09 Nov 2011 Mushrooms – a yet to be recognised superfood?

Fungi, ever more popular with consumers due to their culinary versatility, remain woefully underappreciated as a health food and functional ingredient source. Euromonitor International analyst, Emily Woon, takes a look at their superfood potential, arguing that fungi could be a potent source of functional ingredients.

MUSHROOMS, THE FRUITING BODIES of fungi, are nutritional powerhouses – they contain considerable quantities of essential amino acids (the building blocks of protein), B-vitamins including folic acid, potassium, phosphorus, magnesium, vitamin D precursors and fibre, as well as many other nutrients. At the same time as being highly nutritious, mushrooms happen to be a very low-calorie food. With around 20 calories per 100g fresh weight, they deliver only one fifth of the energy of the same quantity of cooked rice, and 10% that of lean meat.

People the world over have an inherent respect for fungi. Many contain powerful enough chemicals to make them deadly, and the fact that some possess medicinal properties is widely accepted. For instance, the extensive use of medicinal fungi is an integral part of the Traditional Chinese Medicine system which is practiced alongside “conventional” Western medicine in China.

There are plenty of scientific studies attesting to fungi’s health-giving attributes, including antibacterial, antiviral, antithrombotic and even some anticarcinogenic properties. Therefore, the concept that fungi can serve as a source of potent functional ingredients, some of which are suitable for imbuing foods and beverages with added health benefits, does not require a strenuous leap of consumers’ imagination.

A heart-healthy food begging for consumer recognition

In recent years, the selection of mushrooms on offer all year round on retailer shelves has exploded. This is particularly true in Western countries where in the past the only widely available type was the white button mushroom (agaricus bisporus), augmented by, in some countries, short-lived seasonal offerings of local mushroom varieties. Nowadays, the once considered rather “exotic” oyster mushroom (Pleurotus genus) and shiitake mushroom (Lentinula edodes), among others, have secured a firm place in mainstream retailers’ fresh produce aisles.

Consumers have come to appreciate these different types of mushroom in terms of culinary versatility but, unlike in Asia Pacific countries like China and Japan, the link between edible mushrooms and health benefits has not yet wrangled its way into Western consumers’ consciousness.

Shiitake mushrooms’ ability to lower cholesterol, which has been confirmed by numerous studies, for instance, remains virtually unknown, even among the growing consumer base on the look-out for heart-healthy products.

Euromonitor International estimates that in 2010 the value of products with cardiovascular health as their prime positioning focus amounted to US$6.8 billion for the 32 markets in which it conducts in-depth health and wellness research, up from US$5 billion in 2005. According to the World Health Organization (WHO), cardiovascular disease (CVD) is the leading cause of death worldwide, killing 17 million people every year, compared to cancer’s eight million, and its incidence is still very much on the rise. High levels of LDL cholesterol are a major cause of CVD.

Fuelled by the CVD epidemic, products like cholesterol-lowering spreads have taken off, despite their premium pricing. In Western Europe, for instance, value sales of functional spreadable oils and fats (the majority of which are cholesterol-lowering) rose by an estimated 29% over the 2006-2011 review period. Their standard counterparts, on the other hand, just about managed to achieve double-digit growth.

A number of naturally healthy foods with verified heart-health benefits have also garnered widespread consumer favour. Prime examples are olive oil, which registered a global value sales rise of 35% over the 2005-2010 period, and oats, primarily sold as a breakfast cereal. Riding on this trend, PepsiCo’s Quaker Oats brand, for example, boosted its value sales from US$38 million in 2001 to US$150 million in 2010.

The shiitake mushroom, however, which is just as worthy an occupant as olive oil and oats in the realm of heart-healthy superfoods, remains seriously underrated because of a lack of targeted promotion on the cardiovascular health positioning platform.

Rich in ergosterol, a Vitamin D precursor

Another of mushrooms’ healthy attributes which holds much potential for health and wellness success is their high content of ergosterol, a vitamin D precursor.

Vitamin D is essential for strong bones, teeth and the immune system. Evidence is continuing to emerge that vitamin D also plays an important role in cardiovascular functioning, diabetes prevention and respiratory health. Vitamin D is only present in animal foods. Particularly rich sources include oily fish and liver.

In theory, the human body is able to meet its vitamin D requirements through the exposure of skin to the sun, which triggers the conversion of precursor compounds into bioactive vitamin D. However, at some latitudes, the sun’s rays are not sufficient enough to effect this conversion process. Dark skinned people and those who cover up their bodies when outside are at particular risk from vitamin D deficiency, as are the elderly, growing children and people who consume only small quantities of animal-based foods, and vegans who do not eat any at all.

Mushrooms contain the vitamin D precursor ergosterol, which, when they are exposed to ultraviolet light, is converted into vitamin D. In July 2011, the Journal of Agricultural and Food Chemistry published a study, funded by the US Mushroom Council, which compared the vitamin D content of button mushrooms grown in the dark with those treated with a commercial processing technology designed to blast mushrooms with UV light after harvesting in order to increase their vitamin D content. The treatment boosted the mushrooms’ vitamin D content eight-fold compared to those that had not received any light. Other nutrients, such as vitamin C, folate and other B-vitamins, were not adversely affected. Mushrooms treated in this way retain their high vitamin D levels for around eight days.

So, opportunity beckons. On the health and wellness front there is now an emerging trend towards foods which have had their nutritional content augmented in a natural manner, rather than through the addition of functional ingredients. One popular example is milk, whose high omega-3 content is achieved by feeding cows a diet high in omega-3, instead of adding omega-3 ingredients to the milk retrospectively. As consumers are gradually becoming more aware of the importance of optimising their vitamin D intake, vitamin D- enhanced mushrooms should appeal particularly to those who prefer to increase their levels by natural means.

Mushrooms for weight management

As already alluded to, mushrooms’ very low calorific content makes them an ideal ingredient in weight management-positioned foods, as for example in ready meals. The texture and flavour of some mushrooms – and this applies especially to oyster mushrooms – resemble that of meat. This means that mushrooms do not have to be relegated to acting as a bland, low-calorie filler in composite meals but can star as a satisfying main ingredient in their own right.

Fungi are highly complex and variable organisms, and hence the number of functional ingredients that can potentially be derived from them is enormous, with applications in virtually all areas of human health. Weight management is no exception.

Belgian company KitoZyme, for instance, offers a fungus-sourced version of chitosan, a weight management ingredient that inhibits fat absorption in the body. Because chitosan is most commonly sourced from shellfish, KitoZyme’s vegetarian option holds great appeal. According to the company, its version possesses far greater fat binding ability than the animal-derived equivalent. In addition to weight management, it is also useful for cholesterol management because it inhibits the absorption of cholesterol from the gut.

Immune support – mushroom ingredients to rival probiotics

Another intriguing property exhibited by fungi is their ability to modulate the function of the human immune system, and a lot of work is being done by ingredients companies and research institutions to harness this attribute. For example, Japanese ingredients manufacturer Three-B Co, in a collaborative effort with the Center for Innovation and Business Promotion at Hokkaido University, has isolated a compound (trademarked as Bio-God) from an edible type of oyster mushroom (Pleurotus comucoplae, var. citrinopileatus) which induces the secretion of alpha-defensin in the human gut. Alpha-defensin is an antibacterial peptide which increases the body’s resistance to certain strains of harmful bacteria.

Euromonitor International’s health and wellness statistics show that, in its 32 selected markets, value sales of food and beverage products employing the immune support platform as their prime positioning focus increased by 45% over the 2005-2010 review period, amounting to nearly US$2.4 billion in 2010. (At present, this figure excludes infant formula positioned in this manner, but these products will be included in future updates.)

At the moment, pro/pre biotic yoghurt, and in particular pro/pre biotic drinking yoghurt, is still considered the flagship category in immune support-positioned foods, but there is no reason why immune support-positioned products should continue to be almost exclusively focused on probiotics, or why they should remain so narrowly confined to the dairy category in the future.

Consumers are clearly keen on immune health benefits and they will welcome other types of foods and functional ingredients positioned as such, as long as they are backed up by strong enough evidence. After all, persuading consumers in some markets, such as the US for example, that ingesting live bacteria is beneficial to health has been no small feat, and getting the message across has required considerable investment. Mushroom-based ingredients, on the other hand, should be far less controversial to market.