Every day, it seems, I get an email from a well-meaning friend about a new cancer study concerning grapefruit juice, PET bottles, red meat...the list is endless. Or, a news article saying that mammograms and self-examination are a waste of effort.
Since I've recently received my umpteenth email about another presumable cancer-causer, I thought it was time to feature an interview I had with Dr. Gregg Orloff. Orloff teaches the biology of cancer at Emory University in Atlanta, and has developed an award-winning website that explains the biology of cancer: http://www.cancerquest.org/.
"Of all the environmental and behavioral factors that have been investigated for cancer, only a few have shown a clear link," Orloff says.
"It's difficult to make hard conclusions about certain activities and their impact on cancer because studies to-date haven't involved a large enough population or haven't been conducted for a long enough time period to offer anything definite. The data simply doesn't exist at this point."
Still, research has uncovered enough implications between particular behaviors and increased risk that it's worth paying attention to how lifestyle choices impact our health, he says. But in order to understand how behavior and cancer are related, we first need to know what causes cancer to form.
"Cancer is ultimately a result of DNA damage," explains Orloff.
"We know that cancer is derived from a single defective cell that has multiplied. It occurs when a cell strikes out on its own, resulting in unregulated cell growth. These abnormal cells pile up on each other and form masses, which are commonly known as tumors."
Why does a normal cell strike out in the first place? What causes it to become cancerous?
It happens when a particular set oif genes in a cell are altered by mutagens. And, this is where lifestyle behaviors may play a role in cancer. Mutagens enter the human body by means of inhaling, ingesting and absorbing.
They derive from:
* Chemicals in the diet -- For example, charred meat from grilling (the burning process) can cause the formation of chemicals that are thought to be mutagenic.
* Infectious agents -- A problem can occur when a virus actively alters the cells. For example, cervical cancer may result after infection with the Human Papilloma Virus...a viral infection.
* Chronic infections - Cancer can result in response to an infectino. For example, hepatitis has been associated with liver cancer. When cells are killed by infection, they need to be replaced constantly, so there are high amounts of cell division occurring in these tissues. In addition, the body's immune response to fight infection is producing chemicals that can cause mutations.
* Chemicals in the envioronment -- These can be absorbed or inhaled, such as smog and industrial waste.
In other words, every time you expose your body to a cancer risk -- eating buned meat, inhaling cigarette smoke or absorbing coal tar -- mutagens enter your body. And chemicals that are mutagenic can cause DNA damage.
The Luck Factor
If we all take in mutagens, then why does one person develop cancer over someone else?
"In order for a single, normal cell to turn into a cancer cell, it must acquire five to six different changes from mutagens. So, it's a cumulative effect," says Orloff. "Two people can be exposed to the same mutagen, but in one person, the cell dies or remains the same, while the other perosn acquires a mutation in an important gene and develops cancer.
"That's why you see some people smoke their entire lives and not get cancer, and others who 'do all the right things' develop cancer. Luck plays a big role as to who gets cancer and who doesn't. "
In the Genes
There are genetic components to cancer, as well.
"A person can inherit defective genes -- such as BRCA1--which by itself doesn't necessarily cause cancer," Orloff adds. "But a defective gene can increase your chances that some important key genes will be affected by a mutation, giving you a higher risk for cancer."
Another genetic factor that can impact whether one person develops cancer versus another is possessing better DNA repair genes, which respond to DNA changes differently.
In addition, the way your body processes toxins can affect your chances of getting cancer. For example, the liver has enzymes to process and eliminate toxins -- making them soluble so they can be excreted. But this detoxification process can convert a chemical into a mutagen.
Consequently, two people may be exposed to the same risks, but their bodies may process toxins differently.
Whatever your body's genetic makeup, DNA can be damaged by certain behaviors.
The following factors are known to have an associated risk of cancer because of their mutagenic properties:
* Smoking -- Full of mutagens, smotking as well as second-hand smoke is connected to almost all cancers.
* Sun damage -- UV rays are mutagenic and have been proven to cause skin cancer.
* Diet & obesity -- Obesity carries an increase risk of breast and colon cancers. Certain diets can alter the level of growth factors and nutrients (protiens, lipids, sugars) in the blood, which, in turn, can stimulate normal cells to become cancerous, or cause existing cancer cells to grow.
* Alcohol -- Particularly a risk factor for breast, colon and esophageal cancers, alcohol is toxic and must be detoxified, causing stress on the body. The detoxification process can cause DNA damage.
* Medications -- Certain drugs can potentially cause a problem. For example, female children of women who took DES (now outlawed) while pregnant have higher incidences of cervical and uterine cancer.
On the other hand, there appear to be certain behaviors that may help reduce your risk of cancer:
* Exercise - In some studies, exercise has been shown to have positive beneficial effects on breast and colon cancer. The benefits of exercise may be due to a wide variety of effects, ranging from enhanced immune system function to increased GI motility.
* Diet -- Overall, a well-balanced diet with fruits, vegetables and nuts is beneficial. Specifically, foods that contain antioxidants (such as leafy green and cruciferous vegetables) have cancer fighting possibilities.
This is because our bodies produce oxygen radicals, which are highly reactive molecules in cells that act as mutagens and can cause DNA damage. Antioxidants act as interceptor missiles, neutralizing oxygen radicals before they affect DNA.
In addition, studies have indicated that Vitamin D, selenium and calcium might potentially prevent or limit cancer growth.
"None of these things, alone, offers a huge reduction in cancer risk," warns Orloff. "But we know enough from studies to advise people to take care of their body."
The Bottom Line
"There's no holy grail in that if you do this set of behaviors, you won't get cancer," says Orloff. "All you can do is limit your risks.
"It's like avoiding a car accident," he says. "You can limit your risks by wearing a seat belt, not driving late at night, and not driving while talking on the cell phone. But all these things still can't guarantee that you won't get killed in a car accident."
"The same goes for cancer. Individuals have to decide what risks they want to live with."