That sugar causes cancer to grow and spread more quickly is a myth. In this report by Sade Oguntola, experts declared that only excessive weight gain or obesity as a result of excessive intake of sugar may lead to cancer.
There’s a lot of confusing information and advice out there around sugar. It has been made the villain of our diet, but where does the consensus lie between how sugar and cancer are linked?
Does it cause cancer? Does sugar feed cancer cells, making them grow more aggressively? And how does the sugar we consume through food and drink affect our health, and what is exactly the link between sugar and cancer.
The idea that sugar is responsible for kick-starting or fuelling a cancer’s growth is an over-simplification of some complicated processes in the body. In fact, experts say that the alarming warnings that sugar is the “cancer’s favourite food” is a myth that has been circulating on the internet.
“The idea that sugar causes cancer has been controversial and it is one of those myths on cancers. The truth is that all cells, whether cancerous or normal, require glucose and we get glucose from different sources, including food,” said Abayomi Durosinmi-Etti, a Professor of Radiation therapy and Oncology at the University of Lagos.
According to Professor Durosinmi-Etti, “The truth is if you take sugar, and in excess of it, it can lead to obesity . Obesity is one of the well known causes of cancer. I think this is what people noticed and then they think that if you take sugar it will cause cancer. “
What are sugars?
Sugar, in some form, is in many things we eat. But sugar comes in many different forms. The simplest form is just as a single molecule, such as glucose and fructose. These molecules of simple sugars can also stick together, either in pairs or as longer chains of molecules. All of these combinations of molecules are carbohydrates, and are our body’s main source of energy.
The form of sugar most people are familiar with is table sugar, which is a simple sugar that dissolves in water and gives things a sweet taste. Its proper name is sucrose, and it is made up of crystals of glucose and fructose.
Unprocessed foods like honey can be high in simple sugars too. Honey is made mostly of glucose and fructose. Also, starchy foods such as rice, bread, yam and vegetables like Irish potatoes might not taste sweet, but they are high in carbohydrate too.
Glucose, the fuel of life
Virtually every part of the body is made of living cells. These cells help us see, breathe, feel, think and much more. Although their jobs in the body may differ, they all need glucose as fuel or energy to survive and perform their duties.
Basically, the pancreas releases insulin into the body to send sugar into the cells of the body to perform their duties. “Every cell has insulin receptors to help in driving the glucose into the cell. That also means that cancer cells also have insulin receptors,” added Dr Olutoye Ogunnorin, a consultant radiation and clinical oncologist at the University College Hospital (UCH), Ibadan, Oyo State.
And of course, cancer cells could have more insulin receptors than the normal cells in the body since they replicate faster than the normal cells in the body.
So, if for some reason there is no carbohydrate in our diet, cells in the body can turn fat and protein into glucose as a last resort, because they need glucose to survive.
Cancer cells usually grow quickly, multiplying at a fast rate, which takes a lot of energy. This means they need lots of glucose. Cancer cells also need lots of other nutrients too, such as amino acids and fats. It is not just sugar they crave.
Sugar fuels cancer a myth
Unfortunately, this is where the myth that sugar fuels cancer was born: if cancer cells need lots of glucose, then cutting sugar out of our diet must help stop cancer growing, and could even stop it developing in the first place. But, it is not that simple.
According to Dr Ogunnorin, “Studies have not substantiated that if you have more glucose in your system, it means you have more cancer growths.
“Of course, the corollary is the fact that if you starve cancer cells of glucose, it does not mean that it will reduce the growth rate of cancer cells.”
Nonetheless, he decried the bad impact the myth that sugar fuels cancer has had on persons with cancers.
“Those things have a way of stressing patients. For them, now picking which food to eat and not to eat stimulates stress. Stress stimulates chemicals that reduce immunity. This is the same immunity that the patients need to fight cancer.
“Of course, these cancer patients are going through lots of challenges, including that on managing the disease and the treatment they are receiving.
“Chemotherapy has a way of weighing a patient down; and reducing their immune system. They need glucose and as a matter of fact, balance diet to be able to withstand these challenges and function optimally. So, by telling them “do not take sugar”, you are actually depriving them of some basic nutritional needs” he declared.
Ketogenic diet and cancer
What is more, Dr Ogunnorin said another myth people need to be wary of is ketogenic diet as a cancer treatment. “Again, we do not have enough studies to substantiate this. But, we know that high fatty diet actually predisposes some individuals to some cancers, such as that of the breast and ovary,” he added.
The ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that in medicine is used primarily to treat difficult-to-control epilepsy in children. The diet forces the body to burn fats rather than carbohydrates.
Although some “nutritionists” on the internet are propagating research outcomes or claims that had not been extensively tested in large human populations, he said that although this works in a few people, it does not mean that it will work in every cancer case.
He added, “it may work in some few cases, but of course, no two cancers are the same. There cannot be a blanket statement for all cancers. What is a predisposing factor for one cancer may turn out a protective factor for another cancer; so we really need to be very conscious of this fact.”
If sugar doesn’t cause cancer, why worry about it?
Although there’s no evidence that sugar from our diet can cause cancer, Professor Durosinmi-Etti stated that research has shown that eating lots of sugar, over time can cause weight gain or obesity, and scientific evidence shows that being overweight or obese increases the risk of at least 13 types of cancer, including cancers of the breast and ovaries.
He added, however, that some common risk factors for cancer in Nigeria are tobacco use, infections (such as Human Papilloma virus (HPV) and hepatitis), radiation, lack of exercises, and eating mouldy foods.
“We have a high incidence of liver cancer. One cause of that apart from alcohol is eating mouldy foods. Aflatoxin in such foods are known to predispose to cancer of the liver,” he declared.
Ending the sugar confusion
So, how much sugar is safe to eat? The American Heart Association say women should have no more than six teaspoons per day and men should have no more than nine teaspoons per day.
So, the take-home message is that although banishing sugar would not stop cancer in its tracks, individuals can reduce their risk of getting cancer by making healthy choices.
Also, lowering the amount of added sugar in the diets is a good way to help maintain a healthy body weight, and lower the risk of chronic diseases like heart disease, diabetes and Alzheimer’s disease.