Why is Obesity a leading cause of cancer?
Recently Cancer Research UK has launched a new advert on the radio warning people that obesity is the second biggest preventable cause of cancer in the UK after smoking. Most people know that smoking can cause cancer and understand that inhaling toxic substances cannot be good for the human body but why and how does obesity cause cancer? This seems to be the most common question that people ask me on the topic. The answer to this question is complex, as excess body fat can cause a whole host of issues in the body. But scientific research has identified at least 3 key ways in how excess weight can lead to cancer.
Increased Insulin & Insulin Growth Factor 1
Today overweight and obesity are mainly caused by an overconsumption of calories and physical inactivity and sugar is often the culprit of why we overindulge or binge on certain foods as it is very addictive. It can be found in many foods such as processed foods, cereals, refined flours, sweetened beverages and desserts. Going sugar free on a daily basis is one of the hardest things to do as it seems to be virtually in every food.
Insulin is a hormone produced by our pancreas for the metabolism of carbohydrates. Insulin's job is to help cells to receive carbohydrates and bring it into the cell. Once inside the cell it can then use the carbohydrates to produce energy for our body. Without this vital hormone, our body simply couldn’t function for very long.
If you’re consuming too much sugar, one of the things that happen is an increase of insulin in the body. Over time, insulin receptor sites on our cells can burn out and stop responding to the insulin that our pancreas produces causing insulin resistance (type 2 diabetes). This causes an influx of both insulin and sugar in our blood.
Cancer research has shown that cancer cells also have the same insulin receptor sites as our healthy cells but they are often expressed in greater numbers on the cancer cell making them “very hungry” for glucose (carbohydrates) and insulin. Therefore high levels of insulin due to either insulin resistance or excess sugar consumption can fuel cancer cells to grow and thrive.
Insulin-like Growth Factor 1 (IGF-1) is a hormone with a similar molecular structure to insulin. It’s vital to childhood growth and encourages cell growth and proliferation in adults. However, IGF-1 also promotes each of the key stages of cancer development: growth of cancerous cells, vascularisation of cancerous tissue (blood vessel growth) and metastasis.
Milk and dairy products contain whey proteins which cause a rise in insulin, IGF-1 and growth hormone levels and have been linked to the development of certain cancers. One Swedish study studied lactose intolerant people and found that they had a significantly lower risk in developing cancer than those that were not lactose free.
Increase Of Oestrogen
Most People view extra body fat as relatively harmless or as something that they want to get rid of to look and feel better. But excess body fat can do more than just sit there and make your trousers feel tight. Visceral fat is fat that is located around organs and underneath the skin (belly fat) and is often seen in obese people. This fat tissue can produce hormones such as oestrogen and if an individual has a high amount of fat tissue in their body the more oestrogen is produced. Usually high amounts and can promote cell division and tissue growth that can lead to fibroids, cysts, cervical dysplasia and tumour formations in both male and female.
Inflammation
Another major concern about increased visceral fat is that it can also produce inflammatory chemicals called cytokines that can lead to chronic inflammation.
Chronic Inflammation leads to cell DNA damage which causes cells to mutate and dysfunction, making the body more susceptible to form malignant growths.
But visceral fat does more than just lead to inflammation down the road — it becomes inflamed itself by producing something known as interleukin-6, a type of inflammatory molecule. This kind of fat stores inflammatory white blood cells and kicks off a series of autoimmune reactions. Inflammation is at the root of most diseases, and this is why inflammatory belly fat is also linked with other diseases such as cognitive decline, arthritis, diabetes and so on.
If you are worried about your weight or have underlying problems associated with obesity and need help with losing weight please feel free to contact me at evelyn@vibratingwellness.com or check out my 12 Week Weight Loss Programme.
References:
Poll & Stambolic, 2015. Obesity and cancer, a case for insulin signaling,
Cell Death & Disease volume 6
Divella , Raffaele De Luca, Ines Abbate1, Emanuele Naglieri, Antonella Daniele, 2016. Obesity and cancer: the role of adipose tissue and adipo-cytokines-induced chronic inflammation, Journal of Cancer, 7(15) pp. 2346-2359.