Cancer is now the leading cause of death in the United States for people under the age of 85. It surpassed heart disease to become the top killer just a couple of years ago.
October is National Breast Cancer Awareness Month, and achoo! ALLERGY proudly supports breast cancer research. Five dollars from every Blueair AirPod Pink sale goes to the Breast Cancer Research Foundation, which is dedicated to helping find a cure for breast cancer through the funding of genetic and clinical research.
Allergy, Cancer & the Immune System
Is there a connection between cancer and allergy? Yes, and the basis for that connection is the immune system, our body's self-defense system. The immune system includes many different kinds of specialized cells which protect us from disease by killing foreign invaders like bacteria and parasites.
In the case of allergy, the immune system becomes hyper-sensitive to a certain substance (like ragweed pollen, for instance), and immune cells overreact to that substance, causing inflammation and allergy symptoms. In the case of cancer, on the other hand, the immune system often underreacts. After all, cancer cells are nothing more than normal cells with damaged DNA. The immune system does not attack many cancer cells because they appear as "self" rather than dangerous foreign invaders like bacteria.
Since allergic conditions spur the immune system into action, then perhaps allergy sufferers have less risk of developing cancer? Over the past few years, scientists have been researching that question.
Allergy History & Cancer Risk - Medical Studies
A "balanced polymorphism" is a genetic pattern that can offer protection against certain diseases while increasing the risk of others. For example, carriers of sickle-cell anemia are resistant to malaria. Similarly, allergies may protect against some forms of cancer.
A 2005 article in the journal Cancer Research suggests that allergies and asthma reduce the risk of developing brain cancer. (So there's at least one good thing about having allergies!)
Another 2005 article in the American Journal of Epidemiology suggests an inverse association between a history of allergy and cancer mortality - which means that allergies may offer some protection against cancer in general - but the strength of the evidence is limited.
However, not all studies show that allergies reduce the risk of cancer. A 1992 article that appeared in the American Journal of Epidemiology found that males with drug allergies had a 33% increase in cancer risk; in contrast, females with drug allergies showed a 21% decrease in cancer risk. The study also showed that a history of allergies seems to increase the risk of prostate cancer and breast cancer but decrease the risk of ovarian cancer. Moreover, a 2004 article in the journal BMC Public Health suggests that people who have asthma and eczema are more likely to develop cancers of the blood.
The results of these studies suggest that, while a history of allergies may offer some protection against certain types of cancer, the relationship between allergy and cancer is complex and depends on the specific type of allergy and the specific type of cancer. At this point, the evidence is
inconclusive, but more studies are under way.
Inflammation, Allergies & Cancer
Allergic diseases appear to reduce the risk of cancer in some cases, perhaps by keeping the immune system on its toes, so to speak; but too much stimulation of the immune system (too much inflammation) can damage the body and increase the risk of cancer.
A 2007 paper published in the journal Cell describes what could be the long-elusive mechanism through which inflammation can promote cancer.
"Although there is plenty of evidence that chronic inflammation can promote cancer, the cause of this relationship is not understood," says Alexander Hoffmann, an assistant professor of chemistry and biochemistry at U.C. San Diego, who led the study. "We have identified a basic cellular mechanism that we think may be linking chronic inflammation and cancer."
A protein called p100 allows communication between the inflammation and development processes. Some amount of dialogue is beneficial, but too much dialogue (which results from chronic inflammation) can lead to unrestrained development (cancer).
"Studies with animals have shown that a little inflammation is necessary for the normal development of the immune system and other organ systems," explains Hoffmann. "We discovered that the protein p100 provides the cell with a way in which inflammation can influence development. But there can be too much of a good thing. In the case of chronic inflammation, the presence of too much p100 may over-activate the developmental pathway, resulting in cancer."
See Chronic Inflammation & Chronic Disease to learn more.
Immunotherapy: Different Applications for Allergy & Cancer
Immunotherapy for allergy sufferers is commonly referred to as allergy shots. (And now sublingual immunotherapy allergy drops are available as well on a limited basis.) Allergy shots are made up of the allergen(s) that cause allergies. The amount of the injected allergen gradually increases over a long period of time, usually at least two years. Immunotherapy helps the immune system build up a tolerance to the specific allergens so that immune cells do not overreact upon exposure.
Immunotherapy for cancer patients has a much different goal; its effect is nearly the opposite, in fact. The goal of cancer immunotherapy is to somehow "tag" the cancer cells so that the immune system knows to attack them. Allergy immunotherapy attempts to calm down overreactive immune cells, whereas cancer immunotherapy attempts to spur sluggish immune cells into action.
BCG immunotherapy is often used to treat bladder cancer. BCG is a solution of genetically engineered tuberculosis (TB) bacteria that's used as a TB vaccine in some countries. In the cancer treatment, the BCG is administered directly into the bladder via catheter, and the BCG elicits an immune system response. This response activates the immune system's killer cells, and they attack the cancerous cells. For some reason, the immune
response seems to target the cancer cells (as opposed to chemotherapy, for example, which also kills all surrounding healthy cells), perhaps because the BCG has an affinity for the cancer cells and somehow attaches to them. Thus, TB bacteria can be used to "tag" cancer cells.
Revolutionary Allergy Vaccine in Development
Ironically, scientists at Cytos Biotechnology in Zurich are working on an allergy vaccine that also uses genetic material from the TB bug. The harmless DNA tricks the immune system into thinking it's being attacked by a foreign invader, and disease-fighting white blood cells rush into action. This immune response provides protection against allergic responses. The vaccine is still in the early stages of development, but in a most recent trial, 40 adults allergic to dust mites were given either weekly vaccine shots or placebo "dummy" shots for six weeks. Those receiving the real shots quickly became tolerant to dust mite allergen, some being 100 times more resistant.
Sometimes, it seems, the immune system needs outside help to learn what it should attack and what it should not attack. Maybe one day scientists will crack the code of the intricate immune system, and diseases like cancer and allergies will be things of the past.
Environmental Control of Allergens & Carcinogens
Besides the immune system, there's another big connection between allergies and cancer: You can guard against both allergies and cancer by practicing environmental control. Allergens cause allergies, and carcinogens cause cancer; you can decrease your risk of developing diseases by keeping allergens and carcinogens our of your environment.
Visit the Allergy Relief Learning Center to learn all about allergen avoidance and environmental control options for allergy sufferers.
But what about carcinogens? What are they, and how can you avoid them?
Remember that a cancer cell is simply a normal cell with damaged DNA. A
carcinogen is a substance that damages DNA and promotes cancer. Some natural
substances can be carcinogens - like asbestos; ultraviolet radiation in
sunlight, x-rays, and gamma radiation; and Aflatoxin B1, which is a toxin
produced by a fungus that grows on stored grains, nuts, and peanut butter. Some viruses, such as Hepatitis B and human papilloma virus (HPV), have also been shown to cause cancer.
Common man-made carcinogens include various forms of air pollution like
tobacco smoke and certain chemical fumes. You can reduce your risk of cancer by keeping your lungs free of carcinogens with HEPA air purifiers and HEPA masks.
Other man-made carcinogens include formaldehyde (used to make plastics) and vinyl chloride (used to make PVC). Dr. Jospeh Mercola reports that bisphenol A (BPA), an estrogen-like compound widely used in plastic products, is associated with cancer and reproductive disorders. In one study, 95% of people tested had levels of BPA levels that could be dangerous. BPA leeches into food from plastic containers.
To reduce your exposure to BPA and other chemicals in plastic, Dr. Mercola gives the following advice: use only glass baby bottles, dishes, and cups; buy fabric toys instead of plastic ones; store food in glass containers; don't microwave plastic; don't buy canned foods; don't use plastic wrap;
and avoid water in plastic bottles.
You probably even have carcinogens in your antiperspirant deodorant. Aluminum-based ingredients and parabens may mimic estrogen and increase the risk of cancer. Cancer researcher Philippa Darbre, PhD, of the University of Reading, says evidence is mounting that the aluminum-based active ingredient in antiperspirants can mimic estrogen in the body.
"Lifetime exposure to estrogen is the risk factor which is tied most strongly to breast cancer," says Dr. Darbre. "I stopped using these products eight years ago." The Naturally Fresh Deodorant Crystal is free of toxins and carcinogens. One customer says, "I started using this after my mom got breast cancer."
To be on the safe side, avoid all known carcinogens and suspected carcinogens whenever possible.
Cancer Prevention: Healthy Lifestyle Choices
You can also decrease your cancer risk by making healthy lifestyle choices. Medical experts report that two-thirds of all cancers are preventable; that is, they're related to tobacco use, excess weight, poor diet, and lack of exercise. In fact, the University of Texas MD Anderson Cancer Center reports that only five to ten percent of cancers are truly hereditary.
Smoking is the most preventable cause of cancer, responsible for 87% of all lung cancer cases and 30% of all cancer deaths. Alcohol consumption increases the risk of cancer, too. While some studies show that moderate alcohol consumption may be good for the heart, alcohol is linked to cancers of the colon, breast, and liver. In terms of diet, sugar feeds cancer; avoid sugar whenever possible; eat plenty of fresh fruits and vegetables; and make sure that you're getting enough
omega-3 fatty acids from natural sources or supplements.
Poor sleep habits and high stress levels weaken your immune system and may increase the risk of cancer. Opt for healthy sleep with hypoallergenic and orthopedic mattresses like
Finally, you should avoid getting sun-burned, but you should not avoid sunlight altogether! In recent years, there has been much confusion about the role of the sun in causing cancer. Sunlight is the source of life; it's good for you - but not in excess. Exposure to sunlight produces vitamin D in the body, and evidence suggests that low vitamin D levels may contribute to the development of cancer.
Cancer and allergies are both diseases of modernity that continue to increase in prevalence, but you can keep yourself healthy by taking care of yourself, enhancing your immune system with a healthy diet and exercise, and avoiding harmful substances in your environment.
Originally published in the
September 2007 issue of
Allergy Consumer Report.
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