Immune health: Planning the trials and measure for success

Industry and consumer interest in nutritional approaches to boost immune system function show the potential for the area, but challenges remain to building the science to support any such claims, says an internationally-renowned expert.

Philip Calder, Professor of Nutritional Immunology at the University of Southampton School of Medicine in the UK told NutraIngredients-USA.com: “There is huge interest from industry, and perhaps consumers, in the area of nutritional support for the immune system.

“For many people this is reducing the risk of coughs and colds. In theory it’s about protection against much more harmful pathogens,” he added.

At next month’s Nutracon in Anaheim, Prof Calder will present on the topic, Assessment of Immune Function in Human Nutrition Trialsas part of the Digestive health & immunity track. “I will be trying to present the concept that we might be able to influence the immune system through nutritional means,” he explained.

For this, Prof Calder, will highlight the complexity of the immune system, and explain what clinical significance results from laboratory studies may have.

Prof Calder points out the issue of individual variations among health people. A study by his group of 40-65 year old ‘generally healthy’ men showed significant variations amongst the subjects, and this has implications for trial design, he said.

“If you’re doing a study then you need to control for the variables, and that means doing a large enough study,” he said. “In general, larger studies do cost more money, and only the ‘more serious’ companies can compete.

“This is not an area for small companies,” he added.

Even the healthy get sick

In the abstract for his presentation, Prof Calder explains: “Individuals with immune responses significantly below ‘normal’ are more susceptible to infectious agents and exhibit increased infectious morbidity and mortality.

“However, it is not clear how the variation in immune function among healthy individuals relates to variation in susceptibility to infection. Currently, no single marker is available to predict the outcome of a dietary intervention on the resistance to infection or to other immune system-related diseases,” he adds.

In terms of what we measure, and how we measure it, Prof Calder will focus on the immune outcomes of a nutritional intervention following vaccination.

In his abstract, Prof Calder continues: “Some measures are more meaningful than others, and vaccine-specific antibody production, the delayed-type hypersensitivity response, vaccine-specific or total secretory IgA in saliva, and the response to attenuated pathogens, have been identified as the most suitable markers currently available.”

Such techniques have already been used for a small number of nutritional approaches, including prebiotics and probiotics, an area that Prof Calder will cover in his Nutracon presentation.

“Vaccine challenges have been used in these studies,” he said, “and I will talk about translating these results into clinical implications.”

The presentation will not focus exclusively on probiotics and prebiotics, but will also consider trials with vitamins A and E, iron and selenium, he said.

Indeed, we recently reported on the effects of vitamin E tocotrienol-rich supplements on immune response and immune function in healthy women following a vaccination. Findings published in the European Journal of Clinical Nutrition (doi:10.1038/ejcn.2010.184) indicated that women who received daily supplements of a palm tocotrienol complex for one month prior to a single tetanus toxoid (TT) vaccine experienced improvements in their immune response, compared with women who received placebo prior to the vaccine.

Professor Calder’s presentation forms part of Nutracon’s Digestive health & immunity track. Nutracon takes place from March 9-10, 2011. For more information and to register: www.nutraconference.com