A healthy diet is essential for preventing infection and keeping the immune system working properly. But what is a healthy diet? Clearly, if we know which nutrients and food ingredients are healthy, we can ensure we consume enough of them. For some dietary interventions and single nutrients, solid evidence from clinical research has been used to inform the public and provide dietary advice. A well-known example is the use of folic acid before and during the first weeks of pregnancy to prevent neural tube defects in new-borns.
Indeed, all nutrition and health claims used in the marketing of food products must be backed up by scientific evidence. For example, if a food manufacturer has an ingredient that looks like it might boost immunity in cultured cells, they must also prove it does the same in humans. However, food clinical trials are costly and time-consuming, especially if you’re looking for robust results. Being able to test an ingredient’s effect on health in relatively small groups and over short time periods therefore saves manufacturers both time and money.
To address this need, we have designed several proof-of-concept clinical trials. Traditionally, food clinical trials test the effects of a product on the long-term health status of a large group of healthy subjects. However, NIZO’s “human challenge models” rely on a more sensitive marker of health, namely stress resilience.
So how does it work? In these models, healthy volunteers are challenged by exposing them to a moderate external “stressor”. The stressors given to volunteers include mild gut or respiratory infections to test whether a certain ingredient enhances resistance to infection, for example. Starting a few weeks preceding the infection, half of them are given the product of interest while the other half receive placebo. Researchers compare their clinical and physiological responses to see how each group responds to the challenge. Such a model has been used to demonstrate in healthy adults that an ingredient added to infant formula can increase resistance to infection with bacteria that cause diarrhoea. The results of this study were published in The Journal of Nutrition in 2016.
Our clients are always pleasantly surprised to discover that a sufficient number of people are willing to volunteer for these challenge experiments. The controlled settings offer several key advantages, including fewer subjects and shorter timelines. Crucially, these studies also meet the regulatory requirements for substantiating health benefits for the gut and immune system.
However, our researchers don’t only look at clinical outcomes. We also collect biological samples from participants and analyse numerous biomarkers, including microbiome profiles. The wide range of systems and models available enables them to help clients study the mechanism of action of functional ingredients.