In-Vitro Meat

 Healthy Aspects of Natural Meat 

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Why Did Humans Start Eating Meat?

There is no explicit explanation of why meat-eating became an integral part of human history and evolution. Early human ancestors relied on hunting as their main source of protein and energy, and in turn the development of cooking became an important technological advance in the culture and health of Homo sapiens. Many today argue that meat consumption is not necessary to maintain good health. Perhaps with modern knowledge and accessibility to meat alternatives this is true, but the examination of the evolutionary advantages of meat-eating tell a different story.

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Meat has shaped human physiology in more ways than one might imagine; the evidence ranges from cranio-dental and gastrointestinal morphology to the theory of encephalization, a shift in the complexity of the human. In comparison to ancestral human species, human teeth and jaws show significant changes. The size and shape of teeth reveals much about a species’ diet, so these morphological changes suggest a major shift in the human diet towards meat-eating. The human jaw, in comparison to the jaw of its ancestors, is much “more gracile”, with “well-buttressed” teeth featuring shearing crests and smaller molars, which are all characteristic of a diet consisting of less grinding of fibrous plants and tubers and more tearing of animal flesh (Mann, 103). Additionally, the gastrointestinal morphology of modern humans indicates that meat-eating influenced the form of digestion in order to create the perfect omnivorous gut structure. Herbivores have pronounced and developed caecum and colon, while carnivores have acidic stomach and long small intestines. Humans lie somewhere in the middle with an acid stomach, relatively long small intestine, and slightly reduced caecum and colon which suggests reliance on high-quality meat based diet (Mann, 103).

 

The human brain's demands

Finally, the size of the human brain also supports the theory that eating meat had major effects on early humans as the brain is an extremely demanding organ. It requires a very large amount of energy to sustain all of its functions; the bigger the brain, the more energy it demands. The rapid increase in the size of the human brain, or human encephalization, may have been caused by the consumption of meat. Primates, especially humans, have much larger brains than would be expected for their body size. While the cause of such a sharp increase in this ratio is purely speculative, the increase's requirements are not. Development of a brain the size of humans depends on the presence of the polyunsaturated fatty acids which only come from animals (Pereira, 587) as well as increased metabolic function. The demands for increased metabolic function are met in humans by decreasing the mass of the digestive organs (Mann, 104), while the demand for these specific lipids can only logically be met by one source: meat-consumption. Once humans developed meat-eating practices and cooking technologies, their brain size began to increase, which in turn most likely contributed to a cycle without a beginning source; these new brains needed more energy, and the more energy consumed, the more cognitive functions they gained, giving the early human species new advantages and opportunities to adapt.

 

Collectively, this evidence gives a clear and complete picture of meat-eating as an influential change during the early development of the human species. But what makes this practice advantageous and therefore persistent throughout the evolution of Homo sapiens? Find the answer below, in the discussion of meat as an integral part of the ancient and modern human diet.

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How Important is Meat to the Human Diet?

The meat which we consume is a unique product containing compounds that can be hard to find outside of a biological context. Humans (along with other carnivores and omnivores) eat the meat of another animal in order to extract the nutrients it contains which are essential to our health. Animal sources tend to be high in these compounds because they, too, need these compounds to live healthily. The animals, however, get these nutrients from the plants that they eat.

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Because of its convenience as a high concentration energy and nutrient source, meat has become an essential part of the human diet; it not only provides us with protein but also vitamins and minerals, such as iron, vitamin B12, zinc, selenium, riboflavin, niacin, and folate. Deficiencies in any particular nutrient of these sorts can lead to a wide array of health issues: cognitive impairments, anemia, reproductive issues, and problems with cell metabolism. These nutrients are also crucial aspects of healthy human development and disease prevention. In addition, the lipids that come from animal sources in the diet are essential to healthy brain development and function as cranial networks are composed of 60% lipids (phosphoglycerides and cholesterol) that come from animal sources in the diet (Pereira and Vicente, 587). Iron deficiencies can also lead to long-lasting neuropsychological problems, behavioral issues, and developmental delays (Lozoff et al, 1) while folic acid is essential for fetal development (Pereira and Vicente, 590). Many of these compounds also promote healthy metabolic functions and disease prevention, with at least three of them (selenium, B12, and folate) presenting anti-carcinogenic qualities (meaning they reduce the risk of cancer).

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What Does Meat Offer Uniquely; What Makes It So Special?

In addition to the beneficial vitamins and minerals that an animal obtains from its feed, its muscle tissue contains some bioactive compounds that can only be found in a whole living animal. These compounds are the result of multiple biological systems working together in a whole organism to optimize its metabolic functions and exemplify many health benefits when consumed. For example, some endogenous (originating within an organism) antioxidants are metabolized within animal cells by both the endocrine and muscular systems together.

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Carnosine and anserine, CLA, ACE-inhibitory components

Two of these antioxidants, carnosine and anserine, are found only in meat sources in great abundance. Their functions range in relation to their environments, incorporating many health benefits including “a role in wound healing, recovery from fatigue and prevention of diseases related to stress” (Young et al, 908). Another example of these biologically unique molecules that present benefits to human health are conjugated linoleic acids (CLA). These compounds come in many different forms and are produced by different bacterial isomerases in a special compartment of a cow’s stomach, but the most common is formed by a chemical reaction between vaccenic acid and enzymes in the animal’s adipose tissue (Young et al, 907). CLA is responsible for the regulation of many metabolic processes that can lead to disease; it is anti-carcinogenic, anti-atherosclerotic (fights cholesterol buildup in arteries), antioxidative, and immunomodulatory. CLA may also play a role in the control of obesity, the reduction of the risk of diabetes and the modulation of bone metabolism (Young et al, 907). The final example we will discuss is ACE-inhibitory components from connective tissue, which monitor and inhibit the activity of Angiotensin I-Converting Enzyme (ACE). ACE inhibitors originate from enzymatic activity on muscle proteins and fibers and are formed in collagen fibers within intermuscular connective tissue. These compounds present strong anti-inflammatory properties as well as the ability to lower increased blood pressure (Young et al, 906).

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Vegetarianism

Fortunately for those who choose not to eat meat, for whatever reason they may, modern scientific knowledge and technology provides healthy alternatives. Vegetarians (and vegans) can, arguably must, take dietary supplements to make sure that they are consuming the right amounts of these essential nutrients. The common multi-vitamin provides many different compounds, from riboflavin to Vitamin D, to ensure that special dietary constraints do not harm the human choosing them. Due to the undeniable fact that IVM is animal muscle tissue, it will not necessarily have a huge effect on the vegetarian community. There is, however, the possibility that some people will adopt it into their diets because they view it differently from natural meat -- something which will vary throughout personal cases and that we cannot predict.

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What does this all mean for IVM?

According to this evidence, the consumption of meat and its specified compounds may be extremely beneficial, if not essential, to the healthy functioning of the human body. If this is true, IVM may be successful in reproducing only some of the effects of these biological compounds. Any of the vitamins and minerals mentioned above has the potential to be absorbed and incorporated into IVM. The bioactive compounds, however, may not produce such a fruitful yield. In order for these compounds to even exist, there must be an intricate system of biological processes occurring in different tissues that are all connected together by a single blood supply. IVM removes muscle cells from their natural habitat, a complex multi-celled organism, and places them stranded in a limited supply of other nutrients. It is hard to say that the myosatellites will be able to behave in the same way and contain all of these essential compounds due to their lack of natural development. Additionally, it is far-fetched to claim that tissue engineers aiming to produce on a large scale will take the time to isolate these specific compounds from living animals to place them in culture mediums for IVM to utilize. Therefore, IVM may actually be less healthy than natural meat regardless of what additives are proposed.

 

Keep reading to learn about these proposed additives!

 

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 Proposed additives to In-Vitro Meat 

 

Omega-3 Polyunsaturated Fatty Acids

The most talked about possible additive for IVM is Omega-3 polyunsaturated fatty acid. Its benefits include heart health, regulated cholesterol levels, healthy learning and behavior in children, healthy cognition, and depression prevention (Ruxton et al). There are two different categories of Omega-3s: those which come from marine animal sources and those which come from plant sources. The marine animals provide two types: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), while the plant sources provide only one type: alpha-linolenic acid (ALA). EPA and DHA are often considered the healthier omega-3s while ALA is generally considered to have less potent health benefits, although both types do produce many of the desired results. This may be due to the fact that a portion of ALA molecules are converted to DHA once consumed (Mercola). There is evidence however, that ALA has some unique health benefits independent of its conversion to DHA (Poudyal et al, 1051).

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The addition of omega-3 fatty acids to in-vitro meat has been proposed by many supporters of IVM’s potential to be more healthful than natural meat. In order to consider the nutrition of such additions, we must consider which types and how much omega-3 could or should be added to IVM samples as well as the relation of these figures to the recommended servings of fatty acids in the diet.

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Sources of omega-3s for IVM

Cows don’t eat marine animals. There is nothing we can do to change that, so as far as we are concerned there is currently no way to closely manipulate the fatty acid profile of a cow to include EPA and DHA. We are left only with the use of plant-based feed as a source of ALA fortification. IVM opens the door to an entirely new possibility of fortifying meat with DHA and EPA, the kinds of omega-3s that are considered “better” for your health and are absorbed in a much quicker and more efficient way. This becomes possible through total control of the meat sample. Isolating these compounds from marine animal products and adding them to a culture medium could give IVM the potential to consist of high levels of omega-3s that will actually be absorbed by the meat cells and passed along to the human eating them.

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Changes in proportion

The nutritionist recommended ratio of omega-3s to omega-6s (another type of fatty acids found in nuts and soybeans which does not have the same health benefits as omega-3) is 1:1. However, right now the average American's ratio falls between 20:1 to 50:1 which is seriously concerning (Mercola). This implies that balancing of that ratio requires either a huge increase in omega-3s or a huge decrease in omega-6s. Since IVM can’t remove omega-6s without producing a basically inedible product, it may have to rely on the addition of omega-3s only.

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Effectivity of these processes

Regardless of what is put into the culture medium, how can we figure out how much will actually end up in our bodies? Would absorption of fatty acids occur in the same or an equally efficient way when introduced into muscle cells via culture medium versus the gastrointestinal tract of a living animal? Lipids in meat occur as phospholipids in the cell membrane, intermuscular fat, intramuscular fat, and subcutaneous fat (Pereira and Vicente, 589). Because IVM alone lacks connective tissue, intermuscular fat and subcutaneous fat do not apply, while intramuscular fat and phospholipids are the most related. Intramuscular fat is the most influenced by diet, while phospholipids are much less diet-determined (Pereira and Vicente, 589); therefore the easiest target for modification of the lipid profile would be through the intramuscular fat. However, this idea assumes that any lipids supplied by the culture medium would elicit the same uptake rate and processing of such molecules as occurs in the GI tract. Therefore it is highly possible that the meat cells would not be able to absorb these compounds as they do within an organism.

Conversely, this modification is difficult to create on a large scale with modern livestock. The fatty acid profile of humans is a close representation of the composition of their diets, while the fatty acid profile of meat from ruminant (multiple-stomached) animals such as cattle is “only to some extent affected by feeding because unsaturated [fatty acid]s stemming from plant material are fully or partly hydrogenated by microbial processes in the rumen” (Young et al, 907). Maybe, avoiding the GI tract would actually be better for absorption rates, as the cow's stomach breaks down a lot of the fatty acids it eats.

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Iron

There are two types of iron: heme iron and non-heme iron. Heme iron travels on the biological proteins hemoglobin and myoglobin which carry oxygen throughout the bloodstream to supply oxygen to organs and muscles, and therefore is only found in animal sources of food. When consumed, heme iron is digested as a whole molecule and therefore is highly absorbed so that its metabolic functions can be effective (Pereira and Vicente, 589). Non-heme iron comes mostly from plant sources (leafy greens and legumes) as well as dairy. It does not come from hemoglobin or myoglobin and therefore has a different structure than heme iron, meaning it is digested and processed differently by the body. Due to the fact that it is not a lipid-soluble biological molecule and therefore cannot be absorbed easily into the body along with the fact that sources rich in non-heme iron often contain certain iron-uptake inhibiting compounds, it is only absorbed a rate of about 2-20% (589).
 

In the case of IVM, the source of iron becomes a question. In order to effectively transfer enough iron from the culture medium to the meat sample, heme iron would be much more efficient than non-heme iron. However, non-heme iron is a much more plentiful source and would be a better option for mass production. Again, the question arises of how this compound would be absorbed by the meat cells and whether the lack of a living gastrointestinal tract would inhibit the ability of the cells to process the iron compound. Regardless, non-heme iron from plant sources offers a much more sustainable option.

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Moderation

Even though iron is essential for healthy metabolic function, the amount of iron consumed must be monitored, as high iron intake presents multiple health risks such as damage to the intestinal mucosa, release of free radicals (carcinogenic), colorectal cancer, cardiovascular disease, neurodegenerative disease, and inflammation (589). Iron is just one of many compounds that can have both beneficial and detrimental effects, and it exemplifies the danger of making scientific assumptions without significant evidence. In many cases, this evidence might take decades to uncover, therefore affecting multiple generations. John’s Hopkins University recently released a study about the relationship between folate additives and autism. The study found a link between the amount of folate consumed during pregnancy and the likelihood of autism in the child. Previously, research studies found that folate deficiency during pregnancy led to serious neural tube birth defects. So, pregnant women began taking folate supplements in fear of such harmful defects. This precaution, in some cases, led to the excess of folate in the mothers’ diets which researchers now suggest causes increased (almost double the) risk of autism (Benham and Health). This example perfectly illuminates the importance of finding optimal consumption levels rather than over-consuming a product that has been proven a crucial part of the human diet.
 

Vitamins and Minerals
These nutrients (B12, zinc, selenium, folate, riboflavin, niacin, etc.) pose much less of a problem for IVM. They almost exclusively come from plant sources, although they may be transferred to us through the animals we eat rather than directly from the plants themselves. The best way to incorporate them into IVM is to provide algae or blue-green algae in the culture medium which is rich in vitamins and minerals that can be isolated from the algae species (Young et al, 908).

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Adipocytes and Collagen

Due to the fact that IVM does not contain intermuscular fats, the only way to introduce the highly desired meat flavor many know and love is to co-culture the muscle cells with adipocytes, fat cells, and/or fibroblasts, which make an essential part of connective tissue called collagen (Young et al, 908). This is necessary because otherwise, IVM products would lack the flavor and texture of natural meat, likely making them unappetizing. Most of the appeal of meat comes from its texture and aroma, which can almost entirely be attributed to the fat composition of the meat. This essentially means that although it may be possible to add small amounts of some “healthy” compounds, you also have to add in the “unhealthy” things to mimic the fat composition of natural meat. Therefore, if IVM is meant to be sold as a mass produced and consumer-friendly food, all it really offers is the opportunity to add new desirable compounds, but not to remove unwanted ones without compromising appeal.

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Keep reading to learn more about how the ways we make meat delicious might affect our health!

 

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 Meat Preparation 

 

How Does Meat Change When You Cook It? How would these changes affect additions to IVM?

It is possible that through all of this discussion surrounding the nutritional compounds of IVM we have ignored an element that may be one of the most influential. Throughout this analysis, some often overlook the idea that this product’s aim is to be consumed by real people who like real, delicious flavors. Although it is important to understand the composition of raw meat coming from an animal, “it is important to consider the influence of cooking techniques on vitamin and trace element contents considering that humans rarely eat raw meat” (Pereira and Vicente, 589). The action of cooking is actually a series of chemical reactions changing the composition and form of the compounds contained in the meat.

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Problems with cooking

Some of the essential vitamins and minerals we have examined are highly influenced by cooking technique. Vitamin B is water soluble and thermally unstable, therefore B complex levels decrease significantly when meat is cooked. Niacin and riboflavin show lower decreases than B12 and thiamin, yet they all decrease enough to be noted (Pereira and Vicente, 589). Cooking technique is also important in the loss of Vitamin B complexes. Techniques releasing large amounts of water such as boiling would cause more loss, while shorter length techniques where the food is exposed to heat for short amounts of time like stir-frying, would cause less B complex loss (Pereira and Vicente, 589).

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Benefits of cooking

Conversely, cooking can increase some beneficial factors of meat-consumption. CLA levels increase when meat is cooked at temperatures higher than 80 degrees Celsius (Young et al, 907). Additionally, fat can be lost through specific methods of cooking: “grilling, broiling or pan-frying without fat added" (Ono, Berry, & Paroczay, 1985). These methods also result in an increase in polyunsaturated:saturated ratio, "probably because polyunsaturated fatty acids are part of the cell membrane and thus have less contact with the heat” (Pereira and Vicente, 588). This means that when cooked, meat loses more of the harmful saturated fats than it does the beneficial unsaturated fats, suggesting high retention potential of omega-3 fatty acids introduced into IVM.

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You Don't Just Stick a Slab of Steak on a Grill - How Do the Things We Cook With Affect the Health of IVM?

A final consideration about the consumption of IVM is the influence of cooking methods on the health of meat. Common techniques include the cooking of meat using some sort of lipid in order to prevent burning or pan adhesion. The two most widely used lipids in meat preparation are butter and olive oil. Butter’s fat profile is a mixture of different saturated triglycerides, meaning it is a molecule containing three different saturated fatty acids joined together. In addition to these fatty acids, butter contains the infamous trans-fat, which is named according to the angle of adjacent carbon atoms in the molecule. Olive oil, on the other hand, is composed mostly of two monounsaturated fatty acids, omega-9 and omega-6. As a major staple of the mediterranean diet, this plant-based lipid is widely known to produce low-risk for cardiovascular diseases. So, why is saturated fat considered so much worse for human health than unsaturated fat?

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It turns out that diets rich in saturated fats have a strong positive correlation with cardiovascular disease, especially coronary heart disease (CHD), independent of other dietary factors. One Harvard University study and its 20-year followup study shows that not only does saturated fat increase risk of CHD, but “findings continue to support an inverse relation between polyunsaturated fat intake and CHD risk, particularly among younger or overweight women. In addition, trans-fat intake was associated with increased risk of CHD, particularly for younger women” (Oh et al, 672). The inverse relationship between unsaturated fats and CHD is amplified by evidence of the health benefits of cooking with olive oil, which apply to multiple cardiovascular issues. Not only does its use reduce LDL cholesterol (the kind that clogs up arteries and causes blood clots, heart attack, and stroke), olive oil rich diets reduce the amount of insulin needed and decrease blood glucose levels and insulin in those suffering from type 2 diabetes (Covas, 182).

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So, What Does All of This Mean? Is IVM Healthy or Not?

Ultimately, all of this information means that the health status of IVM is teetering in between success and failure. Depending on the series and combination of specific choices made in the synthesis of IVM and the final preparation choices, it could essentially be considered either healthy or unhealthy. If IVM becomes a product in the luxury food market, chances are its preparation will lead it to be considered healthy because people purchasing such an upscale food item most likely have more knowledge of food quality and nutrition. If IVM were to be mass produced at low cost and it was picked up by a major low quality food supplier such as McDonald’s, the chances of its preparation occurring with health conscious, good quality products are low. Therefore, the many other factors influencing the health of IVM may be more influential than solely its chemical composition and manipulability.