Diabetes mellitus is a clinical syndrome characterized by long-term hyperglycemia due to absolute or relative insulin deficiency and insulin resistance. It is classified into type I diabetes (absolute insulin deficiency due to β-cell destruction), type II diabetes (insulin resistance predominant with relative insulin deficiency or insulin deficiency predominant with insulin resistance), special type of diabetes and gestational diabetes according to its etiology. Among them, gestational diabetes is a different degree of abnormal glucose tolerance that occurs or is first detected during pregnancy, accounting for about 80-90% of gestational combined diabetes. The cause of diabetes mellitus is currently unknown and may be related to insulin resistance, which predisposes pregnant women to disorders of carbohydrate, protein, fat, and water and electrolyte metabolism, leading to 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 diabetes are different from those of adults with diabetes, and this article will discuss the relationship between diet and the prevention and treatment of gestational diabetes.
I. Factors related to the development of gestational diabetes
1. Factors of insulin resistance during pregnancy
Autoimmunity and genetics, changes in hormone levels during pregnancy can lead to a decrease in insulin secretion and a decrease in the body’s sensitivity to insulin.
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.
Second, 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 for the treatment of gestational diabetes in conjunction with medication and diet therapy, which can lower blood glucose level and reduce the use of insulin and help treat diabetes.
3.Insulin therapy
When the effect of diet and exercise therapy is not good, according to the results of blood glucose monitoring, combined with the insulin sensitivity of individual pregnant women, insulin is applied reasonably to control the blood glucose level of gestational diabetes.
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.
The key elements of dietary prevention and treatment of gestational diabetes mellitus
1. Control dietary energy intake and maintain reasonable weight gain during pregnancy.
(1) 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 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. The results showed that the average daily total energy intake level was positively correlated with fasting and postprandial glucose during pregnancy, i.e., 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.
(2) Appropriate energy intake during pregnancy
In 2000, the Chinese Dietary Guidelines Nutrient Intakes (DRIs) recommended that the energy intake (RNI) after mid-pregnancy should be increased by 200kcal/day from the non-pregnancy period. 2007, the Chinese Medical Association Obstetrics and Gynecology Society formulated the Recommended Guidelines for Clinical Diagnosis and Treatment of Gestational Combined Diabetes Mellitus, which for the first time put forward the diagnostic criteria and prevention and treatment principles of GDM in China, including the following recommendations The total daily energy intake of pregnant women with GDM is 7531-9205KJ (1800-2200 Kcal/d), generally the daily energy intake is recommended to be not less than 1500Kcal/d in early pregnancy, not 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 a comprehensive manner, such as pre-pregnancy weight, height, pregnancy weight gain and medical condition. In this study, Liu Mei and Wang Zhongzhen divided GDM patients into a diet therapy group with dieticians and a control group with pregnant women controlling their own diet. The results showed that the glucose level of the treated group decreased significantly compared with the level before treatment (P < 0.01), and the incidence of maternal and perinatal complications was lower than that of the control group, while the glucose level of the control group did not change significantly, suggesting that appropriate total dietary energy can improve maternal and infant outcomes and glucose levels in GDM.
(3) 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. At present, the weight gain during pregnancy is evaluated with reference to the range of singleton pregnancy weight gain recommended by the Institute of Medicine (IOM) in 2009, with the aim of providing reference for weight management and energy intake assessment during pregnancy for pregnant women with normal glucose metabolism and GDM.
2. 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 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 unreasonable dietary structure in 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 accounts 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 child. DRIs recommend that daily intake during early pregnancy should not be less than 150g to protect the nutritional needs of the fetus.
3. 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 at least 30g, its physiological functions help digestion of food, reduce cholesterol, prevent excess energy, can significantly improve insulin sensitivity, reduce the occurrence of GDM. zhang et al. found that a daily increase of 10g of fiber 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 blood glucose in GDM. The American Diabetes Association (ADA) encourages people with diabetes to consume whole grains, fruits and vegetables like the general population. 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.
(1) The relationship between Glycemic index GI and GDM.
GI refers to the ratio of the blood glucose tolerance curve of different foods in the baseline area to the standard glucose tolerance area after meals, expressed as a percentage, generally GI is greater than 70 for high GI foods, 55 to 70 for medium GI foods, and 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 should use coarse food, not fine food, simple processing, increase protein in staple food, rapid cooking, less water, more vinegar and high-low combination methods to help prevent the occurrence of GDM and control the blood glucose level of GDM by using food GI.
(2) Other nutrients
There is no evidence to suggest that pregnant women with GDM and pregnant women in general do not use the vitamin and mineral requirements. In recent years, scholars have focused on whether iron, magnesium and vitamin C are related to the prevention and treatment of GDM, but no clear conclusion has been reached. 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.