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Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
Cereal fibre and hypertension: could it be the new salt?
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Cereal fibre and hypertension: could it be the new salt?

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The results from my systematic review indicate emerging evidence that a 10g/d increased intake of soluble cereal fibre can reduce blood pressure in older (>50yrs) and hypertensive adults by between 5 …

The results from my systematic review indicate emerging evidence that a 10g/d increased intake of soluble cereal fibre can reduce blood pressure in older (>50yrs) and hypertensive adults by between 5 and 7mmHg. This reduction is clinically comparable to the expected effects of a salt reduced diet.

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  • Thank you to the chair and to audience. Presenting today the key findings of a research undertaken while I was a Masters student at Sydney University under the supervision of Michelle Celander with the Kellogg Nutrition Team. The research findings have been written up and we are in the process of submitting the manuscript to a peer reviewed journal.
  • Which is why dietary modification is so important. These are well established evidence-based lifestyle modifications. What I’d like to do today is suggest that perhaps cereal fibre has a place in this group of recommendations.
  • To give you an understanding of what first led me to think that cereal fibre might help reduce blood pressure let’s first take a look at the existing body of evidence.
  • The NHF states that there is moderate evidence of an association between cereal fibre intake and CHD, of which HTN is a key indicator. More recently a review presented at the Experimental Biology conference reported consistent evidence of an association between increased cereal fibre intakes and reduced risk of CVD which may be mediated in part through a reduction blood pressureTwo cohort studies have looked specifically at cereal fibre and hypertension and both found a reduced risk of hypertension with increased cereal fibre intake. So the observational evidence appears to indicate a possible role of cereal fibre, but is this backed up with evidence from clinical trials?
  • To date the only reviews on the topic have looked at dietary fibre intake as a whole rather than specifically cereal fibre. Both meta-analyses indicate a moderate reduction of between 3 to almost 6 mm Hg in older and hypertensive populations. However, no systematic review of intervention studies has to date been conducted to look at the role of cereal fibre in hypertension. So that is what I set out to do.
  • A search of Medline and Cinahl databases yielded 59 publications of intervention trials of cereal fibre and its effect on BP. 18 publications met the inclusion criteria and were of good quality
  • Of the 18 studies 8 reported that increased intake of cereal fibre led to a significant reduction in BP, and 10 studies did not report a significant reduction. So, overall there is no consistent evidence of an effectHowever, if we dig a little deeper and it seems that like salt, cereal fibre may have a greater effect in specific population groupsFour of the 18 studies in the review recruited only people with hypertension (BP > 140/90). All four of theses studies in hypertensive populations reported a significant reduction, however the same effect was seen in only a few of the normotensive groups. Similarly, there appears to be an effect of cereal fibre on the blood pressure of older people. The mean age of the 18 studies was 50 years. Most of the studies in older people reported a significant reduction in BP
  • From this small number of studies there appears to be some emerging evidence: Soluble cereal fibre may reduce blood pressure in hypertensive people by up to 7mmHg This is indicated by the evidence from 4 studies which increased soluble cereal fibre intake by between 7 and 12 g/dOf particular interest is the possibility that soluble cereal fibre may have an effect even for people already taking antihypertensive medication. In 3 of the studies all subjects were on medicatio and those with increased cereal fibre intake had a significant reduction in blood pressure below the level they attained with medication. One study was specifically designed to measure the reduction in medication usage.
  • There also appears to be emerging evidence that Soluble cereal fibre may reduce blood pressure in people over 50 years by up to 6.5 mmHg Again, 7 to 12 g /d of soluble fibre lead to reductions in SBPWhile this may seem the result of hypertension being more prevalent in older populations, one well-designed study of normotensive older people did find a significant reduction. More study is warranted to
  • Now a test to see if you’ve been paying attention – who can remember the effect of salt? And that of soluble cereal fibre?So could it be that cereal fibre could have an effect equal to that of salt on blood pressure reduction? While this research does indicate emerging evidence of soluble cereal fibre playing a role in reduction blood pressure we don’t yet have a definitive answer that we can put into practice. It took almost 100 years between the first report in 1904 of an effect of salt on blood pressure before the DASH trials in the 1990s proved conclusively the effect of reduced salt on blood pressure. Scientists continued to ask questions and to figure out the effect. I’m hoping it won’t take us 100 years, to find out more answers about the role of cereal fibre we need to ask more questions.
  • So back to our patient Merv….I would expect that you would still be suggesting he try all these lifestyle modifications, but would you also be adding soluble cereal fibre to those suggestions? The evidence suggests that we should consider it.
  • Transcript

    • 1. ‘High blood pressure is the biggest single cause of death in the world’
      ‘Reducing salt intake by 6g a day …could prevent approximately 2.6 million stroke and heart attack deaths each year worldwide’
      World Action on Salt and Health (WASH)
      Cereal Fibre: could it be the new salt?
    • 2. Cereal Fibre in Hypertension:
      could it be the new salt?
      Michelle Broom APD
    • 3. Hypertension
      1 in 3 Australian adults has hypertension
      Less than half have blood pressure controlled with medication*
      What would you recommend?
      ↓Salt -5 mmHg
      ↑ Fruit and Veg -2.8 mmHg
      ?
      Cereal fibre
      Weight loss
      * BP > 140/90; AUSDIAB study 2000
    • 4. Background
    • 5. Observational evidence
      ‘There is moderate evidence that dietary patterns high in dietary fibre from cereals and fruit are associated with a lower risk of coronary heart disease’
      NHF Position statement (2006)
      Cereal fibre and reduced risk of CVD
      • Consistent evidence: 11/13 prospective cohort and 4/4 cross- sectional
      (Experimental Biology Conference Presentation, 2011)
      • Fibre from grains but not other sources is protective in older people
      (Parks, 2011)
      Cereal fibre and reduced risk of hypertension
      • 2 cohort studies including Health Professional Follow-Up Study
      (Flint, 2009; Leichtenstein and Burr, 1986)
    • 6. Evidence from Intervention Studies
      Dietary Fibre (including cereal fibre) and blood pressure
      • - 3.04 mmHg reduction in SBP in people > 40years: meta-anaylsis of 25 clinical trials
      (Streppel, 2005)
      • - 5.95 mmHg reduction in SBP in hypertensive people: meta-anaylsis of 25 clinical trials
      (Whelton, 2005)
      No systematic review of intervention studies
      of cereal fibre and hypertension
    • 7. Systematic Review of Intervention Studies
    • 8. Study Selection
      Number of publications retrieved from database searches (n=59)
      Number of publications from manual search strategies (n= 24)
      Number of publications retrieved (n=83)
      Duplicates removed (n=11)
      Number of publications screened (n=72)
      Papers excluded on basis of exclusion criteria (n=50)
      Papers excluded after discussion between two investigators on basis of exclusion criteria (n=4)
      Number of publications included (n=22)
      Number of publications on blood pressure included in review
      (n=18)
    • 9. Results
      Population
      Overall: No consistent evidence of an effect of cereal fibre on blood pressure
    • 10. Emerging Evidence
      Benefit of Cereal Fibre for Hypertensive subjects
      Soluble cereal fibre may reduce blood pressure in hypertensive people by up to 7mmHg
      Consistent evidence from four studies*
      • 7 – 12g/day soluble cereal fibre (oat foods, oat bran foods & pysllium)
      • 11. 5 – 7mmHg reduction in SBP (p<0.01)
      • 12. In line with meta-analysis of dietary fibre: -5.95 mmHg reduction in hypertensive populations (Whelton, 2005)
      Medicated patients
      • 3 of 4 studies – all subjects medicated
      • 13. Pins, 2002: 73% halved medication usage
      *Maki, 2007; Cicero, 2007; Pins, 2002; Burke, 2001
    • 14. Emerging Evidence
      Benefit of Cereal Fibre for Older People (>50 years)
      Soluble cereal fibre may reduce blood pressure in older people by up to 6.5 mmHg
      Consistent evidence from four of five studies*
      • 7 – 12g/day soluble cereal fibre (Wheat foods, oat foods & pysllium)
      • 15. 5 – 6.5 mmHg reduction in SBP (p<0.05)
      • 16. Agrees with meta-analysis of dietary fibre: -3.04 mmHg reduction in people > 40 years (Streppel, 2005)
      Tighe, 2010:
      • Normotensive older population
      • 17. Wheat and oat wholegrain foods
      • 18. 5 – 6.5 mmHg reduction in SBP (p<0.05)
      *Tighe, 2010; Maki, 2007; Cicero, 2007; Burke, 2001
    • 19. Evidence to Practice
      Is this realistic?
      Australian Dietary Guidelines 25 & 30g/day (AI) 28 & 38g/day (SDT)
      Australian adults consume 20 & 27 g/day (1995 NNS)
      Australian adults consume 8 – 11g less fibre
      than recommended to reduce risk of chronic disease
      ↑ soluble cereal fibre by 7 – 12g / day
      would help Australians meet the Dietary Guidelines
    • 20. Could cereal fibre have an effect equal to that of salt?
      To find more answers we need to ask more questions….
      Could insoluble cereal fibre also play a role?
      Is our current definition of fibre confounding the story?
      Soluble, insoluble, resistant starch, prebiotics….
      Is the physiology of aging altering the effect of fibre?
      Evidence into Practice
      Not always Black and White
    • 21. Hypertension
      What would you recommend?
      ↓Salt -5 mmHg
      ↑ Fruit and Veg -2.8 mmHg
      ?
      Cereal fibre
      Weight loss
      ↑ Soluble cereal fibre
      -5 to -7 mmHg
    • 22. Appendix
    • 23. References
      Brownlee IA et al. British Journal of Nutrition. 2010;104(01):125-134.
      Burke V et al. Hypertension. Oct 2001;38(4):821-826.
      Cicero AFGet al. Clinical & Experimental Hypertension (New York). Aug 2007;29(6):383-394.
      Flint AJ et al. AJCN 2009; 90: 493-498
      Jenkins DJA et al. AJCN. May 2002;75(5):834-839.
      Maki KC et al. European Journal of Clinical Nutrition. Jun 2007;61(6):786-795.
      Parks EJ. British Journal of Nutrition. 2002;87(SupplementS2):S247-S253.
      Pereira M et al. Arch Intern Med. 2004;164(4):7.
      Pins JJet al. Journal of Family Practice. Apr 2002;51(4):353-359.
      Qi, L et al A comparison of the Literature on the association between intakes of bran, cereal fibre and whole grains and risk and biomarkers of heart disease. Experimental Biology (2011) presentation
      StreppelMT et al. Arch Intern Med. 2005;165(2):150-156.
      TighePet al. Effect of increased consumption of whole-grain foods on blood pressure and other cardiovascular risk markers in healthy middle-aged persons: a randomized controlled trial. AJCN Ahead of print 2010.
      WheltonS et al. Journal of Hypertension. 2005;23(3):7.
    • 24. ↑ soluble cereal fibre by 7 – 12g / day
      What would this look like in a diet?
      Breakfast
      swap toast & jam for high soluble fibre cereal = 5.1g
      Snack
      swap 2 cream biscuits for an 2 oatmeal biscuits = 2.3g
      Dinner
      Add barley to soup or casseroles = 0.8g
      Dessert
      swap ice-cream for oat crusted apple crumble = 1.4g
      Total ↑ soluble cereal fibre = 9.6g

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