WHAT IS VISCERAL FAT AND WHY IS IT IMPORTANT?

Visceral fat refers to an abnormal accumulation of fat deep within the abdominal cavity, surrounding internal organs such as the liver, pancreas, kidneys and intestines.

The amount of visceral fat present has emerged as one of the strongest predictors of disease and death. It has extensive repercussions throughout the body, exerting profoundly adverse effects on every organ. The good news is that it can be addressed and reversed.

FAT TYPES AND LOCATIONS

Body fat can have very harmful or beneficial health effects depending on the type and where it’s located. Fat stored just underneath the skin (superficial subcutaneous fat) actively generates a health-promoting molecule known as adiponectin. Babies have large amounts of this healthy fat. A small amount of superficial subcutaneous fat protects the heart and other organs in adults so it’s not a good idea to eliminate this layer as seen in some bodybuilders, extreme diets or starvation.

The same factors that lead to increasing amounts of visceral fat also lead to fat accumulating in the deep subcutaneous compartment (for example love handles), around the heart (secretes damaging molecules and eventually restricts heart movement) and thigh muscles (can lead to poor mobility at an early age).

VISCERAL FAT MAY BE HIDDEN

It’s important to understand that a significant amount of visceral fat can be present even in individuals with a normal body weight or a BMI within the normal range - the so called TOFI body type (thin on the outside and fat on the inside). These individuals are also at high risk despite their outward appearance. This underlines the importance of assessing the level of visceral fat present.

Conversely, a small minority of people have a significant amount of subcutaneous fat and very little visceral fat. In this case the level of risk depends on where the subcutaneous fat is located. Fat in the superficial subcutaneous compartment is actually protective but deep subcutaneous fat poses similar risks to visceral fat.

VISCERAL FAT HAS SEVERE LONG TERM CONSEQUENCES

Far from an inert storage depot of excess fat, visceral adipose tissue actively secretes a number of damaging chemicals into the bloodstream leading to chronic low-grade inflammation and insulin resistance.

Insulin resistance and chronic low grade inflammation not only lead to type 2 diabetes but are also well recognized drivers of the top causes of chronic illness and death including heart disease, non-alcoholic fatty liver disease, Alzheimer’s disease and cancer. 

In addition there are some common health challenges which have a surprising, yet well-documented connection to visceral fat. These include erectile dysfunction, polycystic ovarian syndrome and poor CoVID-19 outcomes.

VISCERAL FAT AND TYPE 2 DIABETES

A consistently strong association has been demonstrated between increased visceral fat, insulin resistance and the development of type 2 diabetes.

Insulin is the most important hormone responsible for regulating blood sugar levels. When cells become resistant to its effects, glucose accumulates in the bloodstream, leading to type 2 diabetes. Inflammatory substances and hormones released by visceral fat significantly promote insulin resistance by disrupting insulin signaling pathways.

Visceral fat also releases free fatty acids, promoting the accumulation of triglycerides and dyslipidemia (disordered cholesterol metabolism). This is another key factor in the development of type 2 diabetes because this also leads to insulin resistance.

CARDIOVASCULAR DISEASE

Scientific studies have firmly established the connection between visceral fat and cardiovascular disease, encompassing conditions such as coronary artery disease, stroke, and heart failure.

Research has shown that this chronic low-grade inflammation, orchestrated by visceral fat, plays a pivotal role in the atherosclerotic process, damaging the lining of the blood vessels and promoting the buildup of plaque within arteries.

Moreover, visceral fat is associated with cholesterol imbalances, insulin resistance, and elevated blood pressure, all of which are well-established risk factors for cardiovascular disease.

NON-ALCOHOLIC FATTY LIVER DISEASE

Research suggests that visceral adipose tissue plays a crucial role in the development and progression of NAFLD. Significant factors include insulin resistance, release of free fatty acids causing fat to accumulate in the liver and chronic low grade inflammation which all damage the liver cells and increase the long term risk of cirrhosis and liver cancer.

ALZHEIMER’S DISEASE

Emerging evidence suggests a strong association between visceral fat and brain-related disorders, including neurodegenerative diseases like Alzheimer's and vascular cognitive impairment. The mechanisms linking visceral fat to these conditions are multifaceted, involving systemic inflammation, insulin resistance, and vascular dysfunction.

Alzheimer’s is often referred to as “type 3 diabetes” due to the now recognized role of insulin resistance in causing damage to brain tissue. Adipokines released from visceral fat interferes with insulin signaling pathways in the brain leading to impaired function.

Moreover, inflammation triggered by visceral fat may also contribute to the breakdown of the blood-brain barrier, allowing harmful substances to enter the brain - adding insult to injury.

CANCER

While obesity has long been associated with various health risks, recent scientific research has also illuminated the specific role of visceral fat in cancer development. It is now evident that visceral fat is a key contributor to the increased risk of the most common cancers including breast, prostate, colon and other cancers.

Chronic inflammation triggered by visceral fat promotes DNA damage, uncontrolled propagation of new blood vessels and reduced apoptosis (cycling of old, damaged cells) – all factors contributing to the development of cancer. This inflammatory micro-environment has been implicated in various stages of cancer development, including the initial development of cancer, cancer growth and spread to distant organs.

Beyond inflammation, visceral fat also influences cancer risk through alterations in hormone levels. Hormones such as insulin and estrogen, which are modulated by visceral fat, have been implicated in the development of hormone-sensitive cancers such as breast and endometrial cancer.

ERECTILE DYSFUNCTION

Visceral fat can be an important underlying cause of erectile dysfunction (ED) even in individuals who are not overtly obese. It’s not only the total amount of fat present but where this fat is located that’s important.

Insulin resistance, caused by increased visceral fat appears to play a central role in the development of ED. Besides its impact on glucose metabolism, insulin regulates blood vessel dilation by temporarily increasing nitric oxide. However, a lack of response to insulin in the vessel lining can blunt this effect, leading to impaired blood flow and ED. Visceral fat also triggers chronic low-grade inflammation and plaque buildup in the vessel wall, leading to further reduction in blood flow and even greater insulin resistance - a vicious cycle.

Despite the distressing implications, there's hope as, in many cases, ED can be reversed. Addressing the root cause of ED is preferable to merely increasing blood flow temporarily with drugs, given that the damage due to visceral fat occurs throughout the body. Additionally, the efficacy of ED drugs diminishes over time as the condition progresses.

PCOS

Polycystic ovarian syndrome (PCOS) is a leading cause of infertility and metabolic syndrome.

It is widely appreciated that weight gain and insulin resistance are consequences of PCOS. What is becoming more apparent is that PCOS may itself be caused by the high insulin levels seen with visceral fat accumulation.

High insulin levels result in androgen dominance and impaired maturation of eggs in the ovaries. This results in the development of multiple ovarian cysts, reduced fertility and other hormonal issues.

Establishing a causal relationship between visceral fat and PCOS is a reason for hope in terms of addressing this frustrating condition.

COVID-19

It’s widely accepted that obesity leads to more severe CoVID-19 infections. However emerging data indicates that this link is more specifically due to high levels of visceral fat than total body fat. This means that an individual with a normal BMI but high visceral fat will be similarly at risk. This is why it’s important to accurately assess the amount of visceral fat present regardless of total body weight or BMI. If elevated, reducing it is a high priority.

POOR MOBILITY

Accumulation of fat around the organs of the abdomen has several knock on effects including accumulation of fat in the skeletal muscles - so called “marbling” of the muscles. This change weakens the muscles and can result in reduced muscle strength and mobility at a younger age, along with significantly increased fall risk and high mortality in the elderly.

GOOD NEWS!

Despite the profound health burden caused by visceral fat accumulation, the awesome news is that visceral fat can be reduced and these deleterious effects may be reversed by doing so. The earlier you start, the better!

Understanding the root causes of visceral fat facilitates more effective approaches to reduce it. The known causes of visceral fat are discussed in the second part of this series.

TAKE ACTION

The initial focus should be on accurately assessing the amount of visceral fat, implementing measures to reduce it, and monitoring progress over time. This is too important to leave to guess work.

The amount of visceral fat can be estimated by simple measurements like waist size and waist to hip ratio. However these approaches may miss significant amounts of visceral fat.

MRI the most precise way of assessing the quantity visceral fat present. Due to its lack of radiation exposure, it is also safer for repeated testing to monitor progress over time. The major drawback of MRI is that it is an expensive test. Luminnova Health is therefore collaborating with Open MRI to make this useful assessment more accessible.

Despite these efforts, it’s clear that not everyone will have access to this gold standard option. So alternative methods of assessing visceral fat will be outlined in part 3.