Is fiber just a bulking agent that improves the number two? Or, is there more to fiber than meets the eye? We used to think that fiber was simply a non-digestible component of the food that we eat. However, we now know that fiber is actually digestible by gut bacteria. This has been shown to reduce the growth of bad bacteria and improve our body’s ability to absorb vital minerals and other nutrients. The good bacteria in our gut also use fiber to improve blood flow to the colon and to enhance the uptake of electrolytes. So, what happens when we juice fruits and vegetables versus eating the whole plant? Are we just losing the fiber? There is a really important component of dietary health called polyphenols. The majority of polyphenols in our food are attached to fiber. These polyphenols are lost when only the juice is utilized. When eating a plant based diet instead of just the extracted components (e.g. juicing), the good bacteria thrive and are able to detach the polyphenols from the fiber and allow these amazing packets of nutrition to be absorbed in the gut and then utilized by the body.

How Much Fiber?

No. 5 green blendThe minimum intake of fiber recommended for men ages 20-50 years old is almost 40 g per day and for women it’s 25 g per day. However, men only average 15 to 20 g per day and women 10 to 15 g per day. Less than 3% of all Americans meet the recommended intake of fiber. There are many studies that show that groups of people with greater dietary fiber have a much lower risk of various chronic diseases such as Type 2 diabetes, cardiovascular disease, certain cancers, obesity and diverticular disease. It should be noted that there is no single magic bullet when it comes to disease prevention. Adding extracted fiber to diets hasn’t been shown to be as nearly as beneficial. Maybe the focus should not be on dietary fiber per se but instead on a diet that is predominantly centered on the whole plant food and not just some component of the vegetable or fruit.

Breast Cancer and Fiber

What about breast cancer and fiber intake? Over 1 million women/year are diagnosed with breast cancer worldwide. Populations of people that meet or exceed the recommended dietary fiber intake have been shown to have reduced rates of breast cancer. The question remains, however, is it the dietary fiber or is it the company that it keeps that is helping to reduce the rates of breast cancer in these patients? An article from the Journal of the National Cancer Institute showed that every 20 g per day increase in dietary fiber leads to a significant reduction in relative risk for breast cancer. More plant foods in our diet leads to more fiber. Perhaps, the fiber is just a marker for the degree of plant-based nutrition that someone is doing on a daily basis. Vegetarians average about 20 g of fiber per day. However vegan or completely plant based diets average over 40 g of fiber per day. As I mentioned, it appears that it’s not just the fiber but the other nutrients that are naturally ingested when someone consistently eats a plant-based diet.

Colon Cancer and Fiber

Let’s take a look at colon cancer. It has been shown that people who have a high stool pH have higher rates of colon cancer and those with low stool pH have lower rates. Native african populations have a 50 x decrease in colon cancer then those found in the US. When we eat lots of fiber, we preferentially feed the bacteria that utilize fiber and fiber components. Popular probiotics have made their mark by insisting that ingesting more good bacteria such as Lactobacillus and Bifidobacterium will improve overall health. However, it is been shown that people who eat a whole grain, plant-based diet preferentially grow these good bacteria in their gut and reduce the overall gut pH. The less healthy bacteria are then significantly reduced in number. Fiber eating bacteria produce a pH that allows the good fiber eating bacteria to survive. So maybe we shouldn’t be buying probiotics hoping that they will overcome our lack of consistent dietary changes and craving for highly processed, animal based foods. In fact, I suspect that the whole probiotic industry would have never become popular if the Western diet was more like the African diet rich in whole-food plants.

So, the bottom line is eat more fruits and vegetables, get more fiber in your diet and reduce the risk of colon cancer, breast cancer and heart disease!