A reader asked for clarity / dosage levels for fiber intake. This is what I found.
“However, while existing studies encourage high-fiber diets, the specific recommended intake with the specific mechanism of action of different fiber types in treatment has not been clarified”[2024]
The Lancet analyzed observational studies and clinical trials conducted over nearly 40 years. They found that eating at least 25-29g of dietary fiber per day was associated with a 15-30% decrease in all-cause and cardiovascular-related mortality, as well as reduced incidence of coronary heart disease, stroke, type 2 diabetes, and colorectal cancer by 16-24%. [2019]
The United States Department of Agriculture (USDA) has provided guidelines for adults aged 19 years and above regarding their recommended daily values (DV). These guidelines suggest consuming 28 g of fiber. Australia suggests 30g for men and 25 g for women. From looking at prior recommendations from USDA, I am very suspect that is “a bare sufficiency” amount and not optimal.
Note that good bacteria can become bad without enough fiber. Akkermansia muciniphila exacerbates food allergy in fibre-deprived mice [2023]
From A cross-sectional study on the relationship between dietary fiber and endometriosis risk based on NHANES 1999–2006 [2024] We see surveyed amount are by quartile as below which allows us to define ranges based on US consumptions.
- 0-10.9 g Low fiber
- 10.9-18.12 g
- 18.12-27.95 g
- 27.95-111.4 g High fiber
An international study, The association between dietary quality index- international and metabolic risk factors in RaNCD cohort study [2024] has much higher ranges but in thirds and not quarters:
- 0 – 33.33 g Low fiber (i.e. 1/3 of population)
- 33 – 66 g
- Over 66 g High Fiber (i.e. 1/3 of population)
This is consistent with the US tending to low fiber consumption. Another international study report an average of 47 g/day +/1 20g. [2024]
From Global overview of government-endorsed nutrition labeling policies of packaged foods: a document review [2024] we see a constant: “and more dietary fibers •No thresholds for critical nutrients were found”
Effects of dietary fiber on human health [2022]
This summary highlights benefits:
- Reduce obesity
- Reduce diabetes risk
- Reduce Cancer risk including: Ovarian, Pancreatic, Prostate, Brest, Colorectal , Head and neck
- Reduce Intestinal disease
- Reduce the risk of cardiovascular disease.
- Inhibit allergic rhinitis
- Natural chelating agent
Bottom Line
I could not locate any studies that identified an optimal or threshold benefit level (i.e. there was no further health benefit by increasing fiber more). The following is from perplexity.ai, if you have diet restrictions then asking for a menu excluding those items.
What type of diet would get 66g of fiber?
Breakfast
- 1 cup cooked oatmeal (4 g)
- 1 medium apple with skin (4.8 g)
- 1/4 cup chia seeds (9.75 g)
Lunch
- 1 cup cooked kidney beans (13.1 g)
- 1 cup cooked quinoa (5.2 g)
- 1 cup cooked broccoli (2.4 g)
Dinner
- 1 medium baked potato with skin (3.8 g)
- 1 cup cooked split peas (16.3 g)
- 1/2 avocado (5 g)
Snacks
- 1 cup raspberries (8 g)
- 1 medium pear (5.5 g)
- 3 cups air-popped popcorn (3.45 g)
Total fiber: 66.3 g or approximately 1,885 calories
The above was produce by Perplexity.ai. If you have food restrictions, etc. Tell those restrictions to that AI and ask how to get the suggested fibre.
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