The unsung benefits of weight loss

Prof Selim Cellek

Type 2 diabetes is a dangerous condition, often caused by being overweight. But if sufferers ever needed a compelling reason to improve their weight, Professor Selim Cellek has some motivating new evidence: when patients lose weight, any erectile or urinary dysfunction they’ve also suffered rapidly disappears.

Professor of Health and Biomedicine at ARU, Selim is a lifelong specialist in erectile dysfunction (ED). While working on ED “can sometimes be difficult to discuss with a lay person because of the various social stigmas around it”, he says it is a serious problem that needs addressing: 5.1% of 20- to 39-year-old men and 70.2% of men over 70 years suffer from it.

At one point in his career, Selim worked on developing a competitor product to Viagra. It all came about when the lab in which he was doing his PhD discovered nitric oxide, the main molecular signal for the physiology of penile erection. This led to his work being used for the development of the first PDE5 inhibitor drugs such as Viagra, enabling nitric oxide to function.

Then at UCL and Cranfield University he worked for over a decade alongside urology specialists. He became intrigued when he heard news from his colleagues: that when morbidly obese patients had bariatric surgery – an operation on the gut – any urinary dysfunction disappeared along with their diabetes.

What cures one, cures another?

Selim wanted to explore whether this applied to erectile dysfunction too, given that both conditions are caused by the same thing: lack of healthy blood flow. Under his supervision, research was carried out by a PhD student, Maha Aleid of Cranfield University, in collaboration with Anglia Ruskin University and University College London Hospitals NHS Foundation Trust.

Maha surveyed 30 obese men over the age of 30 who were undergoing bariatric surgery. Eighteen of the 30 reported erectile dysfunction before the operation. Within a month following surgery, as their Body Mass Index decreased, all 18 patients reported rapid improvement in both erectile and urinary function. “Previous studies had shown that patients who underwent bariatric surgery show improvement in erectile and urinary function within six months. This study shows that these functions can in fact start to improve far quicker than we expected,” explains Selim. “We don’t yet know exactly why the surgery improves the blood flow to both the bladder and the genitals, though we suspect it is something to do with more nitric oxide being available.”

“Obesity has a negative effect on many things, including urinary and erectile function, which can be extremely tough to live with. It is better, and cheaper, to lose weight naturally of course. Clearly weight-loss surgery is a last resort for patients who are morbidly obese, with a BMI of more than 35kg/m2,” he explains. “This study shows that the benefits of this lifesaving surgery extend further than just weight loss, and it warrants further investigation. ”

Challenge of proof

Selim explains, however, how the study cannot lead to any new drug treatments for ED. The problem is one of proof. “We needed to catch the patients straight after the bariatric surgery – after their diabetes had disappeared but before they had lost weight. Only this way could we prove that any gain in erectile function was due to the reversal of diabetes rather than due to their weight loss. We needed to separate the two things out.”

Sadly this was not to be, as patients were not well enough to take part in research before they lost weight. “That was the most frustrating thing about the research,” says Selim.

What he and his team were after was the holy grail of medical research: a ‘human model’ which is far better than lab or animal models. “Needless to say human models get drugs companies very excited. And drugs are what we are after – they are always better to treat diseases than surgery which is costly and can be stressful on the body and mind”.

A lowered appetite

Another aspect of diabetes is also of interest to Selim: appetite. He explains with excitement how the bariatric surgery changes overnight the food preferences of the patients undergoing it. He reports research by Carel le Roux showed how obese patients before surgery crave fatty foods. As if by magic, after surgery this craving is lost instantly and are drawn to healthier foods lower in fat. “The brain-gut axis links our mind and our gut bacteria in many ways, but we don’t yet know much about it. We still do not know how exactly the food preferences changes so rapidly after bariatric surgery”.

So is Selim saying that slimmer people find it easier to choose healthier food than obese people? "Yes, sure" he says. Who said the world was a fair place?

Research highlights

The best moment in this research: When we noticed that the patients’ urogenital function was improving rapidly after the surgery. It was the “Yes, we were right!” moment.

The most challenging moment: When we noticed (at the same time as the best moment) that the patients were losing weight rapidly, faster than we expected; initially it was upsetting because it meant that we would not be able to test our hypothesis. But eventually it dawned on us that this is great for the patients and once more confirmed how beneficial the bariatric surgery is.