Today’s consumers show increased interest in products claiming to improve overall well-being, such as foods and beverages associated with increasing the body’s natural defenses to fight illnesses ranging from the common cold to life-threatening diseases. Thus, products designed to boost immunity are rapidly emerging as key drivers of the functional foods market.

Today’s consumers show increased interest in products claiming to improve overall well-being, such as foods and beverages associated with increasing the body’s natural defenses to fight illnesses ranging from the common cold to life-threatening diseases. Thus, products designed to boost immunity are rapidly emerging as key drivers of the functional foods market.

The immune system

The human body’s immune and defense systems must possess the strength they need to fight the continuous onslaught of reactive substances that attack and damage healthy cells and, as such, could lead to premature aging and disease. Many variables negatively impact immunity and other defense systems, including stress, lack of sleep, use of antibiotics, age, substance abuse and even genetics.

The most frequent cause of a depressed immune system, however, is nutrient insufficiency. With little picky eaters, this is a major concern. Studies have shown that an insufficiency in just one nutrient can profoundly impair the immune and defense systems. This insufficiency can result from lack of adequate nutrient intake, as well as poor digestion of foods and decreased absorption of nutrients.

Only recently has the vital relationship between digestive health and immunity been fully recognized. The digestive system is the largest immune organ in the human body and has several different kinds of immune and defense functions. For example, digestive enzymes exist throughout the gut, including the saliva, and not only do they break down food, they destroy bad bacteria. The acid in the stomach also destroys most disease-causing bacteria, while the gut produces unique proteins, such as immunoglobulins, which provide protection.

The immunity conferred by the digestive system differs from the immunity provided by lymphocytes. These cells are one of the five kinds of white blood cells circulating in the blood that have important protective functions. Although mature lymphocytes all look pretty much alike, they are extraordinarily diverse and distinct in their functions. They secrete antibodies that target specific bacteria and other invaders, also known as antigens. Antigens are any type of foreign organism or substance - bacteria, parasites or even allergenic foods - that the body recognizes as new, foreign, intrusive or harmful. 

The most abundant lymphocytes are B lymphocytes, often simply called B cells, and T lymphocytes, likewise called T cells. B cells are produced in the bone marrow. The precursors of T cells are also produced in the bone marrow but leave the bone marrow and mature in the thymus, which accounts for their designation. Each B cell and T cell is specific for a particular antigen. A number of nutrients are recognized as promoting growth or priming the functions of B cells or T cells.

The role of good nutrition

Research has shown nutrition affects the expression of genetic makeup and that good nutrition can alter our genetic programming to enhance health and stave off disease. Providing good nutrition to the body is a never-ending effort. Because we live in a time-deprived society, and most consumers cannot slow down enough to consume a balanced healthy diet composed of minimally processed, naturally nutrient-dense foods, consumers are turning to functional foods loaded with immune-boosting ingredients.

There are a number of recognized immune-boosting ingredients, as well as others where the science is still emerging, but look very promising. Dairy Foods takes a closer look at those ingredients that have application in many of the foods and beverages that dairy processors already manufacture.

Aloe vera - Used for thousands of years as a medicine for various topical ailments, aloe vera is increasingly being consumed as an immune system booster.  Aloe vera has adaptogenic properties, which means it increases resistance of an organism to adverse influences such as infection or stress. It is a natural anti-inflammatory and has been shown to promote healthy cell growth. Studies have shown that when consumed over a period of time, users report a greater sense of well-being, with more energy and less anxiety.

Ashwagandha extract - An indigenous Indian herb often referred to as winter cherry, ashwagandha functions as a stimulant, and as such is used in opening up the respiratory tract and treating diseases that originate in the chest cavity. Studies have also shown that it promotes the growth of white blood cells.

Beta-carotene - Produced by plants and converted by the body into vitamin A, beta-carotene harbors potent antioxidant properties. It also has been shown to stimulate and enhance many immune system processes, in particular, increasing the number of T cells.

Colostrum - The first milk produced by female cows and given to newborn calves, colostrum contains active antibodies, which are natural immune-boosting substances.

Curcumin - Found in turmeric, a primary spice in curry and part of the ginger family of herbs, this compound has been used since ancient times to treat a variety of ailments. Specifically, it has been shown to inhibit pro-inflammatory genes and cytokines.

Echinacea - Commonly referred to as the purple cornflower, this botanical is recognized as a remedy for reducing symptoms associated with the common cold. Some evidence suggests that echinacea’s mode of action in immunity is on phagocytic immune cells.

Fruit extracts - Phytonutrients can be extracted from superfruits such as açai and sea buckthorn and made to be virtually flavorless. These concentrated antioxidants have been shown to possess an array of immune-boosting functions.

Glutamine - Historically considered a nonessential amino acid, recent studies show that glutamine may become “conditionally essential” during inflammatory conditions such as infection and injury. Under appropriate conditions, glutamine is essential for cell proliferation. It can also act as a respiratory fuel and enhance the function of stimulated immune cells.

Grape seed extract - The proanthocyanidins found in grape seed extract have been shown to be 20 to 50 times greater than beta-carotene or vitamins C and E at scavenging free radicals. Further, studies have shown that grape seed extract helps promote the structural strength of blood vessels, which in turn helps promote healthy blood pressure levels, heart health and a proper inflammation response, all factors that contribute to immune response.

Green tea extract - As one of the most popular beverages in the world, green tea’s health benefits have been studied for centuries. Packed with flavonoids, where green tea really shines is in its levels of epigallocatechin gallate, or EGCG, another powerful antioxidant. EGCG has been shown to affect migration of immune cells to sites of inflammation and have a positive effect on chronic inflammatory disease. The fermentation process black tea goes through destroys a lot of the EGCG. Green tea, on the other hand, is steamed and not fermented, preserving that EGCG. If that isn’t enough, green tea is also a good source of the amino acid L-theanine, which aids in the production of germ-fighting compounds from T-cells.

Omega-3 fatty acids - The family of fatty acids referred to as omega-3s has been shown to boost immunity by producing white blood cells that destroy dangerous bacteria. Other studies have shown that omega-3s help the body to not overreact to an infection. They also have anti-inflammatory properties, which suggest that they can help slow down the effects of autoimmune diseases.

Probiotic cultures - Select clinically proven probiotic strains have been shown to support the immune system, assisting the body in fighting disease caused by bacteria and viruses. (See sidebar.) Further, a report from Packaged Facts, a Rockville, Md.-based market research firm, entitled Boosting Immunity through Digestion: The Relation among Probiotics, Prebiotics and Digestive Enzymes, shows that consumers are increasingly embracing the relationship between digestive health and immunity.

The report cites data from a poll conducted by Packaged Facts in February 2009 on consumer attitudes about functional foods. Results indicate that digestive health and heart health will be the two key areas of focus for purchasers of functional foods until at least 2013 - and of the two, digestive health is more palatable to consumers. It represents a larger growth opportunity because of its association with immunity, wellness and maintaining or improving good health, often with nearly immediate benefits apparent to the consumer. And, as consumers gain more awareness of the relationship between digestive health and immunity, and immunity as it relates to wellness and prevention of disease, the market for foods and beverages addressing digestive health will expand. 

Selenium - Selenium is believed to have an important role in boosting immune function by strengthening the disease-fighting properties of phagocytes, the white blood cells that destroy invading microorganisms.

Soluble fiber - A new University of Illinois study touts the benefits of soluble fiber, saying that it reduces the inflammation associated with obesity-related diseases and strengthens the immune system. Published in the May 2010 issue of Brain, Behavior, and Immunity, researcher Gregory Freund, a professor at the university’s College of Medicine and a faculty member in the College of Agriculture, Consumer and Environmental Sciences’ Division of Nutritional Sciences explains that soluble fiber changes the personality of immune cells, “they go from being pro-inflammatory, angry cells to anti-inflammatory, healing cells that help us recover faster from infection.” This happens because soluble fiber causes increased production of an anti-inflammatory protein called interleukin-4, he said.

In the experiment, laboratory mice consumed low-fat diets that were identical except that they contained either soluble or insoluble fiber. After six weeks on the diet, the animals had distinctly different responses when the scientists induced illness by introducing a substance (lipopolysaccharide) that causes the body to mimic a bacterial infection.

Two hours after the injection, the mice fed soluble fiber were only half as sick as the other group, and they recovered 50% sooner. And the differences between the groups continued to be pronounced all the way out to 24 hours, according to the study. Further, in only six weeks, the animals consuming the soluble fiber had profound, positive changes in their immune systems.

Vitamin C - Shown to increase the production of infection-fighting white blood cells and antibodies and increase levels of interferon, the antibody that coats cell surfaces, vitamin C is said to prevent the entry of disease. Vitamin C is the most widely recognized immunity booster.

Vitamin D - Known as the sunshine vitamin, vitamin D is critical to replenishing the lining of the gut and maintaining the integrity of the mucosa. This contributes to a healthy digestive system, which in turn leads to improved immune response.

Vitamin E - This powerhouse fat-soluble vitamin has many health-enhancing benefits. It enhances the production of B-cells and may also reverse some of the decline in immune response commonly seen in aging.

Zinc - Best known as the pill to pop when you feel the sniffles coming on, research on zinc shows that not only does it bolster the immune system to fight colds; it can also help stave off other common infections. It does this in part by increasing the number of infection-fighting T cells.  

Probiotic Cheese Linked to Healthier Immune System

Refrigerated dairy products have long been considered an ideal carrier for probiotics because they provide a suitable matrix for live microbes. Now a recently published clinical study in FEMS Immunology & Medical Microbiology (April 2010, DOI 10.1111/j.1574-695X.2010.00658.x) has shown for the first time that commercially produced cheese has the potential to provide immune health benefits when fortified with probiotics.

This study of 31 healthy elderly subjects involved three consecutive phases of monitored cheese consumption. In the first phase, the subjects ate 15 grams of a control cheese at breakfast for two weeks. In phase two, the intervention, they consumed 15 grams of a similar cheese containing a specific probiotic strain (109 colony forming units of Lactobacillus rhamnosus HN001) for the next four weeks. In phase three, the subjects switched back to consuming the control cheese for the last four weeks.

The cheese enhanced with probiotics that was consumed during phase two was shown to significantly improve immunity defense indicators in the subjects’ blood when compared with tests conducted during phases one and three. The findings are especially promising for the elderly, as age-related compromises in the immune system have been correlated to increased frequency and severity of infectious disease and chronic inflammatory disorders.

Lesson Learned: Make Immunity Claims Carefully

During summer 2009, Kellogg Co., Battle Creek, Mich., introduced product packaging claiming that Rice Krispies “now helps support your child’s immunity” and that the cereal has been improved to include “25% Daily Value of Antioxidants and Nutrients - Vitamins A, B, C and E.” The claim was withdrawn from packaging in November 2009 during the height of the swine flu epidemic.

“While science shows that these antioxidants help support the immune system, given the public attention on H1N1, the company decided to make this change,” Kellogg explained in a press release. “We will, however, continue to provide the increased amounts of vitamins A, B, C and E (25% Daily Value) that the cereal offers.”

It likely was coincidental that the “immunity claim” package made it to retail shelves at a similar time as the H1N1 swine flu virus became a national scare and a paramount concern to parents. With increased sensitivity to any marketing claims that even touched on the topic, it was in Kellogg’s best judgment to stop making the claim.

In the big picture, Kellogg was not breaking any laws. The company was not making a disease-related health claim; it was a structure-function type. Further, sufficient scientific evidence is available to support the correlation of these vitamins with boosting immune response. Had the claim not specified children, it likely would not have been an issue.

The new Lifeway BioKefir line of 3.5-ounce shots includes two flavors (pomegranate/blueberry and kiwi/passionfruit) flagged as “Immunity.” In addition to containing ProBoost, the company’s exclusive new blend of live and active probiotic cultures that have been clinically proven to strengthen immune response and alleviate digestive troubles, the Immunity drinks are packed with acerola. This fruit comes from the West Indies and contains more than 1,600 milligrams of vitamin C per 100 grams of fruit. It is also rich in other antioxidants, including carotenoids.