In the last 24 hours #FreeBacon has taken over social media.
Why?
A brief report published in The Lancet on Monday by the World Health Organization (WHO) International Agency for Research on Cancer (IARC) summarized the latest IARC Monograph, volume 114. The topic of this new volume: red and processed meat.
should you give up your bacon?
(get the summary report from The Lancet here..free article if you enter your email address)
As with a lot of new research and guidelines, the media has taken this lengthy report and turned it into a few shocking titles to attract, and scare, readers and viewers: "Hot dogs, bacon, processed meat linked to cancer"- USA Today and "Meat is linked to higher cancer risk..." - NYTimes
But what is the science behind this report? Should we be worried? Should we stop our daily bacon habit?
IARC
The IARC is an interdisciplinary group of scientists who evaluate the carcinogenicity (cancer causing ability) of everything from tobacco smoke, to chemicals, to pollution. They assign a risk classification and publish info in a Monograph, most are available on their website.
Before we get into the details lets talk about their classifications:
- Group 1- Carcinogenic to humans
- Group 2A- Probably carcinogenic to humans
- Group 2B- Possibly carcinogenic to humans
- Group 3- Not classifiable as to its carcinogenicity to humans
- Group 4- Probably not carcinogenic to humans.
On their website they explain how they examine research and determine the appropriate classification in their Preamble. They state that their classifications refer ONLY to the strength of evidence that an exposure to a substance is carcinogenic and NOT the extent, or potency, of its cancer causing activity.
What does this mean? If there are enough research studies that positively link a certain substance to cancer then a Group 1 classification is given. The classification does not quantify the amount of exposure to the substance that would lead to cancer, only that they are associated with each other. For a Group 2 classification, a substance may have a few studies that show association with cancer, but a few that do not. Again, the IARC stress that this classification is not meant to quantify the how much.
How did meat measure up?
Processed meat, encompassing salted, cured, fermented, smoked, preserved meats, received a Group 1 classification. Red meat received a Group 2A classification.
It sounds scary...but based on the IARC's own definitions for criteria for classifications should we be? And should we really be using this information to make diet recommendations?
The answer: NO!
The Lancet summary outlines more information on the types of studies examined by these scientists, it included mostly epidemiological studies. Epidemiologic studies are used to understand and discover patterns in health and disease. In particular, the report states that the committee considered studies to be the best if they separated processed and red meat data and used validated food questionnaires.
From a nutrition and dietetics research standpoint, epidemiological studies offer little in terms of use for diet recommendations. Why? Because as the definition states, they are meant to discover patterns, they are not cause and effect. It is difficult to accurately portray dietary habits through a questionnaire, and it is known that on food intake frequency questionnaires responses are directly related to how many foods are listed. For example, if I fill out a food frequency questionnaire on a list of 500 foods and my sister fills out a questionnaire with a list of 200 foods, it will seem that I eat more than her simply because I had more options to select, when in fact we eat the same amount.
Phew... still with me? Sorry for the research terms but it's important!
For processed meat, 12 of 18 studies (of different types) found that intake was associated with cancer. They found that intake of 50g per day can increase colorectal cancer risk by 18%.
For red meat, 14 of 29 different types of studies found an association with cancer.
Now what?
Remember, these Monographs are not meant to make direct diet recommendations. Their FAQs help explain more. Also remember that the studies analyzed were mostly epidemiological. For red meat, just as many studies showed no association with cancer, as showed association. This suggests confounding factors, bias, and a lot more research to be done. A lot of other research is out there, too, including THIS very recent (May 2015) meta-analysis that found no dose-response between red meat and colorectal cancer and a weak association at best.
Should you change what you eat?
Meat is full of protein, natural fat, B vitamins, iron, and zinc, it is a real food. Red meat is an excellent protein choice in your diet, if you are a meat eater, please don't give that up.
Seriously, can't imagine never eating this again...
But is processed meat "bad" for you? Yes, too much of it is! Don't get crazy about this (2 slices of bacon is about 50 g, as the study suggests), but eating too much of any processed food is bad for you. When it comes to eating processed meats such as bacon, sausage, and lunch meats, choose nitrate/nitrite free varieties. Nitrates form carcinogenic compounds in the body and this has been shown and studied in animals and humans. Buying uncured, nitrate free bacon gives you a processed meat option you can enjoy without guilt, or fear. I like Applegate Farm's brand, Nature's Promise Brand (Giant and Stop & Shop line), Trader Joe's, anything at Whole foods, Oscar Meyer Uncured line. Again, just look out for the words "uncured" and "nitrate free." Remember, the term "natural" means nothing. If the word nitrate or nitrite is in the ingredient list then pass, or enjoy once in a while. If cured processed meat is preferred, or more economical, then try to avoid daily intake.
Although I highly recommend uncured and nitrate free bacon, I would rather you eat half of a pack of cured bacon every morning than eat a giant bowl of cereal every morning. Obesity and diabetes are the chronic diseases that plague our country and don't show any signs of letting up. They lead to cardiovascular disease and kidney disease. What is the driving force? Sugar. Sugar is also the preferred fuel for cancer cells. So put things in perspective, focus on eating a balanced meal with protein, fat, and carbohydrates, and avoid processed foods as much as possible.
Eat real food.
P.S. If you live in the Baltimore area be on the lookout for info about my first every TV spot this Saturday, LIVE where I will be talking about this meat confusion!
