Dietary fibres can bolster the natural immune system to respond faster and more vigorously to infections. Photo Shutterstock PhD student Bart Moerings investigated whether dietary fibres can strengthen our immune system. ‘I was already aware of the positive impact of medication on our immune system, but I did not know dietary fibres can have an equally strong effect.’ Moerings obtained his PhD at the start of April.
‘We wanted to know whether we could temporarily bolster someone’s immune system with nutrition, the Wageningen way’, Moerings clarifies his PhD study.
This is particularly relevant for older people. ‘The elderly contract pulmonary infections relatively easily when they struggle with unrelated health issues. Their immune system appears to be exhausted, causing them to be more vulnerable to infections,’ Moerings explains. ‘We hope to prevent such infections with a natural supplement such as fibre.’
‘We have learned much about our natural immune system over the past decade, and about how we can train it to become stronger and respond more effectively to infections’, Moerings says. ‘Fibre, in particular beta-glucans, appears to play a part. Beta-glucans occur in fungi and bacteria, as well as in yeasts and, for example, grains such as barley. We wanted to know whether the same applies to the fibre arabinoxylan, which only occurs in other grains such as maise, wheat and rice.’
In vitro immune response
Moerings added both fibre types to the blood cells of the human natural immune cells. Half of the cells were enhanced with beta-glucans, while the other half was given arabinoxylans. He then added pathogens to both samples. The blood cells showed an immune response. The same happened when the cells were first exposed to pathogens, followed by adding dietary fibres and a second exposure to pathogens.
Hence, in vitro studies showed that both fibre types are capable of bolstering the natural immune response. Moerings: ‘We saw that the immune response increased in strength when the fibre particles were ground smaller.’
Mice
The effect shown under lab conditions has not yet been confirmed in humans. ‘We are currently at the stage in our research where we are trying to determine what fibre types and concentrations thereof are effective. At this time, it is neither practical nor financially viable to start testing on humans, but we have already tested on mice.’
The mice that were given low concentrations of beta-glucans in their feed showed a better immune response than those who were given nothing. Conversely, arabinoxylans appeared to lower the mice’s immune response.
Moerings: ‘A lower immune response may sound like an adverse effect, and would be if you are trying to strengthen the immune system. But it could serve a different purpose. Diseases such as atherosclerosis and arthritis are caused by an increased immune response, in which case suppressing the response would make sense.’
Health effects
The average Dutch person ingests less than the recommended amount of dietary fibre. ‘I believe that people are not sufficiently aware of the effect nutrition has on their health’, Moerings says. ‘Our knowledge on the effects of unhealthy diets, such as that they can cause lifestyle diseases such as Diabetes 2 and obesity, is increasing, but we don’t yet know enough about the underlying causes and the potential beneficial effects of nutrition.’
