Myths about sugar, "catching" cancer, microwaving and more

You have probably heard about the theory that “sugar feeds cancer”. Perhaps you have also been told that cancer is contagious and you can catch it, like the flu. What about microwaving our food?
Here are some more myths that deserve to be addressed.


“Some types of cancer can be contagious”

Where does the myth come from?

There are a lot of people who think that cancer is a contagious disease, as in "catching" the flu or a cold. Cancer is not contagious in the conventional sense.

The reality behind the myth

No type of cancer is contagious. However, there are two known contagious viruses that can cause cancer: HPV and Hepatitis C. HPV is a known risk factor for cervical cancer and Hepatitis C causes liver cancer. Both viruses can be transmitted through unprotected sexual intercourse, although Hepatitis C is more often transmitted through blood to blood contact such as sharing needles and transfusions (prior to 1992 when blood screening became available).



“Positive thinking will cure cancer”

Where does the myth come from?

Coping with a cancer diagnosis often brings patients out numerous feelings and emotions. It is true that for many years it was believed that certain personality types were more likely to get cancer while others not. At the same time, many cancer patients believe that having positive attitude can actually cure cancer.

The reality behind the myth

While maintaining a positive outlook during cancer treatment is essential, it will not cure cancer. Being optimistic, helps with quality of life during treatment. However, there is no scientific evidence that a positive attitude will cure cancer. Cancer is very challenging for the patient and their family; the pressure to “be positive” may make the person feel lonely and worsen emotional pain. One has to accept their feelings and try to cope with the major life changes that cancer causes.


“Microwaving plastic containers and wraps releases harmful, cancer-causing substances into food”

Where does the myth come from?

Many of us have received emails warning us on the cancer-causing substances released when microwaving plastic containers and wraps. They base this warning on the idea that chemicals leach out of the plastic and into the food. They refer to a component of plastic, called dioxin, which can cause all sorts of health problems.

The reality behind the myth

Microwave-safe plastic containers and wraps are safe to use in the microwave. But plastic containers not intended for use in the microwave could melt and potentially leak chemicals into your food. So avoid microwaving containers that were never intended for the microwave, such as margarine tubs, takeout containers or whipped topping bowls.
Check to see that any container you use in the microwave is labeled as microwave-safe.




“People with cancer shouldn't eat sugar, since it can cause cancer to grow faster”

Where does the myth come from?

Another famous cancer myth spread by many cancer-related websites and reports. According to the myth, eating sugar feeds cancer making it grow faster. This myth has convinced many cancer patients to stop eating sugar hoping that in way, the cancer will stop growing. In addition, cutting sugar off your diet means that you eliminate also beneficial foods, such as fruits.

The reality behind the myth

What we know is that sugar doesn't make cancer grow faster. All cells, including cancer cells, depend on blood sugar (glucose) for energy. But giving more sugar to cancer cells doesn't speed their growth. Likewise, depriving cancer cells of sugar doesn't slow their growth.

This misconception may be based in part on a misunderstanding of positron emission tomography (PET) scans, which use a small amount of radioactive tracer — typically a form of glucose. All tissues in your body absorb some of this tracer, but tissues that are using more energy — including cancer cells — absorb greater amounts. For this reason, some people have concluded that cancer cells grow faster on sugar. But this isn't true.

However, there is some evidence that consuming large amounts of sugar is associated with an increased risk of certain cancers, including esophageal cancer. It can also lead to weight gain and increase the risk of obesity and diabetes, which may increase the risk of cancer.


“Good people do not get cancer”

Where does the myth come from?

As with other myths, in ancient times, illness was often viewed as punishment for bad actions or thoughts. In some cultures that view is still held.

The reality behind the myth

If this were true, how would you explain the 6-month-old or the newborn who gets cancer? These little ones have not been “bad”.

There's absolutely no evidence that you get cancer because you deserve it. People with cancer may feel guilty and also their disease as a punishment. As there is no connection between personality and cancer, patients should stop blaming themselves and focus on facing this condition with the help of their medical team. 


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Other sources include Mayo Clinic &


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