Is there a healthy way to eat meat?
You have seen the packages of low-fat bologna or hot dogs in the grocery aisles. The food industry has long altered the content of fats and other nutrients in meats, dairy, and eggs to promote them as healthy choices. To date, manufacturers of such products have not been permitted to label these foods as “healthy” but that may change soon. Under a proposed rule, USDA-inspected products will be able to use the word “healthy” on labeling and advertising if their fat content consists mostly of mono- or polyunsaturated fats, as opposed to saturated fat. This labeling would apply even if the total fat content is higher than what FDA guidelines allow.
Can meat that is altered to be high in mono- and polyunsaturated fats really serve as a healthy choice? If we focus on eating meat and the reactions it causes, it is quite clear that whatever the fat content, meat is not a healthy choice. Here are nine reasons why this is true that go beyond fat alone.
Elevations of hs-CRP predict the development of serious illness including cardiovascular disease. Multiple studies have found that, even after correcting for confounding factors, meat consumption associates with increased hs-CRP. A recent basic science study performed in mice demonstrated that an amino acid found in high levels in meat, methionine, increased oxidative stress and inflammation and actually reduced heart strength too. A human study just published related meat intake to higher levels of arachidonic acid, another mediator that promotes inflammation and aging, and a diet low or absent in meat was recommended for optimal health.
Another route by which cellular aging may progress is the development of insulin resistance. Scientists looked at how eating certain foods affects the release of insulin. Surprisingly, some protein-rich and fat-rich meats induced as much insulin secretion as did some carbohydrate-rich foods (e.g., beef was equal to brown rice). The researchers found that fish, beef, cheese, and eggs had larger insulin responses per gram than many carbohydrate foods. The scientific fact that meat is insulinogenic is rarely mentioned and may contribute to aging.
IGF-1 is a peptide hormone stimulating cell growth. It’s also linked to higher risk of breast and prostate cancers. Meat eaters consistently have higher levels of IGF-1 than vegetarians or vegans. Breast and prostate cancers are rare in traditional Asian communities, which have a very low intake of meat products. Okinawans, some of the longest-living people on the planet, eat a diet with less than 10 percent of their daily calories from meat. A plant-based fasting-mimicking diet has been shown to reduce levels of IGF-1, which has an anti-aging effect.
In 2011, researchers from the Cleveland Clinic demonstrated that meat eaters produced a metabolite that promotes heart disease, called TMAO. Of great interest, TMAO was not elevated in vegans who were asked to eat a meat meal for the purposes of the study. Egg yolks cause the same reaction. In my clinic, I routinely measure levels of TMAO, and my patients eating meat and egg yolks on a regular basis have elevated measurements. I worry they are aging prematurely and counsel them to substitute beans for beef and chickpeas for eggs.
POPs are toxic synthetic chemicals that accumulate in fat. Some of the POPs are PCBs, dioxins, DDT, and flame retardants used in clothing and furniture. They disrupt endocrine pathways and are linked to cancer, heart disease, hypertension, obesity, and diabetes. POPs enter our body largely from animal products that we eat. For example, levels of PCBs in animal fat found in meat is much higher than the levels found in vegetables, fruits, and cereals.
AGEs are naturally occurring compounds in food and can be increased by cooking on dry heat, such as on a grill. AGEs are associated with a variety of diseases including brain inflammation, diabetes, heart disease, and cancer. Levels of AGEs found in meat are many multiples higher than in any fruit or vegetable. The irony of the chemical term AGE is not to be missed as increased levels of AGEs lead to premature aging and are best avoided by skipping the meat entirely.
Recently, a bizarre addition to the tale of meat and inflammation has been described and a tick is to blame. New data exists that the bite of the lone star tick, quite common in certain areas like Virginia, can cause an antibody to form that reacts to a carbohydrate in meat (yes there are carbohydrates in meat from the blood groups in the flesh) called alpha-gal.
These antibodies can cause a severe allergic reaction the next time and every time red meat is eaten after the antibody forms. In an even newer research study, over 25 percent of heart patients tested had the antibody for alpha-gal, a component of red meat, and those that had the antibody had more advanced heart disease than those that did not have the antibody.
Although studies have linked the consumption of animal foods in general, and red meat in particular, with heart disease in humans, we are still learning new pathways. One new route to develop damaged heart arteries was described in detail in a new animal research study. In most species, a compound called Neu5Ac is produced and converted by an enzyme to Neu5Gc which can be found on blood vessels and other tissues. It turns out that humans lost the enzyme and therefore cannot produce Neu5Gc.
Red meat is rich in Neu5Gc. In this new study, an animal model was created that mimicked humans, unable to convert the A to the G version of the compound. When the lab animals were then fed a diet rich in Neu5Gc and fats (like meat), they developed 2.4 times the atherosclerosis of arteries of the control animals. This elegant science indicates that another biological pathway makes humans poorly suited to depend on red meat for nourishment.
Methionine is an essential amino acid found in animal and plant foods, but it exists in much higher concentrations in red meat, pork, poultry, fish, and eggs compared with plant foods. A theory that a low methionine diet (plant strong) may slow aging and improve insulin responsiveness has been proposed. Researchers at Duke University studied two models of cancer in mice fed on an average and a low methionine diet.
They reported that there were differences in the “one carbon metabolism” and cancer growth and responsiveness to therapy was enhanced by the low methionine diet. They then showed in healthy human volunteers that eating a low methionine diet for three weeks produced the same changes in “one carbon metabolism” as the mice. The easiest way to achieve a lower methionine intake is to limit or eliminate animal foods on the plate.
Based on the multiple ways in which animal foods, particularly red meat, initiate adverse reactions that are far from healthy, labelling meat that has a reduced saturated fat content may be and advance, but it is a long way from earning labelling as a healthy food choice.
Dr. Joel Kahn is Professor of Cardiology, Summa cum Laude grad, Kahn Center for Longevity and GreenSpace & Go, author, “The Plant Based Solution.” www.drjoelkahn.com @drjkahn.
This post was last modified on June 27, 2021 12:54 pm