Diet and Cancer - Help Us Help You!
by Laura B. LaValle, R.D., L.D. and Katherine Wight, R.D, L.D.
Do any of you remember a few years ago when Pepsi Cola introduced a product called Pepsi Free? This product was cola flavored but not cola colored. Perhaps the Pepsi Cola company had an inkling back then that there might be potential risks involved with caramel coloring, or perhaps it was just in response to what was happening at the time where some of the red and yellow food dyes were ordered off the market by the FDA . In general, since food dyes had been a problem, it seems they saw reason with the logic that since food dyes don’t do anything other than turn a food into an artificial color, why consume them?
But it didn’t matter because people had been so conditioned to their cola being brown; Pepsi Free flopped and was dropped by the company. Maybe this time, if consumers are properly educated on the risks of caramel coloring, they will do the right thing and learn to accept products that taste the same but just look different. In other words, support food manufacturers when they are trying to help you!
We have always maintained that eating healthy comes down to two things – trying to reduce your intake of the things that are bad for you and trying to eat as many foods that contain health-promoting nutrients and phytonutrients as you can. That’s not always as easy as it sounds, we know, especially with all the attention grabbing diet headlines that pull us back and forth so much sometimes we don’t know what to do. In reality there are some pretty simple but powerful ways to lower cancer risk. One recommendation in particular not only lowers cancer risk, it helps reduce risk of diabetes and heart disease as well. That is good news for many of you. You only have to be willing to do it.
Diet and Cancer: Sorting It Out
Attention grabbing headlines linking diet with cancer tend to be divided into two camps: the substances that promote cancer (environmental chemicals, food additives, diseases and drugs) and those that protect against cancer (foods, phytochemicals, antioxidants). We’ll discuss three main areas of diet that are strongly correlated with increasing cancer risk – sugar, some meats and some food additives. Caramel coloring is an example of the latter. So what is the story?
Animal tests found that two chemicals in caramel coloring are linked with several types of cancer in rats and mice[i]. Because of this the nonprofit group The Center for Science in the Public Interest (CSPI) is calling for the US Food and Drug Administration (FDA) to ban artificial caramel coloring used in soft drinks and other foods. They are also arguing that the labeling phrase “caramel coloring” is misleading when describing caramel color because it is made with chemicals like ammonia or sulfite. So at the very least they are calling for more accurate labeling names such as “ammonia process caramel” or “ammonia sulfite process caramel.” At the end of the day their position is ‘why gamble on colorings that only serve a cosmetic function in the food supply?’
We couldn’t agree more, but because the cancer findings are from animal studies, it is very difficult to assess how much risk it actually poses for humans. Why take any risk is the CSPI’s point and that point is well taken, but if you really loved soft drinks, would that be enough to make you stop drinking them? Well what if we told you there were other more powerful reasons to think about giving up soda?
Refined Sugars and Flours
What if we told you in addition to containing carcinogens, soda consumption can increase cancer risk significantly by increasing glucose and insulin levels, and this assertion is based on human studies looking at large numbers of people. High glycemic index foods such as soft drinks increase the body’s production of insulin. Over time the body can start to become resistant to the insulin and therefore blood glucose levels start to elevate. This process leads to weight gain (especially around the waist), elevated cholesterols, high blood pressure and these increase risks for heart attacks and strokes among other things, like diabetes. And diabetes increases a person’s risk for a variety of cancers including breast, hepatic, colorectal, and pancreatic cancer.
Many people don’t realize how crucial it is to keep a close eye on their blood sugar levels. A groundbreaking study found that for every 1 point your fasting blood sugar increases beyond 84mg/dL your risk for type 2 diabetes increases by 6%[ii]. This means that if your fasting blood sugar is 98 mg/dL you have an 84% greater risk of developing type 2 diabetes. (That is just below the official number for pre-diabetes, which is 100 – 125 mg/dL).
So how does high blood sugar lead to increased cancer risk? Some scientists think that it could be from chronically elevated insulin itself, which increases inflammation in the body. Others think it’s because it causes a growth factor called IGF to increase. IGF promotes survival and progression of cancer cells and decreases destruction of cancer cells[iii].
Even diet soft drinks have been found to raise risk of diabetes by 67% in people who drink even one or more soft drinks daily[iv]. We don’t need the empty calories from high fructose corn syrup in regular soda, or the 67% greater relative risk of incident type 2 diabetes from diet versions. So caramel coloring or not, any soft drink will increase health risks.
The evidence is getting so damning against soft drinks, they should almost carry a black box warning: “Contains chemicals and ingredients than can cause cancer.” To that we would add “Can cause obesity and diabetes as well.” So, kick this one bad dietary habit and you go a long way to helping reduce many health risks.
By the way, it is not just soft drinks, but high intake of any high- glycemic index foods that has been found in many studies to increase risk of Type 2 diabetes[v], which is most frequently caused by insulin resistance, which also increases risk of some cancers, especially breast cancer[vi]. Some people may have argued that that is because being insulin resistant can cause weight gain, another factor that increases cancer risks. One study found that insulin resistance increased risk of breast cancer, completely independently of body weight[vii]. Yet another study looked to see what food intake was most strongly associated with increased breast cancer risk. Was it animal protein? Fat? Nope - it was intake of sweets. The more sugary and high glycemic index foods eaten, the higher the risk[viii].
Bottom line - it is extremely important to reduce intake of high glycemic index and glycemic load foods, like refined sugars and flours in soft drinks, candies, desserts, baked goods, white breads and pasta and cereals. The best way to do this is to center your meals on low glycemic index foods like vegetables and healthy proteins and fats. While generally healthy, we have found that fruits and whole grains can even raise blood sugar and insulin in some people, so we would add eat fruits and whole grains, only in amounts that allow you to keep your weight and blood sugar well controlled.
Meat Additives and Cooking Meat
Studies on meats and cancer risk have not been consistent. Maybe that is due to a couple of variables like whether the meats you eat contain additives or not or how you cook your meat. Did you read the headline in August 2010 about the link between intake of processed meats and increased risk for bladder cancer[ix]? Sodium nitrite and nitrate are added to processed meats like hot dogs, sausage, bacon, and deli meats in order to preserve the pink coloring we associate with freshness as well as offer some anti-microbial protection (prolonging shelf life). Nitrites and nitrates were the substances that were linked to increased risk of bladder cancer. Specifically, people with the highest consumption of nitrite/nitrate-containing meats had a 30% increased risk of bladder cancer over those with lower intake of these meats.
Heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) are formed when meats are exposed to high temperatures and cooked well done or charred. There is very strong evidence linking these substances with increased cancer risk in humans. One study found that for those who prefer very well done steak, there was a 70% higher risk of pancreatic cancer in those with the highest consumption[x]. So, we recommend learning to cook meats at lower temperature and to avoid overcooking and charring meats. At LMI we favor lean grass-fed meats because they are higher in omega 3 fats that fight inflammation and are much lower in saturated fat and cholesterol than conventional meats. Grass-fed meats need to be cooked at lower temperatures or they get tough, so it’s a good way to force yourself to cook your meat at lower temperatures. We also recommend avoiding high intake of processed meats, unless they are the no-nitrite and no-nitrate -added varieties, which are available.
What Can You Eat?
Is it any surprise that food colorings, preservatives and additives in our diet are linked with increased risk of cancers? But sweets and a well-done steak? We often hear the complaint, “Is there anything left to eat?” The answer is a resounding yes. The trick seems to be to emphasize whole unprocessed foods, sometimes called Grandparent foods, because they are foods that made up the diets of our ancestors. Case in point, although meats with nitrites and nitrates are linked with cancer, the association was not found with non- processed meats, even red meats such as beef, pork and lamb[xi]. Science has also struggled to find a concrete connection between healthy dietary fat intake and increased cancer risk[xii]. That is good news for anyone. When you add the whole list of foods that are known to contain substances that actively fight cancer, there are many foods to add to your “Allowed” list.
First of all, fruits and vegetable consumption in general have been found to lower risks. People who ate the least fruits and vegetables were found to be twice as likely to develop cancer compared to those who ate the most fruits and vegetables[xiii].
The following is a list of foods with anti-cancer compounds or nutrients: avocado, broccoli, broccoli sprouts, cabbage and any other cruciferous vegetable, onions, garlic, berries, curcumin, garlic, grapes, green tea, flax seeds, nuts and seeds, dark leafy greens and tomato products. Real food. No abbreviations or unpronounceable chemical terms. Surely you have seen some of these headlines. For example, brightly colored fruits and berries such as blueberries and pomegranate juice have been in the news a lot lately. These foods are high in flavonoids a group of compounds that interfere with inflammation and carcinogenesis (the spread of cancer), and quench free radicals with their significant antioxidative actions[xiv]. The science is easily applicable to our Metabolic Code Diet recommendations because dehydrated berry powders as well as very small quantities of 100% fruit juice can be used without contributing a heavy sugar load to the diet[xv]. Even a compound in cocoa has now been found to fight cancer[xvi].
Diet and Cancer – How to Make it Easy.
Remember it is your overall dietary pattern that is important. Occasional sweets are probably well tolerated if the diet on the whole is healthy. On the other hand, a typical Western diet that is high in well-done red meat, processed meats, sweets and desserts, French fries, and refined grains is associated with increased risk of not just cancer, but heart disease, diabetes and even depression, while diets that include a lot of plant foods reduce risk of several cancers.
So, eat mostly Grandparent foods a.k.a. whole foods. Avoid artificial colorings, additives, and sweeteners. Decrease your amount of refined sugars and flours in the diet to control blood sugar and insulin levels. Trade in your soda can for real beverages: water, coffee, tea, red wine and a couple of ounces of high polyphenolic fruit juice daily. Don’t overcook or char meats. Eat plenty of vegetables and some fruit. Enjoy low sugar dark chocolate. (And if that still sounds too overwhelming, seek out a registered dietitian for help!)
[ii] JAMA June 2008;121(6):519-524.
[iii] Pharmacotherapy. 2010;30(11): 1159-1178
[iv] Diabetes Care. 2009. Apr;32(4):688-94.Epub 2009 Jan 16.
[vi] Cust A, et al. J Breast Ca Res and Treatment, July 2008.
[vii] Bruning P et al. International J of Ca 52 (4): 511-16.
[ix] Processed Meat Linked to Increased Risk for Bladder Cancer. Cancer. Published online August 2, 2010.
[x] American Association for Cancer Research (2009, April 22). Charred Meat May Increase Risk Of Pancreatic Cancer. ScienceDaily.
[xi] Micha R, Wallace SK, and Mozaffarian D. Red and processed meat consumption and risk of incidence coronary heart disease, stroke and diabetes mellitus. A systematic review and meta-analysis. Circulation 2010
[xii] Intake of dietary fats and colorectal cancer risk: Prospective findings from the UK Dietary Cohort Consortium
Dahm C., Keogh R., et al. Cancer Epidemiology. October 2010 (Vol. 34, Issue 5, Pages 562-567)
[xiii] Block G., Patterson B., Subar A. Fruit, vegetables, and cancer prevention: a review of the epidemiological evidence. Nutr. Cancer, 18: 1-29, 1992.
[xiv] Abrams D, Weil A. Integrative Oncology. Oxford University Press, Inc; 2009. Page 124.
[xv] Fresh Raspberry Phytochemical Extracts Inhibit hepatic lesion in Wistar rat model. Liu Y, Liu M., et. Al. Nutr. Metab (Lon). 2010. Nov 25; 7:84.