To Beef Or Not To Beef
Beef has been an important part of the bodybuilder’s diet for decades, due to the fact that it’s loaded with muscle-building protein while also being a rich source of vitamins and minerals that are important for muscle growth. Some of these include the B vitamins, which provide energy for training by facilitating the conversion of food into energy1 and minerals such as zinc, which promotes testosterone production.2 While these qualities are impressive, there’s also been a long-standing perception that eating steak, hamburger and other red meat boosts the risk for certain diseases.
Is L-carnitine the Reason That Red Meat Causes Heart Disease?
A recent study8 showed that the compound L-carnitine, found abundantly in red meat, may cause heart disease. According to this work, eating red meat provides L-carnitine to bacteria that live in the human gut. These bacteria break down L-carnitine and turn it into a compound called trimethylamine-N-oxide (TMAO), that has been shown to cause atherosclerosis.9 But even more interesting, subjects that typically consumed meat were found to produce significantly higher levels of TMAO than vegetarians after consuming L-carnitine. This suggests that a diet loaded with red meat favors the growth of gut bacteria that convert L-carnitine into TMAO, promoting heart disease.
This study doesn’t conclusively demonstrate that red meat consumption causes cardiovascular disease. So you probably don’t need to immediately stop eating red meat, as there are still some contradictions. For one, TMAO is also found in foods that lower the risk of heart disease10 such as seafood and soybeans, making these results a little bit less persuasive. To further complicate matters, a study published by Dinicolantonio et al.11 indicates that supplements of L-carnitine may actually help heart attack survivors by preventing premature death.
Beef Protein Is Readily Absorbed by the Body for Greater Muscle Growth
Beef is loaded with protein, as approximately 100 grams of beef contains 30 grams of high-quality protein. This protein is also readily absorbed by the body— meaning most of what you consume will be utilized for muscle protein synthesis and muscle growth. Furthermore, beef not only helps younger individuals build muscle, but can it also prevent muscle loss in older people.12 As you age, your body has a harder time synthesizing protein quickly enough to keep up with muscle loss, even if you’re lifting weights. Beef contains copious amounts of essential and branched-chain amino acids that most potently activate mTOR-driven muscle hypertrophy, while preventing muscle atrophy. Therefore, when consumed in large-enough portions, beef protein can counteract age-related muscle breakdown while boosting muscle growth in younger individuals.
Beef Is Loaded With Muscle-Building Compounds
One of the most powerful anabolic components in beef is conjugated linoleic acid (CLA). CLA is a mixture of polyunsaturated fatty acids derived from the omega-6 essential fatty acid linoleic acid. CLA’s major anabolic property comes from its ability to augment testosterone production13 while preventing the conversion of testosterone into estrogen by inhibiting the aromatase enzyme.14 In addition, beef is particularly effective at increasing muscle growth and strength because it has higher creatine content than most foods. This relatively high creatine content in beef enhances muscle growth by increasing the muscle cell’s energy or ATP levels, allowing longer periods of training that ultimately drive greater muscle growth. In addition to creatine’s primary function as an energy source, creatine has also been shown to stimulate muscle cell formation15 and muscle growth by triggering the production of muscle proteins such as myosin.16 More recently, however17, creatine consumption was also shown to cause a decrease in the muscle-depleting molecule myostatin, leading to significant muscle growth.
Red Wine to the Rescue
The previous study by Koeth et al.8 suggests that decreasing beef consumption should be beneficial to your health by reducing levels of unhealthy bacteria that trigger cardiovascular disease. Interestingly, prebiotic compounds in red wine, which are molecules in food that regulate bacteria in the digestive system, were shown in another study18 to also reduce the number of unhealthy bacteria. Since red wine consumption has been shown to decrease cardiovascular disease risk19, perhaps the capacity of red wine to remove certain bacteria also improves heart health. In order to investigate this18, 10 middle-aged male subjects were randomly given either red wine or placebo for 20 days. Red wine consumption was able to reduce the levels of non-beneficial bacteria and potentiate the growth of good bacteria such as bifidobacteria, which would most certainly promote a healthier heart. These results suggest that the continued consumption of beef with the right combination of prebiotics should be good for muscle growth and your overall health.
Conclusion
It appears that red meat has been inappropriately labeled as unhealthy based on its relatively high fat content and propensity to generate unhealthy intestinal bacteria. However, while there are many types of beef, like processed meat, that are high in fat and other molecules that may cause disease, there are also plenty of lean choices of red meat available that are much healthier. In addition, while red meat may negatively influence intestinal bacteria, it is still unknown whether this promotes heart disease.
For most of Michael Rudolph’s career he has been engrossed in the exercise world as either an athlete (he played college football at Hofstra University), personal trainer or as a Research Scientist (he earned a B.Sc. in Exercise Science at Hofstra University and a Ph.D. in Biochemistry and Molecular Biology from Stony Brook University). After earning his Ph.D., Michael investigated the molecular biology of exercise as a fellow at Harvard Medical School and Columbia University for over eight years. That research contributed seminally to understanding the function of the incredibly important cellular energy sensor AMPK— leading to numerous publications in peer-reviewed journals including the journal Nature. Michael is currently a scientist working at the New York Structural Biology Center doing contract work for the Department of Defense on a project involving national security.