B INFORMED:

TOXINS AND CANCER RISKS

Alyson Mandel March 10, 2019

Don’t be Scared, Be Informed

Dr. Pallav Mehta presented convincing data and shared his incredible knowledge about carcinogenic risks in our food and environment at another successful wellness workshop at Balance this week. Dr. Mehta emphasized that we should not let the increasing information about cancer risks in our food and environment paralyze us with fear but rather we should use emerging evidence to better inform the decisions we make about the food we eat and lifestyles we lead.

An important study published in Nature in 2015 showed that 70-90% of cancer diagnoses can be linked to extrinsic factors (Substantial contribution of extrinsic risk factors to cancer development, Song Wu et al., Nature volume 529, pages 43–47, 07 January 2016, published online December 2015). This finding directly contradicted earlier research that cancer was a result of “bad luck” and it motivated a new attention to the link between extrinsic factors and cancer. The most common example given is the now clear relationship between smoking and lung cancer. The study also cited significant epidemiological evidence. For example, “an analysis of immigrants who moved from countries with low cancer incidence to those with high cancer incidence revealed these individuals quickly acquired a higher cancer risk” (https://www.medicalnewstoday.com/articles/304230.php).

Know your Terms

Being an informed consumer of data and food means understanding the central concepts involved. Dr. Mehta provided us with clear definitions of health, toxin, and cancer to help navigate increasing information about their relationships.

Health. The World Health Organization defines health as the "state of complete physical, mental, and social well being, and not merely the absence of disease or infirmity”. (https://www.who.int). Given his focus on integrative medicine, Dr Mehta takes a “whole patient” approach that incorporates all facets of a patient’s life, not just their disease. As a result, he focuses on the nutrition, physical activity and emotional health of his patients recently diagnosed with cancer. His book, After Cancer Care, offers evidence based guidelines and suggestions for achieving healthier patterns in each of these facets.

Toxin. In addition to nutrition, activity and emotional health, Dr. Mehta also addresses the often overlooked topic of toxins, and avoiding toxins in our food and environment (see Chapter 7). Toxins are defined as, “substances that are ingested or inhaled or that we otherwise come in contact with that can cause degenerative diseases to develop or intensify” (After Cancer Care, p.92). Dr. Mehta also used the word “poison” in his definition of “toxin”. He stated that “the dose makes the poison” as any substance in high enough quantities over a long enough time exposure can become harmful.

Cancer. Cancer, in Dr. Mehta’s words, is “caused by a genetic mutation that makes a cell immortal” thus allowing it to engage in abnormal cell growth. So all cancer is genetic but we also need to understand the extrinsic factors that may increase the likelihood of that initial mutation. When talking about extrinsic links to cancer, Dr. Mehta was very clear in explaining that when a person is diagnosed with cancer it is not necessarily because of a specific behavior. The cell mutation that led to their cancer may also have been the result of exposure to a toxin, perhaps during utero or during the course of their life, of which they were completely unaware. Being informed of these relationships can hopefully reduce exposure to potential toxins and ultimately reduce cancer risk.

Proceed with Caution

Before delving into the evidence concerning toxins and cancer, Dr. Mehta reminded us that we have to be informed consumers not only of the food we eat but of the scientific evidence and “facts” we digest. Dr. Mehta began his talk with a list of cautions. A few examples include:

Be wary of fake crises invented especially when they are accompanied by easy fixes
Remember that simply being able to measure the level of a substance doesn’t mean we know the value of that information or what to do with it
Be wary of specialty or fad diets, liver cleanses, detoxes (FYI, Dr. Mehta does not approve of the term “detox”). Review the medical evidence to support claims before following their protocols.
Remember that any research result can be word-smithed to support a certain point of view. Dr. Mehta provided us with a list of “findings” concerning the dangers associated with cruciferous vegetables (think broccoli, brussel sprouts, cauliflower). Each “finding” sounded very scientific, convincing, and terrifying, e.g. broccoli is full of formaldehyde. Dr. Mehta assured us they each statement was either completely false or misleading - e.g. formaldehyde occurs naturally in many foods in low doses, humans naturally produce formaldehyde and it is essential for certain biological functions. It only poses a risk at high doses not naturally occurring (such as in manufacturing).

Review the Data

One way to access information concerning environmental toxins is by accessing the databases of several international agencies - including the World Health Organization (WHO) and the International Agency for Research on Cancer (IARC), as well as organizations within the US such as the EPA, American Cancer Society and the National Cancer Institute.

Dr. Mehta explained that the IARC categorizes all chemicals into 4 groups according to their direct link to cancer. Group 1 category consists of known carcinogens, such as processed meats (e.g. bacon), tobacco, tamoxifen, alcohol and tanning beds. Dr. Mehta emphasized, however, that these categorizations are not based on risk level, only on the evidence of a direct link with cancer. So, there is evidence showing a direct link between bacon and cancer (bummer!) but the risk of eating bacon is not as great as smoking tobacco. Keeping that in mind, you can review the extensive database at the IARC site - https://www.iarc.fr/.

There are several important acts that have been adopted to help consolidate and regulate information about the different health risks of environmental toxins. The United States passed the Toxic Substance Control Act (TSCA) in 1976 to regulate new and already existing chemicals. Unfortunately it grandfathered in thousands of already existing chemicals without any testing, rendering it “toothless” - to borrow Dr Mehta’s term. Furthermore, it depends on a chemical’s manufacturer to supply relevant safety information. https://www.epa.gov/laws-regulations/summary-toxic-substances-control-act

In 2007, the European Union enacted the REACH Act to “improve the protection of human health and the environment from the risks that can be posed by chemicals” https://echa.europa.eu/regulations/reach/understanding-reach. In contrast to the TSCA, REACH requires companies to provide information about the quantity of substances included in products and, furthermore, to show evidence that the substance does not have a negative impact on humans. Dr. Mehta agreed that the European Union has definitely done a better job of regulating potentially carcinogenic substances by using a “precautionary principle”. Following this principle basically means if a substance might be dangerous, don’t use it until it is tested and there is no evidence of a harmful relationship. For example, the EU passed a Cosmetics Directive in 2003 banning 1328 chemicals in cosmetic products. Comparatively, the US has only banned 11 chemicals (that is not a typo, it is actually only 11).

Specific Toxins and the Data

Food Toxins

GMO. Genetically Modified Organisms are modified to have certain traits, such as being resistant to herbicides. Farmers can spray a GMO crop with herbicide and only the weeds will be eliminated. However, there is wide variability in the extent to which a crop absorbs the herbicide. There is increasing, and very recent, evidence showing a link between glyphosate (the chemical found in the herbicide RoundUp) and cancer. Glyphosate is a Category 2A substance - probable human carcinogen. Although there has been ongoing debate about its link to cancer, a study published just this year provided evidence that high levels of exposure to glyphosate increases cancer risk by 41% for non Hodgkins Lymphoma (https://www.sciencedaily.com/releases/2019/02/190214093359.htm). The findings came from an analysis of preexisting data - a meta analysis (i.e. no new empirical data was gathered) which showed a consistent relationship between glyphosate based herbicides and this type of lymphoma. Dr. Mehta specifically referenced this new data. Here are a few of his suggestions for avoiding toxins resulting from herbicides:

Eat Organic. Here is the USDA definition of the label organic: Organic food is produced by farmers who emphasize the use of renewable resources and the conservation of soil and water to enhance environmental quality for future generations. Organic meat, poultry, eggs, and dairy products come from animals that are given no antibiotics or growth hormones. Organic food is produced without using most conventional pesticides; fertilizers made with synthetic ingredients or sewage sludge; bioengineering; or ionizing radiation. https://www.nal.usda.gov/afsic/organic-productionorganic-food-information-access-tools

A recent study published in the Journal of American Medical Association found that “a higher frequency of consumption of organic food was associated with a reduced risk of cancer” https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2707948. In keeping with the theme of being a critical consumer of research, it is important to point out that this study was predominantly female, relatively young and that organic consumption was measured by self report. These are all potential limitations to the study and thus these findings need to be replicated. However, the results are significant because they are the first to directly link organic food consumption and reduced cancer risk.

If Organic is not an option, then Avoid the Dirty Dozen. Each year the Environmental Working Group (EWG) publishes a list of produce that contained the highest level of pesticide residue (or the most number of different pesticides) of those items tested. You can find this list at https://www.ewg.org/foodnews/dirty-dozen.php

The 2018 list looked like this::

Strawberries
Spinach
Nectarines
Apples
Grapes
Peaches
Cherries
Pears
Tomatoes
Celery
Potatoes
Sweet bell peppers
Hot peppers*

2. Acrylamide and Food Preparation. Interestingly, certain types of food preparation, such as frying, can create toxic chemicals in foods, such as potatoes. Dr. Mehta explained the mechanisms that make fried starchy foods a cancer risk. Acrylamide is a Category 2A carcinogen (same as Round Up). It forms naturally when foods high in starch, such as potatoes, are fried. It is not the potato itself, but the way in which it is cooked that creates the cancer risk. Equally fascinating (at least to me) was that Dr. Mehta suggested a few concrete, easy steps that can help minimize the production of Acrylamide - such as washing potatoes before frying and storing potatoes in the refrigerator.

2. Red Meat. The IARC has classified red meat as a Category 1 carcinogen (https://health.clevelandclinic.org/link-red-meat-cancer-need-know/). There are two different mechanisms linking the consumption of red meat with an increased cancer risk. First, all red meat contains a chemical (Neu5gc) that our bodies instinctively recognize as foreign matter and consequently, our antibodies attack. It is this process that can lead to increased inflammation and increased cancer risk associated with the consumption of red meat.

Second, the way in which red meat is often prepared can increase its potential as a carcinogenic risk. Two compounds (HCAs and PAHs) are created when red meat is cooked at high temperatures. Both of these compounds have been found to be “mutagenic” - meaning they can cause DNA mutations and are thus considered a carcinogenic risk. They are particularly found in the smoke that results from the meat fat dripping on the grill. Dr. Mehta suggested leaving the grill open when cooking red meat and not charring the meat (just don’t have Bobby Flay over to dinner when you do this). https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cooked-meats-fact-sheet.

Research, such as a report published in The Lancet Oncology, has most often linked the consumption of both processed meats and red meat to colorectal or colon cancer (https://doi.org/10.1016/S1470-2045(15)00444-1.

Dr. Mehta recommended limiting red meat consumption to 12 oz per week for men and 8 oz per week for women.

3. Fish. The biggest carcinogenic risk associated with the consumption of fish is Mercury. Dr. Mehta explained that mercury is in our air, gets into the ocean water through rain, and then algae converts this mercury into methylmercury which sinks to the ocean floor. As a result, guidelines suggest the avoidance of eating bottom feeder fish (e.g. catfish, flounder). Furthermore, due to bioaccumulation along the food chain, Dr. Mehta recommended avoiding the consumption of large fish (e.g. swordfish and tuna), since mercury can build up at each step along the food chain.

Dr. Mehta also emphasized the benefits of eating fish as part of a healthy diet. Fish, such as salmon, is high in Omega 3 which is an extremely important fatty acid associated with many health benefits, including reduced cardiovascular and cancer risk.

4. Sugar. Dr. Mehta debunked the myth that sugar “feeds” cancer. It does not. The consumption of sugar is not directly linked to cancer risks. However, there are secondary pathways that “ might create an environment where cancer evolution is more likely to occur” https://integrativeonc.org/news/research-blog/205-does-sugar-feed-cancer.

Dr. Mehta explained that sugar intake can lead to a spike in insulin and the hormone IGF-1 (insulin related growth factor). Some studies with animals have found IGF-1 receptors on cancer cells. In addition, studies conducted with humans who have Laron’s Syndrome, a rare condition in which there is a total absence of IGF-1 in the body, have found an almost zero incidence of cancer. These findings have lead to the hypothesis that IGF-1 might promote the proliferation of cancer cells. It is important to remember that IGF-1 is an essential hormone in our bodies and helps regulate normal growth development. However, research does suggest that elevated levels of IGF-1 might make it more likely for cancer cells to grow.

In addition, the link between sugar intake and obesity has been well substantiated and provides an additional way in which sugar may be linked to increased cancer risk.

5. Other Food Related risks Dr. Mehta went through many other potential toxins in our food and environment which I will quickly summarize:

artificial sweeteners - not considered a risk anymore
dairy - casein in dairy also causes a rise in IGF-1 and is associated with increased cancer risks. Dr. Mehta referenced The China Study published in 2004 which first showed a link between animal protein and elevated cancer risks. Again, children especially need dairy in their diets, precisely because of its influence on IGF-1 which is important for normal growth. However, Dr. Mehta recommended a single daily serving of dairy for adults.
radon - definitely test for levels of Radon in your house if you have not already (this is usually done during the sale of a house). Unfortunately, Pennsylvania has the highest level of radon of all 50 states. Dr. Mehta mentioned Radon.com as a resource for more information (https://www.radon.com/)

Household Toxins

Dr. Mehta primarily focussed on food toxins in his talk but he did address both cosmetic and other environmental risks as well. Air pollution is a Category 1 carcinogen according to the IARC. India and China have the most number of cities with the poorest air quality which means that a significant portion of the earth’s population is living in a carcinogenic environment.

Here are some of Dr. Mehta’s suggestions to minimizing toxins in your home and environment:

Use a hepa filter
Remove shoes inside your home
Keep air circulating in your house (crack a window)
Use only BPA and BPH free plastics or glass/ceramic containers
Get rid of toxic cleaning supplies.
- I liked Dr. Mehta’s metric for determining if a cleaning product is toxic. If any label on it says Danger or Poison it is very toxic, if it says Warning it is moderately toxic, and if it says Caution is slightly toxic. Try to use a product that doesn’t have any of these label.
Get rid of nonstick pans
Get rid of vinyl shower curtains

Take A Balanced Approach

I particularly appreciated Dr. Mehta’s balanced approach to making these difficult decisions as we maneuver through our lives. I dreaded going to the grocery store the morning after attending Dr. Mehta’s talk but I actually left the store feeling confident about the decisions I made based on the knowledge his talk had provided (it wasn’t easy but I did forego the bacon).

At the conclusion of Dr. Mehta’s talk, Amy Carolla, Balance owner, asked him for the most important things we could do to minimize our exposure to toxins or to reduce cancer risks. Here was his response:

“Include cruciferous vegetables in your diet and choose products from companies that do good work”

This advice feels very accessible and provides a good framework with which to navigate through the increasing, and often scary, evidence about the toxins that exist in the food we eat and in our environment. Having this information shouldn’t make us fearful, it should help us feel empowered to make the healthiest choices available to us. “Quality of life matters”, Dr. Mehta explained, so you should be able to enjoy a meal and enjoy your life. Words to live by.

Pallav Mehta, MD, is Director of Integrative Oncology and Director of Practice Development at the MD Anderson Cancer Center at Cooper in Camden, New Jersey. He is a medical oncologist/hematologist with expertise and interest in breast cancer and integrative oncology and is board certified in oncology, hematology and integrative medicine. He is a member of Living Beyond Breast Cancer’s Board of Directors. He is co-author of After Cancer Care: The Definitive Self-Care Guide to Getting and Staying Well for Patients After Care.

Resources

After Cancer Care: The Definitive Self-Care Guide to Getting and Staying Well for Patients after Cancer. Gerald Lemole, Pallav Mehta, et al., 2015.

Copies of Dr Mehta’s book are available at Balance.

Substantial contribution of extrinsic risk factors to cancer development, Song Wu et al., Nature volume 529, pages 43–47, 07 January 2016, published online December 2015.

International Agency for the Research of Cancer website https://www.iarc.fr/

The World Health Organization: https://www.who.int

Environmental Protection Agency. https://www.epa.gov/laws-regulations/summary-toxic-substances-control-act

Environmental Working Group website with “Dirty Dozen list” https://www.ewg.org/foodnews/dirty-dozen.php

Study of Glyphosate (Round Up) and its link to cancer https://www.sciencedaily.com/releases/2019/02/190214093359.htm

Organic food consumption and cancer risks study https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2707948.

National Cancer Institute - information about meat and cancer link

https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cooked-meats-fact-sheet