Alternative Protein Sources: balancing Food Innovation, Sustainability, Nutrition, and Health
Proceedings of a Workshop—in Brief
On August 17–18, 2022, the Food Forum of the National Academies of Sciences, Engineering, and Medicine held a virtual workshop titled Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health. It explored the state of the science on alternative sources—proteins from plant or animal cells or fermentation—with respect to diet quality, nutrition, and sustainability. Across three sessions, presenters discussed current challenges in the alternative protein landscape, including the health, environmental, and socioeconomic impacts of increasing alternative protein intake and implications for the industry, consumers, and regulators. Presenters also looked at different food processing methods for developing alternative protein products and considered how to balance these technological innovations to optimize nutritional content, affordability, and accessibility.
This Proceedings of a Workshop—in Brief highlights the workshop presentations and discussions and is not intended to provide a comprehensive summary of the information shared.1 The information summarized here reflects the knowledge and opinions of individual participants and should not be seen as a consensus of the participants, Food Forum, or National Academies.
CURRENT PROTEIN CHALLENGES
On August 17, the opening session examined current protein challenges, including the role of protein in diet, the wide-ranging impacts of increasing alternative protein intake, and the ethical underpinnings of the debate around alternative proteins.
Dennis Bier, Baylor College of Medicine and Children’s Nutrition Research Center, described the role of protein in the diet and opened by remarking that “without proteins, life itself would be impossible.” As the body’s structural components, he explained, proteins serve a range of essential functions: (1) as enzymes, they catalyze essentially all metabolic reactions; (2) as hormones, they serve as interorgan messengers; (3) as carrier proteins, they function as interorgan transporters; and (4) as antibodies, they constitute the adaptive immune system. Consumed proteins are absorbed primarily as amino acids or di-/tripeptides, although the enterocyte’s ability to differentiate between animal, plant, or alternative
1 The workshop agenda, presentations, and other materials are available at https://www.nationalacademies.org/event/08-17-2022/alternative-protein-sources-balancing-food-innovation-sustainability-nutrition-health (accessed August 25, 2022).
protein source origins is not well understood. He noted that each amino acid has a unique function and—unlike carbohydrates or fat—amino acids have no storage reservoirs.
Obligatory nitrogen losses have long been used to calculate dietary protein requirements, said Bier. According to nitrogen balance studies, the estimated average requirement of protein equivalence is about 0.66 kg/day and the recommended daily allowance is approximately 0.8 g/kg of body weight (Rand et al., 2003). A challenge in measuring protein metabolism from urinary nitrogen, however, is the variability of nonprotein nitrogen across different foods, which is typically 5–10 percent; amino acid digestibility and availability is similarly variable, 60–90 percent across different plants. Bier characterized existing methods for modeling dietary protein requirements (e.g., nitrogen balance, labeled nitrogen, amino acid kinetics) as limited, with none for measuring protein requirements in a free-living state. He added that, contrary to popular wisdom, increasing protein intake—even dramatically—does not yield a statistically significant increase in lean body mass (Bhasin et al., 2018), although consuming too little can increase mortality risk in people with end-stage renal disease (Kovesdy et al., 2010).
Principal constraints in achieving protein adequacy from plants include the amount of protein available per volume of food eaten, protein density, and energy supplied by nonprotein sources, said Bier. Although 20 grams of protein per day can be readily achieved through animal sources and some high-quality nonanimal sources without increasing total calorie intake, lower-quality nonanimal sources require a substantial increase in caloric intake to achieve protein adequacy (Pinckaers et al., 2021). To more accurately measure and study protein intake, Bier suggested developing outcome variables that include a reliable estimate of lean body mass (e.g., total body potassium or nitrogen) and an appropriate measure of lean mass function to differentiate between active versus water-based lean body mass.
Frank Hu, Harvard University, explored the health and nutritional impacts of increasing alternative protein intake. He opened by reporting the dramatic increase in meat production and consumption worldwide in recent decades, particularly in Asia and South America, and cautioned that the current animal protein–oriented food system is not sustainable due to population growth and the system’s adverse health and environmental effects. Both the 2015 Dietary Guidelines Advisory Committee and EAT-Lancet Commission have recommended plant-based dietary patterns to improve both human and planetary health. He explained that greater consumption of animal protein has been linked to increased risk of chronic conditions, such as diabetes (Malik et al., 2016). In contrast, diets rich in minimally processed plant foods are associated with benefits such as cardiovascular health and reduced diabetes risk (Guasch-Ferré et al., 2019; Ma et al., 2020). He added that modeling estimates suggest that replacing 3 percent of energy from animal-sourced protein with plant protein significantly lowers mortality risk (Song et al., 2016).
Hu predicted that alternative proteins will be instrumental in meeting the expanding global demand, possibly reducing environmental impacts associated with traditional meat production. Analyses indicate that consuming plant-based alternatives can reduce greenhouse gas emissions and energy, water, and land use compared to traditional red meat consumption. The only randomized controlled trial comparing the effects of substituting red meat with plant-based meat on cardiovascular risk factors found significant reduction in LDL cholesterol (Crimarco et al., 2020). However, Hu advised that increasingly popular plant-based meat alternatives are often heavily processed, with suboptimal nutrient composition and high levels of sodium and fats, and plant-based diets that rely too heavily on these alternatives and less on whole or minimally processed foods may increase chronic disease risk (Satija et al., 2016).
Hu outlined pros and cons of alternative protein sources—including plant-based meat alternatives, mycoprotein, insects, algae, and laboratory-grown meat—and emphasized the need to diversify sources and focus on overall diet quality rather than protein exclusively. According to Hu, the longer-term impacts
of alternative proteins on human and planetary health remain to be seen and a fundamental change in the food system requires not just technological innovation but policies to create a food environment in which healthy and sustainable food choices are accessible and affordable.
Zach Conrad, William & Mary, discussed the environmental impacts of increasing alternative protein intake. He reviewed evidence related to the diet-sustainability hypothesis, formally introduced in 1986, which holds that healthier diets are more environmentally sustainable. He reported that two systematic reviews conducted in 2015 and 2016 found that (1) greater intake of plant-based compared to animal-based foods is associated with improved environmental sustainability indicators and (2) health-promoting diets are associated with more sustainable outcomes (Dietary Guidelines Advisory Committee, 2015; Nelson et al., 2016). A 2020 systematic review concluded that research continues to support the finding that dietary patterns higher in plant-based foods benefit environmental sustainability but does not support the claim that healthy dietary patterns are necessarily more environmentally sustainable (Reinhardt et al., 2020). He highlighted another study comparing multiple indicators of environmental sustainability and normalized protein intake, which found that the contribution of different protein foods to sustainability differed depending on the indicator used (e.g., greenhouse gas emissions, land use, water depletion, water eutrophication, and particulate matter).
However, Conrad emphasized the importance of considering how these data are being normalized across different environmental sustainability indicators; normalized total protein intake is a useful comparator, but others could also be valuable. He concluded with research questions to bolster the evidence base for the nutrition-sustainability hypothesis. He suggested linking sustainability indicators to actual rather than theoretical dietary patterns, investigating whether sustainability outcomes are consistent across different measures of healthy eating, and considering how to balance trade-offs between nutrition and sustainability outcomes in developing dietary guidance.
Jayson Lusk, Purdue University, explored the socioeconomic impacts of increasing alternative protein intake in the diet, beginning with an overview of the economics of U.S. protein production. About 80 percent of total consumption comes from animal and dairy sources, versus 20 percent from plant sources (Pasiakos et al., 2015; Philips et al., 2015). He reported that roughly 45 percent of agriculture land use is permanent pasture and 43 percent is planted cropland, of which just 1 percent is devoted to plant-based protein sources. Corn, soybeans, and wheat—which farmers are most incentivized to produce—represent about 80 percent of cropland. Lusk added that in 2020, according the U.S. Department of Agriculture (USDA) World Agricultural Supply and Demand Estimates, around 70 percent of the total $364 billion in farm commodity receipts were related directly to producing or feeding animals; nonanimal protein food crops (e.g., grains, nuts) represented just a small share.
Lusk said that advocates of plant-based protein have made efficiency arguments that feeding protein to humans instead of livestock would require fewer farm acres devoted to those crops; however, questions remain about farm profitability. Surveys of farmers indicate that up to 90 percent believe that profitability would fall or remain the same if plant-based protein increased to 25 percent of the overall protein market, but almost two-thirds said that they would not be interested in a contract to grow a crop for use in a plant-based meat alternative, which Lusk described as reflecting an underlying negative perception in the farm community about those products (Mintert and Langemeier, 2021). Lusk also noted that even though the costs of producing 1 gram of protein are generally lower for plant-based sources, his research suggests that most consumers prefer to keep eating meat products and are willing to pay more to do so.
To illustrate current market trends for plant-based meat alternatives, Lusk reported that novel plant-based proteins are more popular among younger consumers. Between 2018 and 2020, their share in total ground
meat sales doubled from about 4 to 8 percent—but it has since declined overall. Between 2020 and 2022, no significant demand shift toward plant-based meat patties has occurred, a trend that Lusk predicted will continue unless prices fall and/or new options are available. Finally, he considered the extent to which these alternatives are either substituting animal-based sources or expanding the overall meat market. He posited that it is a combination: causing some substitution of animal products and also pulling people into the market who would not have been buying much meat otherwise.
Garrett Broad, Rowan University, and Robert Chiles, Penn State University, presented on the ethics of the ongoing debate around alternative proteins with respect to technology, animal welfare, and sustainability. Chiles characterized the current historical moment in terms of multiple sustainability crises, with the debate over alternative proteins deeply embedded in a broader sense of societal angst about the future fueled by socioeconomic inequality, rapid social change, and declining trust in our institutions. Alternative protein technologies could reduce costs and improve environmental outcomes for the urban majority—and hypothetically reduce animal suffering in the global food system—but also disrupt the livelihoods and culture of the rural minority, said Chiles.
To explore the ethics of these debates, Chiles highlighted tensions between rights-based theories, which hold that the ends do not justify the means, and utilitarian theories, which are based on the greatest good for the greatest number. Differing ethical perspectives on technology and animal foods are also vital to understanding the alternative protein debate, added Broad. He theorized that an individual’s ideological position on a scale from techno-optimism to techno-skepticism is a key pole that shapes the debate around alternative protein. People who fall on the techno-optimist side tend to embrace more technology-focused, centralized, industrial-scale, and utilitarian solutions to intractable dilemmas; techno-skeptics skew toward more rights-based, local-scale, decentralized, and culturally tailored solutions. Broad introduced the concept of “meat attachment” as another key pole; people with high levels of meat attachment tend to espouse the ideological commitment that meat is “natural, necessary, normal, and nice.”
Using those two poles as the axes of an ethical matrix, with techno-optimism/skepticism on the vertical axis and level of meat attachment on the horizontal axis, Broad introduced four categories to describe the key discursive communities in the alternative protein debate. “High-Tech Vegans” are situated in the techno-optimist and low meat–attachment quadrant; this community would tend to promote the production of alternative meat because most people will not become ethical vegans. “Ecomodernists” are also on the techno-optimist axis, but with greater levels of meat attachment, and tend to promote innovating protein in all its forms to meet demand. “Plant-Based Foodies,” in the techno-skeptic and lower meat–attachment quadrant, tend to advocate for reduced meat consumption through local, whole-plant foods rather than technological solutions. “Carnivore Traditionalists,” also in the techno-skeptic quadrant, but with high meat attachment, tend to focus on industrial food—both factory-farmed and laboratory-produced—as the core problem. He and Chiles concluded by discussing examples of initiatives that are attempting to bridge these ideological divides by promoting collaborative and open-source food and agricultural initiatives in alternative protein.
IMPLICATIONS FOR THE INDUSTRY, CONSUMERS, AND REGULATORS
The second session focused on implications of alternative protein products from industry, consumer, and regulatory perspectives.
Patrick Brown, Impossible Foods, provided an industry perspective of alternative protein products. He characterized the use of animals in the global food system as destructive, leading to a collapse of global biodiversity and ultimately a disastrous effect on the biosphere’s viability. About 85 percent of the entire human land footprint is devoted to animal agriculture, and the total amount of biomass released into the atmosphere as CO2 during land use conversion for animal agriculture equals about 22 years’ worth of fossil fuel emissions at the current rate.
The mission of Impossible Foods is to completely replace the use of animals by 2035, said Brown. He maintained that this could reverse the collapse of biodiversity and avert climate catastrophe by allowing that vast amount of land to recover its original biomass and, by halting livestock emissions from animal agriculture, mitigating large concentrations of greenhouse gas emissions on a shorter time line. Rather than attempting to change consumers’ preferences for animal products or advocating for government regulation of what consumers can eat and farmers can grow, Impossible Foods has approached this issue as a technology challenge, Brown explained. Its approach has been to build a new platform—using plant ingredients to match the biochemical and biophysical properties that determine the salient sensory and nutritional properties of meat—to replace the roles of animals in the food system and then let consumers choose. He described these alternatives as more nutritious, environmentally sustainable, and economical to produce. He also predicted that their prices will decline as technology evolves and production moves toward operating at scale. Brown ended with optimism that replacing animals with plant-based technologies would create a foundational opportunity to redesign and optimize the agricultural system to directly convert proteins and fats from plant crops into human food.
Mark Messina, Soy Nutrition Institute Global, focused on plant-based meat alternatives as transition and maintenance foods. According to Messina, meeting the escalating global protein demand by 2050 within current environmental limits is a primary challenge facing the global food system in this century. At current maximum intake levels, the global demand would require production of almost 80 percent more protein (Henchion et al., 2017). Messina contended that if populations shift toward a plant-based diet for health, environmental, and animal welfare reasons, then it will be critical to determine how best to produce the plant protein the world will need. Legumes and their subsets (pulses and beans) are affordable, good sources of protein and fiber and have a low environmental footprint, yet they remain underused around the world, noted Messina. He surmised that legumes are unlikely to contribute substantially to national and global protein intake, because consumers will probably not eat enough to shift the current animal:plant intake ratio in developed countries from 2:1 to 1:1. His view is that the new generation of plant-based meat alternatives that emulate the orosensory properties of meat could gain mass appeal, both aiding in the transition to a more plant-based diet and making it easier to maintain that diet.
Next, Messina considered how these alternatives compare nutritionally to meat and legumes. A trial comparing them to animal-based meat found several beneficial effects and no adverse effects from their consumption (Crimarco et al., 2020), and some research suggests that they may positively affect the gut microbiome (Toribio-Mateas et al., 2021). Relatively little research has compared plant-based alternatives to legumes, but the latter provide protein, fiber, B vitamins, iron, and potassium and may also reduce risk of cardiovascular disease, obesity, and overall mortality. On the other hand, a key advantage of plant-based meat alternatives over legumes is that they can be fortified with shortfall nutrients in plant-based diets, such as iron, zinc, vitamin B12, and calcium, and tailored to meet the needs of specific populations.
Sherry Frey, NielsenIQ, discussed consumer perspectives on alternative protein sources based on her organization’s research. Plant-based products are currently enjoying a “halo effect”—consumers are interested in the perceived health component, with “healthy” being the most common descriptor they use. However, their research suggests that consumers are often confused about what constitutes “plant-based” and how to make choices. For instance, consumers tended to conflate meat alternatives made with beans, vegetables, and grains with those made from isolated proteins. In choosing plant-based foods and beverages, she said that consumers are looking for realistic analogs that are natural and minimally processed, with labeling about sustainability or the environment.
The past 3 years have seen huge growth in plant-based alternative food sales, although that has begun to decline somewhat for alternative meats; Frey reported that alternative meat and seafood sales are currently lowest
among all plant-based foods. Alternative fresh and fully cooked meat products represent about 1.2 percent of the total fresh and fully cooked meat across the total store, with a roughly 38 percent price premium versus conventional products.
According to Frey, consumers cite taste, health, and nutrition as their top three reasons for regular use of meat alternatives, with animal welfare and the environment also driving increased interest. She noted that the emerging popularity of flexitarianism is also a key element of alternative meat consumption, with about 20 percent of households purchasing both meat and alternatives versus just 1 percent purchasing only alternatives. However, meat alternatives may not always meet consumer expectations, and trial and repeat consumption have been declining. Media coverage has shifted somewhat toward the negative as sales and units have decreased. A reason for this decline, she hypothesized, is that consumers may be paying more attention to the alternatives’ health attributes and processing level; many of them contain artificial ingredients.
Paul Hanlon, Abbott Nutrition, provided his perspective as an industry toxicologist responsible for evaluating the safety of alternative protein products. He explained that all food ingredient safety assessments—which may be triggered by a new food, a new process, or a new consumption pattern—address three major areas, and these considerations are not limited to the safety assessment of alternative proteins.
The first step is to define what the ingredient is, including manufacturing process and specification, said Hanlon. Alternative proteins include those manufactured from protein isolates extracted from traditional foods (e.g., oats, corn, soy) or using precision fermentation, whereby a microorganism is precisely modified to efficiently produce food substances (e.g., fungal-produced beta-lactoglobulin, yeast-produced beta-lactoglobulin, yeast-produced ovomucoid). He emphasized that establishing specifications for purity and impurities is critical to evaluating safety. For an alternative protein, purity specifications could include the “good for you” components, such as protein content, amino acid profile, fiber, and minerals; impurities are components that should be minimized, such as microbiological contaminants or heavy metals.
The second step is to evaluate how much of the ingredient people are consuming in foods that incorporate it, explained Hanlon, and how much of each of those foods people generally consume. He noted that this approach generally relies on conservative assumptions in which alternative proteins fully replace the conventional proteins used in a wide array of food products.
The third step is to determine whether the amounts consumed will be safe, said Hanlon. A key consideration is whether the alternative protein is different from the traditional proteins and, if so, how to demonstrate that these differences do not pose any incremental safety concerns. He explained that hypothesis-driven safety assessments are used to (1) review available information to identify potential risks associated with the traditional protein; (2) identify any significant differences with alternative versus traditional proteins in either production or composition; and (3) assess whether available information supports the safety of the traditional protein or it is necessary to conduct additional safety studies, such as assessments of general toxicity or genotoxicity.
Jeremiah Fasano, U.S. Food and Drug Administration (FDA), described regulatory decision-making tools for novel food technologies. As these continue to be generated by innovations in science and technology, FDA combines long-standing authorities with policy and scientific knowledge to regulate food safety, he explained. FDA’s authorities are set forth in the Federal Food, Drug, and Cosmetic Act (1938) and 1958 amendments, which mandate premarket approval for new uses of food additives.
The statutory definition of a food additive is broad: “any substance the intended use of which results or may reasonably be expected to result in its becoming a component or otherwise affecting the characteristic of any food, including any substance intended for use in producing, manufacturing, packing, processing, preparing, treating, packaging, transporting or holding food.” A key exception to this definition is the “generally
recognized as safe” (GRAS) provision: “Unless the substance is generally recognized, among experts qualified by scientific training and experience to evaluate its safety, as adequately shown to be safe under the conditions of its intended use.” GRAS substances are not subject to premarket approval requirements, although a voluntary premarket program is available. He explained that for GRAS to be applied to an ingredient, the evidence for its safety must be generally available, generally accepted, and tied to reasonable certainty of no harm from intended use.
According to Fasano, FDA has routinely evaluated ingredients derived from microbial fermentation (e.g., enzyme preparations, recombinant proteins, and biomass) using genetically engineered microbes through its premarket programs since 1990, when the first one to produce an ingredient for use in conventional food was evaluated and affirmed as GRAS. For human food products incorporating cultured cells from livestock and poultry, FDA and USDA’s Food Safety Inspective Service (FSIS) share oversight. FDA oversees cell isolation, cell line establishment, and cell culture and works with FSIS to transfer oversight during removal of cultured cells from the bioreactor for processing, packaging, and labeling. For animal cells from other species (including seafood) and all uses involving food for animals, FDA oversees the entire process from cell isolation to market. Fasano described FDA’s approach to the safety assessment of substances added to food as based on some key authorities and established standards of safety but flexible and adaptable to a wide variety of new technologies that are developed as science evolves, but it continues to rely on established standards of safety. FDA considers production processes to gain insight into how they may affect properties or safety of food, so the information needed to establish safety may change if a process changes, he added.
Douglas Balentine, FDA, provided an overview of the labeling of alternative protein foods. For most consumers, the food label is an important source of information to help them make choices and understand foods’ nutritional composition and benefits. Existing labeling requirements for all foods are applied to all alternative protein foods to ensure that labels are meeting a consumer’s expectations and needs. FDA may consider issuing guidance around how to apply the labeling guidelines appropriately for these new products as it deems necessary, as it is doing for plant-based beverages.
Balentine outlined required components on a food label, including statement of identity, net quantity of contents, name and place of business, ingredient statement, nutrition (unless it has an exemption), allergens (if applicable), and other material facts. He highlighted several components relevant to labeling of alternative protein products. The statement of identity is the name of the food, which may be required by law or regulation (e.g., butter) or could be its common name (e.g., tomato soup). If the name is not sufficiently clear, as may be the case with these products, then an appropriate description may be required (e.g., soy-based yogurt alternative). An ingredient statement is also mandatory, with each component listed by common name—this is important for novel alternative protein sources with which consumers may not be familiar. Allergen disclosures in the ingredient statement are vital for consumers who may not be aware of the allergenic potential of certain alternative proteins (e.g., dairy proteins fermented from yeast or other fungi). He explained that as new alternative ingredients enter the market, they may lead to new allergies or be cross-reactive with people who have other food allergies.
Balentine noted that nutrient content claims are likely to appear on new alternative protein foods to differentiate them from animal-based products; however, health claims about the relationship of a food substance to a health condition require FDA preapproval, and function claims about the relationship to a function must be supported by sound science, although premarket approval is not required. General claims—including claims about sustainability—must be truthful, not misleading, and viewed in context of the entire label, he clarified.
BALANCING ALTERNATIVE PROTEIN PROCESSING INNOVATION WITH SUSTAINABILITY, HEALTH, AFFORDABILITY, AND ACCESSIBILITY
The third session, held on August 18, explored strategies to balance innovation in the alternative protein landscape within a circular food system.
Liz Specht, Good Food Institute, charted the alternative protein landscape to consider how to feed up to 10 billion people by the year 2050 sustainably, securely, and safely. She emphasized that cycling calories through animals is inherently thermodynamically inefficient, equivalent to 85–97 percent food waste in production—which is untenable for a growing population. Specht described conventional meat supply chains as antiquated, lengthy, and highly vulnerable to production volatility and biosecurity threats (e.g., zoonotic disease outbreaks, antibiotic resistance). However, despite increasing awareness, global meat demand shows little sign of slowing. Thus, she proposed that meat should be produced differently—without the animal—rather than trying to convince consumers to change their diets.
According to Specht, alternative proteins from plants, fermentation, and cultivated animal cells represent a scalable, tractable, market-based solution poised for rapid growth. These platforms can yield a finished product in just hours or days, while also averting the risks associated with conventional meat production and offering environmental improvements at a potential scale of fourfold to tenfold. She characterized hybrid products that leverage multiple new modalities (e.g., cultivated fat cells mixed with plant-based protein sources) as the future of alternative proteins as this landscape continues to expand and move toward a circular bioeconomy. Although global meat companies are increasingly receptive to alternative protein production platforms, Specht reported that market penetration remains low, at just 1–2 percent in the United States. Moreover, alternative proteins remain substantially underinvested as a climate solution relative to their impact. The private sector alone will be unable to scale up this industry quickly enough to mitigate climate, public health, and food security risks, she predicted.
Specht offered three strategies to accelerate the transition toward alternative proteins: (1) building a robust innovation ecosystem supported by investments in open-access research and development to reduce costs and improve product desirability; (2) ensuring a clear path to regulatory approval to reduce market barriers to entry and incentivize market uptake; and (3) investing in supply chain and manufacturing infrastructure to alleviate production bottlenecks, accelerate scale-up, and aggressively drive down costs. She called for efforts to improve sustainability, cost, flavor, and nutrition across the value chain and address technical needs and research gaps for existing production platforms. Specht suggested that the lack of open-access knowledge is hampering the efforts of private companies seeking to bring products to market, urging governments to address the gap in open-access research funding and promote interdisciplinary approaches to address bottlenecks related to the technical workforce needed.
David Julian McClements, University of Massachusetts Amherst, discussed the design, production, and properties of plant-based foods. He said that ingredient manufacturers are seeking sustainable, abundant, and affordable protein sources that can be used to formulate foods that look, taste, and feel the same as the animal-based product they are designed to replace.
Meat, seafood, egg, and dairy products are all complex colloidal dispersions that require multisensory engineering to mimic their properties using plant-based proteins, explained McClements. Plant-based proteins can be extracted from a wide range of sources and offer different functional characteristics (e.g., foaming, emulsifying, binding, gelling) based on their behavior and underlying molecular characteristics. He delineated the characteristics of ideal sources: abundant, economically viable, sustainable, reliable and consistent from batch to batch, easily and economically extractable, functionally fit for purpose, and with multiple sources if supply chains are disrupted. However, identifying sources with those desirable attributes will require better understanding the structure and functional characteristics of plant proteins.
McClements noted that many plant-based products on the market have poor nutritional value compared to their animal-based counterparts, underscoring the need to create plant-based foods with nutritional profiles that match or exceed animal-based products. He suggested that key considerations in nutritional design and fortification include nutrient composition, nutraceuticals,
and dietary fibers; once formulated, the products should be tested for not just sensory attributes but also characteristics such as nutrient digestibility, absorption, bioavailability, and microbiome effects. Creating products for health and nutrition will require in vitro digestion models and in vivo human feeding studies. Although the food industry has long focused on taste, cost, and convenience as the drivers of consumer preferences, he called for a shift toward designing ethics, resilience, sustainability, and health from product inception.
David Kaplan, Tufts University, presented on the use of cellular agriculture and tissue engineering to generate the next-generation foods, whereby cells harvested from animals are used to create structured tissues as animal substitutes, using no part of the animal. He explained that the first step is to establish cell populations, typically using a biopsy taken from the muscle, to collect cells that are isolated, purified, and characterized to generate stem cells from both muscle and fat tissue. Stem cells are immortalized so they do not need to be repeatedly harvested from the animal, which can lead to variability issues. A large-scale cell culture is then used to generate large numbers of cells from a few initial cells, which are grown on biomaterial substrates that facilitate cell adherence, propagation, and differentiation into muscle, fat, and other tissue types used to make products after tissue maturation, harvest, and processing. A major advantage in cellular agriculture is direct access to these cells, which allows for greater control of the outputs in terms of cell composition for generating healthier foods, Kaplan noted.
Cellular agriculture currently faces multiple technical challenges, said Kaplan, particularly around cost and scalability. Growing cells that recapitulate the highly dense structural hierarchy of muscle tissue is complex and expensive, and the ability to achieve food-relevant production scale remains to be seen. Efforts are ongoing to ameliorate costs by reducing or eliminating the need for serum and growth factors, which are the costliest components of growth media. New textile engineering techniques are also being used in tissue engineering to generate cell-laden fibers that can achieve higher densities than traditional suspension or cell culture methods, which could help scale up production. Another challenge pertains to using genetic engineering to immortalize cells, which is the practice for bovine stem cells and yields genetically modified food products that may or may not be acceptable to consumers.
Kaplan highlighted alternative cell sources, including insects and other nontraditional species, as an opportunity to reduce costs and enable the future production of foods that are more therapeutic and personalized. For instance, cultivating foods from insect cells (entomoculture) is far less expensive than animal cells, because it does not require serum or specialized growth factors and the cells can be grown in suspension with little process control required yet have the same or improved nutrition compared to mammalian cells used in meat.
Mario Ferruzzi, University of Arkansas for Medical Sciences, described formulation and processing considerations in developing products with alternative and emerging protein ingredients. He explained that as ingredients, proteins are components that serve a multiplicity of functions in a diverse array of finished products, including water binding, viscosity building, gelation, emulsification, foaming, nutrient and flavor binding, and color formation.
As the alternative protein product landscape continues to evolve toward products sold in a “raw” state for cooking but generated by ingredients that are already heavily processed, it is giving rise to new challenges in formulation and processing, Ferruzzi said. These include creating the appropriate color for raw and ultimately cooked products, simulating texture, matching and masking flavors, and ensuring nutrition content, stability, and safety. To illustrate, he described how formulating ground beef alternatives must match the visual appearance and flavor (both raw and cooked) by manipulating other ingredients, including color ingredients, moisture control agents, and oils and fats to mimic the natural chemistries of home cooking.
Ferruzzi concluded by raising several open questions regarding formulation of alternative or emerging protein ingredients: (1) whether products should match or exceed nutritional values of the products they mimic, (2) whether formulations have potential unintended consequences that impact nutrition or safety, and (3) how to manage the risks and optimize the benefits of the presence of other components from plants.
James House, University of Manitoba, discussed current considerations in food processing and protein quality. He explained that the fundamentals of protein quality have two overarching components: amino acid composition, or how well the amino acid pattern matches amino acid needs; and protein digestibility and availability, or the extent to which the amino acids are digested, absorbed, and ultimately made available for metabolic demands. Plant-based proteins, particularly from whole-food sources, typically present with lower digestibility due to the encapsulating effect of the cell wall and the presence of protease inhibitors.
House maintained that the increasing interest in processed plant-based protein sources in North America underlines the need to appropriately position them for consumers to find them. Protein claims could be on front-of-pack labels, allowing for statements such as “rich in protein” or “excellent source of protein.” North American regulatory frameworks require protein quality substantiation for content claims, he noted; in the United States, these are substantiated using the Protein Digestibility-Corrected Amino Acid Score. However, it can be more difficult for whole plant–based protein sources versus processed products to carry these claims. The industry is struggling with several technical considerations related to these harmonizing methods for substantiating protein content claims (as required by FDA) and analytical considerations related to variability in these measures and the need to use a bioassay based on animal models. House suggested that if protein quality is to be maintained as a criterion, sources of variation (e.g., genotype, environment, processing, nutrition, climate) must be better understood.
Illeme Amegatcher, General Mills, focused on considerations for developing dairy products made from alternative proteins. Consumers are shifting toward dairy alternatives for taste, health, lifestyle, and environmental reasons, but many are seeking those that taste and function like the traditional dairy products. Replicating taste, texture, and functional attributes in alternative products to promote greater consumer acceptance remains a challenge. The approach of Amegatcher’s start-up within General Mills is to leverage precision fermentation–derived proteins in their applications as a tool to develop solution-oriented products with higher consumer acceptance. They combine these nonanimal proteins with plant proteins and other ingredients and then apply their proprietary process to yield nonanimal products with a taste and functionality like dairy. Amegatcher highlighted the ongoing challenge of securing a sustainable supply of precision fermentation–derived ingredients, given the limited number of suppliers.
Andrea Liceaga, Purdue University, examined edible insects as an alternative protein source. This has been an avenue of increasing interest in recent years due to insects’ high nutritional value and level of protein quality and quantity, which is equal to or even higher than conventional animal proteins. She explained that edible insects contain all essential amino acids and are good sources of fiber, monounsaturated fats, vitamins and minerals, and bioactive peptides. Moreover, in terms of sustainability, producing insect protein likely has a much lower environmental impact than most traditional proteins, she added.
Insects have been part of the human diet for thousands of years, and more than 2 billion people worldwide eat them today, Liceaga said, yet social taboo is the primary challenge. Although many consumers associate insects with poison or disease, studies demonstrate that they will eat food knowing that it contains insects if they cannot see the whole insect. This highlights the opportunity for food scientists to develop familiar foods with insects in nonrecognizable forms, such as in a powder; their nutrients can also be extracted for use in human food, animal feed, or health products.
An effective method for extraction is to use enzyme technology to break down the protein and separate it from the insect exoskeleton, where the chitin is located, said Liceaga. The protein hydrolysates or protein powders can then be more easily used in food formulation due to their enhanced functional properties. Over the past decade, insects have been successfully processed using other methods commonly used for traditional protein sources. She underscored the importance of considering the impact of these various methods on nutritional and sensory quality, and functional properties, as well as on the safety aspects—particularly the allergenicity of insect protein. Liceaga explained that some individuals who are allergic to shellfish or crustaceans are likely also allergic to insects, because some edible insect species contain tropomyosin proteins that cross-react with those of shellfish. However, evidence suggests that processing insects with enzymatic proteolysis using commercial enzymes may be effective in eliminating the immunoresponse in patients who are allergic to shrimp or shellfish.
During the final discussion, panelists included planning committee members Rodolphe Barrangou (North Carolina State University), Douglas Balentine (FDA), Nicole Tichenor Blackstone (Tufts University), Naomi Fukagawa (USDA), and Patricia Williamson (Cargill); they were asked to identify the single biggest driver of change in the current protein landscape. Blackstone emphasized the need to invest in cutting-edge interdisciplinary research and development, including basic science, to move the field forward and avert potential unintended consequences that often emerge when developing new technologies in different geographies. Balentine highlighted the challenges of encouraging consumers to adopt and regularly purchase these new products in development and finding sufficient raw materials for production to meet demand as the market increases. Fukagawa said that the source of protein is a negligible consideration as long as the amino acids that the body needs are available; thus, the focus should extend beyond the source of alternative food to other relevant factors, such as climate, cultivar, management procedures, processing, availability, accessibility, affordability, and equity. Williamson identified the consumer as a primary driver, with taste, cost, and texture remaining major hurdles to acceptance. She then highlighted the need for evidence-based, consumer-friendly claim substantiation for product formulations that balance taste, functionality, affordability, and health.
Panelists were also asked about the greatest gap to be addressed in moving forward collectively. Williamson and Blackstone both highlighted the need for greater consumer acceptance and understanding about these novel technologies and the benefits they can deliver. Balentine encouraged seizing the opportunity to build sustainable food systems that take advantage of a global ingredient market in a way that sustains existing food systems. Asked how to change the way that proteins are distributed, manufactured, processed, and grown to provide both sustainability and nutrition, Blackstone called for harnessing public- and private-sector interest to foster less polarized and more meaningful engagement between the alternative protein and livestock sectors. Balentine suggested focusing on simple, powerful messaging about harnessing the power of plants.
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DISCLAIMER This Proceedings of a Workshop—in Brief has been prepared by ANNA NICHOLSON as a factual summary of what occurred at the meeting. The statements made are those of the rapporteur or individual workshop participants and do not necessarily represent the views of all workshop participants; the planning committee; or the National Academies of Sciences, Engineering, and Medicine.
REVIEWERS To ensure that it meets institutional standards for quality and objectivity, this Proceedings of a Workshop—in Brief was reviewed by D’ANN L. WILLIAMS, Johns Hopkins University Bloomberg School of Public Health. LESLIE SIM, National Academies of Sciences, Engineering, and Medicine, served as the review coordinator
STAFF HEATHER COOK, CYPRESS LYNX, and MARIAH BRUNS, Food and Nutrition Board, Health and Medicine Division, National Academies of Sciences, Engineering, and Medicine.
SPONSORS This workshop was partially supported by the American Heart Association; Cargill, Inc.; Coca-Cola Company; Conagra Brands; Center for Science in the Public Interest; Danone North America; Feeding America; General Mills, Inc.; Institute of Food Technologists; Keurig Dr Pepper; Mars, Inc.; Mondelēz International; National Institutes of Health; Ocean Spray Cranberries, Inc.; U.S. Department of Agriculture; and U.S. Food and Drug Administration.
For additional information regarding the workshop, visit https://www.nationalacademies.org/event/08-17-2022/alternative-protein-sources-balancing-food-innovation-sustainability-nutrition-health.
Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2022. Alternative protein sources: Balancing food innovation, sustainability, nutrition, and health: Proceedings of a workshop—in brief. Washington, DC: The National Academies Press. https://doi.org/10.17226/26826.