Health & Wellbeing

How much dietary fiber do you need to reduce high blood pressure?

How much dietary fiber do you need to reduce high blood pressure?
Increasing dietary fiber intake can reduce high blood pressure
Increasing dietary fiber intake can reduce high blood pressure
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Increasing dietary fiber intake can reduce high blood pressure
Increasing dietary fiber intake can reduce high blood pressure

Dietary fiber is known to reduce blood pressure, but there’ve been no guides on how much you need to eat to reap the rewards – until now. A new study has confirmed that dietary fiber lowered blood pressure independently of medication and quantified how much of it would lower high blood pressure.

When I was a kid, my mum was very fond of using the word ‘roughage’ to describe an element of what she considered the perfect diet. Roughage is just another name for dietary fiber: the parts of the food we eat that the body can’t digest. It aids the passage of food and waste through the gut and feeds beneficial gut bacteria.

Lifestyle interventions, including changes to diet, are the first-line treatment for hypertension or high blood pressure (BP). Previous studies have found that people who eat a lot of dietary fiber have significantly reduced risk of – and lower mortality from – heart disease and stroke. However, guidelines on hypertension don’t specify the benefit of dietary fiber.

Monash University researchers undertook a meta-analysis of studies into the effect of dietary fiber on hypertension, providing the quantifiable amount of dietary fiber that women and men need to eat to reduce their BP.

“Dietary fiber has emerged as a crucial yet underappreciated part of hypertension management,” said the study’s lead author, Francine Marques, from Monash’s School of Biological Sciences. “Our study emphasizes the evidence supporting the effectiveness of dietary fiber in lowering blood pressure and reducing the risk of cardiovascular events.”

The meta-analysis showed that higher dietary fiber intake was associated with a significant reduction in BP independent of medications taken to control hypertension. According to the evidence they reviewed, for women with hypertension – a BP of 140/90 mmHg or higher, according to the WHO – the recommended intake of dietary fiber should be more than 28 g per day; for men with hypertension, more than 38 g per day. Each additional 5 g per day was estimated to reduce systolic BP (the top number) by 2.8 mmHg and diastolic BP (bottom number) by 2.1 mmHg.

The researchers say the benefits of dietary fiber flow from its positive impact on the gut microbiome. Dietary fiber allows bacteria to produce short-chain fatty acids with anti-inflammatory and immune regulatory functions that contribute to lower BP.

“Our study highlights the urgent need for healthcare providers to prioritize dietary fiber as vital for hypertension management,” Marques said. “By incorporating dietary fiber into treatment plans and empowering patients to increase their intake, we can significantly reduce the burden of hypertension and improve cardiovascular outcomes.”

Westernized diets are notoriously lacking in ample fiber. The University of California San Francisco (UCSF) notes that the average dietary fiber intake among US adults is about 15 g per day. Here are some of UCSF's tips for ensuring more fiber in your diet:

  • As a general rule, include at least one serving of whole grains (e.g., rice, corn, oats, quinoa, bulgur) in every meal
  • Choose wholegrain bread (look for one with the highest amount of fiber per slice)
  • Cook with brown rice instead of white
  • Add beans to your salads – each ½ cup serving is around 7 to 8 g of fiber
  • Two or three times a week, substitute legumes (e.g., lentils, peas, broad beans, chickpeas, peanuts) for meat in things like soups and curries
  • Eat at least five servings of fruit and veggies a day (fresh fruit is better than canned) – adding fruit to cereal is an excellent place to start, so is having fresh fruit for dessert
  • Swap out fruit juices for whole fruits

The study was published in the journal Hypertension.

Source: Monash University via Medianet

Interesting article. However, it does leave me with the same questions I have every time I read one about good diets. What is a serving of fruit or for that matter a serving of anything (size/amount)? Which fruits are best? Is the amount different for women as opposed to men?
Soluble or insoluble or doesn't it matter?
Fermentable or non-fermentable? I do wonder about the comment about canned vs fresh fruit. Does the canning process really reduce or degrade dietary fibre?
Aross, Australian government advice is a serve of vegetables is 75 grams.

As someone who does read nutritional labels, I can say that reaching the recommended 38 grams per day is bloody hard. Most green (frozen) veggies only have about 2 to 3 grams per 100 grams, excepting green peas which have 5.6 grams. The grainy, brown, multigrain and seeds bread I buy is usually in the 5 to 6 grams per 100 range. Psyllium husk might be an option at about 1.7 grams per heaped tea spoon (80% fiber content) mixed into water or vegetable juice to kill the taste.
I dig it. Super important
Mat fink
I eat muesli for breakfast after discovering how feeding my lower gut bacteria with fibre greatly improved my mood. Good to hear it is also good for blood pressure as well. If I'm farting I'm laughing. Good job I like beans as well. If the farts stop it's because I've probably killed off the bacteria with Alcohol or too much dairy so I don't do that any more.
The problem with that in the West is that so much of our food, especially fruits and grains, is poisoned by pesticides and herbicides, or is genetically modified. I'd love to see sample diets for men to get a more solid idea of what they're proposing. Have to go back through nutritionist Mary Enig's Nourishing Traditions and Eat Fat, Lose Fat books again.