More than weight loss
Bariatric surgery not only helps morbidly obese patients lose weight, but also helps to treat metabolic syndrome.
MOST people commonly associate bariatric surgery with the treatment of last resort to help morbidly obese patients lose weight.
While they are not wrong, there is more to this type of procedure than getting rid of excessive kilos.
As Hospital Canselor Tuanku Muhriz senior consultant gastrointestinal and obesity surgeon Associate Professor Datuk Dr Nik Ritza Kosai Nik Mahmood explains, bariatric surgery is also known as metabolic surgery.
The difference when it comes to using each term is the main purpose for which the surgery is being performed.
“If your primary aim is to make the patient lose a lot of weight, then it is called bariatric surgery; because ‘baros’ in Greek means weight, so it’s surgery to reduce weight,” he says.
“If the primary aim is to resolve metabolic problems – in particular, diabetes – then it is called metabolic surgery.
“But it’s actually the same thing. “And most patients who undergo metabolic surgery suffer from obesity as well.”
Diabetes is one of five conditions included under the umbrella term of metabolic syndrome.
The others are high blood pressure (hypertension), high total cholesterol, high low-density lipoprotein (LDL) cholesterol, and obesity with a waist circumference of more than 35 inches for women and more than 40 inches for men.
A person is considered to have metabolic syndrome when they have at least three out of these five conditions.
Assoc Prof Nik notes that while the loss of a large amount of weight has always been associated with a decrease in diabetes, research in recent years has objectively shown this improvement.
He gives the example of a study that followed two groups of obese patients who did not originally have diabetes when the study started.
One group underwent bariatric surgery, while the other had the best medical treatment available to reduce their weight.
After being followed for over 10 years, it was found that the group who underwent bariatric surgery had an 88% lower risk of developing diabetes, compared to the other group.
“The protective effect against diabetes and metabolic syndrome is profound in those who underwent bariatric surgery,” he comments.
Looking beyond weight
As such, those eligible to undergo bariatric surgery are not just considered based on their weight alone.
According to the consensus statement put together by the Society of Endoscopic and Laparoscopic Surgeons of Malaysia and the Malaysian Bariatric Society, aside from body mass index (BMI), the presence of metabolic syndrome, obesity-related diseases and age are also factors in the decision to perform bariatric surgery.
The statement, published in March 2021 in the Medical Journal of Malaysia, lists the main indications for bariatric surgery as: > Treatment of morbid obesity in patients with a BMI of 37.5 or above (without any other illnesses).
> Treatment of morbid obesity in patients with a BMI of 32.5 or above, and metabolic syndrome or heart disease risk, following inadequate weight loss even after medical therapy and lifestyle modifications.
> Treatment of poorly-controlled metabolic syndrome or other obesity-related diseases in patients with a BMI of 32.5 or below, after thorough discussion with the multidisciplinary clinical team involved in the patient’s care.
Patients must also be between the ages of 18 and 65 years old.
However, under special circumstances and after consultation with a physician, paediatrician, orthopaedic surgeon, clinical psychologist or surgeon, bariatric surgery can be considered for morbidlyobese adolescents who have already reached a certain level of bone maturity.
Assoc Prof Nik points out that there are two reference ranges for BMI and weight: one from the World Health Organization (WHO) and one for the Asia-pacific region.
“The reason why there are two separate definitions for obesity is because, one, Asians tend to develop metabolic problems at a lower BMI.
“So you want to target obesity early, before the complications of metabolic syndrome set in.
“Number two is that obesity is very, very common now in Asia, especially in the Indian subcontinent, China and South-east Asia.
“And the problem is that the rate of metabolic issues tends to be double, or maybe triple, in the obese Asian population; hence the recognition that we need to treat these patients earlier.
“That is why they reduced the goalpost,” he says, explaining that the BMI ranges for Asians are lowered by 2.5 units.
So, for example, an Asian is considered obese starting from a BMI of 27.5, compared to non-asians, who are considered obese starting from a BMI of 30.
Restricting tummy space
While there are a number of types of bariatric surgery, Assoc Prof Nik says that they can all be categorised into those that are restrictive and those that involve malabsorption.
For the former, the most common type of procedure is a sleeve gastrectomy.
“This basically entails reducing the capacity of the stomach by removing two-thirds of it in a longitudinal manner, so you leave one-third of the stomach in,” he explains.
He adds that surgeons use a calibration tube in order to standardise the amount of stomach left in the patient.
The idea behind this procedure is to literally remove the amount of space available to hold eaten food, thus drastically reducing the amount of calories the patient consumes.
The body is then forced to utilise the fat within the body for energy.
Fat, as Assoc Prof Nik points out, is the most modifiable component of a person’s weight.
The other three components – bone, muscle and water – usually do not have much impact on weight once we have reached physical maturity.
“Say, before the operation, 100% of your energy comes from carbohydrates.
“Now, maybe around 20-30% comes from carbs, so 70-80% has to be generated from fat, so you burn fat and this is why you lose inches,” he explains.
The second effect of the removal of so much of the stomach is a decrease in the levels of the hormone ghrelin, which is mainly produced by stomach cells.
Ghrelin is also known as the “hunger hormone” as it signals to the brain that the stomach is empty and that it is time to eat.
So, patients who have undergone a sleeve gastrectomy will also experience a decrease in their hunger and appetite.
Meanwhile, the third effect is the basis of the metabolic effects of the surgery.
Says Assoc Prof Nik: “When you make a stomach narrower, if you look at physics, the narrower the diameter, the higher the internal pressure.
“So when the internal pressure goes higher, the speed of gastric emptying is faster.
“So the small intestines will receive a fast delivery of food that we have eaten.
“And that will stimulate cells called L cells in the distal ileum to produce a hormone called GLP-1.
“Now GLP-1 is an important precursor that stimulates our pancreas’ beta cells to produce more insulin.”
Therefore, a sleeve gastrectomy has the indirect effect of managing diabetes by triggering weight loss and a direct effect by increasing the production of insulin, he says.
He adds that this procedure is the most common type of bariatric surgery, accounting for about 70% of such operations worldwide.
Double effect
Unlike the restrictive types of bariatric surgery, those procedures that have a malabsorptive component typically involve some form of bypass.
According to Assoc Prof Nik, the surgery does not cut or remove any part of the body, but instead, reroutes parts of the gastrointestinal system to achieve its desired effects.
The two most common types of this procedure are the mini-gastric bypass and the Roux-en-y surgery.
The first aspect of such surgeries is also restrictive in nature.
“Basically, what we are trying to do is to control the volume that the patient eats.
“What we’re doing is creating a small pouch in the stomach by making a partition, unlike a sleeve gastrectomy where you just straight cut it and remove,” he says, adding that this is so that the procedure can be reversed in the future if needed.
The second aspect involves bypassing a certain length of the small intestines so that less of the consumed nutrients are absorbed into the body.
“When the food is less absorbed, then you go into a controlled malnutritional state,” he says.
Of course, the longer the length of small intestine that is bypassed, the less nutrients will be absorbed.
However, Assoc Prof Nik says that the rule is that surgeons will not bypass more than one-third of the small intestines.
This is as the more small intestine that is bypassed, the higher the likelihood of nutritional deficiencies.
“We can be greedy and made people lose more weight, but then they get problems like more profound nutritional deficiencies.”
The key, he says, is to achieve a balance between sustainable, longterm weight loss and minimal side effects.
He notes that the sleeve gastrectomy is the most popular type of bariatric surgery because it has the least side effects.
The most common side effect in this procedure is gastroesophageal reflux disease (GERD) where stomach acid flows back into the oesophagus due to a weakening of the sphincter between the two organs.
However, the double effect of malabsorptive procedures like the mini-gastric bypass results in higher weight loss, as well as better results in resolving diabetes, which is often taken into consideration against its higher risk of side effects.
Common side effects of this type of procedure include small intestine ulcers (especially in those who smoke and/or use steroids and painkillers), dumping syndrome and malabsorption.
Dumping syndrome occurs when the food passes too rapidly into the small intestines, causing too much of the glucose to be absorbed in that area.
This can result in symptoms such as nausea, diarrhoea, light-headedness and feeling jittery, among others.
Lifelong discipline needed
While the effects of bariatric surgery occur fairly quickly, it is essential for patients to realise that it is not a one-time fix-all solution.
As Assoc Prof Nik points out: “You can lose weight, but you can always regain the weight if you are not disciplined.
“This is why, after surgery, it is essential for patients to come for regular follow-up.”
The follow-up sessions allow doctors to monitor the patient’s progress in their weight loss, as well as their other medical problems, if any.
Continued advice on diet and supplements is also provided during these sessions as patients will definitely experience a change in their eating habits.
However, these habits are easily reversible if patients do not control their diet and exercise as needed.
Assoc Prof Nik notes that the environment in Malaysia is neither conducive to controlling our diet nor exercising.
Therefore, patients need to put in continuous effort to maintain their weight loss.
“At the end of the day, the third main factor is the patient themself,” he says.
“By right, you have to sit down and think, ‘I’ve gone through bariatric surgery because I’ve tried everything and it has failed.
“’Now I’ve lost 50kg. It would be a shame if I do not appreciate what I’ve gone through and change my lifestyle forever’.”