Influence of soluble corn fibre on markers of immunity & inflammation
Research type
Research Study
Full title
Soluble corn fibre and markers of immunity and inflammation in older adults: a randomised controlled trial
IRAS ID
317212
Contact name
Philip C Calder
Contact email
Sponsor organisation
University of Southampton
ISRCTN Number
ISRCTN15979195
Duration of Study in the UK
0 years, 8 months, 31 days
Research summary
Research Summary:
As people age their immune system can become weaker and there is often an increase in inflammation which contributes to common age-related diseases. These include heart disease, metabolic disease such as type-2 diabetes, the loss of muscle mass and strength known as sarcopenia, the weakening of bones known as osteoporosis, some cancers, and possibly dementia. A weaker immune system means older people can be more susceptible to infections and that some vaccines may not work as well as in younger adults.
The “healthy” bacteria in the intestine (called gut microbiota) have an influence on the immune system and inflammation. Interestingly, intestinal bacteria also change with ageing and this can result in the loss of protective function and in the movement of harmful bacterial toxins and whole bacteria from the gut into the blood. Why these changes occur and how we can improve this in ageing are not understood. What we do know is that the intestinal bacteria can be altered by diet. Fibre intake is considered essential for optimal gut health including maintaining healthy gut bacteria. However, most people do not eat enough fibre. We plan to investigate whether fibre supplements improve measures of the immune system, inflammation and intestinal bacteria in people aged over 60 y. The fibre we will use will be soluble corn fibre. This resists digestion and absorption in the small intestine and passes to the large intestine where it can be fermented by the gut microbiota. Soluble corn fibre has been shown to beneficially modify gut microbiota but its effects on the immune system and inflammation have not been tested in older people.
We plan to compare the effects of soluble corn fibre on the immune system and inflammation and gut microbiota with the effects of a placebo which is a poorly digested sugar called maltodextrin.
Summary of Results:
Intake of fibre is low in the UK. The latest data indicates that only 9% of UK adults eat as much fibre as they should and that average intake of fibre among older adults is just over half of what is recommended. Fibre is important for normal bowel function and also decreases the likelihood of getting bowel cancer. Fibre also promotes healthy gut bacteria. This is turn is believed to help the immune system to work and to help to control inflammation in the body. Older people can lose healthy gut bacteria and may have weak immune systems and increased inflammation. This is not good for their health. Getting insufficient fibre maty link all of these things together. To study this we carried out a placebo controlled trial in 72 people aged over 60 years. They had a usual average fibre intake of about 20 g each day (two-thirds of what is recommended). If they were in the fibre group they took an extra 20 g of soluble corn fibre each day for 12 weeks. This was a powder they stirred into cold drinks. If they were in the placebo (“dummy”) group they took a harmless powder that is not a fibre. 67 out of the 72 people who started the study finished it. We collected fecal samples at the start and end of the study to measure the bacteria present. We found that eating fibre increased the numbers of several different types of healthy bacteria in the feces. We collected blood at the start and end of the study to measure the numbers of different types of immune cells in the blood and to test how well those cells worked in laboratory tests. We also measured the amounts of chemicals in the blood that indicate inflammation. However, despite the changes in the gut bacteria there were no changes in immune cell numbers or function and only some small changes in the chemicals marking inflammation.
REC name
South Central - Hampshire A Research Ethics Committee
REC reference
22/SC/0414
Date of REC Opinion
28 Dec 2022
REC opinion
Further Information Favourable Opinion