More Reasons Not to Eat Red Meat
In Michigan, we savor our summers. Maybe this is because the summer months consist of our only three months of warm weather. Nothing is more exciting than the heralding of another warm summer. This may sound funny, but I know that summer is here when my nose has experienced three things: The smell of fresh cut grass, sunscreen lotion on my kids and, finally, meat on the grill. While I don't exactly fancy myself a carnivore, I do enjoy the occasional flesh source of protein on my plate. And, at special times, this includes red meat. So, it is with a bit of self-conviction that I offer a fresh take on the negative health consequences of eating red meat.
As virtually everyone is aware, red meat is high in cholesterol and saturated fat. It still holds that increases in cholesterol pose a risk for plaque build-up in the coronary arteries leading to heart attacks. This still holds true. Other ills related to red meat consumption have emerged, however. And these findings hit at the two biggest killers of Americans: heart disease and cancer.
Red Meat and Cancer Risk
Studies have shown consistently over the past couple of decades that there is a link between red meat consumption and colon cancer. Curing of meat products such as hot dogs, bologna, lunch meats, ham, and bacon further increases the risk. More recently, a dose-dependent correlation was found in this risk relationship. A well-done (no pun intended) study found that daily consumption of 50 grams per day of red meat increased colon cancer risk by 21%, and when consumption increased to 100 grams per day, the risk increased to 29%.
Science has been working toward refining this link, understanding why red meat products are more risky. The jury is still out, however. Red meat does contain more fat, protein, and iron, so perhaps this simple dose relation increases risk. The heme component of iron (this is what makes red meat red) has been shown to enhance production of N-nitroso compounds in cells. Theoretically, these substances can promote mutations leading to cancer. Processed red meats contain higher amounts of nitrites and sodium, causing some to speculate a causal relationship. Finally, the hydrocarbons found in the char produced with grilling have been implicated. But, while these substances have been shown to be carcinogenic, side-by-side comparisons with grilled poultry consumption have not shown risk. To date, nothing has been isolated among these possible culprits.
Colon cancer is not the only cancer associated with red meat consumption. An analysis showed an association with prostate cancer rates with increased consumption of processed red meat cooked at high temperatures. Similarly, increased risk was also seen for cancer in the esophagus, kidneys, lung, and bladder. No association was found with pancreatic, breast, and uterine cancers.
Non-Cholesterol Related Increases in Heart Disease Risk
Recent studies have made associations with coronary artery (heart) disease beyond cholesterol. These surround a substance called trimethylamine-N-oxide (TMAO), which is known to promote atherosclerosis (hardening of the arteries). These studies have shown that a compound prevalent in red meat called carnatine. Bacteria in the intestinal tract have been shown in these studies to metabolize carnatine to a precursor of TMAO, which is absorbed into the blood and then converted to TMAO.
While some small scale studies are available which do strengthen the association between carnatine consumption and heart disease, more conclusive, large-scale analysis is needed. This research does enhance the notion, however, that red meat consumption in regular, higher quantities is bad for the heart.
While too much of most things is a bad thing, it appears that more and more reasons are emerging to curb our regular consumption of red meat. While research is strengthening the association between red meat consumption and cancer, the latest studies are finding previously unknown causal factors in heart disease. More research is needed on the carnatine connection to heart disease and its association with how the bacteria in our intestinal tract. For the carnivorous optimists out there, however, science may develop and enhance preparation techniques or digestive augmentation to eliminate this risk. Until this time, maybe it's best to throw some chicken or fish on the grill instead.
Live, and live well!