The amount of fibre and the type of protein you eat is linked to chronic inflammation, according to the findings of a recent study published in the journal Nutrients.C-reactive protein (CRP) is a protein produced by the liver that signals inflammation in the body. Chronically elevated CRP levels are linked with several chronic health conditions that are leading causes of mortality (death), including cardiovascular disease (e.g., heart disease and stroke), diabetes, chronic kidney disease, and cancer. Nutrition is one factor that can affect CRP levels, likely via changes in the composition and metabolic activity of the gut microbiome (bacteria, fungi and viruses). Previous studies have found that people with higher intakes of dietary fibre were less likely to have elevated CRP levels, while other studies have found that eating plant protein is associated with lower CRP levels compared to animal protein. This study set out to explore the relationship between dietary fibre, protein, and inflammation in older adults.Researchers conducted a cross-sectional analysis of 128,612 UK Biobank participants aged 60 years or older. Participants in this study had completed an average of five 24-hour dietary recalls and had CRP levels measured.The UK Biobank study is a large prospective cohort study of 500,000 participants from the general UK population who were aged between 37 and 73 years at recruitment. The study aims to help identify the causes of a wide range of chronic health conditions in middle and old age. At the start of the study, participants completed questionnaires, provided blood, saliva, and urine samples, and underwent physical measurements such as height and weight. In this analysis, researchers assessed participants’ dietary fibre intake, total protein intake, and intake of plant and animal protein. They then looked at the relationship between these dietary factors and high-sensitivity CRP (hsCRP) levels in the blood.After adjusting for several other lifestyle, socioeconomic, and health factors that might affect the relationship between diet and CRP levels, the researchers found that:
Higher intakes of dietary fibre were associated with lower levels of CRP. When they divided participants into four groups based on fibre intake, those in the highest fibre group had CRP levels that were 0.42 mg/L lower than those with the lowest fibre intake.
Higher levels of vegetable protein were also associated with lower levels of CRP, while total and animal protein intakes were associated with higher CRP levels. Participants with the highest intakes of vegetable protein had CRP levels that were 0.27 mg/L lower than those with the lowest intakes. Participants with the highest animal protein intake had CRP levels 0.40 mg/L higher than those with the lowest intake.
These associations were stronger in individuals with two or more chronic health conditions. In these participants, those with the highest intakes of animal protein and lowest intakes of dietary fibre had levels that were 0.65 mg/L higher than those with low animal protein and high fibre intakes.
The association between total protein intake and higher levels of CRP was explained by animal protein intake. In participants with two or more chronic health conditions, higher intakes of animal protein were linked with higher CRP levels regardless of the amount of vegetable protein they ate.
Overall, the highest levels of CPR were seen in participants who combined a high intake of animal protein with a low intake of dietary fibre.
The authors conclude that, particularly in individuals with multiple chronic health conditions, eating more fibre and choosing more plant protein over animal protein may help reduce inflammation in the body.The study has a few limitations, including the reliance on self-reported dietary intake (although they used multiple dietary recalls) and the fact that CRP was measured only at the start of the study. The study population is also mostly white British adults and healthy volunteers, so the findings may not be generalisable to other groups, including the general older adult population.Read more:
Dr Kate Marsh is an is an Advanced Accredited Practising Dietitian, Credentialled Diabetes Educator and health and medical writer with a particular interest in plant-based eating and the dietary management of diabetes and polycystic ovary syndrome (PCOS).
