vegeMeat cancer prevention is at the top of our menu today. This is a follow-up to last week’s post (Bacon Cancer) which discussed the cancer hazards of eating meat. This blog is focused specifically on how we can minimize our risk, while still deriving the enjoyment and nutritional benefits of eating meat.
This blog contains a lot of detail – if you just want the practical advice, skip forward to the Summary section near the end.
Meat Cancer Prevention: Guardian Angels
Last week we labeled the harmful elements in meat as evil spirits trying to do us harm. If there are evil spirits in our food, are there also guardian angels to defeat them?
Most concern about bacon cancer and other meat cancers has been focused on finding the foods, additives and cooking methods that have the least cancer-causing effect. However, research has also uncovered evidence that some foods may help block the bad effects of food carcinogens. What little evidence exists comes from epidemiological studies of people, plus biochemical research on animals.
Here are the potentially protective foods that can help meat cancer prevention:
– Fiber. Fiber derived from eating fruits and vegetables is considered to be a “protective factor” for meat cancer prevention. Conversely, people who consume low amounts of fiber seem to have an increased risk of contracting cancer by consuming meat.
– Chlorophyll. The chlorophyll from vegetables also appears to counter the risk of meat-caused colon cancer.
– Calcium. Calcium seems to suppress cancer caused by both red meat and processed meat when consumed at the same time as the meat. Calcium helps precipitate heme within the large intestine so that it does not promote tumor growth by converting to nitrosamines. However, not all forms of calcium are equal: calcium carbonate suppresses cancer, while calcium phosphate does not.
– Coffee. Drinking coffee may have a weak effect in suppressing various forms of cancer, including cancer of the digestive tract. However, the case is far from being proven.
This website has previously cited health benefits from coffee, alcohol and berries. However, it’s wise to drink in moderation. Too much alcohol may itself cause cancer, or may weaken the body’s ability to fight it.
Meat Cancer Prevention: False Angels
Many other foods have been studied in hopes of finding still more, and more effective, approaches to meat cancer prevention. The following hoped-for saviors are still unproven:
– Antioxidants and olive oil, taken either separately or together, have given inconsistent anti-cancer results in various studies.
– Eating fish or poultry, as noted above, has shown a weak cancer-preventive effect in some studies but not in others.
– Ascorbates (vitamin C) are added during meat processing to reduce the formation of nitrosamines, therefore researchers have looked to see whether vitamin C could also block nitrosamine production in the digestive tract. Unfortunately, the chemistry of ascorbic acid is very complex and in the presence of fat, vitamin C may actually increase nitrosamine formation. I conclude that we can’t yet be sure whether vitamin C fights cancer or encourages it, when consumed along with meat.
Meat Cancer Prevention: You Must Eat the Good Stuff at the Same Meal!
At least in the case of fiber and calcium, the cancer-fighting benefit comes from suppressing chemical reactions during digestion that would otherwise convert healthy foods into cancerous chemicals.
For the most effective meat cancer prevention, it’s important to eat your fruits and vegetables during the same meal. Because it takes a couple of hours to empty the stomach after eating, this ensures that the guardian angels will be well mixed with the evil spirits, as both undergo digestion.
When you eat healthy foods to fight Alzheimers, heart disease and other maladies, it doesn’t matter when you eat them. Such foods, if they are effective, act only after they are digested and enter the bloodstream. So long as they are absorbed properly into the blood, your body doesn’t care when you consume them.
However, cancer of the digestive system is different: since the bad chemical reactions happen within your body during digestion, you need the good stuff to be present at the same time. A fruit salad at lunch followed by a gigantic steak at dinner will do you no good at all. Instead, you need to put both foods into your body during the same meal.
Meat Cancer Prevention: Exorcising the Evil Spirits
A careful reader will have noted that although meat, especially processed meat, is a strong cause of cancer, the guardian angels to counteract it are relatively weak and ineffective. However, there are steps that anyone can take to attenuate the evil spirits, so that our bodies, with the help of the “angel foods,” can gain the benefits of a meat diet while fending off cancer.
Here are some important ways to exorcise those bad actors.
Buy Uncured Meat. You should be suspicious of the word “natural” on a packaged food because there is no legal definition of what “natural” means. However, the concept of “natural” food, meaning food that has undergone minimal processing, is definitely sound.
One way you can ward off digestive cancer is to replace the processed meats in your diet with meats without additional nitrate or nitrite. Try to buy “uncured” meats – read the label and make sure that it has no added nitrate or nitrite. Uncured bacon is readily available at grocery stores. If you are diligent, you can also find uncured hot dogs, lunch meat and sausages. Many markets carry the Applegate Farms brand; Trader Joe’s also carries uncured meats under its own label, including full-sized hams. Uncured meats are also for sale online.
Note that the label “uncured” on a meat for sale in the United States is a USDA designation meaning that it has not been preserved using added nitrates and nitrites. It does not mean that the meat is raw. If the meat has been preserved by other means, such as with salt and spices, it is safe to eat as is unless the package instructions specify that it requires cooking.
Uncured meats are just as tasty and a lot healthier for you – however, they generally have a shorter shelf life. Usually you should eat or freeze them within a week after opening the package. Nola and I buy uncured bacon and freeze the slices in plastic freezer bags, using parchment paper to separate individual slices. We can easily remove however many slices we need for a recipe, and they cook just as easily as non-frozen bacon.
Another tasty yet natural form of processed meat is prosciutto. However, be sure to read the label: you want the ingredients to be pork and salt – nothing more. Traditional prosciutto is preserved by salt and does not require nitrates or nitrites for proper shelf life.
Cook Safely. This blog has previously discussed ways to barbecue meat more safely by the use of marinades and smart cooking. A useful research article by Alaejos and Afonso compiles a number of recommendations to reduce carcinogens in cooked meat, which I present here in slightly edited form:
– Choose lean cuts. Apply lower temperatures and shorter cooking times.
– Grill or pan fry only at low temperature (less than 180 Celsius = 350 Fahrenheit).
– Turn food frequently during cooking.
– Avoid direct contact of meat and fish with a naked gas flame or charcoal.
– Do not let meat drippings dry out before making gravy.
– Avoid browning of foods or, at least, remove the crust and charred parts of fried or grilled meat, poultry, and fish.
– Cook meat and fish in aluminum foil to reduce charring.
– Remove the skin from barbecued chicken.
– Rather than grilling, use other cooking techniques: boil or poach fish; stew beef; or microwave either.
– Before grilling, precook meat in an oven or microwave to reduce time on the grill.
– Use marinades that contain little or, preferably, no sugar; if you want a sugared barbecue sauce, add it only after cooking.
– Cook meat and fish together with foods containing phenolic antioxidants such as tomatoes, carrots and other vegetables. Kebabs, anyone?
Choose Lower-Heme Meats. All meat contains blood, and blood contains heme. Heme is valuable since it’s a good source of iron, an essential nutrient. However, if you are not iron-deficient, then it’s a good idea to choose meats with less heme, since heme is partly converted to carcinogens during digestion.
Note that if you are concerned about not getting enough iron, there are plenty of non-meat sources of iron:
– Vegetables, notably beans, peas and spinach, are good sources of iron. However, vegetable iron is two times less readily absorbed by the body. Therefore vegetarians are advised to consume twice as much iron from food as non-vegetarians.
– Fish, especially shellfish and sardines, are another non-meat source of iron. Although the iron in fish is often classed as heme iron, it is biologically quite different from iron in mammal meats. Fish rely on hemocyanin to transport oxygen to their tissues, which differs from hemoglobin by having copper atoms rather than iron atoms. I can find no literature associating the iron in seafood with an increased risk of cancer, and in fact there are a few studies that show consuming fish as protective against cancer.
Nevertheless, let’s assume that you are not ready to give up animal meat, but would still like to reduce your risk of disease. Once you stop buying meats with nitrates added and cook your meat more safely, meat cancer prevention may be simply a matter of eating more low-heme meat and less high-heme meat. The sources I consulted give differing numbers for the heme content of meat. They are usually within twenty percent of each other, although in a few cases I found values that are a factor of two apart. Absolute accuracy is not to be expected, because heme content varies with cut of meat, cooking method and degree of doneness, and perhaps other factors.
In any case, here are my estimated heme values for various common animal meats, in micrograms of heme per gram of meat:
This list offers some surprises. I was startled to see “dark meat” poultry (chicken thigh and duck meat) ranking above bacon, and pork and veal so low on the list. It may not be a joke to refer to pork and veal as the “other white meat.” They are lighter in color because they contain less heme, and that means that they are almost as noncarcinogenic as the blandest, whitest breast of chicken.
Although the most lurid news headlines have featured cancer from bacon, bacon ranks pretty low on this list – provided that it is uncured bacon and that it is not overcooked. If an average serving is two ounces (two slices) of bacon and four ounces of chicken, then a serving of bacon contains about the same heme as a serving of chicken breast. Bacon cancer, get thee behind me!
In any case, here are my takeaways from this list:
– Liver and other organ meats should be only a rare treat;
– Try to eat more fish, pork and chicken (and veal, if your personal preferences allow it); and
– Eat fewer hamburgers and steaks.
Summary – Meat Cancer Prevention
Here are the key points from the discussion above: you can help prevent cancer from eating meat by taking some or all of the following steps:
– At the same meal that you eat meat, consume some “guardian angels”: fruit or vegetables, and calcium (from milk or supplements);
– If you buy processed meat (hot dogs, bacon, ham, sausage, lunchmeat), buy the type labeled “uncured” and check the label to make sure that it contains no added nitrates or nitrites;
– Cook safely by using nonsugary marinades and cooking at lower temperatures; if you want to grill or barbecue, shorten the time on the fire by pre-cooking the meat in oven or microwave;
– Eat more fish, chicken, pork and veal; eat fewer hamburgers and steaks.
As mentioned at the beginning of the previous blog on Bacon Cancer, cancer is exceedingly complicated and there is a great deal that we simply do not know about why it occurs and how to prevent it. However, it makes sense to use the limited knowledge that scientists have amassed to make thoughtful choices about the foods we buy, cook and eat.
If you keep meat cancer prevention in mind at the grocery store and in restaurants, you can make healthier choices while still enjoying the pleasure of good food.
– Developing a Heme Iron Database for Meats According to Meat Type, Cooking Method and Doneness Level
– Dietary Sources of Iron
– Iron Content of Duck
– Iron, table of values per serving
– Meat that Contains High Iron
– Nutrition Comparison of Veal & Pork
– Selected Food Sources of Iron
– Top 10 Foods Highest in Iron