High fiber diet can prevent these fatal diseases

By Naveed Saleh, MD, MS, for MDLinx
Published May 20, 2019

Key Takeaways

If you have yet to get on the high-fiber bandwagon, hop on board. According to recent research published in The Lancet, people who consume plenty of dietary fiber and fiber-rich whole grains have lower rates of non-communicable diseases, including colorectal cancer (CRC) and heart disease.

Rich sources of fiber include vegetables, fruits, and whole grains. Globally, the majority of people eat fewer than 20 g of dietary fiber each day. In the United States, fiber consumption among adults averages 15 g daily.

Fiber-rich whole foods that need to be chewed while still retaining their structure in the gut lead to increased satiety and weight control. These fiber-rich foods can also improve lipid and glucose levels. The breakdown of fiber in the large bowel by gut bacteria also protects against CRC.

In previous reviews and meta-analyses, researchers have only looked at single indicators of carbohydrate quality and few diseases. Thus, it has yet to be elucidated which foods to recommend for protecting against a range of conditions.

To that end, researchers of the current study conducted a series of systematic reviews and meta-analyses that were sponsored, in part, by the World Health Organization to inform the creation of new fiber recommendations, and to ascertain which types of carbohydrate may offer the best protection against non-communicable diseases and weight gain. They analyzed 185 observational studies containing data representing 135 million person-years and 58 clinical trials involving 4,635 adult participants.

In all, the investigators noted a 15% to 30% reduction in all-cause and cardiovascular-related mortality upon comparing subjects who ate the most vs least amounts of dietary fiber.

The consumption of food rich in fiber also decreased the frequency of heart disease, stroke, type 2 diabetes, and CRC by 16% to 24%. In other words, for every 1,000 subjects, there were 13 fewer deaths and 6 fewer cases of coronary heart disease (CHD) among those who ate fiber-rich foods.

Total deaths and incidences of CHD, type 2 diabetes, and CRC dropped by 5% to 27% for every 8 g of fiber consumed daily. Furthermore, the researchers observed an increase in protective benefit in terms of stroke and breast cancer. Eating 25 g to 29 g of fiber daily provided adequate protection against disease. However, higher intake of dietary fiber could provide greater benefit, according to findings.

Total deaths and incidences of CHD, type 2 diabetes, and CRC decreased by 2% to 19% for every 15-g increase in whole grains consumed each day. Higher consumption of whole grains was linked to a 13% to 33% reduction in non-communicable disease risk. In other words, there were 26 fewer deaths per 1,000 people due to all-cause mortality and 7 fewer cases of CHD per 1,000 people among those who ate higher amounts of whole grains.

The researchers also found that eating foods with a low glycemic index and low glycemic load proffered only limited protection against diabetes and stroke only. Foods with low glycemic indices or loads may also contain added sugars, saturated fats, and sodium, which could have confounded results.

In meta-analysis of clinical trials, boosting fiber intake was significantly linked to lower body mass and lipid levels.

Overall, the authors recommended increasing dietary fiber intake and replacing refined grains with whole grains to curb the risks associated with a gamut of diseases. Of note, people with low iron and mineral levels should be careful when consuming high levels of fiber, which can leach iron from the body.

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