Increase in the intake of daily fiber reduces risk of cardiovascular disease in older adults, according to a study reported in JAMA Network Open.¹Â This association was particularly seen for cereal fiber.

Shivakoti and coauthors examined the association between total dietary fiber intake and source of fiber with inflammation. They also studied the role of inflammation in the relationship between fiber intake and cardiovascular disease. Researchers recruited 4124 adults, aged 65 years or older, from the Cardiovascular Health Study from 1989 to 1990. Sixty percent of the study population were women. Consumption of dietary fiber (cereal, vegetable or fruit) was assessed with the help of a food frequency questionnaire. Every 6 months, the study participants were followed up in person and also via telephone till 1990 and then telephonically every six months to 2015. The total daily fiber intake was 16.3 g; the mean cereal fiber intake was 4.2 g/day, fruit fiber intake was 5.2 g/day, while vegetable fiber intake was 6.9 g/day. Men, Black participants (4.4%), smokers (current or former), those who frequently consumed alcohol and those not well-educated (less than high school education) ate less of total fiber including vegetable and fruit fiber.

A total of 1941 CVD events (stroke, myocardial infarction and atherosclerotic cardiovascular death) were documented during the follow up period of nearly 12 years (median). The risk of heart disease was reduced in adults who consumed an extra 5 g of total fiber daily with hazard ratio of 0.95 and also cereal fiber with HR 0.86. Significantly lower CRP, IL-6 and IL-1 receptor antagonist (IL-1RA) levels were noted with consumption of more than 5 g per day of total fiber. IL-1RA is an anti-inflammatory cytokine. An increase in total fiber intake of 5 g/day was associated with significantly higher levels of soluble CD163

Of the three fiber sources examined, only cereal fiber was associated with lower inflammation and according to the authors, “vegetable and fruit fiber intakes were not consistently associated with lower levels of inflammatory markers”. Less than 20% of the inverse association between CVD and cereal fiber was due to inflammation suggesting that factors other than systemic inflammation may be in play in this relationship.

This study has shown that increased consumption of total fiber was associated with lower inflammation and reduced risk of cardiovascular disease. This protective effect was more evident for cereal fiber than for fruit or vegetable fiber. The authors suggest further studies to validate their findings.

Reference

1. Shivakoti R, et al. Intake and sources of dietary fiber, inflammation, and cardiovascular disease in older US adults. JAMA Netw Open. 2022 Mar 1;5(3):e225012. doi: 10.1001/jamanetworkopen.2022.5012.