It is thought that about 1 in 20 cancers are linked to obesity, and the longer you are overweight for and the more weight you carry, the higher the risk is – though it is important to remember that not everyone who is obese will develop cancer in their lifetime, and being a healthy weight does not preclude you from developing it either.
How does obesity cause cancer?
The more excess weight that somebody has and the longer they are overweight, the higher their risk of developing cancer.
To understand why, we need to look at what fat is doing in the body. Fat cells don’t just hang around. In fact they release signals to the rest of your body and these signals can cause our cells to divide more, resulting in cancer.
What cancers are caused by obesity?
Research shows being overweight and obese to increase the risk of thirteen different types of cancer: breast, bowel, pancreatic, oesophageal, gallbladder, womb, ovarian, kidney, liver, upper stomach, myeloma, menangioma and thyroid.
How can you reduce your risk?
Losing weight isn’t easy and studies have shown that crash diets are unlikely to bring long-term success. Small changes to lifestyle habits are likely the most successful way of reducing weight and health risks.
It is also important not to forget about healthy habits such as increasing your physical activity and eating a well-balanced diet, as well as improving stress and sleep habits.
Looking for more information on the science? There are three main ways in which too much fat can increase the risk of cancer:
Growth hormones:
Fat is stored in fat cells, which can produce growth hormones such as insulin, which can tell cells to multiply more often. The more cells divide, the higher the chances of an error in the DNA, and therefore mutations that can lead to cancer. Insulin can also increase the production of other hormones, such as oestrogen (see below), further increasing cancer risk.
Sex hormones:
Fat cells also release oestrogen, which can trigger cells to divide more quickly in the breasts and the womb. This can be especially problematic for people who are past their menopause, as they naturally produce less oestrogen.
Inflammation:
The accumulation of fat around internal organs - also called visceral fat – is thought to be especially problematic. Visceral fat cells of people with obesity tend to be large in size and number and exist in an environment with relatively little oxygen.
As well as this, certain immune cells migrate to the fatty areas to clear up dying or dead fat cells. This can lead to inflammation, and if this inflammation goes on for too long, it can damage the body’s ability to respond to insulin, meaning that more insulin is produced, leading again to increased cell division. The inflammation itself can also stimulate cells to divide faster, further increasing the risk of cancer.
Your cancer and obesity FAQs:
We break down the facts, and answer some of your most frequently asked questions about the link between obesity and cancer.
Does losing weight reduce your risk of cancer?
Yes. Especially for people who have overweight or obesity, losing weight can help to lower your cancer risk. It is important to lose weight in a controlled and healthy way – please remember to seek advice from your doctor before embarking on any new diet or exercise programme.
To find out more about how to reduce the risk of cancer by tackling lifestyle habits, take a look at the Better Health campaign by the NHS.
Most importantly - please remember that you should always check in with your GP if you notice any concerning symptoms - regardless of your weight.
How does obesity increase the risk of cancer?
Obesity or being overweight increases your risk of cancer because of how fat cells influence the rest of your body. Research has shown that fat cells send out signals which can cause our cells to divide more than normal, and this increase in cell division can cause cancer.
How is research helping us understand obesity and cancer?
Dr Hector Peinado in Spain is investigating how obesity helps cancers to spread. By better understanding how lifestyle factors can drive cancer progression, he hopes this work funded by Scottish cancer charity Worldwide Cancer Research will lead to new ways to treat and prevent it.
Also in Spain, Professor Raul Mendez has made an exciting discovery about how to protect against diet-related obesity. He hopes to use this to explore new ways to reduce obesity, which would have major implications for cancer and other obesity related diseases.
Dr Tracy O’Mara in Australia has discovered that weight circumference is one of five important risk factors for endometrial cancer. This important breakthrough could lead to early detection, personalised interventions and ultimately better outcomes for patients.
Without the support of Curestarters like you, we cannot fund more vital research like this that will uncover new ways to prevent cancer. Will you join us today?
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