“It is high-fructose consumption that turns on fat production and storage in your liver through a process called lipogenesis.” ― Mark Hyman
Introduction | The Role | Adipose Tissue | Subcutaneous Fat | Visceral Fat | Liver Fat | Body Composition | Final Thoughts | Takeaway Points | References | Disclaimer
Introduction
The body fat that naturally occurs in the tissues of the human body can be classified as subcutaneous fat or visceral fat. Another type of fat that is crucial for our health is liver fat. All of these fatty tissues, if present in excess, are linked with the development of health ailments such as the metabolic syndrome, type 2 diabetes, obesity, and non-alcoholic fatty liver disease [NAFLD]. Applying lifestyle changes that include a whole-foods-based, nutrient-dense diet, physical activity, and intermittent fasting has been proven to have beneficial effects on these conditions.
The role of fat in our bodies
Human body fat is referred to as adipose tissue. Even though fat is commonly regarded as an unsightly part of our makeup, it plays multiple important roles in the overall function of our bodies. Adipose tissue influences both cellular functioning and overall systemic functioning. Not only is it involved in maintaining lipid and glucose homeostasis, but it also influences metabolic processes.
"On one hand, adipose tissue stores energy in the form of lipid and controls the lipid mobilization and distribution in the body. On the other hand, adipose tissue acts as an endocrine organ and produces numerous bioactive factors such as adipokines that communicate with other organs and modulate a range of metabolic pathways."[23]
The main building blocks of adipose tissue are called adipocytes [white, beige, and brown fat cells], but it also includes pre-adipocytes, macrophages, endothelial cells, fibroblasts, and leukocytes. Having both too much and too little adipose tissue in the body is linked with a range of health complications, such as obesity on the one hand and anorexia and lipodystrophy on the other.
Adipose tissue
As we've already said, most adipose tissue is made up of fat cells, which are called adipocytes. Since adipocytes are primarily responsible for storing energy, each of them contains lipid droplets, which are fat storage organelles that regulate the cellular transport, storage, and utilization of lipids. There are three types of adipocytes:
white-fat cells are the most abundant adipocytes in the human body. Their primary roles are for storing energy [as triglycerides], for energy mobilization [as fatty acids], and for endocrine regulation of energy homeostasis. They possess few cellular organelles, including a small mitochondrion and a large, single lipid droplet.
brown fat cells are the most metabolically active fat cells found in the human body. They contain high concentrations of both lipid droplets and mitochondria, which makes them a primary source of heat production [non-shivering thermogenesis]. Their brown color is due to the presence of a heme cofactor called cytochrome oxidase.
beige fat cells, also called brite adipocytes, are found in the spaces between white fat cells. They play a role in non-shivering thermogenesis [heat production] stimulated by the sympathetic nervous system. Beige fat cells are dynamic in nature. They are able to increase the number of their mitochondria when exposed to external stimuli to support thermogenesis, and once the stimulants are withdrawn, the numbers of the mitochondria decrease. They also contain a few lipid droplets that store fat for energy production.
White adipose tissue consists of white and beige [brite] adipocytes. It is also the most abundant type of fat in the human body. Its main function is energy storage, but it also plays a role in hormone secretion, protects the body from temperature changes, and cushions internal organs. An excessive expansion of white adipose tissue throughout the body is associated with metabolic dysfunction and a range of health conditions associated with the metabolic syndrome.
Brown adipose tissue consists only of brown adipocytes. This type of fat tissue is the most abundant in infancy, and it diminishes as we develop and grow older. Adults store their brown fat in the upper back, around the vertabrae, and in the supraclavicular area. The main function of brown adipose tissue is heat generation.
The components of white adipose tissue can go through the processes of "beigeing" and "browning" if provided with a proper environment. Such processes, however, require an external stimulus such as, e.g., cold exposure, exercise, or substances like resveratrol or quercetin.
Subcutaneous fat
Subcutaneous fat, also known as subcutaneous adipose tissue [SAT], is the type of fatty tissue found underneath our skin. More precisely, it is the deepest layer of our skin that separates it from the muscles. Its main function is to protect our muscles and bones from injuries, control body temperature, provide a circulatory connection between the skin and muscle tissues, and attach the skin to the layers beneath it. It is an important tissue that, in the right amount, is good for our health and helps keep things in balance. According to functional medicine, subcutaneous fat constitutes approximately 90% of total body fat in a healthy body.
Impact on health
As mentioned above, SAT is a key component of our bodies' makeup. However, the excessive amounts and large deposits that cause us to gain weight in the belly, thighs, arms, buttocks, and hip areas can lead to health complications. The subcutaneous fat consists mostly of white adipose tissue, which expands by increasing the number of fat cells and/or by increasing the size of the cells. It is very often linked with an elevated risk of developing metabolic disorders as well as a symptom of potentially increased visceral fat deposits.
What causes subcutaneous fat?
SAT can increase its mass due to overeating, the consumption of nutrient-deficient and processed foods, excess glucose consumption, a sedentary lifestyle, a lack of physical activity, and hormone secretion such as estrogen[6][7].
How to lose excess subcutaneous fat
Excessive subcutaneous fat can be diminished by making lifestyle changes. A healthy, nutrient-dense, fiber-rich, whole-foods-based diet is a first step to losing an unnecessary amount of weight. Next to that, regular physical activity, such as walking, biking, jogging, or working out, will help boost the metabolic processes that burn fat tissue. Lastly, drinking enough water, getting good quality sleep, and taking care of proper sleep hygiene can further elevate our bodies' abilities to burn fat tissue.
Visceral fat
Visceral fat, also known as visceral adipose tissue [VAT] or simply "hidden fat," is a harmful type of fat composed of white adipose tissue. It is located in the abdominal area and builds up in the spaces between the internal organs, such as the liver, pancreas, kidneys, and intestines.
A healthy person carries around 10% of their total fat mass as visceral fat in their intra-abdominal area. This type of adipose tissue plays multiple roles, such as energy storage, cushioning the internal organs and protecting them from damage, hormonal signaling, and even affecting our immune function[8].
Impact on health
Excessive abdominal fat accumulation, also described as abdominal obesity, is linked with many pathologies related to metabolic health. The complications of a high percentage of visceral fat include its influence on hormones such as adiponectin and insulin. Adiponectin regulates glucose levels, lipid metabolism, and insulin[9]. High amounts of visceral fat inhibit its functioning and lead to the development of inflammation, obesity, insulin resistance, type 2 diabetes, hypertension, kidney disease, liver disease, cardiovascular disease, stroke, and even cancer.
What causes visceral fat?
A VAT buildup in the system takes place due to improper nutrition. A diet high in carbohydrates, sugars, trans fats, and processed foods contributes to the increased VAT scores. In addition, sedentary lifestyles, a lack of physical exercise, and chronic stress[11] contribute to VAT accumulation.
How to lose excess visceral fat
The key element to combating abdominal obesity is identifying and addressing the contributing factors. Adopting a healthy, nutrient-dense, fiber-rich, whole-foods-based diet is an essential first step. Also, a low-carbohydrate diet is effective in reducing fat tissue[12]. In addition, regular physical activity, a good night's rest, limiting stress, and removing chronic stressors from our direct environment will further boost the chances of reducing the visceral fat buildup. Another proven strategy is intermittent fasting[13].
Liver fat
Liver fat is a naturally occurring component of the liver's structure. The liver can be found in the upper right abdominal quadrant, just below the diaphragm. It sits on top of the digestive tract, kidney, and right stomach. It is composed of hepatocytes, cells that activate lipids for energy production and store excess fat particles as lipid droplets. The liver performs a vast array of functions, including maintaining glucose and lipid homeostasis, cholesterol production, glycogen synthesis, detoxification, bile production, and blood clotting regulation. It weighs around 1.4 kg [3.1 pounds]. A healthy buildup of fat in the liver tissues is regarded as not higher than 5% [75g] of its weight.
Impact on health
Liver fat becomes potentially harmful to our health when it exceeds the 5% mark of the liver's weight. It is believed that the accumulation of liver fat in the range of 5%–33% poses a mild risk of health complications. Whereas, 33%–66% is a moderate risk, and 66% and over is a severe health threat[14].
Excess accumulation of fat as lipid droplets within hepatocytes promotes the condition known as hepatic steatosis. When hepatic steatosis becomes a chronic condition, it impairs liver metabolism and causes non-alcoholic fatty liver disease [NAFLD], insulin resistance, and inflammation. Moreover, it is associated with obesity, type 2 diabetes, and dyslipidemia.
What causes liver fat to build up?
Excessive, ongoing, and prolonged alcohol consumption is the primary cause of fatty liver disease [FLD]. Conversely, non-alcoholic fatty liver disease [NAFLD] is associated with pre-existing health conditions like insulin resistance, obesity, type 2 diabetes, and other components of the metabolic syndrome. Additionally, it is believed to be influenced by the excessive intake of fructose, a common ingredient in both table sugar and high-fructose corn syrup.
How to combat liver fat buildup
In order to reduce the accumulation of fat in the liver, lifestyle changes need to be adopted. In NAFLD, it is necessary to address the metabolic issues that we are dealing with. The improvement of metabolic parameters can be achieved through such strategies as a healthy, whole-foods-based, nutrient-dense, low-carbohydrate diet, physical activity, and intermittent fasting. Furthermore, nutrients such as turmeric, vitamin E, omega-3 fatty acids, and milk thistle have beneficial effects on the liver and its function[19].
Assessing body composition and liver fat
The body mass index [BMI] is the method that has been used for the longest time to determine the composition of the human body. However, this measurement is not precise enough. It does not differentiate between a variety of factors that have an impact on the final calculation, such as the amount of body fat versus the amount of muscle. A person with a higher fat tissue content, for example, and an athlete with increased lean muscle tissue will both have elevated BMI scores. However, this assessment method will not reveal such specific information as what causes an increase in their BMI.
Bioelectrical impedance analysis [BIA] is an alternative method for determining body composition. It is a low-cost, safe, and quick test. It measures our bodies' water reserves' resistance to a low-grade electric current. The more water we have [muscle mass stores the majority of our body's water], the less resistance we have to the current. The higher the fat content, the higher the impedance to the electric charge. Among the disadvantages of this assessment procedure is the fact that it provides more accurate results with repeated, long-term analysis than with a single test.
Dual-energy X-ray absorptiometry [DXA] is another method for determining the composition of the body. It is a non-invasive procedure that employs x-ray beams to assess bone density, bone-free fat mass, and fat mass. The amount of radiation a patient is exposed to ranges from 1–10% of the total amount of the chest x-ray. DXA is a highly accurate measuring method for body composition and tissue distribution, as well as osteoporosis.
Liver fat and liver health assessment methods include blood tests that look at liver enzymes, blood lipid counts, and blood sugar levels. Also, imaging tests like an ultrasound, a CT scan, and magnetic resonance elastography can be used to figure out the health of the liver with varying degrees of accuracy. Finally, in some cases, a biopsy is required to obtain a more complete picture of the liver's condition.
Final Thoughts
Fat tissue is an important part of the human body, and it serves many important functions. Keeping your body healthy and in balance will let all of its parts do their jobs and contribute to homeostasis and health as a whole. However, if the amount of fat we store is excessive, it affects many metabolic processes and may lead to disease development. If we have too much subcutaneous and visceral adipose tissue in our bodies, this can contribute to metabolic syndrome. Liver fat is equally dangerous if it accumulates in disproportionate amounts. Identifying and addressing these issues is a fundamental element of improving the state of our health. Adopting lifestyle changes that promote healing and recovery will boost the body's ability to redeem itself.
Takeaway Points
Adipose tissue is a type of fat tissue that is composed of three types of fat cells: white fat cells, beige fat cells, and brown fat cells.
Subcutaneous fat is located underneath our skin and constitutes 90% of the overall fat tissues in a healthy body.
Visceral fat is located in the abdominal area and surrounds internal organs. It is one of the most dangerous types of fatty tissue if it is present in excess.
Liver fat becomes harmful to human health when it exceeds 5% of the weight of a healthy liver.
A healthy diet, physical exercise, stress reduction, and good-quality sleep are lifestyle strategies that help combat excessive fat tissue buildup.
Body mass index [BMI] measurements lack precision in determining one's body composition.
Bioelectrical impedance analysis [BIA] and dual-energy X-ray absorptiometry [DXA] are more viable options to assess body composition.
Liver fat assessment methods include blood tests, an ultrasound, a CT scan, magnetic resonance elastography, and a biopsy if needed.
References
This article contains 23 citations:
Disclaimer
Read carefully: