You know the drill: Would you like your steak rare, medium rare, medium, medium well, or well-done? Most would argue that your choice in this case is a matter of personal preference. Do you enjoy the taste of blood? Do you like your beef rouge, pale pink, or brown?
Although scientists have long warned about the carcinogens associated with grilled meat and fish, little has been truly established in terms of an exact cause-and-effect relationship between eating charred hamburgers and being diagnosed with cancer. (However, numerous studies have linked cancer in lab animals with consumption of grilled meat due to its high levels of known carcinogenic compounds called heterocyclic amines and polycyclic aromatic hydrocarbons.)
And it's not just the grill itself that's amping up the danger in your ribeye—it's the "doneness." A 1999 study tied well-done meat to a higher incidence of colorectal cancer, and a 2010 review confirmed its link with other cancers as well. But enough about our colons; what about our brains?
A study from New York's Icahn School of Medicine at Mount Sinai published in the Proceedings of the National Academy of Sciences has even worse news for those who like their beef blackened. Apparently, a diet high in glycotoxins—found in high-concentration in well-done meat—is a risk factor in developing age-related dementia. Quick—grab a Post-it and write down where your keys are now.
OK, not right now. But if you're chowing down on brown-to-the-core burgers for lunch every day and are trying to keep your wits about you as long as possible in late life, it might be worth rethinking.
In the study, mice were who were on a diet high in glycotoxins called Advanced Glycation End products, or AGES, were found to have significantly higher likelihood of developing dementia-like symptoms. They also had greater levels of amyloid beta proteins—the basis of "brain plaque" in Alzheimer's patients—in their brains.
The second part of the study followed the eating habits, insulin levels, and cognitive function of 93 people over the age of 60 living in New York over the course of nine months. Researchers tested the quantity of AGEs in their blood as well as their consumption of foods high in glycotoxins. The results: the subjects with the highest blood levels of glycotoxins had more pronounced symptoms of cognitive decline.
Because this was such a small-scale study in a concentrated region, further evidence is needed before drawing strong conclusions on what methods of cooking and eating meat are the most harmful on a whole.
But with a growing body of evidence pointing towards the negative health effects of grilled, smoked, and well-done meats, it may be advisable—at the very least—to learn to love your steak medium-rare.