Article 42. Obesity and Adrenal Cortical Lesions, Infertility, and Pregnancy Risks
10. Obesity and Adrenal Cortical Dysfunction
The adrenal glands are located above the kidneys and their function is to secrete a variety of important hormones that regulate the body's physiological functions. Each adrenal gland is shaped like a bun, consisting of an outer cortex surrounding an inner medulla. Obesity increases fat around the kidneys, causing damage and potentially leading to chronic nephritis or nephrotic syndrome.
The adrenal cortex secretes three hormones:
(1) Glucocorticoids
(2) Mineralocorticoids
(3) Sex hormones
Among the hormones most closely related to obesity are glucocorticoids, with cortisol, also known as hydrocortisone, being the most important. Cortisol is an essential hormone for human survival, helping the body cope with emergencies, increasing resistance to inflammation, and regulating metabolism. Glucocorticoids have a significant impact on fat metabolism; they can rapidly induce the breakdown of adipose tissue and alter its distribution across the body, causing fat to concentrate primarily in the trunk, such as the chest, abdomen, back of the neck, above the collarbone, and mesentery, while the limbs accumulate relatively less fat. This severe imbalance manifests as abdominal obesity. Therefore, when excessive cortisol secretion occurs for various reasons, resulting in hypercortisolism, the main clinical manifestation is abdominal obesity. Some patients first notice abnormalities by feeling that their pants are becoming increasingly tight at the waist and increasingly loose at the legs, vividly illustrating the development of abdominal obesity.
So, is there a slight change in cortisol in the causes of simple obesity, especially abdominal obesity? To date, many studies have been conducted on this topic: some believe that people with simple obesity have a slight increase in cortisol, which inhibits corticotropin-releasing hormone (CRH) in the brain, thereby stimulating neuropeptides, increasing energy intake, and leading to obesity.
In addition, some researchers have found that leptin secreted by fat cells can inhibit the function of the adrenal cortex. Since people with simple obesity are resistant to leptin, it is suspected that leptin reduces the inhibitory effect of the adrenal cortex due to resistance, thereby causing obesity.
In any case, it is important to differentiate between simple obesity and Cushing's syndrome, as their clinical manifestations are sometimes very similar. Moreover, Cushing's syndrome is mostly caused by tumors of the pituitary gland or adrenal gland, and most cases can be cured by surgery. Therefore, it is even more important to distinguish between them and make a clear diagnosis.
11. Obesity and Infertility
Obese women may experience menstrual irregularities due to ovarian dysfunction. It has been reported that approximately 40% of obese women experience amenorrhea or oligomenorrhea, and are more prone to infertility and endometrial lesions. Furthermore, obese women are at higher risk of developing preeclampsia, or of developing other complications during childbirth or the postpartum period.
It is generally believed that excessive obesity easily leads to abnormal fat metabolism and adversely affects the endocrine glands throughout the body, disrupting the balance of female hormones and thus causing infertility. Clinically, many obese women experience menstrual irregularities, delayed periods, scanty menstruation, or even amenorrhea. Furthermore, even if excessively obese women become pregnant, they are prone to preeclampsia, posing a significant risk to both themselves and their babies; excessive obesity also increases the burden on the heart, increasing the risk of heart disease, which is extremely detrimental to pregnancy.
Traditional Chinese medicine believes that excessively obese women have a lot of phlegm and dampness in their bodies. Phlegm and dampness obstruct the flow of qi and prevent the body from conceiving, which is why they are unable to conceive for a long time after marriage, or experience delayed menstruation or amenorrhea.
12. Obesity and Pregnancy
Many women believe that they should provide the fetus with sufficient nutrition during pregnancy, so they try to eat as much as possible and eat a variety of oily and meaty foods, resulting in a rapid increase in weight. Little do they know that obese women may encounter many problems throughout their pregnancy and childbirth.
First, obese pregnant women are more likely to experience pregnancy complications. Statistics show that 75% of pregnant women weighing over 90 kg will experience some form of pregnancy complication, the most common and dangerous of which is preeclampsia, accounting for 43.6% of all cases, and in severe cases, termination of pregnancy may be necessary.
Secondly, obese pregnant women are more prone to gestational diabetes. Pregnancy is one of the periods in a woman's life when she is most susceptible to developing diabetes, especially for obese women. Obesity itself, combined with complications such as preeclampsia and gestational diabetes, has a serious impact on fetal development, greatly increasing the incidence of miscarriage and even stillbirth. Moreover, due to maternal obesity and overnutrition, especially gestational diabetes, the fetus is often overweight or malpositioned, and abdominal obesity leads to weak abdominal muscles, resulting in dystocia. This increases the probability of forceps delivery, vacuum extraction, and cesarean section, increasing the chances of neonatal injury and death.
Furthermore, excessive abdominal fat in obese women makes prenatal examinations difficult for doctors. If a cesarean section is necessary, the surgical procedure becomes very inconvenient. Therefore, pregnant women should pay attention to a balanced diet and appropriate exercise to avoid excessive weight gain; obese women, in particular, should have regular checkups during pregnancy to monitor their health and the development of the fetus.
13. Obesity and Thyroid Disease
The thyroid gland is located in the front of the neck, and its main function is to secrete two types of thyroid hormones:
(1) Triiodothyronine (T₃)
(2) Thyroxine (T₄)
Thyroid hormones play a vital regulatory role in the human body, primarily in two aspects: ① regulating cell differentiation and development; ② regulating various metabolic functions, especially fat metabolism. Their effect on fat breakdown is greater than their effect on fat synthesis. Therefore, when thyroid hormone secretion is excessive, i.e., hyperthyroidism, patients often experience weight loss. Conversely, when thyroid hormone secretion is insufficient, i.e., hypothyroidism, patients may experience obesity, and many hypothyroid patients also have lipid abnormalities.
The main mechanism by which hypothyroidism causes obesity is the lack of thyroid hormones, which inhibits both lipid synthesis and degradation. In other words, less is synthesized and less is consumed, resulting in fat accumulation. Additionally, decreased energy expenditure, reduced physical activity, and depression in hypothyroid patients all contribute to obesity.
It's important to note that while most hypothyroid patients experience weight gain, only a small percentage are truly obese. The majority of hypothyroid patients don't experience increased body fat accumulation; rather, the weight gain is due to water retention caused by hypothyroidism. This water contains a large amount of protein, so the resulting edema is not pitting; that is, although there is swelling, pressing with a finger won't leave a dent. Supplementing these patients with thyroid hormone can quickly eliminate the excess water, leading to rapid weight loss, sometimes even returning to pre-illness levels. However, if the weight gain is truly due to fat deposition, then supplementing with thyroid hormone will not immediately restore the previous weight. Hypothyroidism rarely causes true obesity because it also causes significant appetite suppression, reducing food intake and preventing weight gain. Regarding the involvement of thyroid hormone in the causes of simple obesity, extensive research has been conducted. Results show that the vast majority of individuals with simple obesity have normal thyroid hormone levels, with only a small minority exhibiting slightly elevated T₃ levels. Some studies suggest that people with simple obesity may have low-normal thyroid function, resulting in weaker thermogenesis and less fat consumption. However, this hypothesis has not yet been definitively confirmed and requires further research.