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Teri Lichtenstein

To Grain or Not to Grain?

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A few weeks ago, I attended a live webinar event, where two well-respected dietitians discussed the use of the “low carb healthy fat” diet (LCHF) approach to help people with a range of lifestyle diseases (e.g. Diabetes) manage their health outcomes. These teams of dietitians have achieved some remarkable results with their patients, including improved glycemic control, lower blood cholesterol and better liver function test results.

There is no shortage of research suggesting that a LCHF diet may be just as effective as low-fat diets in improving metabolic risk factors, managing diabetes and reducing weight.1,2 People with insulin resistance, metabolic syndrome and type 2 Diabetes may be particularly good candidates for a lower-carbohydrate prescription, and a number of leading health organisations have come out in support of these types of diets.

 

 

Nutrition is Not an Exact Science

Of course, like most things in nutrition science, for every body of evidence promoting a specific dietary approach, there will be research to contradict that approach. The evidence reviewed by The Institute of Medicine suggests that energy density, rather than a particular ratio of macronutrients, can lead to obesity.3 Although a high fat diet will be energy dense, the fat component alone will not lead to obesity unless energy is chronically consumed in excess of energy expenditure. This argument also applies to carbohydrates. The type of carbohydrate can also markedly influence energy density of the diet. For example, it is easier to increase the energy density of the diet by consuming energy dense drinks with added carbohydrates, compared to whole grain foods, vegetables and fruits, because the extra energy intake from the former source is generally not compensated by a reduction in energy intake from other foods. We know that there has been a major shift in westernised dietary habits over the last few decades, with an increase in consumption of highly refined carbohydrates and sugar. To add to this, less than 4% of us eat enough vegetables every day.4 This is contradictory to what dietary guidelines actually recommend.

In defence of the low-carb-healthy-fat approach that is recommended by dietitians who advocate this diet, the diet would contain a range of high quality foods (e.g. fruits, vegetables, nuts, yoghurt) that would be more nutritious than high-carbohydrate-nutrient-poor foods that are often eaten in a typical Western diet. When it comes to specific nutrients, one could even argue that the LCHF approach may not require the Recommended Dietary Intake levels (RDI) for nutrients such as thiamine, as there is less carbohydrate to metabolise. One of the presenters in the webinar has published a paper in BMJ, using a hypothetical case study design to assess the nutrient intake of a LCHF diet, and concluded that a well-planned LCHF diet would exceed the minimum nutrient reference value thresholds, except for female iron requirements, which achieved between 86-98% of the threshold. 5

 

But What About….?

However, as I sat watching this webinar, I couldn’t help being left pondering about the long term effects of cutting out or significantly reducing one major food group – whole grains.

We know that whole grains, one of the major food groups, are a vehicle for a range of key nutrients within the Australian diet. Take bread for example (one of the most commonly consumed whole grain foods). Bread is a major source of dietary fibre, iron, thiamine, as well as folate and iodine that has had mandatory fortification to bread making in Australia since 2009. Importantly, following folic acid fortification in Australia, there was a statistically significant 14.4% decrease in the rate of neural tube defects across the population (excluding Victoria, ACT and Tasmania where insufficient data was available).6

 Whole grains feature in dietary guidelines all over the world, and with good reason. Whole grains have been linked to a lower risk of type 2 Diabetes, overweight and obesity, cancer and cardiovascular disease. 7 And whilst fruits and vegetables (part of the LCHF diet) do contain some fibre, whole grains are generally a richer source and also contain a variety of different  fibre types, essential for gut and overall health.

Based on various meta-analysis, an appropriate dietary fiber intake, for example by consuming more whole grain compared to a low intake of whole grain, is linked to a significant disease risk reductions for type 2 diabetes and cardiovascular disease, 8, 9 while evidence is growing that weight management may also be supported favourably. 10.11

 

LCHF and the gut microbiome

Another benefit of whole grains is that they generally contain a lot of prebiotic fibres, including resistant starch, which ferments in the colon to produce short chain fatty acids that lower the PH of the colon. A lower pH has been shown to slow down the proliferation of cancer cells and decrease the production of toxic by-products.

 

A LCHF diet will naturally be lower in prebiotic fermentable fibres compared to a higher carbohydrate diet. Given the importance of fermentable fibres to maintain a healthy and diverse gut microbiome,12 what would this mean for someone who is following the LCHF approach? Diets low in fermentable fibres have been shown to reduce total bacterial abundance,13 and this makes sense as a reduction in fermentable fibres means less-energy sources for the gut microbes, who depend on substrates to colonise? On the other hand, eating prebiotic fibres and resistant starch will allow for proliferation of intestinal bacteria, as shown in the table below. 14

 

Effects of non-digestable carbohydrates on gut microbiata

Bacterial Abundance Gene richness Lactobacilli Bifidobacteria Clostridia Enterococcus Roseburia Eubacteria Ruminococcus
Fibre / prebiotics ↑↓
Resistant starch

 

A Grain of Truth

I certainly learned a lot from this informative webinar looking at the science underpinning the LCHF diet and how to apply in practise. There most certainly is a place for this type of diet for some individuals and any diet that gets people eating more whole foods can only be a good thing.

But for now, I think I will go and make myself a piece of whole grain toast to feed my brain and fuel my body, as I ponder where the exciting world of nutrition science will take us next!

 

 

Yours in good health,

 

 

 

 

Teri Lichtenstein, APD
The Healthy Grain Nutrition Ambassador

 

References:

 

  • Hu Tian et al. Effects of Low-Carbohydrate Diets Versus Low-Fat Diets on Metabolic Risk Factors: A Meta-Analysis of Randomized Controlled Clinical Trials. American Journal of Epidemiology 2012 May; Vol. 176, No. 7
  • Ajala O et al. Systematic review and meta-analysis of different dietary approaches to the management of type 2 diabetes. Am J Clin Nutr 2013;97 ;505-16
  • Raynor H.A. et al. Dietary energy density and successful weight loss maintenance. Eat Behav. 2001 Apr; 12(2): 119-125
  • Australian Health Survey: Consumption of food groups from the Australian Dietary Guidelines . 2011-12
  • Zinn C. Rush A, Johnson R. Assessing the nutrient intake of a low-carbohydrate, high-fat (LCHF) diet: a hypothetical case study design. BMJ Open. 2018;8:e018846
  • Australian Institute of Health and Welfare. Monitoring the health impacts of mandatory folic acid and iodine fortification. 2016. Available online: https://www.aihw.gov.au/reports/food-nutrition/monitoring-health-impacts-of-mandatory-folic-acid/contents/table-of-contents
  • Zhang B et al. Association of whole grain intake with all-cause, cardiovascular, and cancer mortality: a systematic review anddose–response meta-analysis from prospective cohort studies. European Journal of Clinical Nutrition (2018) 72, 57–65
  • Aune D et al. (2016) Whole grain consumption and risk of cardiovascular disease, cancer, and all cause and cause specific mortality: systematic review and dose-response meta-analysis of prospective studies. BMJ 353:i2716
  • Ma X et al. (2016) Association between whole grain intake and all-cause mortality: a meta-analysis of cohort studies. Oncotarget 7(38):61996
  • Albertson AM et al. (2016) Whole grain consumption trends and associations with body weight measures in the United States: results from the cross sectional National Health and Nutrition Examination Survey 2001–2012. Nutr J 15(1):8
  • Vanegas SM et al.(2017) substituting whole grains for refined grains in a 6-wk randomized trial has a modest effect on gut microbiota and immune and inflammatory markers of healthy adults. Am J Clin Nutr 105(3):635–650
  • Holscher HD. Dietary fiber and prebiotics and the gastrointestinal microbiota. Gut Microbes. 2017; 8(2): 172–184
  • Halmos EP et al. Diets that differ in their FODMAP content alter the colonic luminal microenvironment. 2015 Jan; 64(1):93-100
  • Singh RK et al. Influence of diet on the gut microbiome and implications for human health. J Transl Med. 2017; 15: 73.

 

Microbiome – The missing link in the gut-brain axis

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With the ever expanding trend of gut health that seems to be overtaking mainstream media, there is a lot more information about the role of food in affecting mood, and ongoing research investigating the link between our gut microbiome and mental health. 1,2  Whilst there is some persuasive animal research data, human studies are more limited and the science is probably still a long way off from being conclusive enough to recommend specific therapeutic actions to treat a range of mental health conditions.

We know that there is a direct line of communication between our guts and our central nervous system, commonly referred to as the “gut-brain axis” and Nutritional psychiatrists assert that the “gut-brain” connection is the crux of managing anxiety and depression for many people. 3 And with more than 38 trillion bugs residing in our digestive system, it makes sense that the state of our gut microbiome would have a significant impact on our brain health. Research is still in its infancy and many questions remain regarding the causality between the gut microbiome and mood-related behaviours, specifically mental health conditions and illness such as anxiety and depression. 4,5

Do alterations in gut microbiota result in depression or does a depressive state induce modification of some gut species within the gut and potentially contribute to more severe depression? Certainly a chicken and egg conundrum and one that requires further investigation.

Ref: Molecular Psychiatry (2016) 21, 738-748;

doi:10.1038/mp.2016.50

 

Modifying the gut microbiome to improve mental health?

As with most aspects of science, specifically nutrition science, research doesn’t always provide clear answers.  This is complicated also by the bi-directional relationship between the brain and the gut.

In some studies, rodents showed an onset of depressive behaviour following faecal transplantations from patients with MDD (major depressive disorder), and in others mental induction of stress and depressive behaviour in rodents resulted in reduced gut microbiota richness and diversity.,6,7,8  Systematic reviews of human studies have also found that supplementation with psychobiotics (prebiotics  and probiotics) may help to treat mental health illnesses, but more clinical trials are needed to assess efficacy. 9,10, 11

There are many influencing factors that can alter the microbial community. From where one lives (farm vs. urban city) to illness, stress and overuse of antibiotics. In fact a recent large population study reported that treatment with a single antibiotic course was associated with an increased risk for depression and anxiety, rising with multiple exposures. 13 Of course one of the biggest influencers on the microbiome is diet. Eating a high fat diet has been associated with changes to the diversity of the gut microbiome and reduced synaptic plasticity (ability of synapses to respond to environment) 14,15. In addition, a lack of sufficient fermentable fibres to feed the growth of healthy bacteria can result in a decline in overall bacterial diversity, decreased gut cell wall integrity and increased gut permeability, all of which can influence brain function.

Whilst we are probably a long way away from having any clear cut answers, one thing we do know for certain is that our gut microbial communities has a major influence on mental health disorders, and perhaps a ‘microbiome-gut-brain’ model may be more appropriate. 12

 

The magic of short chain fatty acids

Bacterial metabolites from the gut can have a substantial influence on the regulation of the microbiome-gut–brain axis. When SCFAs (short chain fatty acids) are produced by the fermentation of dietary fibre,  this stimulates the sympathetic and autonomic nervous system, which modulates brain development and behaviour. 16,17 SCFAs have a number of other ‘gut-brain’ roles including regulating brain tissue homeostasis, and releasing gut peptides, which in turn affect gut-brain hormonal communication and can influence appetite control. 18,19

There is no doubt that short chain fatty acids are important molecules and play a key role in the microbiome-gut-brain axis link. Whilst we may be a long way off from truly understanding how they exert their magic, surely it can only be beneficial to include dietary fibres that produce these moleucles in our diet?

 

The future of health and happiness

The advances in our understanding of the role of the microbiome in brain activity and mental health have been remarkable, and the potential value of microbiome analyses in revealing mechanisms that underpin altered brain development and mental illness is hugely exciting. As the gut-brain axis is extended to include the microbiome, scientists are faced with greater insights, yet also more challenges, to understand the complicated processes behind altered brain function and mental health. The challenge lies in pinpointing the cause and effect of specific bacteria, and translating the results into treatments. And this isn’t easy. Could it be a similar case to that of the human genome – another great hope in predicting disease and personalised preventative medicine, but which becomes more impenetrably complex the more we learn about it? The only difference is that, unlike your genome, which you can’t do an awful lot with, your microbiome is potentially modifiable.

 

 

Yours in good health,

 

 

 

Teri Lichtenstein (APD)
The Healthy Grain Nutrition Ambassador

 

References:

  1. Winter G. et al. Gut microbiome and depression: what we know and what we need to know. Rev Neurosci. 2018 Aug 28;29(6):629-643
  2. Clapp M. et al. Gut microbiota’s effect on mental health: The gut-brain axis. Clin Pract. 2017 Sep 15; 7(4): 987
  3. Carabotti M. et al. The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Ann Gastroenterol. 2016; 29(2): 240
  4. Dash S. et al. The gut microbiome and diet in psychiatry: focus on depression. Curr Opin Psychiatry. 2015 Jan;28(1):1-6
  5. Dash S. et al. The gut microbiome and diet in psychiatry: focus on depression. Curr Opin Psychiatry. 2015 Jan;28(1):1-6
  6. Kelly JR. et al. Transferring the blues: Depression-associated gut microbiota induces neurobehavioural changes in the rat. J Psychiatr Res. 2016 Nov;82:109-18
  7. Macqueen G. et al. The gut microbiota and psychiatric illness. J Psychiatry Neurosci. 2017 Mar; 42(2): 75–77
  8. Rogers GB. Et al. From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways. Molecular Psychiatryvolume 21, pages 738–748 (2016)
  9. Wallace Caroline. Milev Roumen. The effects of probiotics on depressive symptoms in humans: a systematic review
  10. Schmidt K. et al. Prebiotic intake reduces the waking cortisol response and alters emotional bias in healthy volunteers. Psychopharmacology 232(10) · December 2014
  11. Sarkar a. et al. Psychobiotics and the Manipulation of Bacteria–Gut–Brain Signals. Trends in Neurosciences, November 2016, Vol. 39, No. 11
  12. Cryan JF, O’Mahony SM. The microbiome-gut-brain axis: from bowel to behavior. Neurogastroenterol Motil 2011; 23: 187–192
  13. Lurie I. et al. Antibiotic exposure and the risk for depression, anxiety, or psychosis: a nested case-control study. J Clin Psychiatry 2015; 76: 1522–1528.
  14. Liu Z. et al. High-fat diet induces hepatic insulin resistance and impairment of synaptic plasticity. PLoS One 2015; 10: e0128274.
  15. Daniel H. et al. High-fat diet alters gut microbiota physiology in mice. ISME J 2014; 8: 295–308
  16. Kimura I. et al. Short-chain fatty acids and ketones directly regulate sympathetic nervous system via G protein-coupled receptor 41 (GPR41). Proc Natl Acad Sci USA 2011; 108: 8030–8035.
  17. Macfabe DF. Et al. Short-chain fatty acid fermentation products of the gut microbiome: implications in autism spectrum disorders. Microb Ecol Health Dis 2012; 23; doi: 10.3402/mehd.v23i0.19260.
  18. Prinz M. et al. Microglia and brain macrophages in the molecular age: from origin to neuropsychiatric disease. Nat Rev Neurosci 2014; 15: 300–312.
  19. Wren AM. Bloom SR. Gut hormones and appetite control. Gastroenterology 2007; 132: 2116–2130

Will probiotics and prebiotics have a role in treating allergies in the future?

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The microbiota in our gut are our best “frenemies”. That’s because we have this amazing eco system within our guts that acts like a double edges sword; our microbiome can promote immune and metabolic health, but it can also promote inflammation, when triggered by ‘invaders’ (e.g. allergens, pollen, dust).

The hundreds of trillions of microbes that are found in the human body are concentrated specifically within skin and mucosal surfaces (i.e. Gastro and respiratory tracts. There is a very complex network of immunological interactions that take place in these tracts in order for our immune system to be able to distinguish between “good” and “bad” microbes. These highly controlled mechanisms must be able to discern when immune tolerance is required or when effective attacks against pathogens are necessary. However, in many westernised countries, there have been a number of imbalances in the interactions between the microbiome and immune cells, that has resulted in exacerbated allergic responses and asthma in both animal models and humans.

For many people, the start of Spring is a happy time. The blossoms are out, the days are warmer and the smell of summer is on its way. But for 4.5 million Australians (nearly 1 in 5), the arrival of Spring means loading up on hay fever medication, staying indoors and keeping tissues nearby.

For almost three decades, a growing body of research has linked the increases in asthma and allergy rates to ‘the hygiene hypothesis’1 – the idea that our modern urban living environments have become too sterile and germ-free, leading our immune systems to become imbalanced and reactive. 2

 

The early life opportunity

When it comes to allergy and asthma, researchers believe that most of the protection is conferred very early in life, starting with the development of the foetus in the womb where beneficial microbes may help to “train” the immune system. Contrary to what was previously hypothesizes, we now know that babies are not born with a sterile gut, and the stability and diversity of the gut microbiome increases during the first 3 years of life, with various factors influencing this development including mode of birth delivery, breast or bottle feeding, microbial environment (e.g. living on a farm or in a city, dogs in the house or no dogs) and antibiotic use. 3, 4, 5, 6, 7

A 2016 study from the University of California San Francisco found that babies who were lacking particular gut microbes at one month old were three times more likely to develop allergic reactions by age 2, and asthma by age 4. The paper demonstrates that the perturbed microbial ecosystem present in these at-risk babies produces molecules that reduce the abundance of a key type of immune cell known to help prevent allergy. The researchers surmise that having fewer of these cells leads to a hyperactive immune system and eventually to chronic asthmatic inflammation of the lungs. 8

 

The microbiome in allergy and asthma

It was previously thought that healthy human lung tissue was sterile, but in the last decade, studies have shown that the respiratory mucosa has its own microbial population. As it happens with the gut microbiota, the airways microbiome also develops very early in life and is influenced by the number of microbes in the environment, age, health status, and birth mode. Children raised in farms or who live with animals (e.g. dogs or cats) are exposed to a higher microbial diversity in house dust, which leads to higher nasal microbiome diversity and less risk of asthma and respiratory allergies (e.g. Hayfever)

People with altered gut and lung microbiomes could revert these imbalances  through the use of pre and probiotics to support restoration. Unfortunately, it is not as simple as adding a whole lot of pre and probiotics to a capsule and simply swallowing a magical pill. The inflammatory responses experienced by asthma and hay fever sufferers is influenced by a multitude of factors including the environment, nutrition, as well as the status of the gut and respiratory microbiome. It will be necessary to determine if variations in the microbiome are the cause or effect of allergies and asthma, and longitudinal studies are essential to control for different confounding factors. The ultimate goal is to understand whether aspects of the microbiome are linked to disease and whether manipulation of the microbiome will be useful to preserve lung function, prevent, and treat allergies.

And in the meantime, the good news is that the for those who suffer from Spring time sniffles, this hay fever season is likely to be less severe as a result of Australia’s drier-than-average winter season.

 

Yours in good health,

 

 

 

 

Teri Lichtenstein (APD)
The Healthy Grain Nutrition Ambassador

 

References:
  1. Okada H et al. The ‘hygiene hypothesis’ for autoimmune and allergic diseases: an update. Clin Exp Immunol. 2010 Apr; 160(1): 1–9.
  2. West CE et al. The gut microbiota and inflammatory noncommunicable diseases: associations and potentials for gut microbiota therapies. J Allergy Clin Immunol. 2015 Jan; 135(1):3-13.
  3. Lozupone CA et al. Diversity, stability and resilience of the human gut microbiota. Diversity, stability and resilience of the human gut microbiota. 2012 Sep 13; 489(7415):220-30.
  4. Dominguez-Bello MG at al. Delivery mode shapes the acquisition and structure of the initial microbiota across multiple body habitats in newborns. Proc Natl Acad Sci U S A. 2010 Jun 29; 107(26):11971-5.
  5. Yatsunenko T, Rey FE et a. Human gut microbiome viewed across age and geography. 2012 May 9; 486(7402):222-7.
  6. Harmsen HJ et al. Analysis of intestinal flora development in breast-fed and formula-fed infants by using molecular identification and detection methods. J Pediatr Gastroenterol Nutr. 2000 Jan; 30(1):61-7.
  7. Tanaka S et al. Influence of antibiotic exposure in the early postnatal period on the development of intestinal microbiota. FEMS Immunol Med Microbiol. 2009 Jun; 56(1):80-7.
  8. Fujimura KE et al. Neonatal gut microbiota associates with childhood multisensitized atopy and T cell differentiation. Nature Medicine volume 22, pages 1187–1191 (2016).

日本功能食品

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人们普遍认为,日本在许多行业都处于领先地位。去年访问这个国家的时候我亲身感受到了这一点,日本人日常生活的高效率让我感到惊讶。东京复杂的火车系统便很好地说明了,哪怕是再复杂的一个东西,也能够有办法让它高效运作!

我们切换到一个风马牛不相及的话题—功能性食品。日本人是功能食品的早期开发食用者之一。所谓功能性食品,是指除了提供能量、维生素、矿物质等基本营养成分之外,还提供特定健康益处的食品。80年代初,日本学术界从三个功能层面来定义功能食品:第一是营养性,第二是感官性,第三是生理性。1随着人们对功能食品的兴趣愈浓且功能食品市场逐渐活跃,1991年日本厚生劳动省 (MHLW) 建立了“特定保健用食品” (FOSHU) 监管体系,来对食品标签上声明的对人体的影响进行监管和批准。这是第一次针对促进健康或预防疾病的特性来为食品贴标签并分类而做出的法律明文规定。

FOSHU系统的引入,是为了鼓励人们通过食用有科学依据的功能食品来保持健康,并预防生活方式疾病。FOSHU的审批流程非常严格,为了通过审批,必须有充分的证据证明产品的有效性,同时必须对有效成分进行鉴定以保证其安全性。在此基础上,2015年厚生劳动省又建立了一个新系统-“营养机能性食品声明” (FNFC)。

对于特定保健用食品 (FOSHU),日本政府需要评估其安全性和功效,消费者事务局 (CAA) 只批准符合要求的食品标签。 然而FFC只是一个通告系统,制造商需要满足六个标准即可在食品包装上做出健康益处声明。2这种自证系统类似于澳大利亚和新西兰的FSANZ健康申明系统。

日本是公认的世界上最健康的国家之一,肥胖率极低。 这与日本人爱吃的黏黏糊糊的食物有关吗? 纳豆是黏糊食物的代表。 它是发酵的大豆,看起来很难吃并且有一种奇特的味道,很难被日本以外的消费者接受,它相当于澳大利亚的Vegemite。纳豆中的粘稠粘液可以通过结肠细菌发酵并产生短链脂肪酸,这可能是纳豆促进肠道健康和控制体重的秘密。

 

无论一个产品是否具有FOSHU或FNFC认证,日本人对功能性食品的需求并不会减弱。已有的健康声明声称,乳铁蛋白、壳聚糖和甘草苷等成分都与降低内脏脂肪有关。

日本科研人员还指出,用无活性的益生菌制剂能观察到益生菌效应,这为从益生菌中提取益生元成分打开大门。在这个功能性食品已然成为主流的市场中,引入像BARLEYmaxTM这样的具有益生元效应的全谷物可以称得上是天时地利人和。

日本超市里有20多种的BARLEYmaxTM产品。其中包括早餐格兰诺拉麦片、荞麦面、饼干、能量棒、米粉、果泥汁、便当和饭团。

虽然日本走在时代的前沿,但在全球范围内,消费者逐渐开始意识到食用益生元的好处,以及食用益生元对许多慢性病带来的积极影响。消费者开始探寻能将这些益处与肠道菌群变化联系起来的功能性食品。

The Healthy Grain公司最近委托Tim Crowe博士做出一份战略研究评论报告,以检验BARLEYmax™大麦益生元是否支持消化系统健康。在此报告的积极结论的基础上,The Healthy Grain公司已正式通知FSANZ (澳新食品标准局) 这一自证的健康声明。

诸多澳大利亚和新西兰食品生产商都使用BARLEYmax™ 生产富含益生元的食品,现在他们可以在包装上添加产品可促进消化系统健康的声明。这些声明对于当代消费者来说至关重要,很多消费者越来越重视肠道健康,并在寻找能够帮助实现这一目标的功能性食品。

如果你的公司对如何将BARLEYmax™作为功能性食品配料感兴趣,请与我们联系,讨论战略研究评论报告中的发现。
祝身体健康。

 

 

 

泰瑞•李奇登斯坦,执业营养师
The Healthy Grain品牌大使

 

参考文献:

  1. Shimizu T. Health claims on functional foods: the Japanese regulations and an international comparison. Nutr Res Rev.2003 Dec;16(2):241-52.
  2. Maeda-Yamamoto, Mari. Development of functional agricultural products and use of a new health claim system in Japan. Trends in Food Science and Technology. Volume 69, Part B, November 2017, Pages 324-332

定义消化系统健康

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打开任何主流媒体的页面,你可能很快就会发现“肠道健康”这个词。作为营养专家,我们也被各种讨论肠道健康的医学文献淹没,这些文献主题多样,有的讨论肠道与大脑活动的直接联系,也有讨论争议话题的,比如使用面部微生物移植来治疗一系列疾病等。

在所有关于肠道的讨论中,尽管各种术语在科学期刊中被广泛使用,但大家对“肠道健康”的实际定义或临床术语“消化系统健康”的共识很少。1,2,3,4我们的消化系统包括唾液腺、口腔、食道、胃、肝脏、胆囊、胰腺、小肠、结肠和直肠,因此科学界要想达成一个简单相关的定义来涵盖所有的消化系统是相当不易的。

 

健康的定义

世界卫生组织将健康定义为“一种身体、心理和社交全方面健康的状态,而并非单单是没有疾病或体弱。”5

因此,我们可以使用这个健康的定义来解释消化系统健康,即在没有胃肠道紊乱或疾病的情况下,整体的身心健康。然而,从科学的角度来看,这个定义并不是很清楚,也无法提供可测量的生理指标来判断一个人是否处于良好的消化健康状态。如果肠道的角色是为了宿主的整体健康而发挥最佳功能,那么是否有可以用来评估肠道功能的实体是很重要的。影响肠道各方面功能的一个明显实体,便是微生物群落生态系统。

 

肠道微生物群

肠道菌群由1014个细菌组成,主要分布在大肠内。大量证据表明,肠道微生物是实现肠道健康的关键功能实体。6、7、8、9微生物群落在实现和维持肠道健康方面起着许多作用,从防止致病菌的定植,到维持完整的胃肠道屏障和调节免疫系统 (见下图)。正常肠道微生物群的一些特征可表明消化道健康状况良好,这包括无细菌过度生长,肠道微生物群的组成正常且充满活力,无胃肠道感染,或抗生素相关性腹泻。10

 

肠道微生物对胃肠道屏障的作用机制

Reference: https://bmcmedicine.biomedcentral.com/articles/10.1186/1741-7015-9-24#Tab1

 

娇贵的微生物群落生态系统

保持健康的微生物群落就像养护草坪一样。有了合适的肥料 (即益生元),我们的草皮 (即肠道中有益的微生物) 就会茁壮成长。当抗生素等干预措施极大地改变了肠道菌群的数量和组成时,对肠道生态系统的精心管理就变得愈发重要。如果没有适当的治疗,特别是在严重干预之后,生态系统可能会变得不平衡,不良微生物接管生态系统,就像野草破坏草坪一样。虽然我们开始了解健康的微生物群落是什么样的,但是对如何最有效改变微生物群,以及如何选择对特定人群有效的方式的认知,尚处于初期阶段。

参考文献: Lozupone_et_al-2012-Nature. Diversity, stability and resilience of the human gut microbiata

 

益生元—肠道肥料

在寻找消化健康的终极定义的过程中,若将肠道菌群比喻成宝箱,那么益生元便是宝箱中的黄金,是真正的无价之宝。“益生元”这一个概念大约在20年前引入,这个词的定义也有过一些变动,且定义的使用仍存在差异。对益生元的普遍共识定义,是“宿主微生物选择性利用的一种基质,具有健康效益”。

 

果聚糖 -肠道的终极肥料

在所有益生元中,果聚糖因其对人体的有益健康作用而受到了广泛的关注和研究,特别是它对肠道健康和肠功能的功效。

果聚糖益生元主要是果糖的聚合物,是洋葱、大蒜、谷物 (包括大麦和小麦)、龙舌兰、洋蓟、芦笋和韭葱等各种食物中天然储存的碳水化合物。果聚糖是膳食纤维的组成成分,众所周知,膳食纤维对促进排便规律性、增加粪便重量和运输时间有益。果聚糖是益生菌刺激益生菌繁殖的选择性基质,它能帮助寄主维持理想的微生物生态系统,是消化健康的必需物质之一。

 

果聚糖在消化系统健康中的作用

果聚糖进入大肠后,肠内微生物菌群发酵增加。短链脂肪酸 (SCFAs) 是结肠细菌进行果聚糖发酵的最终产品,被结肠上皮细胞吸收和利用,刺激它们的生长以及盐和水分的吸收,从而通过渗透压增加盲肠的湿度,促进肠蠕动。12 因此,通过维持正常的肠道运输规律和增加排便次数,果聚糖可以促进消化系统健康。

 

BARLEYmaxTM 益生元支持消化系统健康

果聚糖按聚合度 (DP) 分为小 (2 – 4)、中 (5 – 10) 和相对大的链长 (11 – 60个果糖单位)。术语FOS 代指来自蔗糖的DP约3-5的短果聚糖,而低聚果糖指DP 3-10来自天然菊粉的分子。12 BARLEYmaxTM全谷物的果聚糖构成是独一无二的,主要由DP范围3-12的果聚糖组成,包括FOS和菊粉。

The Healthy Grain公司已委托外界做出一份战略研究评论,罗列出BARLEYmax™大麦益生元支持消化系统健康的证据。

 

在此报告的积极结论的基础上,The Healthy Grain公司已正式通知FSANZ (澳新食品标准局) 这一自证的健康声明。如果你想了解更多关于The Healthy Grain的这份战略研究评论报告和BARLEYmax™益生元的信息,请在下面的评论中告诉我们,或发送电子邮件给我们,我们将与你取得联系。

 

祝身体健康。

 

 

 

 

泰瑞•李奇登斯坦
The Healthy Grain营养大使

 

参考文献:
  1. Tuohy KM, Probert HM, Smejkal CW, Gibson GR: Using probiotics and prebiotics to improve gut health. Drug Discov Today. 2003, 8: 692-700. 10.1016/S1359-6446(03)02746-6
  2. Ferguson LR, Shelling AN, Lauren D, Heyes JA, McNabb WC, Nutrigenomics New Zealand: Nutrigenomics and gut health. Mutat Res. 2007, 622: 1-6. 10.1016/j.mrfmmm.2007.05.001
  3. Johnson IT: Gut health, genetics and personalised nutrition. Genes Nutr. 2007, 2: 53-54. 10.1007/s12263-007-0020-y.
  4. Jacobs DM, Gaudier E, van Duynhoven J, Vaughan EE: Non-digestible food ingredients, colonic microbiota and the impact on gut health and immunity: a role for metabolomics. Curr Drug Metab. 2009, 10: 41-54. 10.2174/138920009787048383
  5. World Health Organization.Constitution of the World Health Organization as adopted by the International Health Conference, New York, 19–22 June 1946; signed on 22 July 1946 by the representatives of 61 States (Official Records of the World Health Organization, no. 2, p. 100) and entered into force on 7 April 1948. In Grad, Frank P. (2002). “The Preamble of the Constitution of the World Health Organization”. Bulletin of the World Health Organization. 80(12): 982.
  6. Fasano A, Shea-Donohue T: Mechanisms of disease: the role of intestinal barrier function in the pathogenesis of gastrointestinal autoimmune diseases. Nat Clin Pract Gastroenterol Hepatol. 2005, 2: 416-422
  7. Nieuwenhuis EE, Blumberg RS: The role of the epithelial barrier in inflammatory bowel disease. Adv Exp Med Biol. 2006, 579: 108-116. full_text.
  8. Meddings J: The significance of the gut barrier in disease. Gut. 2008, 57: 438-440. 10.1136/gut.2007.143172
  9. https://www.researchgate.net/publication/51223482_Human_nutrition_the_gut_microbiome_and_the_immune_system
  10. https://bmcmedicine.biomedcentral.com/articles/10.1186/1741-7015-9-24
  11. https://www.ncbi.nlm.nih.gov/pubmed/28611480
  12. Schaafsma G, Slavin JL. Significance of Inulin Fructans in the Human Diet. Compr Rev Food Sci Food Saf 2015;14:37-47.

Fruits of the Season

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One of the many reasons that I love living in Melbourne is that we have such well-defined seasons. At the moment we are right in the middle of a very cold winter. Everywhere I look I see bare trees, grey clouds and people wearing thick coats and gloves. The other thing I see is the delicious array of mandarins in the grocery stores, a sure sign of the colder weather.

Mandarins originally hail from Southern China and are named after the Chinese officials of the Imperial Court – the ‘Mandarins’. Luckily for those of us who live in Australia, this juicy fruit is widely available and comes in a variety of types. It is high in vitamin C, which makes it a perfectly timed seasonal fruit to help stave off winter colds.

Mandarins are an extremely versatile fruit and whilst they are delicious on their own, they can be included in a variety of cooking and baking recipes. I recently made a delicious mandarin pudding, which I adapted from the Monday Morning Cookbook Recipe and included BARLEYmax flour for an extra fibre boost. I love cooking with BARLEYmax flour as I find, unlike some other alternative flour types, that you don’t need to change too much of a regular recipe to accommodate the different flour structure. It adds a delicious nutty flavour and a light brown colouring to most baked goods.

This pudding recipe is a perfect warmer winter and can be enjoyed with a dollop of fresh cream or ice cream for real comfort food.

Ingredients

  • 50g butter, at room temperature
  • 100g castor sugar
  • 2 tsp finely grated mandarin zest
  • 2 eggs, separated
  • 1/3 cup BARLEYmax flour
  • ½ tsp baking powder
  • 200mL full cream milk
  • 1/3 cup mandarin juice
  • Cream or ice cream to serve
Method

  1. Preheat an oven to 180°C . Butter 4 x 1-cup ovenproof ramekins.
  2. Beat the butter, sugar and zest until pale and fluffy.
  3. Add the egg yolks, one at a time, beating well after each addition.
  4. Add the flour and baking powder and mix well. Stir in the milk and juice.
  5. In a separate bowl, whisk the egg whites until stiff, then fold into the batter and mix until smooth.
  6. Pour into the prepared ramekins, then place them in an ovenproof dish. Pour boiling water into the dish until it comes halfway up the sides of the ramekins.
  7. Bake for 45 minutes or until the puddings are golden. Serve immediately with cream or ice cream.

Recipe adapted from Monday Morning Cooking Club: The Feast Goes On

 

I’d love to hear from you – what’s your favourite winter treat?

 

 

 

Teri Lichtenstein (APD)
The Healthy Grain Nutrition Ambassador

关于抗性淀粉的六个事实

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抗性淀粉包括从植物性食物中提取的部分淀粉,这种淀粉可以抵抗小肠中胰腺淀粉酶的消化,随后到达大肠,在那里被细菌发酵。抗性淀粉有许多公认的健康益处,包括改善血糖控制和降低患心血管和肠道疾病的风险。

现如今,消化系统健康这一概念在食品制造商、科学家和消费者群体中愈发流行,抗性淀粉也逐渐成为一个热门术语。抗性淀粉常被媒体和健康专家认为是实现最佳消化健康的关键膳食纤维之一。虽然有越来越多的证据支持这些说法,但我们仍然不够了解这种独特的淀粉,以及它是如何带来这些健康益处的。

为了帮助营养专家和食品科学家更好地了解抗性淀粉,我们对这一尚未被充分了解,但非常重要的益生元纤维的独一无二的特性进行了更深入的研究。

 

  • 五种类型

现阶段我们已经鉴定了多达五种不同类型的抗性淀粉。不同的食物含有不同类型的抗性淀粉,有些食物含有多种类型1,2

  1. RS1包括细胞壁内无法获取的淀粉。它耐热,因此是许多食品的首选成分。
  2. RS2包含淀粉颗粒,其结构限制了消化酶的可及性。在烹饪之后,由于淀粉糊化,大多数淀粉变得非常易消化。
  3. RS3是烹饪后形成的淀粉,存在于冷却的意大利面、土豆和面包皮中。RS3因其热稳定性而受到食品制造商的关注。在烹饪过程中,RS1和RS2会被破坏,而RS3可以形成。
  4. RS4包括食品制造商用于改变淀粉功能特性的改性淀粉。
  5. RS5是一种抗淀粉酶消化的淀粉脂复合物。RS5可以促进短链脂肪酸如丁酸盐的形成,丁酸盐可以预防肠癌。

 

  • 含抗性淀粉的食物1

许多人都知道抗性淀粉存在于全谷物、煮熟后冷却的意大利面、米饭以及青香蕉中。但实际上很多不太容易联想到的食物也都富含抗性淀粉。下表列出了一些比较冷门的食物。

 

食物类型 抗性淀粉 (每100g)
扁豆 25.4
玉米 25.2
小麦 13.6
薯片 4.8
意大利面 3.3

 

 

 

  • 抗性淀粉改善肠道菌群

虽然抗性淀粉对健康有诸多好处,但是很多人不知道这些好处是如何得以实现的。抗性淀粉中直链淀粉比例高,而支链淀粉比例低。正是这种物理结构允许抗性淀粉通过触发细胞信号通路来改善肠道菌群,这些细胞信号通路都与减少糖尿病和肥胖相关。这一现象发生的确切机制仍然未知,堪称是新兴营养学的一个令人兴奋的研究领域。

 

  • “第二餐效应”

每天食用15-30克抗性淀粉,可以提高多达50%的胰岛素敏感性。3,4 抗性淀粉对降低餐后血糖水平也非常有效。这就是所谓的“第二餐效应”。如果你在早餐时食用抗性淀粉,那么过了几个小时后吃午餐时,会产生较低的血糖峰值。5 通过改善胰岛素敏感性和降低血糖水平,抗性淀粉可以降低患代谢疾病的风险。

 

  • 抗性淀粉比普通淀粉含有更少的卡路里。

在减肥方面,抗性淀粉的功能与可溶性纤维相似,它能增加饱腹感并降低食欲。短链脂肪酸可以引发荷尔蒙的释放,从而降低食欲 (瘦素、肽YY、胰高血糖素样肽)。 这是一个前景无限的研究领域,可能有助于对抗全球肥胖趋势。

 

  • 抗性淀粉通过短链脂肪酸传递健康益处

我们听到很多关于结肠中抗性淀粉发酵和短链脂肪酸 (SCFAs) 产生的信息。但到底是什么使SCFAs如此有用呢?

这些SCFAs包括醋酸盐、丁酸盐和丙酸盐,它们可被人体吸收或被细菌用来获取能量。SCFAs有着诸多益处,包括:

  • 刺激血液流向结肠
  • 促进营养循环
  • 抑制病原菌生长
  • 帮助人体吸收矿物质
  • 防止我们吸收有毒/致癌化合物

结肠中SCFAs的数量与人体摄入的碳水化合物的数量和类型有关。如果我们摄入足量的抗性淀粉,就能有大量的SCFAs。

这段视频解释了SCFAs在喂养饥饿的肠道菌群中所起到的作用。

CSIRO建议抗性淀粉的摄入量应超过每天20克,这几乎是目前典型西方饮食的四倍。6 根据最新的全国营养调查,澳大利亚成年人的抗性淀粉摄入量约为每天3-9克,成年男性比女性摄入更多的抗性淀粉。7

由于抗性淀粉的建议摄入量显著高于目前消费者的实际摄入量,因此抗性淀粉的消费具有相当大的提升空间,食品生产商有机会推动抗性淀粉的消费。开发创新食品应在其中加入天然的抗性淀粉来源成分,以帮助世界各地的消费者实现最佳的消化系统健康。

 

对抗性淀粉有疑问?欢迎在下面发表评论!

 

 

 

 

 

泰瑞•李奇登斯坦
The Healthy Grain营养大使

References:

A Winter Warmer for Your Gut

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My late granny was a great cook. I loved visiting her house and seeing her big cast iron pot sitting on the stove as I knew there would always be something delicious bubbling away inside. I inherited this wonderful pot and every winter I use it to make hearty soups and stews. It always  brings back great memories of warm tummies filled with comfort food that was eaten together around the dining table.

This week I made a roasted vegetable soup in the family pot. Roasting the veggies really draws out the flavour and this winter recipe is a perfect family meal all on its own providing an abundance of different coloured vegetables as well as the different whole grain fibres found in the BARLEYmax kibble.

It’s a hearty, warm and delicious soup that’s perfect for a cold winter’s day….or night.

Ingredients

4 Roma tomatoes, cut in half
3 carrots, diced
1 onion, cut into quarters
1 red pepper, diced
3 zucchini, diced
1 small eggplant, diced
200g butternut pieces
3 tbsp extra virgin olive oil
2 litres vegetable stock
1 bay leaf
½ cup dried porcini mushrooms
1 cup BARLEYmax kibble
Chopped parsley
Salt and pepper to taste

 

Method

  1. Preheat an oven to 200°C.
  2. Spray a large roasting pan and arrange tomatoes cut side down in the pan. Along with the other vegetables. Drizzle the olive oil all over the vegetables and place in the oven. Roast for about 50 minutes or until the vegetables are soft.
  3. Remove half the vegetables and process in a food processor until smooth.
  4. Place the remaining vegetables into a large pot with the vegetable stock, mushrooms, bay leaf and kibble.
  5. Simmer on a low heat for 45 minutes or until the kibble is softened. Then stir in the processed vegetables.
  6. Add the parsley and season with salt and pepper as required. Add extra stock if the soup is too thick.

I hope you and your family enjoy this nutritious (and delicious!) winter warmer as much as mine do!

 

 

 

 

 

Teri Lichtenstein (APD)
The Healthy Grain Brand Ambassador

 

Let Food be Thy Medicine

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In Australia, we have just started our winter season, which means increased sales of cold and flu medicine, more work absenteeism and in some states,  we have even run out of supplies of the flu vaccine!

Whilst the cold air and frosty weather would have some impact on our health, emerging science is showing a greater association between food and the gut for overall immunity and there is certainly more truth than ever in the age old saying that ‘we are what we eat.’

All the food that we eat and drink passes through our GI tract, which is lined with mucous that contains millions of bacteria, commonly known as the gut microbiome.  A healthy person will have a balanced microbiome with diverse types of bacteria, allowing the body to harvest nutrients from food, whilst at the same time reacting to harmful pathogens that can cause illness and disease.

Illness, stress, overuse of antibiotics are some of the factors that can result in an unbalanced gut microbiome, which can lead to gut inflammation and decreased ability to fight infection and increased illness. Diet plays a critical role in supporting good immunity via a balanced microbiome, especially fermentable fibres , which encourage growth of healthy bacteria. This is known as the “prebiotic effect” when these fibres are selectively utilised by the host microorganism to confer a health benefit. 1

A typical Western diet of high fat, high protein processed foods is low in these fermentable fibres, which can result in an imbalance of bacteria within the gut. A lack of sufficient fermentable fibres to feed the growth of healthy bacteria results in a decline in overall bacterial diversity, decreased gut cell wall integrity and increased gut permeability (often referred to as ‘leaky gut syndrome’) . As a result, specific immune pathways are affected, leading to greater increase of illness and disease.

To combat illness and disease, we need to let food be our medicine. We need to feed the trillions of bacteria with prebiotic fibres from foods such as fruits, vegetables, legumes and whole grains. When the bacteria break down these fibres through fermentation, short chain fatty acids (acetate, propionate, butyrate) are produced, which nourish the lining of the cell wall and help to maintain immunity.

There is increasing research into prebiotic fibres and stimulation of the immune system. It is possible that the effect is indirect, that is it is mediated through the increase in healthy bacteria such as lactobacillus and bifidobacillus. Or it is possible that the prebiotics may act directly on the immune system. The gut contains the largest pool of immune cells in the body which are separated only by a single layer of cells from the gut lumen and so the dietary components might be able to act directly on these immune cells.

One thing is for certain though, the path to illness or good health goes directly via our gut. So whilst the flu shot may help stave off winter illness, make sure you look after your gut at the same time!

Yours in good health this winter,

 

 

 

 

Teri Lichtenstein (APD)
The Healthy Grain Brand Ambassador

 

 

Reference:
  • https://www.ncbi.nlm.nih.gov/pubmed/28611480

Time to Start Befriending your Farts

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My 6-year-old son has a new favourite book. It’s called “No One Likes a Fart”, authored by the oh so funny Zoe Foster-Blake. In the story, poor little fart just wants to try find a friend but of course everyone he tries to meet is not interested in befriending him due to his rather unpleasant odour. Luckily, like most fairy tales, the story has a happy ending. But this did get me thinking that even though the story line mimics the real world where farting is something we would rather not talk about and certainly avoid in public; this unwelcome gas is generally a positive sign of good gut health and should perhaps be embraced in a more welcoming manner.

No One Likes A Fart by Zoe Foster-Blake

Flatulence (commonly known as farting) is caused by gas produced when we digest food. The bacteria in our gut breakdown carbohydrate and protein through fermentation and produce gas by products including methane, nitrogen and carbon dioxide. The varying smell will depend on the ratio of gases, which is ultimately influenced by the foods that we eat.

Eating foods that are high in fibre can produce a lot of gas. Whilst this may be embarrassing, the upside is the multitude of benefits that are achieved from eating gut-friendly fibre. All fibre is important for good health, but especially foods that are naturally high in resistant starch, as this nutrient has been shown to have many positive benefits including increased immunity and reduced risk of bowel cancer and diabetes. Foods that are naturally high in resistant starch include legumes, cooked and cooled rice and potatoes, green bananas, as well as whole grains like BARLEYmaxTM.

Foods that are known to produce smelly farts include things like cabbage, broccoli, onions, leeks and garlic, so if you find your farts are starting to smell a bit too much, it may be best to avoid these foods. There are some people that have difficulty digesting FODMAPS, a type of short-chain carbohydrates that can cause gut pain. When the small intestine does not break down FODMAPs, they are fermented in the large intestine by gut bacteria, which can lead to bloating and excess gas production.  Some people respond well to a diet that restricts FODMAPS including onion, garlic, wheat, honey, legumes and some fruits. However, it is important to undertake this type of diet with the help of a dietitian as it is not a long-term diet. Once gut issues have settled down, FODMAPS can usually be reintroduced back into the diet.

So, remember that farting is perfectly normal and, in most cases, a good sign of a healthy gut, even if those around you feel otherwise! So, I may just send a note to Zoe Foster Blake and suggest that perhaps she could write a follow up children’s story called “Everyone Should Like a Fart”, what do you think?

 

 

 

 

 

Teri Lichtenstein (APD)
The Healthy Grain Brand Ambassador

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