Article: Formulating Foods and Beverages for Enhanced Immunity -- October 2007
One of the top trends in foods for 2007, if not the top trend, is nutritional health. Healthy products, which up until recently have been referred to as “functional foods,” include items that enhance immunity. Many ingredients have been found to enhance immunity and are popping up in new products on store shelves everywhere. Some of the more common ingredients are discussed here.
Prebiotics and Their Sources
Prebiotics are indigestible food ingredients that encourage the growth of bacteria as they pass through the digestive system. Their role in improving immunity is a subject of great interest to food manufacturers.
“Prebiotics enhance the immune system in two ways,” states Lorraine Niba, business development manager for a well-known starch supplier. “First, by enabling the growth and proliferation of beneficial bacteria, the pathogenic and harmful bacteria are depleted and destroyed. Secondly, fermentation of prebiotics produces short chain fatty acids and lactate, which lower intestinal pH and maintain integrity of the epithelial cells that line the colon (colonocytes). This lower pH and stronger colonocytes protect against the harmful bacteria,” she adds.
“Prebiotic fibers have many sources and are naturally found in grains like wheat, corn, oats and barley; legumes like beans, peas and soybeans; fruits and vegetables like apple and grapefruit pectin; and roots like chicory. Milk oligosaccharides also have prebiotic activity,” offers Niba. “Many new ingredients are showing great potential as commercial prebiotic fibers. These include: isomalto-oligosaccharides (which contain a combination of isomaltose, isomaltotriose and panose), soy oligosaccharides (raffinose extracted from soy whey) and xylo-oligosaccharides,” Niba explains.
Easily incorporated into foods and beverages, many prebiotic fibers are water-soluble, disperse extremely well and can be added to a wide variety of foods and beverages such as breads, baked goods, nutrition bars, dairy products, soymilk, fruit juices and smoothies.
Soluble corn fiber and resistant starches are promising prebiotics that offer a variety of benefits to both producers and consumers. Prebiotic soluble corn fiber is a smaller molecular weight compound than resistant starch, and the 1-2 and 1-3 linkages cannot be broken down in the human body. Resistant starches are protected from digestive hydrolysis by three methods: seed coats, specific intact granule structures, or crystallized or retrograded non-granule structures.
“Soluble corn fiber has been found to increase the numbers of probiotic organisms found in the large intestine. These organisms can ferment the soluble corn fiber to produce beneficial fatty acids such as butyrate, which is a fuel for intestinal cells and associated with intestinal health,” states Lisa Sanders, a nutrition scientist (R&D) for a well-known starch supplier.
“While there are no official recommendations for amounts of prebiotic fiber to be consumed in a day, soluble corn fiber has shown beneficial prebiotic effects at 12g to16g per day. It has been well-tolerated without adverse effects at doses equivalent to 100% of the daily value for fiber, which is 25g per day for women and 38g per day for men, according to the Institutes of Medicine,” states Sanders.
“Currently, studies are investigating the immune-enhancing effects of soluble corn fiber. In vitro studies show encouraging results, where it has similar prebiotic effects to inulin, a well-researched fiber for immune enhancement,” she adds.
“Soluble corn fiber can be successfully formulated into all kinds of foods and beverages. Easy to use, it is a transparent fiber, meaning there is no change to color or flavor. Functioning like corn syrup, it can be easily added wherever corn syrup is used. However, being non-sweet, it can also be used in savory applications as a bulking agent or for fiber addition. Calorie reduction is possible, as it is only 2Kcals per gram,” states Michelle Schwenk, food scientist at a supplier of soluble corn fiber and resistant starch.
“Resistant starch is the only starch that has prebiotic activity because it is resistant to digestion, and thus reaches the colon. Other starches are digested and do not reach the large intestine,” explains Niba. “When prebiotic fibers are selectively metabolized (fermented) by colonic bacteria, they produce short chain fatty acids with health benefits.”
Probiotics are bacteria that can be added to food products that will enhance beneficial fermentation in the digestive system. Probiotics ferment differently, depending on the specific nature and structure of the prebiotic fiber present. Probiotic organisms like bifidogenic bacteria and Lactobacilli rapidly ferment prebiotic fibers containing fructo-oligosaccharide chains. On the other hand, a wider range of bacteria including Saccharolytics more slowly ferment prebiotics that contain dextrin chains. “Because of these differences, a combination of different types of bacteria in probiotics is more effective,” advises Niba.
Probiotics and the Immune System
According to Dan O’Sullivan, Ph.D, associate professor of the Department of Food Science and Nutrition at the University of Minnesota, “Probiotics can enhance the immune system in two ways. First, proteins and other structures on the outside of the organism stimulate a positive immune response when they pass by the immunogenic regions of the GI tract, specifically the Peyer’s Patches. And secondly, when some cells die, are broken apart by the bile system and their cell content is released, changes in the methylation of the DNA and deoxycytosine and deoxyguanine (GC) content positively stimulate the immune response.”
“The immune system is very complex,” explains Mirjana Curic-Bawden, senior scientist for a supplier of probiotics. “A balanced gut microbiota has a positive impact on immune regulatory functions,” she adds. “In order to modulate immunity, probiotic organisms must reach immune cells that are capable of recognizing receptors or that are sensitive to probiotic-specific catabolites. Certain probiotic strains belonging to Bifidobacterium lactis, L. casei and L. rhamnosus were shown to stimulate cells involved in immune regulation. Other studies have shown that specific probiotic strains can modulate the ratio of certain markers (Th1 and Th2) and are effective in reducing the development of allergy and setback inflammatory bowel disease,” she explains.
“We do know that as much as 70% of the human immune system is located in the digestive tract, where probiotic bacteria have their effect,” offers Gregory D. Miller, Ph.D., M.A.C.N., and executive vice president of Science and Innovation at Dairy Management Inc.™
As researchers continue to investigate different kinds of probiotic bacteria, each strain’s unique healthful characteristics will become better understood. For instance, Activia®, a probiotic yogurt from Dannon™ marketed to promote regularity, contains a branded probiotic agent.
“Dairy is an ideal vehicle for probiotics. In fact, most of the probiotics Americans consume today come from the growing category of fermented dairy foods, such as yogurt and yogurt drinks,” says Miller. One reason dairy is a good medium for probiotics is that probiotic bacteria need to reach the digestive tract in sufficient numbers to be effective, and the buffering effects of dairy foods appear to help the bacteria survive the trip through the digestive system.
The lower temperatures and shorter storage times associated with dairy products also promote probiotic viability and stability. In addition, probiotic bacteria seem to thrive on the nutrients found in dairy products. Research conducted at the Nestle Research Center in Switzerland showed that Bifidobacterium longum, a widely used probiotic strain, actually prefers lactose (milk sugar) over glucose as its primary carbon source. Researchers at the Wisconsin Center for Dairy Research at the University of Wisconsin in Madison are evaluating potential uses for probiotics in cheese.
Chocolate also is proving to be a good conduit for probiotics. Barry Callebaut announced earlier that it would be the first to launch chocolate with probiotics to strengthen the immune system and improve the nutritional profile of chocolate.
Probiotics on the Market
“Most of the probiotics that are currently on the market are of human origin, but it is not an absolute requirement,” states Curic-Bawden. Probiotics can be isolated from the GI tracts of healthy infants or from mother’s milk. The most common probiotics are Bifidobacterium, Lactobacillus acidophilus, L.casei, L. reuteri, L. rhamnosus and L. plantarum. Certain yeast strains such as S. boulardii are also known to have a probiotic effect. Curic-Bawden stresses: “The species name should indicate, but not necessarily mean, probiotic activity.” A potential probiotic strain has to have substantial clinical documentation before it can be marketed and promoted as a probiotic. Documented strains receive alphanumeric designations like LGG, BB-12, LA-5, etc.
As U.S. consumers grow more accepting of the idea of “healthy bacteria,” the market for probiotics is growing. In 2005, the U.S. market for yogurt and drinkable yogurt was about $9.7 billion, according to Packaged Facts. By 2010, this market is predicted to hit $15 billion. Activia®, the probiotic yogurt from Dannon™, is one of the most successful product launches ever.
At the 2007 IFT Student Association’s Product Development Competition, one of the top winning products was Trés Jelée, a one-of-a-kind, gelatin-based snack combining soy protein and probiotics in a nutritious, 100-calorie cup. The creation can be eaten as a healthy snack, meal addition or as a light dessert and is a non-dairy alternative that offers a triple blend of probiotic cultures.
The live, active cultures used to develop the product were Lactobacillus acidophilus, Bifidobacterium longum and Bifidobacterium lactis. Lactobacillus acidophilus was intended to target the small intestine while Bifidobacterium longum and Bifidobacterium lactis target the large intestine. The target dose for each organism was 1 X 109 CFU/g. In the original formulation, 1 X 109 CFU/g of each probiotic culture was added to the product. After six weeks of shelflife, it could be verified that over 1 X 107 CFU/g of Bifidobacteria and over 1 X 107 CFU/g of Lactobacillus acidophilus remained viable in the product. A larger initial dose will be added to the product in future formulations to ensure 1 X 109 CFU/g of probiotic cultures remain in the product through two months of shelflife.
Trés Jelée creates it own unique market niche by combining the benefits of soy protein and probiotics in a product unlike any other. This innovative combination and the interest expressed by many of the IFT attendees has resulted in high expectations for success if Trés Jelée is launched. The process of patenting the product is ongoing, and Trés Jelée may eventually appear on grocery store shelves.
Once the desired probiotic or probiotic mix is identified, food manufacturers have to consider just how much to add to guarantee its effectiveness. “To confer a probiotic effect, the selected strain(s) must be present at sufficient levels, which is strain-dependent and varies from 1 billion to 10 billion per serving (or per day). Hence, probiotics have to be present at high levels, survive during shelflife in application and not change the taste, flavor or appearance of the final product,” Curic-Baldwin explains.
Antioxidants, Vitamins and Minerals
According to Diane Hnat, senior marketing manager for a vitamin supplier, “Vitamins A, E and D have direct regulatory actions on leucocytes by modifying intercellular and intracellular communication pathways.” Chronic deficiencies of many trace nutrients, such as zinc and copper, can impair development of the immune system. Often found on food product labels are claims of “good source” or “excellent source” of vitamins or minerals. A good source is considered 10% to 19% of the recommended daily value, where an excellent source is at least 20% of the daily value per serving. “If the positioning of the food is to maintain the body’s immune defenses, these amounts would be typical,” adds Hnat.
Hnat continues, “Beverages are often a common vehicle for fortification in general; therefore, a beverage with nutrients to enhance immunity would undoubtedly be well-received.” A powdered drink mix currently on the market, Crystal Light on the Go Immunity, made by Kraft Foods Global Inc., claims on the label that the product “Helps Maintain a Healthy Immune System.” The product is enhanced with vitamins A, C and E and makes an “excellent source” claim for these vitamins.
There are various market forms of vitamins and minerals available that have been developed. Suppliers also provide special blends of nutrients for their clients’ specific needs.
New research suggests that North American cranberries may contain compounds called proanthocyanidins that can help ward off certain types of flu viruses by preventing the viruses from attaching to host cells. Other health benefits associated with cranberry consumption include: alleviating and preventing urinary tract infections in women; retarding ulcer-causing H. pylori infection; and gum disease prevention.
Antioxidant activity, which enhances immune function, can also be found in a wide variety of plant foods including fruits, vegetables grains, nuts, teas, chocolate and more.
Omega-3 Fatty Acids
Omega-3 fatty acids have shown promise in alleviating symptoms of certain autoimmune diseases including rheumatoid arthritis and ulcerative colitis, an inflammatory bowel disease. Clinical studies looking at omega-3 fatty acid supplements for inflammatory joint conditions such as rheumatoid arthritis often conclude that omega-3 fatty acid supplements can reduce tenderness in joints, decrease morning stiffness and reduce the amount of medication needed to treat rheumatoid arthritis.
Studies also indicate that diets plentiful in omega-3 fatty acids (and low in omega-6 fatty acids) may benefit people with other inflammatory disorders, such as osteoarthritis, by decreasing inflammation.
According to a University of Maryland Medical Center website, preliminary research suggests that omega-3 fatty acid supplements (ALA) may decrease inflammation and improve lung function in adults with asthma. In another small, well-designed study of 29 children with asthma, those who took fish oil supplements rich in EPA and DHA for 10 months experienced improvement in their symptoms when compared to children who took a placebo. Considering the anti-inflammatory characteristics of omega-3s, it is possible that omega-3 fatty acids could help treat a number of related immune conditions.
Mintel reports that more that 1,000 products that contained omega-3s were launched globally last year, with most of them in the dairy, bakery and processed meat and fish categories. New product launches with omega-3 have increased each year, due to widening consumer knowledge and acceptance of its benefits.
There was a time when the fishy taste associated with fish oil prevented consumer acceptance of products incorporating omega-3s. However, today’s technology allows many foods to utilize the benefits of omega-3s with no flavor or odor issues. One supplier uses a “double shell protection” for the omega-3 ingredients, “producing a free-flowing, dry powder with a unique molecular construction that locks in the health benefits and locks out even the slightest hint of fishiness,” according to company literature.
Foods incorporating omega-3 fatty acids now include milks, yogurts, juices, bread products, pizza, waffles, tortillas and many other new products which seem to be jumping onto store shelves as we speak. Omega-3s are one of the top functional foods ingredients of 2007.