Updated: Nov 12, 2020
Meats of all kinds tend to be the major source of protein for people in the western part of the world. There are few things to mention here about protein before looking at different meats. People in general are consuming too much protein. High protein intake, especially animal protein, increases the risk for various diseases and earlier death. Switching from animal based protein to plant protein sources has been shown to reduce the risk for chronic diseases and mortality.
When we look at societies around the world where people live the longest and have low disease rates like the Blue Zones and even Mediterranean region, people don't consume high amounts of protein and these societies are all plant-based, be it exclusively plant-based or predominantly where more than 90% of calories come from plant-based foods. The major protein source for people in these regions tend to be beans, lentils, tofu, chickpeas, whole grains, nuts, seeds and vegetables. Those that do consume meats consume it in very small quantities and quite infrequently.
Research funded by the NIH showed that people who ate protein mostly from plant sources were 27% less likely to die of any cause and 29% less likely to die from heart disease. Furthermore, researchers discussed that replacing just 5% of calories from animal protein to plant protein could decrease risk for dying from any cause including heart disease by 50% and replacing only 2% of calories from processed meat protein to plant protein to be associated with a 32% reduced risk of death. Furthermore, red meat, poultry and processed meat have all been found to increase your risk for cardiovascular disease, according to a study published in JAMA Internal Medicine.
One can find individual studies pointing towards the health benefits of eating meat due to its protein content and certain nutrients. There are three important things to consider here.
Protein is originally made in plants and one can get ample protein and all the essential nutrients eating a plant-based diet without consuming meat.
Meat doesn't just have protein. It has other compounds as well that can be detrimental to health, such as saturated fat, cholesterol, heme-iron (highly inflammatory), L-Carnitine (which converts to TMAO in your body) and more.
Animal protein itself also increases risk for insulin resistance, ageing, IGF-1 stimulation which can induce cancer growth, and increases higher acidic load to your kidneys due to different amino acid profile compared to plant protein.
When looking at if something is healthy, always look at "compared to what".
Compared to processed meat, red meat is healthy. Compared to red meat, chicken is healthy. Compared to chicken, fish is healthy. Now compared to any animal sources of protein, plant protein sources have been shown to be much healthier. So if one does choose to consume meat, it is important to limit it significantly and get most of protein requirements met from plant sources. Plant sources of protein provide fiber, vitamins, minerals, antioxidants, phytochemicals alongside meeting your protein requirements.
Red meats include beef, lamb, mutton, pork, veal, venison, and goat.
World Health Organization declared red meat as group 2A carcinogen.
WHO discusses that the association has been found mainly in colorectal cancer but that it also has been found for other cancers like pancreatic and prostate cancers. Red meat increases risks for various diseases and overall mortality. A study published in the British Medical Journal tracking diets of over half a million participants found the intake of red and processed meats have also been associated with higher mortality from all causes, along with cancer and diseases of the digestive, circulatory and respiratory systems. Increased consumption of red meat has also been significantly associated with increased C-reactive protein (a response to inflammation and a biomarker for diseases such as cancer and heart disease), HA1c (diabetes risk indicator), and stored iron (iron in excess is associated with diabetes, cancer and heart disease).
A review published in the Journal of Internal Medicine looked at potential health hazard of eating unprocessed red meat and processed red meat. They found consumption of unprocessed red meat was found to increase risk for diabetes, coronary heart disease, heart failure, death from heart disease, stroke, breast cancer, colorectal cancer and advanced prostate cancer. They also found consumption of processed red meat to increase risk for several chronic diseases, such as diabetes, death from heart disease, colorectal cancer, pancreatic cancer, cancer mortality and total mortality.
Red meats also increase risk for chronic kidney disease. Study published in the Journal of Renal Nutrition found people who consumed the most red and processed meat to have increased risk of chronic kidney disease by 73% and 99%, respectively when compared with those who consumed these the least. Substituting just one serving of either with plant-based protein was found to lower disease risk by up to 30%. This could be due to various benefits of replacing animal protein with plant protein such as higher intake of nutrients that help improve kidney function, lower dietary acid load and decreased intake of AGEs (advanced glycation end products).
Furthermore to adverse health effects of consumption of processed meats mentioned above, The World Health Organization declared processed meats to be type 1 carcinogen. Processed meats include meats that have gone through salting, curing, fermentation, smoking or other processes that enhance flavour or preservation. These meats can contain pork, beef, other red meat, poultry, offal or even meat by-products. Common examples include hot dogs, bacon, sausages, ham, chicken nuggets, beef jerky, canned meat and meat based sauces.
The World Cancer and the American Institute for Cancer Research (AIRC) have also declared that "the evidence on processed meat and cancer is clear-cut. The data show that no level of intake can confidently be associated with a lack of risk."
Processed meat doesn't only increase colorectal cancer risk, but also for breast cancer, prostate cancer, pancreatic cancer and overall cancer mortality. Consumption of processed meat also increases risk of cardiovascular disease and death from cardiovascular disease.
There is no safe amount of consumption of processed meats.
Chicken is often recommended as a healthier protein choice. Once again, it is important to consider, "compared to what". Compared to red meat, chicken is a better alternative. Now comparing to a plant protein like chickpeas, there's no competition. Chicken is high in saturated fat and have cholesterol while lacking fiber, antioxidants, and phytochemicals. As discussed, plant protein reduces risks for many diseases and overall mortality in comparison to animal protein.
Often red meat is touted to increase cholesterol levels and heart disease risk and chicken is recommended as an alternative. A randomized control trial comparing red meat, white meat and nonmeat protein sources found red meat and white meat equally to significantly raise LDL ("bad") cholesterol.
Findings support favoring nonmeat protein sources and that white meat to be no better than red meat when it comes to cardiovascular disease risk.
Chicken is also one of the major sources of sodium and in the age group 20-50, it is the number one source of sodium. Along with additives, salt is generally injected into chicken meat to increase the weight as it's sold by the pound and when you inject sodium, it sucks in water. Excess sodium is the number one dietary risk factor for death worldwide as it increases risk for heart disease, high blood pressure as well as kidney disease.
Fish is generally considered a healthier animal protein option due to its high omega-3 content. As discussed here, we do not however need fish to get enough omega-3 fatty acids. Now the question is if one is getting enough omega-3 from plant sources, does adding fish make our diet even healthier? The truth is we don't know.
Studies looking at 100% plant-based whole food diet have found it to be one of the healthiest dietary patterns and have been associated with the lowest risks certain cancers, type 2 diabetes, cardiovascular disease and obesity. What we don't know is if adding fish to a healthy whole food plant-based diet would add any further benefits as that requires further research.
Generally speaking, when people consume fish, they switch from other animal protein options like red meat, processed meat or poultry. This will most certainly lead to better health outcomes, which is a probable explanation of the benefits associated with fish. Now if a person switches from fish to a plant protein source such as beans, that will definitely benefit their health further.
The benefits shown of fish consumption are most probably not due to fish consumption itself but rather what it is replacing in one's diet.
One aspect not discussed enough is the pollutants in the ocean which contaminate the fish. The contaminants in fish include heavy metals (e.g. mercury) and pollutants such as dioxins and PCB's. Fish are also contaminated with microplastic particles and microplastics are a source of BPA, a potentially toxic chemical and known endocrine disrupter. Although we don't have enough research showing the effects of contaminated fish on health, we do have research showing it's best to avoid these individual pollutants and toxins for better health. PCB's have been associated with increased risk for type 2 diabetes and obesity and environmental toxins have been implicated for cancer.
We also have to consider the sustainability factor of eating fish considering 90% of global have been overfished or fished at capacity.
Asking people to switch from other types of meats to fish is simply not a sustainable option. Overfishing is leading to ocean habitats being damaged and reducing natural biodiversity with possible irreversible long term consequences for planetary health. Furthermore, fish farming is causing pollution and environmental damage. Due to the conditions farmed fish are raised in, their nutritional content are also adversely affected as farmed fish can have a higher fat content, especially saturated fat and omega-6 fatty acids while having lower omega-3 fatty acids.
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