Reader BD gave me this challenge this week: “I would love your nutritionist opinion on this article about fiber.”
The article “Does a High-Fiber Diet Prevent Disease?” Sebastian Rushworth – a resident physician in Stockholm who graduated from medical school in 2020 – questions what he says, “the popular belief today that fiber is an important part of a healthy diet”.
Rushworth points out that observational data (studies of people’s reported habits) “find a correlation between a low-fiber diet and pretty much any chronic illness you might want to look at. For the most part, however, the randomized studies that have been carried out have not produced any evidence of a benefit from increased intake of dietary fiber. “
Here are my thoughts.
Nutritional knowledge is constantly evolving. And while the evidence this doctor presented in 2016 and 2017 seems to question the health benefits of fiber, now there are even more reasons to seriously keep this component in our diet.
An important topic that has emerged recently in the nutritional field is this: Studies of the effects of individual nutrients (such as fiber) often don’t tell the whole story. Because of this, nutritionists – including those who wrote the Current Nutrition Guidelines for Americans 2020-2025 – are now focusing on dietary patterns, rather than isolated nutrients.
What does that mean?
The health benefits I get from taking a pure fiber supplement may not be the same as from a combination of high fiber foods like vegetables, fruits, and whole grains. That is why we advise current recommendations on nutrient-rich foods. In other words, fiber is a nutrient that appears to work in tandem with other components of a healthy diet.
Before we set aside our high fiber foods, we should remember that there are numerous types of fiber in different foods. Studies that deal only with one type or another can miss the big picture.
And remember, each type of fiber plays a unique role in nourishing the health-promoting microbes in our gut. These good intestinal beetles boost our immunity, improve our ability to absorb certain nutrients, and even play a role in controlling our weight. Low fiber intake reduces the healthy variety of these goodies, say molecular scientists.
Rushworth’s statement that “there is simply not enough data to draw firm conclusions about the effects of fiber on cardiovascular disease risk” might well be true. However, there is strong evidence that dietary patterns like the Mediterranean or Dietary Approaches to Stop Hypertension (DASH) diets can improve blood pressure and other symptoms of heart disease. These diets are high in high fiber foods.
I rest my case.