Sometimes medical studies don't just uncover new health-related facts - they also serve
as useful reminders. One that does just that appeared in the August 2 online edition of the medical journal Cancer. In this study, researchers found that additives in processed meats - including nitrites, heterocyclic amines (HCAs), and polycyclic aromatic hydrocarbons (PAHs) - can contribute to bladder cancer.
In the study, researchers followed the study participants – approximately 300,000 men and women aged 50-71 years – for seven years and tallied the results of the dietary questionnaires they completed. They found 854 people diagnosed with bladder cancer, with those who had the most nitrite in their diets – from all sources including meat – and those with the highest intake of nitrate plus nitrite from meats, had a 28-29% increased risk of developing bladder cancer, compared to those with the lowest intakes.
The association of processed meats - including bacon, and a slew of luncheon meats - commonly called "cold cuts" – with cancer is not new. There have been earlier studies that found similar links. For example:
In the study, researchers followed the study participants – approximately 300,000 men and women aged 50-71 years – for seven years and tallied the results of the dietary questionnaires they completed. They found 854 people diagnosed with bladder cancer, with those who had the most nitrite in their diets – from all sources including meat – and those with the highest intake of nitrate plus nitrite from meats, had a 28-29% increased risk of developing bladder cancer, compared to those with the lowest intakes.
The association of processed meats - including bacon, and a slew of luncheon meats - commonly called "cold cuts" – with cancer is not new. There have been earlier studies that found similar links. For example:
- Earlier this year, the Journal of Family Health Care published recommendations on dietary aspects of cancer prevention from the World Cancer Research Fund International in London. After an expert panel reviewed the evidence, which they graded "convincing" or "probable", they produced a series of 10 recommendations to reduce the risk of developing cancer. High on the list included consuming a diet high in plant-based foods, and avoiding processed meats and salty foods.
- A study appearing in the March 7, 2006 issue of the NCI Cancer Bulletin, involving more than a half million men and women in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, found a significant association between a type of gastric (stomach) cancer and processed meat consumption.
- A 2005 study appearing in the June 6, 2006 issue of the Journal of the National Cancer Institute found a link between processed meats and pancreatic cancer.
By the way, there is another food choice mentioned in these other studies as potentially dangerous, and at the risk of inciting cattlemen, it's the kind of food that goes "moo"; red meat. Besides processed meats, the three studies I listed above also point to a causal relationship between red meat and various cancers. In fact, regular consumption of red meat has been linked with cancers of the lung, breast esophagus, larynx, stomach, kidney, endometrium, ovaries and prostate.
So what are these dangerous compounds in meat?
Nitrites and nitrates are members of a class of chemicals known as nitrosamines which are added to food as a preservative and to enhance the appearance of the products. These foods include sausage, hot dogs, bacon, lunch meat, and canned meats and soups. They have long been shown to be harmful to both humans and animals. Nearly all processed meats are made with sodium nitrite - a proven precursor to highly carcinogenic nitrosamines. When consumers eat processed, cured meat products, nitrosamines are formed in the body that, research shows, can promote the growth of various cancers. This should not be confused with the naturally-occurring nitrates found in fruits and vegetables, which are NOT harmful.
Heterocyclic amines (HCAs) are the carcinogenic chemicals formed from the cooking of muscle meats including beef, pork and fowl. HCAs form when amino acids - the building blocks of proteins - and creatine, a chemical found in muscles, react at high cooking temperatures. Researchers have identified 17 different HCAs resulting from the cooking of muscle meats that may pose human cancer risk. One study, by researchers from NCI's Division of Cancer Epidemiology and Genetics, discovered a link between individuals with stomach cancer and the consumption of cooked meats.
The researchers found that those who cooked beef medium-well or well-done had more than three times the risk of stomach cancer than those who cooked meat rare or medium-rare. They also found that people who ate beef four or more times a week had more than twice the risk of stomach cancer than those who ate beef less frequently. Other studies have found an increased risk of developing colorectal, pancreatic, and breast cancer with high intakes of well-done, fried, or barbecued meats.
Polycyclic aromatic hydrocarbons (PAHs) are a group of over 100 different chemicals that are formed during the incomplete burning of coal, oil and gas, garbage, or organic substances like charbroiled meat. PAHs can also be formed during the curing and processing of raw food prior to cooking.
Dr. Block’s Tips
At the Block Center, a key component of our integrative program is anti-cancer, or “Life Over Cancer,” nutrition. Though each treatment plan is tailored to the needs of each patient, nutrition plays a key role whether a patient is fighting metastatic disease, wanting to prevent a recurrence, or is interested in disease prevention. We strongly recommend patients eliminate red meat and get their protein from plant-based sources such as lentils, chickpeas, tofu, tempeh, veggie burgers and wheat-gluten products such as seitan. However, if someone is going to eat red meat, we suggest limiting portion size. 3 ounces is considered one serving (about the size of a deck of cards). Look for lean, grass-fed organic sources of animal protein. Better substitutes for red meat might include: lean wild game such as venison, ostrich and buffalo, turkey burgers, eggs fortified with omega-3, and, the very best animal food choice, cold water omega-3 rich fish.
Please consider that wheat gluten is highly inflammatory and many of us become ill when using it. With so many other options for people, Seitan might not be the best idea. It is thought that one out of every 6 of us has a degree of gluten intolerance, cuasing internal inflammation, a precursosr to cancer, Those with the genetic intolerance, i.e. celiac dx, are at greater risk of lymphoma and possible other cancers.
Thanks for the great blog and the wonderful research that finally includes nutrition!
Posted by: Kristine Noonan | 10/06/2010 at 10:40 AM