AS we approach the Christmas season, we should balance the joys and indulgences that the season traditionally brings, with the care needed to prevent excesses and life-threatening choices. Overeating and over-imbibing are hallmarks of the season, and so we should be mindful of the short- and long-term consequences of such exploits.

RISK TO OUR CARDIOVASCULAR HEALTH

Many people do not know that the risk posed by excessive weight and obesity is not dependent on the amount of fat, but rather on where the fat is stored. This concept was fully discussed at the recent meeting of the European Society of Cardiology.

Males, in particular, are disposed to accumulating fat in the abdominal cavity, a condition that is called visceral obesity and which is a high risk form of obesity. In contrast, the Director of Research at the Quebec Heart and Lung Institute in Canada found that, in women, the fat that is found in the lower body accumulated around the hips and thighs is actually protective against cardiovascular complications.

In research that was done over 25 years ago, computer tomography (CT scanning) was used to scan the abdomen of research volunteers who were asymptomatic. The research found that there was remarkable individual variation in the susceptibility to put on fat in the abdominal cavity around the internal organs, and that some individuals had a lot of intra-abdominal visceral fat tissue. These individuals have what has been referred to as insulin-resistance syndrome or “metabolic syndrome”. This metabolic syndrome or insulin resistance was found to be associated with excess fat around the intra-abdominal organs and produce metabolic environments that increase the risk of developing type 2 diabetes and cardiovascular disease.

WHY IS ABDOMINAL FAT MORE DANGEROUS?

When you have excessive intra-abdominal fat, it reflects the fact that your subcutaneous fat tissue, (the layer under your skin), was not able to properly expand to facilitate extra fat. Specifically, when you eat more than your body expends or needs to maintain its energy balance and weight (a situation called positive energy balance), the bodies of some people seek to protect the “lean” organs — the heart, the liver, the kidneys, and the skeletal muscles — against the dangerous accumulation of harmful fat by expanding the subcutaneous fatty tissue to hold the excess. These people therefore store their excess fat under their skin.

However, some people are unable to expand their subcutaneous fat tissue to hyperplasia (a multiplication of sub-cutaneous fat cells), and so get a fat “spill-over”. The excess energy is stored around the heart (epi-cardial fat), in the liver (liver steatosis), and infiltrates the skeletal muscles. These all cause an increased risk profile for cardio-metabolic events. Clearly then, you do not see the most dangerous form of fat as it is being stored deep inside the abdominal cavity around the gut and other organs there.

Many imaging techniques have confirmed this fact since those early research studies. The more intra-abdominal peri-visceral fat you have, the more likely you are to have fat around your heart (epi-pericardial fat). You are also more likely to have fat in and around your liver (called a “fatty” liver), which will lead to conditions such as atherogenic dyslipidemia, (developing fatty deposits in the blood vessel wall), type 2 diabetes, and their sequelae — a condition which is the consequence of a previous disease or injury. Fat that infiltrates your skeletal muscles and your kidneys contribute to further increasing your risks for hypertension.

TAKE-HOME MESSAGE

The key take-home message is to be aware of and take specific action regarding the “enemy within”. It is not the fat that you can see accumulating below the skin that causes major damage to your cardiovascular health, but that which is accumulating invisibly deep within your abdomen and in your lean muscle tissue that will produce the greatest damage.

Whilst we customarily measure weight, height, and calculations of body mass index (BMI), we now should always be measuring our waist circumference — abdominal girth — as a vital sign. So, if we compare two individuals who have the same BMI, the one who has the more expanded waistline is the one more likely to have the more harmful intra-abdominal visceral fat, and therefore more prone to cardiovascular events.

Another important indicator for cardiovascular events that we should measure in overweight and obese persons is relative cardio-respiratory fitness. Many studies have shown that for people with the same body weight, those that have better cardio-respiratory fitness are the ones with the lower risk of developing bad cardiovascular outcomes. So, simply put, among our loved ones and in the wider society, we should be on the lookout for two things — dangerous abdominal fat, and individuals who are unfit.

MANAGING LIFESTYLE

Simply improving one’s nutritional quality will also make a difference. Utilising olive oil, nuts, and almonds can reduce one’s cardiovascular risk by as much as 30 per cent. And for people with abdominal fat, simply becoming active and staying physically active can reduce one’s cardiovascular risk for heart disease (coronary artery disease) by up to 50 per cent. Physical activity matters. Physical activity is extremely helpful, if not crucial for high-risk obese people to reduce their risk for heart disease and heart attacks. This reduction in risk occurs even if a loss of body weight does not occur.

So, measuring and targeting nutritional quality, measuring and targeting sedentary behaviours, measuring waist circumference, and measuring physical fitness in order to seek improvements in all of these are crucial ways in which we may help ourselves and others to improve both the quality and length of our lives.

Derrick Aarons MD, PhD is a consultant bioethicist/family physician, a specialist in ethical issues in medicine, the life sciences and research, and is the ethicist at the Caribbean Public Health Agency — CARPHA. (The views expressed here are not written on behalf of CARPHA).