How is obesity linked to cancer

Obesity as a cancer risk - maintaining a healthy body weight


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Obesity could soon overtake smoking as the leading cause of cancer. Because while the number of cancer cases due to tobacco consumption is falling steadily, the number of overweight people is statistically increasing. In terms of the development of all cancers, obesity accounts for an estimated 16 percent. If all people were to maintain their normal weight, around 25,000 cancer cases could be avoided each year in Germany alone.

The biological causes

Adipose tissue that has accumulated in the body does not simply rest - on the contrary, it is hormonally active and mixes up the hormonal balance properly. As a result, the metabolism changes and messenger substances are formed, which lead to the increased release of insulin and insulin-like growth factor-I (IGF-I) and thus to a kind of chronic inflammation. This can promote cancer.

The latest findings made it possible to decipher the mechanism running in the cells ‘and even offer a kind of solution. The enzyme ACC1 plays an important role in fatty acid synthesis. However, the messenger substances leptin and TGF-β released by obesity prevent the enzyme from working, so that less ACC1 activity takes place in the corresponding tissue. For example, a significantly reduced ACC1 content could be detected in a tissue with metastases. Researchers tried successfully to use an antibody against the leptin receptor: Fortunately, the spread and metastasis could be contained considerably. Research is currently being conducted into whether this is actually a promising therapeutic concept. It would undoubtedly be practical, as it would minimize the risk of metastases before an operation.

For which types of cancer is obesity relevant?

The association between obesity and cancer has now been confirmed with certainty in a number of cancers, including esophageal cancer, colon and rectal cancer, and kidney cancer in both sexes, and breast cancer, cervical cancer, pancreatic cancer, and gallbladder cancer in women. Obesity does not only play an important role in relation to the development of cancer, however. Scientists found that obesity in the case of breast cancer is associated with a 35 to 40 percent higher risk of metastasis and relapse.

Parameters for determining risk

In order to be able to determine an increased risk of cancer, two parameters in particular are currently being collected: The extent of overweight or obesity based on the Body Mass Index ‘(BMI) and the fat distribution based on the waist circumference.

The body mass index (BMI)
The Body Mass Index, or BMI for short, is calculated using the following formula:

  • Body weight (in kilograms)
    Height x height (in meters)

  • An example: A woman weighs 69 kilos and is 1.70 meters tall.
    1.70 x 1.70 = 2.89.
    69 : 2,89 = 23,8.

  • The BMI can be classified as follows:
    • Below 18.5: Underweight
    • 18,5–24,9: Normal weight
    • 25–29,9: Obesity
    • 30–34,9: Obesity (obesity) grade I.
    • 35–39,9: Obesity grade II
    • ≥ 40: Obesity grade III

The waist circumference
As has been found in the past, the fat distribution pattern also plays a major role in the risk of cancer. Abdominal fat, which can be estimated using a simple measure, the waist circumference, is particularly unfavorable.

The following are guidelines for the waist circumference:

  • ≥ 80 cm for women or ≥ 94 cm for men: increased risk of secondary diseases
  • ≥ 88 cm for women or ≥ 102 cm for men: Belly obesity (abdominal obesity) with a significantly increased risk of secondary diseases

The gut fat
Two other parameters that play a role in the distribution of fat and the risk of cancer are the subcutaneous fat tissue located directly under the skin and the visceral (intestinal) fat that envelops the internal organs. Compared to subcutaneous fat, visceral fat is more frequently associated with insulin resistance, which leads to diabetes, type 2 diabetes mellitus. Visceral fat is also more likely to emit messenger substances that are associated with inflammation, such as interleukins and tumor necrosis factor-alpha.

For colorectal cancer, it has been shown that the greater the amount of visceral fat in study participants, the more often adenomas, i.e. precursors of colorectal cancer, occurred. According to the interpretation of the study authors, this may explain the often proven relationship between BMI, waist size and the risk of colon cancer and its precursors.

The amount of subcutaneous and visceral fat can be determined using the imaging methods computed tomography (CT) and magnetic resonance imaging (MRI). Since neither method is suitable for routine diagnosis of fat distribution, the BMI and waist circumference are still used to identify people at high risk. The visceral obesity index can also be determined, which is gender-specific based on waist circumference, BMI, blood fat levels (triglycerides) and HDL cholesterol.

Lose weight with a healthy diet

The 10 rules for healthy eating

Eating a balanced diet helps maintain weight and is good for your health. The German Nutrition Society has defined ten rules for correct and healthy eating based on current scientific knowledge.

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1. Interdisciplinary guideline of quality S3 for the prevention and therapy of obesity. AWMF register: 050/001, as of April 2014

2. Keum N et al .: Visceral Adiposity and Colorectal Adenomas: Dose-Response Meta-Analysis of Observational Studies. Ann Oncol. 2015; 26 (6): 1101-1109

3. Lauby-Secretan B et al. Body Fatness and Cancer - Viewpoint of the IARC Working Group. N Engl J Med 2016; 375 (8): 794-798

4. Rios Garcia M et al. Acetyl-CoA Carboxylase 1-Dependent Protein Acetylation Controls Breast Cancer Metastasis and Recurrence. Cell Metab 2017; 26 (6): 842-855.e5.

5. Press release of the German Cancer Research Center (DKFZ) from August 25, 2016: Avoid being overweight - avoid cancer! Questions to Rudolf Kaaks about the current publication by the cancer research agency IARC.

6. Theses R. Overweight soon to be the main cause of cancer. Pharmaceutical Newspaper 2014; 159 (34): 41

7. Cancer Research UK: Does obesity cause cancer? As of September 2018.

8. Diabetes Information Service Munich: Diabetes and Cancer. As of September 2016.

Last updated: 02/21/2019

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Last accessed on: May 19, 2021 4:01 pm