Protein bars, powders, veggie burgers, and imitation meat products have different health and environmental considerations depending upon the primary protein source used and the addition of sodium, fillers, and other additives. In addition, there is variance in processing and safety testing of each product. This summary of the predominant protein ingredients that compose these products distills available science and research to inform decisions about the products’ potential as healthy meat alternatives.
- Soy protein isolate
- Textured vegetable protein
- Isolated pea protein
- Whey protein
- Insect protein
- Lab-grown meat
Soy protein concentrates and isolates, soy leghemoglobin
Soy protein isolate (SPI) is a processed product (often in powdered form) extracted from the soybean legume. Hexane is frequently used as a solvent in the manufacturing of SPI. Hexane is a neurotoxin and is highly explosive, posing health and safety risks to processing plant workers. It is also an air pollutant that contributes to the formation of ground-level ozone, which is associated with adverse human health impacts.
Soy protein concentrate is similar to SPI in that it is a high protein product (65-90%) derived from soy, typically found in powdered form. The protein is extracted using drying or extraction processes to remove oils and sugars from defatted soybean meal. However, it generally retains more vitamins, minerals, and dietary fiber than SPI.
Many of the health benefits of eating soy only apply to whole full-fat soybeans, minimally processed, or fermented soybean products such as tempeh or tofu. The benefits or risks of SPI may differ considerably. For example, SPIs contain varying amounts of phytoestrogens, including genistein, with estrogenic action that could promote estrogen-sensitive breast cancer, but whole soy products have been shown to be protective. Processed soy foods such as veggie burgers, protein powders, or meat alternative products containing SPIs are often high in sodium or additives, such as dyes, gums, and preservatives.
In general, legumes have lower environmental impacts than other food groups with respect to greenhouse gas emissions and land and water usage in production. However, processing soy into ingredients for meat analogs increases the impacts of the aforementioned environmental indicators, and soybean production is associated with higher pesticide and fertilizer use than the production of other legumes. More than 70 percent of soybeans grown in the United States are used for animal feed. Human consumption is the second largest market, followed by biodiesel.
Ninety-four percent of soybean acreage in the United States is genetically modified. If included in a meat protein alternative produce, soy-based ingredients should be organic or non-GMO. Otherwise, the product may contain higher concentrations of pesticides due to the condensing and extraction process, and independent research has shown that there is no scientific consensus regarding GMO safety.
Plant heme/leghemoglobin products are made by genetically modifying yeast by inserting leghemoglobin (hemoprotein found in the root nodules of leguminous plants) genes (often from soy) to create high protein, plant-based meat substitutes through a fermentation process.
Impossible Foods, one of the few companies utilizing this technology, asserts by using genetic engineering, they reduce the amount of acreage, water, and carbon dioxide emissions required to produce enough plant heme to make plant-based meat analogs look and taste more like beef. It bases its reductions in environmental impact in comparison to industrial beef production systems that do not have the soil-building capacity of pasture-based beef production systems that use rotational grazing, intercropping, mixed-species grazing and other strategies to build healthy soils, reduce carbon emissions, and protect water quality. The life cycle assessment, funded by Impossible Foods, calls out the environmental concern of increasing demand for plant-based oils used in the production of plant-based burgers should they increase in production. Increased demand has the potential to increase land-use pressures in biodiversity hotspots, but could be avoided through responsible land stewardship practices.
While leghemoglobin is the ingredient that provides a “meaty” taste to plant-based burgers, it is not the primary source of protein in Impossible Foods’ products. Rather, soy protein concentrate provides the bulk of the protein content, while soy leghemoglobin is used specifically for flavor and color.
Impossible Foods filed a “generally recognized as safe” (GRAS) notice with FDA asserting the reasons the company believes soy leghemoglobin to be safe for human consumption. In 2018, FDA issued a GRAS notice. In a memo prepared by FDA for a phone conversation with Impossible Burgers in 2015, FDA stated, “FDA described the need for the notifier to provide strong scientific evidence when establishing safety. FDA stated that the current arguments at hand, individually and collectively, were not enough to establish the safety of soy leghemoglobin for consumption.” This, however, does not mean FDA considers these products to be unsafe and therefore they can still be sold for human consumption. In 2019, FDA amended its color additive regulations as it concluded that “there is a reasonable certainty of no harm from this use of soy leghemoglobin as a color additive.”
However, more research is warranted to determine the long term health impacts of soy leghemoglobin consumption, especially given that these products are new to the consumer market. The agency based its decision on studies submitted by Impossible Foods and independent research is needed to truly verify the safety of the products.
Soy protein isolates and soy leghemoglobin should not be consumed by people who have adverse reactions to soy.
Textured vegetable protein (TVP) is a meat analog or meat extender that is typically made from soy, but can also be made from wheat, oats, cottonseed, or other plants. As these product are frequently made from soy, many of the environmental and human health concerns associated with soy protein isolate apply to TVP.
Wheat is also a common ingredient in TVP. Similar to soy, wheat has a long history as a valuable food source in many cultures globally. However, the health benefits gained from consuming wheat or other grains apply to whole grains, and are not gained when the wheat is processed into TVP.
There are also environmental considerations regarding wheat production, which are compounded by the additional water and energy required to process wheat into TVP. There is growing interest in producing wheat more sustainably given its high demand. Wheat is typically grown as a monocrop and has been associated with significant land use changes, including expanding croplands into formerly uncropped areas. This intensification of land cultivation has resulted in greenhouse gas emissions associated with soil disturbance and loss of organic matter, increased pesticide and herbicide use, increased fertilizer use resulting in contamination of surface and ground water due to leaching and runoff (especially of nitrates and phosphates), and decreased water holding capacity in the soil resulting in soil erosion and nutrient loss.
Similar to soy protein isolates, TVP is used in the manufacture of processed foods that are often high in sodium and additives such as dyes, gums, and preservatives.
Textured vegetable protein may contain soy, wheat, oats, cottonseed, or other processed plants and should not be consumed by those with soy or wheat allergies, Celiac disease, or non-Celiac gluten sensitivity.
Isolated pea protein
Isolated pea protein is made by removing fiber and starches from peas in order to isolate the protein. The outer shell of the pea, which contains insoluble fibers is mechanically removed. Then, the peas are milled to produce a flour. The protein which is water soluble is then separated from the fiber and starch by wet filtration and centrifugation resulting in a purified protein powder. Pea protein is used as an additive in baked products as well as a meat substitute or meat extender as it is high in protein (85 to 90 percent) and also has good binding capabilities.
In general, legumes such as peas have lower environmental impacts than other food groups with respect to greenhouse gas emissions and land and water usage in production. They also have the capacity to increase soil fertility though “fixing” nitrogen gas in the atmosphere to bioavailable forms that can be used with plants, and therefore can be used in rotation with other crops. Water and energy inputs associated with pea protein are higher than that of whole dried peas or pea flour due to the process of extracting the protein from the whole peas. Research is lacking regarding the full scope of environmental and human health impacts associated with isolated pea protein.
Consuming pea protein is not nutritionally equivalent to eating whole peas. While there are higher protein levels in isolated pea protein, it is lacking the nutritional benefits of the fiber and starches present in whole peas.
Mycoproteins are high protein, high fiber, non-mushroom producing, lab-grown fungi. The fungi are grown in fermenters in a liquid solution using fusarium venenatum (a fungus that occurs naturally in soil) and adding oxygen, nitrogen, glucose, and minerals. The fungi are then dried and combined with egg or other binding ingredients to make a finished product.
Proponents of mycoproteins assert that they use less land and are associated with lower greenhouse gas emissions than meat. However, data is limited on a full life cycle analysis of mycoprotein production.
The Center for Science in the Public Interest maintains a database of foods and food additives that are ranked on safety. Mycoprotein is listed as an ingredient to avoid. While this product does contain high protein content as well as dietary fiber, as with other meat analogs, it typically is used in foods that are high in sodium and additives such as dyes, gums, and preservatives. There is also concern products containing mycoprotein can cause adverse reactions such as nausea, vomiting, diarrhea, and allergic reactions.
Research is lacking regarding the full scope of environmental and human health impacts associated with mycoproteins.
These products should be avoided by individuals known to have adverse reactions to fungi and are also not recommended to completely replace meat in the diets of children three years of age and under because of the low energy densities and satiating effects.
Plant heme/leghemoglobin products are made by genetically modifying yeast by inserting leghemoglobin (hemoprotein found in the root of leguminous plants) genes (often from soy) to create high protein, plant-based meat substitutes.
Impossible Foods, one of the few companies utilizing this technology, asserts by using genetic engineering, they reduce the amount of acreage, water, and carbon dioxide emissions required to produce enough plant heme to make plant-based meat analogs look and taste more like beef. It bases its reductions in environmental impact in comparison to industrial beef production systems which do not have the soil-building capacity of pasture-based beef production systems that use rotational grazing, intercropping, mixed species grazing and other strategies to build healthy soils, reduce carbon emissions, and protect water quality. The life cycle assessment, funded by Impossible Foods, calls out the environmental concern of increasing demand for plant-based oils used in the production of plant-based burgers should they increase in production. Increased demand has the potential to increase land use pressures in biodiversity hotspots, but could be avoided through responsible land stewardship practices.
Impossible Foods filed a “generally recognized as safe” notice with the U.S. Food and Drug Administration asserting the reasons the company believes soy leghemoglobin to be safe for human consumption. In a memo prepared by the FDA for a phone conversation with Impossible Burgers in 2015, the FDA stated, “FDA described the need for the notifier to provide strong scientific evidence when establishing safety. FDA stated that the current arguments at hand, individually and collectively, were not enough to establish the safety of soy leghemoglobin for consumption.” This, however, does not mean the FDA considers these products to be unsafe and therefore they can still be sold for human consumption.
The recipe used to create the Impossible Burger contains wheat and soy and is not suitable for those with allergies to these foods or those with Celiac disease.
Whey protein is a dairy product and is formed when casein and whey in milk are separated. It is typically treated as a byproduct of the dairy industry. While whey can be consumed in liquid form, it is more frequently dried and sold in form of protein powder. Whey protein powders may be labeled either as food or a dietary supplement, which determines the manufacturing and testing procedures used to ensure consumer safety.
The environmental impacts of dairy products including whey are highly dependent on the type of agricultural system used to raise cows. Large-scale, conventional dairy farms have become more efficient with energy, water, and land use in the last two decades, but have also contributed to numerous environmental and public health concerns, including drinking water contamination, antibiotic resistance, and community physical, mental, and social health impacts. Globally, dairy farming accounts for approximately 4 percent of total anthropogenic greenhouse gas emissions.
In contrast, pasture-based meat and dairy operations using a system of rotational grazing on perennial forage crops have the potential to reduce net greenhouse gas emissions, build soil, protect water quality, reduce antibiotic use, and promote better animal welfare. However, there are still energy and water inputs associated with producing, storing, and transporting dairy products, regardless of the system used to raise the cows.
As a dairy product, whey protein carries these environmental impacts with additional energy and water inputs from drying and packaging the whey protein. According to the whey powder manufacturer MyProtein, 720 pounds of liquid milk is required to produce one five-pound bag of whey. Research is lacking regarding the full scope of environmental and human health impacts associated with whey protein powder as compared to other dairy products.
The positive and negative health impacts of dairy consumption have been debated in recent decades. As a processed product, whey protein does not have the same nutritional profile as whole, liquid milk and often has additives such as artificial colors or flavors that may have adverse health impacts. Additionally, protein powders can be labeled and sold either as food or as dietary supplements, which determines the manufacturing and testing procedures used to ensure consumer safety.
Individuals with a dairy allergy or lactose intolerance should not consume products with whey protein.
Insects have been widely consumed around the world for their nutrition and flavor. Entomophagy, the consumption of insects, is more common in regions of Mexico, Africa, and many Asian countries. Interest in insect consumption in the United States, however, is a more recent phenomenon.
Insects are commercially farmed and then milled into a protein-rich powder often called “flour.” This protein powder is used to make a variety of products, including power bars, bread, cookies, pasta, and chips. Depending on the stage of development and type of insect consumed, nutrition can vary greatly. According to the Food and Agriculture Organization, many insects provide good amounts of energy and meet amino acid requirements for human protein needs in addition to a variety of micronutrients, minerals, and healthy fats. The most popular insects consumed in the United States are crickets and mealworms which can offer comparable protein to beef per 100 grams weight.
Although several life cycle assessments have been conducted on commercial insect farming, research is limited on the environmental impacts of the nascent industry. Generally, claims that insects are a more environmentally friendly option are based on their feed efficiency ratio, a measurement that indicates how much food an animal would need to consume to put on a desired weight. Insects, more than any traditional livestock, are much more efficient at converting what they eat into mass. To gain one kilogram of weight, crickets require 1.7 kilograms of feed. (A standard U.S. chicken requires 2.5 kilograms, pigs need 5 kilograms, and cattle require 10 kilograms.) Insect rearing also requires less water than a traditional livestock operation and can be done in urban areas, since they require less land and can be raised in vertical spaces. Insects emit far fewer greenhouse gas emissions than traditional livestock.
Commercial insect farming, however, does require significant energy and labor costs. Insects require heat to thrive. The processing of insects into protein powder and other value-added food products has not been extensively studied but requires expensive machinery as well as additional energy and water.
The European Food Safety Authority generally considers insect protein to present no more risk than any other animal protein with regard to food-borne illnesses and diseases. The U.S. Food and Drug Administration allows insects to be consumed as food if production follows the guidelines of the Food Drug and Cosmetics Act. However, there are some concerns that insects may build up heavy metals (such as arsenic), which have not yet been evaluated.
Most insects have an exoskeleton similar to that of a crustacean and therefore can pose allergy concerns for people allergic or sensitive to shellfish.
Lab-grown meat is meat produced in a laboratory environment using animal cells that are fed nutrients and incubated to promote cell growth.
The process used to grow meat in a lab requires animal cells to begin the culturing process, and fetal bovine serum (made with blood obtained from the fetuses of cows that are found to be pregnant when slaughtered) is used in the culturing medium to promote cell growth. As cows are still needed to produce lab-grown meat, the impacts associated with producing cows (soil, climate, and water impacts) still apply. Only a small number of cells are required to start a culture, so far fewer animals would be required to produce the lab-grown meat for food. A full life cycle assessment is required to better evaluate the environmental impact of this process. However, a modeling exercise concluded it could be more energy intensive to produce meat in a lab setting than in a conventional animal agriculture system, although land use and agricultural inputs would be far less.
Proponents of lab-grown meat argue that it could be produced to have a superior nutritional profile and comparable energy use to conventional meat. Research is lacking regarding the full scope of environmental and human health impacts associated with lab-grown meat, especially in comparison to pasture-based or integrated agricultural systems.
As an emerging food technology, there are potential social barriers to lab-grown meat being widely adopted. According to a 2014 survey conducted by the Pew Research Center, 80 percent of Americans said they would not be willing to eat meat that was grown in a lab. Lab-grown meat has the potential to increase the disconnect between consumers and their food. As it uses fetal bovine serum, lab-grown meat still requires animals to be slaughtered and therefore carries ethical implications for humane treatment of farm-raised animals.
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