Muffin Tops and Beer Bellies – What is Visceral Adipose Tissue?

Muffin-Top-VAT

What does your belly say about you?

Shakespeare once said “A rose by any other name would smell as sweet”. However true that may be, there’s nothing sweet about that extra abdominal fat you’re storing, despite the nickname you’ve so lovingly attached to it. Whether you have nicknamed your tummy fat as your food baby, spare tyre, middle-aged spread, muffin top, beery belly, love handles, buddha belly, apple or mumma muffin, when it comes to body fat, where you store it can be more indicative of your health and disease risk rather than how much you actually have. In fact, it has been well established that abdominal fat is more related to health risk than whole-body fat, especially when it comes to chronic conditions like heart disease, stroke and diabetes.

What is that abdominal fat made up of?

Visceral Abdominal Tissue

Abdominal (belly) fat is comprised of two types of fat:

1. Subcutaneous fat:

This fat, also known as Subcutaneous Adipose Tissue (SAT), is found just below the surface of the skin. This is the “pinch my fat” type of fat, and can be roughly estimated by your doctor, dietitian or personal trainer using calipers.

2. Visceral Fat:

This fat, also known as Visceral Adipose Tissue (VAT), is found around the body’s vital organs, deep behind the abdominal wall. It is comprised of omental and mesenteric fat cells.

Visceral fat, or Visceral Adipose Tissue (VAT), is much less obvious than subcutaneous fat and is therefore also called “hidden fat”. It cannot be measured using calipers or a pinch test. Even using a tape measure to measure waist circumference is a rough guesstimate. VAT is only visible with the use of CT scans, MRI or DEXA Corescan technology. DEXA Corescan is exclusively available, on the Central Coast of NSW, at Riverside BodyScan.

Does it matter, that you have a hidden store of Visceral Adipose Tissue? What is the big deal? Read on, to understand why not all places that we store fat are created equally.

What health risks are associated with visceral fat?

  1. Cardiovascular disease: Abdominal obesity is closely linked to cardiovascular disease. That means that those with extra VAT have increased risk of a heart attack, heart failure and/or stroke. Studies have shown that excess VAT is associated with elevated triglycerides, reduced HDL (good) cholesterol, increased blood pressure and increased fasting glucose (high blood sugar). Furthermore, a higher visceral-to-subcutaneous fat ratio is associated with common cardiovascular disease risk factors.
  2. Type 2 Diabetes: A study published in the May 2008 issue of the American Journal of Clinical Nutrition supported the association between abdominal fat, insulin resistance and elevated blood sugar levels (hyperglycemia). Visceral fat causes a release of excess free fatty acids that are linked with insulin resistance. That means your body isn’t dealing with sugars well, and the next step is diabetes associated tissue damage.
  3. Metabolic Syndrome: This syndrome, also known as syndrome X, is characterised by elevated blood pressure, dyslipidaemia, central obesity, and impaired glucose metabolism. Weight loss, increased physical activity and a high fibre diet rich in fruits, vegetables, whole-grains and monounsaturated fats significantly improved all aspects of metabolic syndrome.
  4. Cancer: Overweight and obesity are associated with increased risk of certain cancers, including colorectal and colon cancer, particularly in men. Research has shown that abdominal visceral fat is a much greater risk factor than subcutaneous fat, and that obesity is associated with worse cancer outcomes.

So, we’ve decided that VAT is bad news, given that it worsens the risk factors for heart disease, blood pressure, metabolic syndrome and cancer. The next question is, how do I know how much I have?

How can I measure my VAT?

MRI, CT Scan or DEXA Scan are ways of measuring your VAT. DEXA is the most cost effective, and has a negligible radiation dose, when compared to CT. As part of your Advanced Body Composition Scan, if your BMI is between 18 and 40, you will receive a CoreScan result, in grams, which will tell you how much VAT you have. As a guide, athletes and very healthy and fit people usually have less than 100g on a DEXA scan. Males with a “beer belly” can have over 3.5 kg. This CoreScan result is a number easily tracked, over time, to see how well your exercise and healthy eating are reducing your VAT. And the good news is, your body really does want to be rid of it.

Now that you’ve measured your VAT, what affects the amount of it, and what can be done about it?

What factors influence visceral Fat?

  1. Age & Gender: The amount of visceral fat increases with age in both genders, and this increase is present in normal weight (BMI, 18.5 to 24.9) as well as in overweight (BMI, 25 to 29.9) and obese subjects (BMI > 30 kg/m2), but more so in men than in women.
  2. Total body fat: The amount of visceral fat tends to be lower in lean and normal weight individuals, compared to those who are obese. It is important to remember, however, that there can be there can be considerable differences in abdominal visceral fat even when individuals may have a similar BMI and percent body fat.
  3. Energy Intake: Increased energy intake above an individual’s requirements has been shown to increase intra-abdominal visceral fat . Numerous studies have shown that weight loss and weight gain, particularly in females, leads to visceral fat being lost or gained respectively . Furthermore, numerous studies have shown that all forms of weight loss lead to more visceral fat being lost compared to subcutaneous fat (percentage wise) at the abdominal level . This is supposedly because the fat cells found in the intraabdominal cavity (omental and mesenteric adipocytes) are more metabolically active and sensitive to fat loss (lipolysis).
  4. Triglycerides: Triglycerides are a type of fat (lipid) found in your blood. When you eat, your body converts any excess calories it does not immediately need into triglycerides, which are stored in your fat cells. Later, hormones release triglycerides for energy between meals. If you regularly eat more calories than you burn, particularly calories from refined carbohydrates (hello sugar!), and not so good fats (deep fried foods and snack foods), you may have high triglyceride levels in your blood. Fatty tissue in the body derives most of its storage fat from circulating triglycerides. It has been demonstrated that fat uptake from triglycerides is higher in visceral adipose tissue (omental), than in abdominal subcutaneous fat.
  5. Genetics: Results from recent studies have suggested that there are various genes that could play a role in determining body fat and regional fat distribution in humans. The accumulation of fatty tissue in the abdominal region in particular is partly influenced by genes. So, if you come from a family of apple-shaped people, you may be more at risk, if you put on excess fat, of carrying it around the middle.
  6. Physical Activity: Studies have shown a beneficial effect of physical activity on abdominal fat accumulation, and the converse negative effect of physical inactivity. Greater physical fitness has been shown to reduce visceral adipose tissue more profoundly than subcutaneous fat, which is good news– Your body wants to get rid of the VAT.
  7. Diet: Food and diet is the single most important factor when it comes to overall health, disease risk and weight loss. It has been shown that for every kilo of diet-induced weight loss, there is a corresponding reduction in visceral adipose tissue (VAT) of approximately 3-4cm2 (2-3%). Therefore a 12kg weight loss would equate to a 30-35% reduction in VAT. A 1cm reduction in waist circumference has also been shown to correspond with a 5cm2 (4%) reduction in VAT at the L3 level. While more studies are required to identify what macro-nutrient ranges lead to the greatest reductions in VAT, it is well known that storing visceral fat is likely in high carbohydrate diets particularly from high glycaemic foods and added sugars, high saturated and trans fat intakes, and excessive alcohol intakes compared to subcutaneous fat.

In conclusion, visceral fat or visceral adipose tissue (VAT) is the sneaky fat that lurks around your organs, in your abdomen, and raises the risk of heart disease, diabetes, metabolic syndrome and cancer. However, the good news is that we can now measure it, and you can do something about it, and track the changes as you do. This fat, while being risk-laden, is also sensitive to healthy changes in diet and exercise. Your healthy body will burn it off, quickly, and you’ll probably add years to your life!

References

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2017-08-15T15:52:18+00:00 Education|

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