Mycoprotein

Nutritional and Health Properties

Abstract

Mycoprotein is derived from the filamentous fungus Fusarium venenatum, first discovered in the 1960s. Mycoprotein is high in protein and fiber and low in energy and saturated fat and contains no trans-fat or cholesterol. A systematic search of the PubMed identified 13 human studies investigating the health properties of mycoprotein, with some evidence of sustained satiety, improved metabolic profiling, and muscular protein synthetic response that warrants ongoing investigation. Mycoprotein is produced commercially, with low environmental impact, and is used as an ingredient in products marketed under the Quorn trademark.

Mycoprotein first emerged in the early 1960s when the British Industrialist Lord Rank sought to find a new safe and alternative source of protein that could be used to offset the global food crisis fueled by population growth.¹ By 1967, Lord Rank and the Rank Hovis McDougall group had tested more than 3000 soil organism samples from across the world and identified Fusarium venenatum from a garden in Marlow, Buckinghamshire, in the United Kingdom.¹ It was discovered that this aerobic microfungus could convert carbohydrate into protein—a process that could be applied on a larger scale to produce food-grade protein, today known as mycoprotein (Figure 1). Mycoprotein was approved for sale by the UK Ministry of Agriculture, Fisheries, and Food in 1985 and is now produced by Marlow Foods in three 150 000-L fermenters each capable of producing ca. 2 tonnes per hour of mycoprotein.² In its first stage of production, F venenatum is grown in an aerobic fermentation system using carbohydrate and nutrient substrates required for growth.³ The mycelium of the fungus is then heat-treated to reduce the ribonucleic acid content to approved levels. Once the ribonucleic acid levels are reduced, the suspended hyphae are centrifuged and recovered and the supernatant contains mycoprotein.⁴ Steaming, chilling, and freezing processes during the final stages of production give mycoprotein a meat-like structure similar to chicken when observed under a microscope (Figure 2). Table 1 compares the nutritional composition of mycoprotein and Quorn mince, which is around 88% mycoprotein by weight.⁵

FIGURE 1.: How mycoprotein is produced.

FIGURE 2.: Texture of soya (top), poultry (middle), and Quorn (bottom).

Currently, expanding populations and limiting natural resources are again leading to demands for alternative dietary proteins.⁶ It has been estimated that 1 billion people already have inadequate protein intakes.⁷ The global population is further expected to rise from the current 7.2 billion people to 9.6 billion by 2050, stretching protein shortfalls even further.⁷ Recent analysis from the US National Health and Nutrition Examination Survey (2001–2014) showed that teenage girls (14–18 years) and older (≥71 years) non-Hispanic black men are most likely to have inadequate protein intakes, with 11% and 13%, respectively, having population percentages below the Estimated Average Requirement (children aged 1–3 years, 0.87; children aged 4–13 years, 0.76; boys aged 14–18 years, 0.73; girls aged 14–18 years, 0.71; adults aged ≥19 years, 0.66 g protein kg⁻¹ d⁻¹).⁸ Alongside the need for more extended protein sources, trends are changing the form of protein that consumers desire. Flexitarianism, or semivegetarianism—a portmanteau of “flexible” and “vegetarian”—is a contemporary trend that is gaining popularity, especially among young women.⁹ The movement to reintegrate plant protein or sustainable meat substitutes alongside or instead of animal protein is also fast gaining momentum.^6,10

Sustainable protein sources are also important in endeavors to meet protein requirements of aging populations—a life stage where protein intake is regarded as an important dietary approach to maintain muscle mass, strength, and preservation of independence.¹¹ Increasing life expectancy rates indicate that sarcopenia prevalence, presently between 5% and 40% of the general population, will increase further.^12,13 Although sarcopenia clearly has a multifactorial pathogenesis, nutritional status, including the balance of essential amino acids, has an important role to play—particularly as essential amino acids stimulate muscle protein synthesis to a greater extent than nonessential amino acids.^13,14 It has also come to light that the current Recommended Dietary Allowance for protein (0.8–1.2 g/kg/d) may be inadequate because the timing and distribution of protein consumed across a day are now thought to be potentially as important as the overall quantity.¹⁵

Given the expected expansion in population growth, coupled with current consumer demands, the present article presents the nutritional and health aspects of mycoprotein, with particular focus on satiety, metabolic, and muscular health.

MYCOPROTEIN FACTS

• ○ Mycoprotein was developed during the Green Revolution, a time when there were concerns about feeding growing world populations.
• ○ F venenatum is an Ascomycota (division of the fungi kingdom), 1 of the largest groups within the fungi family, and includes truffles and morels.
• ○ Fermentation—the same age-old processes used to create beer and yogurt are used to convert F venenatum into mycoprotein.
• ○ Steaming, chilling, and freezing processes give mycoprotein a meat-like structure similar to chicken when observed under a microscope.

NUTRITIONAL PERSPECTIVES

In accordance with European Commission, nutrition claims that can be made for mycoprotein are as follows: (1) “high in protein,” that is, at least 20% of the energy value of the food is provided by protein; (2) “low in fat,” that is, contains no more than 3 g of fat per 100 g of solids; (3) “low in saturated fat,” that is, does not contain more than 1.5 g of saturated fatty acids per 100 g of solids; and (4) “high in fiber,” that is, contains at least 6 g of fiber per 100 g.^16,17 It should, however, be noted that regulations vary among countries, and in US regulations, “high” means 20% of the Daily Value per reference amounts customarily consumed (RACC).¹⁸ Mycoprotein is an important provider of dietary fiber, containing around 5 g per RACC. Because the Daily Value for fiber in the United States is 25 g, mycoprotein would therefore meet the US standard for the claim of “high” in fiber.

As seen in Table 2, using US data for RACC¹⁹ and from the US Department of Agricutlure Food Composition Database,²⁰ the nutritional profiles of plant- and animal-based food sources can be compared. Mycoprotein is lower in energy than some nonanimal protein sources. Protein levels in mycoprotein are similar to that of cooked chicken. With respect to protein, it should be noted that approximately 8% to 10% of the protein analyzed is nonprotein nitrogen. When looking at the RACC, mycoprotein has one of the lowest total fat and saturated fat profiles—providing less than 1 g of saturated fat per portion. It is also free from cholesterol and trans-fats.

As shown in Figure 3, mycoprotein is an important source of fiber. The dietary fiber present in mycoprotein is naturally occurring, and typically one-third of this is chitin (poly n-acetyl glucosamine) and two-thirds is β-glucan.²¹ Linear β-glucans (from cereals) and branched β-glucans (fungi; yeast) have been shown to have immunostimulating effects and participate in physiological processes related to the metabolism of fats in the human body.^22,23 Using the RACC and US Department of Agricutlure Food Composition Database data, it seems that mycoprotein contains more fiber than almonds, black beans, chickpeas, and peanuts do. However, it should be considered that the fiber foods between these food substances vary, with nuts and legumes contributing important nondigestible carbohydrates and lignin that are intrinsic and intact in plants.²⁴

FIGURE 3.: Total fiber (g/RACC serving).

TABLE 1: Nutritional Composition of Mycoprotein and Quorn Mince (per 100 g)

TABLE 2: Nutrient Profile of Mycoprotein Compared With Other Protein Sources (per RACC Serving)

Mycoprotein also provides a wide spectrum of inorganic compounds, and when applying European Commission nutrient claims, mycoprotein falls under the category of being “high” in zinc, selenium, phosphorous, manganese, copper, and chromium and a “source” of riboflavin.^17,25 Mycoprotein is lower in iron than meat and does not provide vitamin B₁₂. Zinc from this dietary protein may also not be as biologically available as from classic meat foods, although cooking methods may impact bioavailability.²⁶

Safety

In 2001, the US Food and Drug Administration deemed mycoprotein as safe for use in food generally, excluding meat and poultry products and infant formula.²⁷ According to the Food and Drug Administration, there are 160 commonly consumed foods with the capacity to cause a rare allergic response.²⁸ The “Big 8” are eggs, fish, milk, peanuts, shellfish, soy, tree nuts (eg, almonds, cashews, pecans, pistachios, and walnuts), and wheat, which account for 90% of food allergic reactions.²⁸ Mycoprotein, along with every other protein source, therefore has some allergenic potential.²⁹ However, the prevalence of this is rare—the rate of reported adverse reactions to Quorn is quite low at 1 reported illness per 683 665 packs,²⁹ and for most individuals, mycoprotein represents a safe foodstuff.

MYCOPROTEIN NUTRITIONAL CHARACTERISTICS

• ○ Mycoprotein is high in protein (>20% of the energy value of the food is provided by protein) and fiber (provides >5 g per serving).
• ○ Mycoprotein is low in total and saturated fat and an excellent source of fiber (>5 g per serving).
• ○ This meat-free protein can provide an alternative source of healthful protein and contribute to a balanced plant-based eating style.

HEALTH PERSPECTIVES

A PubMed database search was undertaken to identify human, peer-reviewed studies investigating interrelationships between mycoprotein, satiety, metabolic, and muscular health. The following search terms were used to identify studies: “mycoprotein” combined with “satiety,” “metabolic health,” “cholesterol profile,” and “muscle mass.” The results were reviewed to identify relevant publications. As shown in Tables 3 and 4, a total of 13 English-language trials and studies were identified.^5,30–41

TABLE 3: Mycoprotein: Satiety and Metabolic and Muscular Health—Study Methods

TABLE 4: Mycoprotein: Satiety and Metabolic and Muscular Health—Study Findings

Satiety and Energy Intake

Of the 13 identified trials, 5 noted reduced energy intakes or satiety effects after mycoprotein ingestion.^{31,32,34,37,38} An early study with 18 lean healthy adults showed that mycoprotein eaten as a part of a meal and providing 11 g of fiber reduced evening energy intakes by 18%, implying potential effects in relation to later satiety.³⁷ Similarly, other early work with 13 healthy women showed that the ingestion of 130 g mycoprotein reduced energy intake on the day of the study (by 24%) and the next day (by 17%).³⁸

Work conducted with 43 overweight women (mean body mass index, 27.4 kg/m², and age, 30.1 years) who ate 3 laboratory meals (220 g pasta with chicken, tofu, or mycoprotein) on 3 test days demonstrated that subsequent food intake was lower after mycoprotein and tofu preloads, indicating satiety effects.³⁴ Another study on 35 overweight adults providing 32 g of protein from isocaloric mycoprotein or chicken meals found that lunchtime energy intakes were significantly lower after earlier mycoprotein ingestion.³² Building on this study, research conducted on 55 healthy overweight and obese adults found that ad libitum energy intake significantly reduced by 10% (67 kcal) after consumption of a high-mycoprotein risotto meal (132 g) compared with an isoenergetic chicken meal at a high content.

Metabolic and Cholesterol Profile

With regard to metabolic health and cholesterol profile, 9 studies were identified. Five noted improvements in blood lipid levels.^5,36,39–41 In 1 of the first trials, cookies providing 20 g F venenatum improved cholesterol levels among 100 adults studied.⁴¹ Other early work found that mycoprotein ingested as cookies (26.9 g dry weight/d; 130 g Quorn at normal moisture content) significantly reduced plasma cholesterol by 13% and low-density lipoprotein cholesterol by 9% and high-density lipoprotein cholesterol increased by 12% compared with the control diet providing meat when eaten by individuals with slightly increased cholesterol levels at baseline.³⁹ Ishikawa³⁶ also found that subjects with increased cholesterol levels were most likely to benefit from mycoprotein consumption. A more recent intervention study found that 88 g of wet weight mycoprotein daily (dry weight equivalent to 21 g Quorn) eaten daily over 6 weeks significantly reduced total and low-density lipoprotein cholesterol, particularly among those with higher baseline blood cholesterol levels (≥4.19 mmol/L).⁵ Improvements in cholesterol profiles may be attributed to the fact that mycoprotein does not contain cholesterol.

Four studies observed improvements in markers of glycemia and insulinemia.^30,31,33,35 One of the first studies allocated healthy adults (n = 19) to drink a ≈330 mL milkshake containing 20 g mycoprotein or no mycoprotein in the control milkshake. Shakes were closely matched for energy, carbohydrate, fat, and protein, although the fiber content was higher in the mycoprotein versus the control shake (5.0 vs 1.1. g) The shake providing mycoprotein resulted in a 13% reduction in glycemia 60 minutes post ingestion.³⁵

Work by Bottin et al³¹ has found that all doses of mycoprotein—44, 88, and 132 g—significantly reduced 24-hour insulin levels compared with chicken controls that were closely matched for energy and macronutrient content when consumed by overweight and obese volunteers aged 18 to 65 years with a body mass index of 25 to 32 kg/m². Earlier research by the same team on 35 overweight individuals also showed that 30 g mycoprotein from a soup significantly reduced insulin levels at 15, 30, and 45 minutes after the consumption when compared with a whey protein control.³³ More recent work on 12 healthy young men given a test drink providing 20 g milk protein or a mass matched bolus of mycoprotein (20, 40, 60, and 80 g) found that mycoprotein ingestion led to slower but more sustained hyperinsulinemia and hyperaminoacidemia compared with milk when measured during a 4-hour postprandial period, with these effects seeming to plateau with the 60 to 80 g bolus.³⁰

Muscle Protein Synthesis

One study recently assessed the bioavailability and insulinotropic effects of mycoprotein. The trial, which comprised 15 healthy young men ingesting mycoprotein in a dose-response manner, found that 40 g mycoprotein (ie, 18 g total protein) was sufficient to stimulate a muscle protein synthesis response whereas 60 g mycoprotein (ie, 27 g total protein) was considered ample to optimal stimulate muscle protein synthesis rates in healthy young men.³⁰ These important findings highlight mycoprotein as a bioavailable and insulinotropic protein source that could stimulate muscle protein synthesis.³⁰

MYCOPROTEIN HEALTH PERSPECTIVES

• ○ When consumed as part of a healthy diet, evidence indicates that mycoprotein consumption has potential satiety effects and reduces energy intake at subsequent meals.^31,34,37
• ○ Mycoprotein ingestion could improve cholesterol and low-density lipoprotein profiles, particularly for those with elevated levels at baseline.^5,39,40
• ○ Mycoprotein seems to be a useful and bioavailable source of dietary protein that can help to stimulate muscle protein synthesis.³⁰

DISCUSSION

Mycoprotein was developed in the 1960s to overcome protein shortages and is now sold in 16 countries as Quorn.⁴² Mycoprotein was first approved for sale in the United Kingdom in 1984⁴³ and approved for the US market in 2002.²⁷ Meat analogs such as mycoprotein are sought on a global scale by vegetarians, vegans, and those who and seek alternative proteins with a taste and texture similar to meat.⁶ In the United States, data show that those 2 years or older overconsume between 126 and 167 g of total meat daily, the intake majority within the protein food group—around 43% of the total protein available in the US food supply.⁴⁴ Additional increased demands for meat are forecast to come from Asian markets, with China already consuming more meat than either the United States or the European Union does.⁴²

Consequently, from an environmental perspective, the world will require alternative proteins that provide sustainable solutions, with lower carbon footprints producing fewer greenhouse gas emissions. As mentioned, the global population is anticipated to rise from the current 7.2 billion people to 9.6 billion by 2050,⁷ and our understanding of climate change continues to evolve. How we produce foods with potential health benefits is becoming increasingly important. Greenhouse gas emissions, land shortages, water usage, and restricted or controlled use of antibiotics are all putting strains on traditional protein production methods.⁴² Subsequently, for the present and succeeding generations, novel and safe dietary proteins such as mycoprotein are important to support health while having a lower carbon footprint.

From a nutritional point of view, mycoprotein is particularly unusual in that it provides high amounts of protein and fiber but has a low fat profile.⁴² In particular, its protein profile has been found to promote muscle synthesis, which has relevance in sports nutrition and supporting healthy aging.³⁰ Given today’s obesogenic environment and the general underconsumption of dietary fiber in Western regions, mycoprotein provides a useful high-fiber food source that is comparatively lower in energy, fat, and sodium compared to other protein sources. Health professionals, including dietitians, may play an important role imparting information about mycoprotein as a valuable and alternative protein source.

Finally, as seen in the studies reviewed, it seems that mycoprotein may show great promise for satiety, metabolic, and muscular anabolic effects, largely attributed to its high protein and fiber and low fat profile.³⁷ Bearing this in mind, this novel protein source could potentially play a role in helping to support a healthy lipid profile and subsequent heart health. Ongoing randomized controlled trials using mycoprotein in healthcare settings would be worthy of continued investigation.

Conclusions

In conclusion, mycoprotein has been growing in popularity internationally for over 5 decades. It has been on the market since 1985 and has a long-standing reputation of being safe, with its allergencity risks being no higher than that of some other protein sources. This innovative protein source can be consumed by nonmeat consumers, as well as those looking to keep their meat intakes aligned within dietary guidelines. Its low energy, low fat, and high fiber profile makes it an ideal healthy protein source. Emerging evidence also indicates wider benefits from mycoprotein consumption, including potential satiety and metabolic and muscular benefits. Healthcare professionals should be interested in advocating the use of mycoprotein within American diets.