It’s fascinating that our gut is home to trillions of bacteria that influence many aspects and functions of our daily lives. Our gut microbiome is a key player in our overall system influencing digestion, cardiovascular processes, and even the skin. Research is shedding light on how various diets influence our gut microbiota and whether the change is beneficial or detrimental to our health. With the growing interest in plant-based diets, we begin to wonder: what is the science behind meat intake? How does meat specifically influence our gut microbiota and what are the resulting effects it has on our body?
Meat is a staple in many common diets due to its higher levels of dietary protein and fat content. Meat comprises of several categories: red meat (beef, lamb, goat, bison), poultry (chicken and turkey), pork, and seafood. Breaking down meat into its macronutrient contents, most meats contain higher levels of dietary protein and fats. To better understand the effects of meat on our gut microbiome, we also need to know the effects of dietary protein and fats on the microbiome.
Protein and Gut Microbiome
Dietary proteins is an essential macronutrient as your body uses protein to build and repair tissues. Our bodies also use protein to make enzymes, hormones, and other body chemicals. Protein is also an important building block of bones, muscles, cartilage, skin, and blood. With consumption of animal-based proteins, counts of bile-tolerant anaerobes such as Bacteroides, Alistipes, and Bilophila were noted to increase. Similarly, a high protein/low carbohydrate diet has been linked to reduced Roseburia and Eubacterium rectale in their gut microbiota and a decreased proportion of butyrate in their feces. The animal-based protein influence on these bacteria results in an increase of trimethylamine-N-oxide (TMAO), a proatherogenic compound that increases the risk of cardiovascular disease and a decrease in short-chain fatty acids (SCFA), which is commonly linked to inflammatory processes such as inflammatory bowel disease (IBD).
Fat and Gut Microbiome
Dietary fats are not just a source of energy; they function as structural building blocks of the body, carry fat-soluble vitamins, are involved in vital physiological processes in the body, and are indispensable for a number of important biological functions including growth and development. Intake of a high-fat diet increases total anaerobic microflora and counts of Bacteroides while decreasing levels of Lactobacillus intestinalis. This change in the balance of our gut microbes affects our resistance of insulin, a key player in our skin physiology. Impaired insulin resistance can lead to troubling skin diseases such as acne and psoriasis, with many other diseases still being studied and linked.
Breakdown of Protein & Fat
Depending on your preference of protein, whether it be red meat, white meat, or seafood, they all vary in composition of protein and fat. Also, the method in which you cook your protein can affect the protein and fat content of your food. Understanding your choice of protein, the type of cut, and method of cooking allows you to narrow in on the protein and fat content of your meals.
The method of cooking affects the protein and fat content per serving because water content decreases and nutrients become more concentrated during cooking. For example, a raw steak may provide 24g of protein per 100g, but a cooked steak may be 30g of protein per 100g due to less water content meaning less weight.
There are many different cuts of meat and depending on what body part the meat comes from, it can vary in protein and fat content. Generally, raw red meats (beef, lamb) provide 20-25g of protein and depending on the leanness can vary from 10g-20g of fat per 100g serving. Raw white meat (chicken, turkey) provide 19-24g of protein and anywhere from 0.8g-1.0g of fat from chicken breast to 9.3g of fat from turkey drumsticks with skin. Raw seafood (fish, shrimp) provide 20-24g of protein and vary greatly from 0.5g of fat per 100g in shrimp to 6.3g of fat per 100g in salmon. For more specific data on varying proteins, check out this link.
Meat Effects on the Skin
Meat, composed of fats and dietary proteins, changes the levels of microbial species within the gut microbiota. How does that affect our skin? The gut and skin are more closely related than they seem! Our gut’s purpose is to absorb nutrients from foods that we digest; these nutrients contribute to stimulating processes benefiting our skin. For example, our gut absorbs amino acids from meat that play a role in restoring skin collagen synthesis. Western diets, popular for their animal-based foods, relate to increased risk of inflammation, cardiovascular disease, diabetes, and obesity. Also, eating plenty of meat in a diet increases insulin-like growth factor-1 (IGF-1), which may make an individual more susceptible to acne and inflammation.