High intake of dietary fiber and whole grains leads to a healthier life, study finds
People who eat lots of high-fiber and whole grain foods have lower risk of heart disease, stroke, diabetes and other chronic diseases than people whose diets are low in fiber, a study commissioned by the World Health Organization (WHO) says, Reuters reported.
Observational studies and clinical trials conducted over nearly 40 years reveal the health benefits of eating at least 25g to 29g or more of dietary fibre a day, according to a series of systematic reviews and meta-analyses published in The Lancet.
For every 8 gram increase in fiber eaten a day, total deaths and incidences of heart disease, type 2 diabetes and bowel cancer fell by 5 to 27 percent, the study said. Protection against stroke and breast cancer also rose.
25g to 29g of dietary fiber a day
A good target for those wanting to reap health gains would be to eat 25g to 29g of dietary fiber a day, the analysis found. But the data also suggested higher dietary fiber intakes could give even greater protection.
Our findings provide convincing evidence for nutrition guidelines to focus on increasing dietary fiber and on replacing refined grains with whole grains. This reduces incidence risk and mortality from a broad range of important diseases,” said Jim Mann, a professor at the University of Otago, New Zealand who co-led the research.
Most people worldwide consume less than 20 g of dietary fibre per day. In 2015, the UK Scientific Advisory Committee on Nutrition recommended an increase in dietary fibre intake to 30 g per day, but only 9% of UK adults manage to reach this target. In the US, fibre intake among adults averages 15 g a day. Rich sources of dietary fibre include whole grains, pulses, vegetables and fruit.
Health benefits come from fiber’s chemistry
Mann said the health benefits of dietary fiber - contained in foods such as whole grains, pulses, vegetables and fruit - come from its chemistry, physical properties, physiology and its effects on metabolism.
Fiber-rich whole foods that require chewing and retain much of their structure in the gut increase satiety and help weight control, He said. “(And) the breakdown of fiber in the large bowel by the resident bacteria has additional wide-ranging effects including protection from colorectal cancer.”
While their study did not show any risks associated with dietary fibre, the authors note that high intakes might have ill-effects for people with low iron or mineral levels, for whom high levels of whole grains can further reduce iron levels. They also note that the study mainly relates to naturally-occurring fibre rich foods rather than synthetic and extracted fibre, such as powders, that can be added to foods.
"Kula chakula chenye kiasi kikubwa cha nyuzi na nafaka nzima kunasaidia afya, utafiti unaonyesha kuwa watu wanaokula vyakula vyenye kiasi kikubwa cha nyuzi na nafaka nzima wana hatari ya chini ya kupata ugonjwa wa moyo, kiharusi, kisukari na magonjwa mengine ya muda mrefu kuliko watu ambao chakula chao kina nyuzi chache, ""alisema utafiti uliofanywa na Shirika la Afya Ulimwenguni (WHO)." Utafiti wa uchunguzi na majaribio ya kliniki uliofanywa kwa karibu miaka 40 unafunua faida za afya za kula angalau 25g hadi 29g au zaidi ya nyuzi za lishe kwa siku, kulingana na mfululizo wa ukaguzi wa kimfumo na uchambuzi wa meta uliochapishwa katika jarida la The Lancet. Kwa kila gramu 8 za nyuzi zinazotumiwa kwa siku, idadi ya vifo na vifo vya ugonjwa wa moyo, ugonjwa wa kisukari wa aina ya 2 na kansa ya matumbo hupungua kwa asilimia 5 hadi 27 kwa kila siku. Ulinzi dhidi ya kiharusi na kansa ya matiti pia uliongezeka. Kwa wale wanaotaka kupata faida ya afya, lengo zuri lingekuwa kula gramu 25 hadi 29 za nyuzi za lishe kwa siku. Lakini data pia ilionyesha kwamba ulaji wa nyuzinyuzi za chakula unaweza kutoa ulinzi mkubwa zaidi. """Ugunduzi wetu hutoa ushahidi wa kusadikisha kwa miongozo ya lishe kuzingatia kuongeza nyuzi za lishe na kuchukua nafasi ya nafaka zilizosafishwa na nafaka nzima." "Hii hupunguza hatari ya kuambukizwa na vifo kutokana na magonjwa mbalimbali muhimu,"" alisema Jim Mann, profesa katika Chuo Kikuu cha Otago, New Zealand ambaye aliongoza utafiti huo." Watu wengi duniani kote wanakula chini ya gramu 20 za nyuzi za chakula kwa siku. Katika mwaka wa 2015, Kamati ya Ushauri ya Sayansi ya Chakula ya Uingereza ilipendekeza kuongezeka kwa ulaji wa nyuzi za chakula hadi 30 g kwa siku, lakini ni 9% tu ya watu wazima wa Uingereza wanafanikiwa kufikia lengo hili. Kwa mfano, nchini Marekani, watu wazima wanakula wastani wa gramu 15 za nyuzi kwa siku. Vyanzo vyenye kiasi kikubwa cha nyuzi za chakula ni pamoja na nafaka nzima, mboga, mboga na matunda. "Mwanasayansi wa Kimataifa, Dr. Mann, alisema ""faida za afya za nyuzi za chakula - zilizomo katika vyakula kama vile nafaka nzima, mboga, mboga na matunda - zinatokana na kemia yake, mali za kimwili, fizikia na athari zake kwenye kimetaboliki.""" Vyakula vyenye nyuzi nyingi vinavyohitaji kutafuna na kuhifadhi sehemu kubwa ya muundo wake katika matumbo huongeza kuridhika na kusaidia kudhibiti uzito. "Uvunjaji wa nyuzi katika utumbo mkubwa na bakteria ya makazi ina athari za ziada za kina ikiwa ni pamoja na ulinzi dhidi ya saratani ya colorectal. ""Wakati utafiti wao haukuonyesha hatari yoyote inayohusiana na nyuzi za lishe, waandishi wanabainisha kuwa ulaji wa juu unaweza kuwa na athari mbaya kwa watu wenye viwango vya chini vya chuma au madini, ambao viwango vya juu vya nafaka nzima vinaweza kupunguza viwango vya chuma." Kwa upande mwingine, utafiti huo unazungumzia vyakula vyenye nyuzi nyingi, badala ya nyuzi za synthetic na zilizochukuliwa, kama vile poda, ambazo zinaweza kuongezwa kwenye vyakula.