Exploring Alternative Proteins: Impact on Human Health and the Environment

Ellis Becker,   Nicole Brotter, and Olivia Pearl

 Scenario 

 The Academy of Nutrition and Dietetics is the United States' largest organization of food and nutrition professionals. They hired us, a team of environmental scientists and dietitians, to analyze the efficacy of various alternative protein sources in terms of both human health and environmental sustainability. To do so, we explored a series of studies regarding nuts, eggs, and tofu, and examined their respective production and consumption impacts in terms of human health and the environment. Stay tuned to find out how you can eat and live sustainably.  

Introduction

In order to conceptualize the “health impacts” of each protein, we based our findings on the Food and Drug Administration’s (FDA) nutrition labels, potential health benefits of consuming the protein, and detrimental impacts it can have on the body. By honing in on both the nutritional facts and benefits, we will be able to present unbiased information, and let the reader determine which is healthiest, based on their subjective view of health and wellness. The “environmental impacts” will be based on the amount of energy and resources necessary to produce each protein category. By analyzing the products as separates, we plan to compare each aspect of their impacts in order to determine which protein source is the most environmentally sustainable. 

Through the exploration of past scholarly work, we will be making an effort toward answering our main research question: given that research has traditionally emphasized the environmentally destructive nature of meat production, which protein alternative is optimal for consumers in terms of human health and environmental impacts, between eggs, nuts, and tofu? In terms of eggs, we will be focusing on the details of its production, such as aspects of its lifecycle, the resources needed for egg production, the resources needed to maintain the hens, and more; but when focusing on egg’s health impacts, we will be focusing on the efficiency of egg protein, as well as, the traditional FDA food label. Regarding nuts, we will be looking into the inputs for growing nuts and how the trees impact the environment. In terms of health, we will be reviewing sources about its traditional nutrition label attributes, its benefits, and how it plays a role in popular diets, like the Mediterranean diet. For tofu, we will be highlighting aspects of its production, particularly focusing on the fact that different types of tofu have varying impacts on both health and the environment. While we will still be looking at the FDA nutrition label regarding tofu, we will also look into its tendency to contain biogenic amines that affect the body. Additionally, since tofu is consumed differently across various cultures, we will be emphasizing the health and environmental impacts of tofu based on its soybean type, preparation of tofu, and its properties. This will give us a more confident idea of how consumers can maximize utility in terms of health benefits and environmental attributes. 

 Protein Analysis 

Eggs

Eggs are one of the most widely utilized protein sources in the modern-day globalized diet. In the U.S. alone, over 75 billion eggs were produced in 2010 and that number has since risen. Globally, many rely on eggs as sources of protein, as keeping chickens is a generally low-cost practice. Derived from hens, eggs are very efficient protein sources, with one egg containing up to six grams of protein. According to a 2014 Harvard study, one large egg contains approximately 72 calories, 6.3 grams of protein, and 4.8 grams of total fats (Harvard, 2014). Consequently, there are negative impacts that egg consumption can have on human health, including increased cholesterol levels and a higher likelihood of cardiovascular disease. Additionally, these effects tend to vary based on a number of demographic factors, which will be further explored. Environmentally, egg production requires a number of inputs, including land, feed, energy, and all of the additional inputs that go into those. With this said, the most effective way to examine the overall environmental impacts of egg production is through a life-cycle assessment, focusing specifically on U.S. egg production.

Regarding health, eggs are an inexpensive and highly nutritious food source that contains a significant amount of protein, as well as many important micronutrients. These include calcium, zinc, and iron, among others. According to a 2015 study done by Jose Miranda, there is significant evidence that eggs also contain compounds that can aid in the therapy and prevention of chronic diseases, including anti-cancer, anti-hypertensive, and antioxidant compounds. One example of this is carotenoids, which can boost one’s immune system, reduce inflammation, and can reduce the risk of macular degeneration and cataract formation. Eggs also contain a significant amount of vitamins, including 270 and 41 International Units of Vitamins A and D, respectively. Eggs also contain phosvitin which can reduce melanin levels in human skin.

There are also several negative health impacts that come from eggs, and particularly from overeating eggs. The most commonly known adverse effect is the high cholesterol levels in eggs, with one large egg containing up to 186 mg of cholesterol (Harvard, 2014). That being said, egg consumption should be considered similar to the consumption of various other protein-rich food sources. It is important to note that demographic differences are vital in exploring the health impacts of any food source, and eggs are no different. It has been found that, while eggs do contain much cholesterol, only 30% of the human population would hyper-respond to dietary cholesterol, while 70% would not (Miranda et al., 2015). This response is dependent on ethnicity, genetic makeup, hormonal factors, body mass index, the rest of one’s diet, and a number of other factors. 

Regarding environmental impacts, a comparative life-cycle assessment of U.S. egg production effectively analyzed approximately the supply chain impacts of one-quarter of pullets and one-third of laying hens in 1960 and 2010 was conducted for the Egg Industry Center by Nathan Pelletier and his colleagues. Processes associated with the foreground system, in essence, those that are inputs to the egg production supply chain that are also involved in other supply chains, included fertilizers, pesticides, energy, and transportation. Other inputs included agricultural feed, nitrogen and phosphorous emissions, crop processing, and livestock production, among others. Despite technological advancements, the results of these comparative impacts are surprising. Regarding energy carriers, overall impacts were significantly higher for every energy source except for coal in 2010 than in 1960. The largest differential came from natural gas, which in 2010 led to over 325% more acidifying, eutrophying, and greenhouse gas emissions. Additionally, the cumulative energy demand in 2010 for natural gas, diesel, fuel oil, gasoline, and propane was almost 300% that in 1960 (Pelletier et al., 2014). To clarify, cumulative energy demand refers to the total direct and indirect energy used throughout the life cycle, including that expended during extraction, manufacturing, and disposal. These drastic and devastating impacts have not only had an effect on energy use, but also in other areas of the supply chain. In discussing the environmental impact of fertilizers, which has actually decreased, the authors even say that despite this progress, “declining EROI values for energy production effectively offset these gains'' (Pelletier et al., 2014). Although emissions for nitrogen, phosphorus, and potassium fertilizer were all lower in 2010 than in 1960, cumulative energy demand was much higher for nitrogen and phosphorus fertilizer. Again, this is another indication that despite a reduction in emissions from fertilizer, energy use has greatly increased. Transportation follows a similar trend, as emissions for rail, road, and ocean freight have decreased since 1960, but cumulative energy demand for all are higher. Specifically, cumulative energy demand for road freight in 2010 was more than 250% that of 1960 (Pelletier et al., 2014).

All of this being said, the primary input factors for egg production in 1960 were drastically different. Historically, feed inputs have had the most weight in regard to impact categories, specifically in greenhouse gas emissions and cumulative energy demand. However, given changes in feed composition which led to decreased emissions, manure management has been the primary impactor in recent decades. With these improvements, in producing one kilogram of eggs, there have been significant reductions in acidifying, eutrophying, and greenhouse gas emissions, with a slight decrease in cumulative energy demand. However, this will still produce up to 70 grams of acidifying emissions, 20 grams of eutrophying emissions, and over 2,000 grams of greenhouse gases.

Nuts

Nuts, and almonds, in particular, act as an effective source of protein and provide many with essential nutrients. Beyond its health benefits, almonds can also be grown and harvested in a sustainable way, with few greenhouse gas emissions. 

Health-wise, almonds are packed with nutrients. In addition to being great protein sources, almonds are rich sources of carbohydrates (mainly dietary fiber), fatty acids, proteins, and amino acids, as well as vitamins, minerals, and secondary metabolites ( Barreca, et al., 2020).  Another interesting benefit is that the various ways of intake (ie. raw or roasted) do not alter the composition or health benefits of the almond during digestion (ibid.). Studies concluded that regular consumption of almonds also controlled blood lipid levels, contained high levels of antioxidants, and were anti-inflammatory (ibid.). However, it is important to note that the degree of consumption matters, and benefits won’t be maximized if it does not match serving size. The regular serving size of almonds is one ounce or about 23 almonds or ¼ cup (Journal of the American College of Cardiology, 2019). One ounce provides about 165 calories, 6 grams of protein, and 14 grams of fat (ibid.) Through consuming said serving size regularly, the health benefits of almonds are more likely to be stronger. 

Nuts benefit health in a complementary way too. Studies have shown that consuming a Mediterranean diet slows the progression of Type 1 Diabetes Mellitus (Calabrese, 2021). Typically, a Mediterranean diet limits animal protein to small amounts and supplements this with alternative protein sources, like nuts. By replacing meat with almonds and other nuts, not only will the aforementioned regular health benefits be received, but their consumption can contribute to the quelling of serious diseases. 

On top of their many health benefits, almonds have the potential to be grown in a sustainable way. A California study that examined the sustainability of almond trees concluded that if a farmer uses biomass recycling when replanting orchards,  the loss of carbon from soil cultivation can be offset   and almond yield can be improved (Jahanzad et al., 2020). Biomass recycling is an extremely efficient way to create soil sustainably -- through bio mass recycling, farmers are able to use any form of food waste, manure, sludge, and more to convert into soil (MEIWA, 2017) . The study also concluded that biomass recycling reduced the amount of stress the almond tree endured due to drought (Jahanzad et al., 2020). The sustainable potential for growing almonds is there, however, the key is implementing such changes, which in many cases is easier said than done.  Biomass recycling is a great idea in theory, but in order to see its benefits at a large scale, producers all over have to uptake a new practice and invest in a machine that actually transforms waste into soil.

Another important aspect of almonds’ carbon footprint is accounting for the almond supply chain. While it may never be a reality to cut out the time and reduce the mileage of which almonds travel to get from producer to consumer, it is an important factor to consider in the general sustainability of almonds as they can be grown in limited environments.  It is important to note that growing almonds also requires a significant amount of water. In order to grow one single almond, 1.1 gallons of water is necessary, and one pound requires  1,900 gallons  (Kogon, 2017) .  However, this is if almonds are being grown in a traditional way. Farmers are beginning to utilize deficit irrigation and studies are showing that even when water usage is reduced, almond yield is not affected. Researchers measured the almond trees' stem water potential levels for several weeks of, which indicates the amount of physiological water stress felt by the almond trees during various growth cycles  (Stewart, Fulton, Krueger, Lampinen, & Shackel, 2011) .  When it came to irrigation, researchers chose to keep the almond plants under a moderate to mild amount of stress, meaning the trees would receive a lesser amount of water. R egulated deficit irrigation resulted in “a total average annual consumptive-water-use savings of 5.3 inches over the 5-year period, and yearly savings ranged from 10% to 15%, or 5.2 to 6.1 inches” (Ibid.).  

   Finally, in the grand scheme of growing produce, it is important to understand how almonds rank among other fresh foods grown from the ground. A  study spent time gathering various greenhouse gas emissions of different fresh foods, and through various studies created a database measuring the carbon output used to produce a uniform unit of food. Compared to field-grown vegetables and fruits and cereals, tree nuts, which included almonds, had a slightly higher value of CO2 emissions (Clune et al., 2017). However, if sustainable growing practices were to be used, greenhouse gas emissions could be reduced.  

Tofu

Tofu is a soy-derived protein that is predominantly consumed in East and Southeast Asian countries, but due to recent trends in western diets, focusing on reducing saturated fat and cholesterol, it has become a popular protein globally (Aziadekey et al., 2002). With that being said, there are a variety of forms in which tofu is produced: soft tofu, firm tofu, and processed tofu (extra-firm tofu). Tofu’s versatile nature, of being able to be served boil, fried, or steamed, and its cheap prices, make it an accessible food option to many populations. 

It is no secret that tofu is an efficient meat alternative, as it provides significant protein without many of the detrimental health impacts of meat. In fact, tofu contains all of the nine essential amino acids that are vital to a healthy and balanced lifestyle (Indraningsih, 2018). Not only does it contain protein, but it is also an excellent source of calcium, iron, and minerals, such as magnesium, phosphorus, copper, zinc, vitamin B1, and more (Indrianingsih, 2018). With having such a high protein and vitamin count, tofu continues to impress with having a low-calorie count (Yue et al., 2019). Another aspect of tofu that increases its health benefits is that it contains saponins. Saponins are compounds that are thought to have protective impacts on heart health and can be a vehicle in improving blood cholesterol and increasing the disposal of bile acids, thus lowering the risk of heart disease (Indrianingsih, 2018). Besides the nutrients tofu has, its nutrition label is also indicative of its health benefits. According to a Harvard study, a serving size of tofu, considered at approximately two ounces, is only forty-eight calories. Since people typically eat two servings in a meal or approximately one hundred calories, they are taking in about ten grams of protein and hardly any sodium (4.6mg), fat (5g), and carbohydrates (2.6g) (Harvard). Finally, another study ultimately concluded that a major benefit of tofu is the lack of animal-borne diseases that may come with the consumption of traditional animal proteins, such as mad cow disease in beef products (Indrianingsih, 2018).

While tofu has proven to be an effective protein alternative, there are aspects of it that can be seen as harmful to human health. An example of this is tofu’s patterns of containing biogenic amine. The presence of biogenic amines in food may lead to toxicological risks and health problems (Yue et al., 2019). Knowing that different forms of tofus have different properties, it is important to note that the highest biogenic contents are in firm tofu, which is believed to be a product of its manufacturing processes (Yue et al., 2019). Additionally, the prolonged processes and storage time are examples of uncontrolled factors that contribute to the higher biogenic amine levels of firm tofu (Yue et al., 2019).

As soy products have become more globally popular, their impact on the environment has greatly increased. Besides tofu, soy is responsible for edible vegetable oil, biofuel, and a variety of protein sources (Boerema et al., 2016). Interconnected with the detrimental impact of soy processing, as during South America’s “soybean boom,” there is also typically an extreme increase of deforestation. Although this isn’t a direct correlation, the recent 80% of deforested land in Brazil is mainly used for cattle ranching, which is also where soybean cultivation happens to take place (Boerema et al., 2016). Thus we see that without even the processing of tofu, developing the soy takes a toll on the environment. This pattern is happening globally. This is due to the fact that soybeans aren’t only taking up land, but they are a huge source of trade income for countries. Brazil and Argentina, in particular, export many soy products. Europe tends to import soy from these countries, which also impacts the way they map out their lands, as urbanization in Europe has led to the fact that they have less space to grow soy and process it (Boerema et al., 2016). When looking at the environmental impacts of tofu, it does not compare to the harm the meat industry poses. Some disadvantages of soybean trade, though, are loss of wood and non-wood materials, loss of water regulation, loss of climate regulation, and more (Boerema et al., 2016).

 Comparative Analysis and Conclusion 

When it comes to being a consumer, it is important to know the health and environmental impacts foods have. In particular, our team focused on eggs, nuts, and tofu, and how these proteins compare nutritionally and environmentally. In order to see which protein source has the best health impacts, we must compare the data from the studies we analyzed. In terms of the nutritional label, tofu has the least calories, with 45 calories for about two ounces. Eggs are second behind tofu at 72 calories for one full egg, and finally, nuts, specifically almonds, are calorically dense with a serving of one ounce being 165 calories. It is important to note that in terms of ranking these proteins regarding calories, context and biases must be taken into account. For an average American citizen, tofu would be superior in this sense as it has the least amount of calories, but for those in developing countries, for instance, they would likely favor a protein with more calories. Next highlighting the nutrient value, we see that these protein sources have sufficient amounts of protein and other vitamins and minerals. Having the most protein, tofu serves about ten grams of protein per serving. Eggs and nuts follow with both having about six grams of protein per their respective serving sizes. While all protein alternatives contain nutrients, eggs and tofu are far more beneficial than almonds. Specifically, eggs and tofu have beneficial attributes including but not limited to zinc, iron, and calcium. Although these protein sources contain many beneficial health attributes, it is important to recognize their detrimental impacts. Eggs are incredibly high in cholesterol, and cholesterol has been shown to have health repercussions for humans. Tofu also holds a flaw. Despite not being a product derived from animals, many forms of tofu contain biogenic amines which studies have been known to pose toxicological risks and human health problems. Additionally, navigating the presence of biogenic amines in tofu can be complicated due to its many variations. While almonds do not have the same harmful impacts, it is important to note how its little serving size is leading in calories and fat content.

 Data from Harvard University. 

When it comes to the potential for sustainable production, it is clear that almonds take rank. However, this statement can only be made if farmers were to abide by practices like biomass recycling to reduce greenhouse gas emissions and deficit irrigation to conserve water. Tofu poses an issue for sustainability because of the harm soybean land cultivation impresses on the environment, which is most often done at the cost of forests around the world. While egg production has become significantly more sustainable over the past several decades, the cumulative energy demand that comes from its supply chain is still significant. There are several factors that go into growing eggs, that of which almonds and tofu either have less of or none at all. To cultivate eggs, fertilizers, pesticides, energy, agricultural feed for chicken, nitrogen phosphorous emissions, and crop processing for the chicken feed, are required for the process. With so many energy inputs to produce one unit -- chickens, crops for chicken feed, and then the time it takes to feed the chicken adequately to produce an egg -- emissions are incredibly high. Tofu has far fewer manufacturing steps -- the soybean is harvested then transferred to the factory to be made into soy milk which is then processed and turned into tofu. Almonds go from the tree to be packaged and distributed. Exempting the greenhouse gas emitted by transportation and distribution, producing eggs requires many more steps and energy relative to tofu and almonds. Therefore, almonds are ranked first in environmental sustainability relative to tofu and then eggs. 

Overall, when it comes to comparing the environmental and health impacts of each protein alternative, all of the options are efficient in their own ways. Knowing that meat products are detrimental to health and the environment, it is important to highlight what protein alternatives can help lead a sustainable life. With that being said, we can see how eggs, nuts, and almonds all hold benefits as well as harmful attributes, so implementing them into a diet moderately would be beneficial for a healthy balance. As mentioned before, taking a look at the Mediterranean diet shows a great example of how a plant-derived, protein-enriched diet should look. While this holds true, we must reiterate how environmental sustainability is a priority of ours. Even though balance is important nutritionally, we must note that eggs are the most detrimental environmentally, then following tofu and almonds. The different methods in which tofu and almonds can be processed determine their impact on the environment. All in all, this analysis of comparing eggs, nuts, and tofu, in terms of their health and environmental impacts, gave our team the notion that we should focus on balancing these sources, as they are all important parts of diets.

Citations

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