessive carbohydrate intake during pregnancy is associated with elevated postprandial blood glucose, especially excessive intake of high glycemic index foods in carbohydrate foods. Too little intake is prone to ketosis and hypoglycemia, especially in early pregnancy, which has more serious effects on mother and baby. DRIs recommend that daily intake during early pregnancy should not be less than 150g to protect the nutritional needs of the fetus.
5. Dietary fiber intake is beneficial to improve blood sugar level.
Dietary fiber is divided into soluble and insoluble dietary fiber, the daily intake should be not less than 30g, its physiological function helps the digestion of food, reduce cholesterol, prevent excess energy, can significantly improve insulin sensitivity and reduce the occurrence of GDM. zhang [8] et al. found that an increase of 10g of fiber per day can reduce the risk of GDM by 26%. Dietary fiber is mainly derived from plant foods, and soluble dietary fiber can delay food absorption and help reduce postprandial glucose in GDM. The American Diabetes Association (ADA) encourages people with diabetes to consume whole grains, fruits and vegetables as the general population does. However, too much dietary fiber can cause a series of digestive intolerance reactions, such as gastrointestinal flatulence, abdominal pain and diarrhea, and can affect the absorption and utilization of iron, calcium and zinc in pregnant women.
6, food production glycemic index (Glycemic index GI) and the relationship between GDM.
GI refers to the ratio of the postprandial blood glucose tolerance curve of different foods within the baseline area to the standard glucose tolerance area, expressed as a percentage, generally GI greater than 70 for high GI foods, 55 to 70 for medium GI foods, less than 55 for low GI foods. It is an indicator of the effect of food or diet composition on blood glucose concentration. Studies have shown that foods with high GI can stimulate the pancreatic islets to secrete more insulin to keep blood glucose stable in the normal range, but long-term consumption of foods with high GI can cause the occurrence of GDM due to abnormal glucose metabolism as a result of decreased compensatory capacity of pancreatic β-cell function. Liu Mei et al. conducted a study on the dietary treatment of 35 pregnant women with GDM, and the results showed that the blood glucose level of pregnant women with GDM was well controlled by choosing low GI foods and coarse and fine combinations of fruits and staple foods according to the glycemic index on the basis of controlling the total energy and reasonable energy supply ratio of the three major nutrients. In clinical practice, it is recommended that pregnant women use coarse food not fine, simple processing, increasing protein in staple foods, rapid cooking, adding less water, eating more vinegar and high-low combination can help prevent the occurrence of GDM and control the blood glucose level of GDM by using food GI.
7.Other nutrients
There is no evidence that GDM pregnant women and ordinary pregnant women in terms of vitamin and mineral needs do not use. In recent years, scholars have focused on whether iron, magnesium, vitamin C, etc. are related to the prevention and treatment of GDM, but there is no clear conclusion. Pregnant women should consume adequate amounts of vitamins and minerals as recommended by DRIs, and consume more fruits and vegetables rich in folic acid, iron-rich animal liver, blood, lean meat and iodine-rich seafood, etc.
Conclusion
Fetal growth and development during pregnancy, restricted exercise patterns during pregnancy and inappropriate arbitrary weight control, insulin resistance factors during pregnancy and limited use of glucose-lowering drugs during pregnancy all make the prevention and treatment of GDM more complicated than the treatment of adult diabetes. Reasonable control of total energy intake, maintenance of appropriate weight gain during pregnancy, appropriate carbohydrate restriction, ensuring adequate protein and dietary fiber, and reasonable fat intake diet can be used as the principles of GDM prevention and dietary treatment, and if dietary treatment is unsatisfactory, pregnant women with GDM need to use insulin therapy in a timely manner, while encouraging postpartum breastfeeding of pregnant women with GDM and strengthening lifestyle modification to prevent the occurrence of chronic diseases. The occurrence of chronic diseases.