Tuesday, October 1, 2013

Brains and Grains

More than just fibre, non-starch polysaccharides may help your brain
 
Article written by guest expert Dr Talitha Best, Central Queensland University and adjunct Research Fellow at the University of South Australia with research and clinical interests in exploring the effects of diet and nutrition on cognition and well-being.

The brain is a complex organ that, like every other organ in the body, requires nutrition to support optimal function. Research is now showing that everyday mental functioning, such as mood, memory and cognitive performance, can be impacted by diet. More than just dietary fibre to help maintain healthy bowels, non-starch polysaccharides found in grains, plants and fungi may be dietary components that support brain health.
 
Just like non-resistant starches, non-starch polysaccharides (NSP) have an important role to play in health. Whilst the structural and functional properties of these NSP’s are diverse depending on the variety and source, it is clear that they play an important role in promoting better health outcomes. These include, lowering blood cholesterol, improving blood glucose regulation and insulin sensitivity, immune function, cardiovascular function, gastrointestinal structure and function, as well as prebiotic effects.1
 
A wide range of NSP such as arabinogalactans, arabinoxylans, and mixed beta glucans, found in many cereals, grains, legumes, plants and fungi, are emerging as functional dietary components. The application of these complex saccharide compounds to brain function is a new emerging area of research. Whilst there remains a large research gap in the understanding of the mechanisms by which these polysaccharides impact the brain, at present there are preliminary human studies that suggest a positive impact on neurocognitive function in humans.
 
Specifically, in a randomized controlled study, a group of 75 athletes were given barley derived mixed beta-glucan extract for 4 weeks and were assessed on mood outcomes. At the end of the study, compared to placebo, those that had received the 250mg or the 500 mg dose reported improved mood outcomes, as reduced tension, confusion and fatigue, and increased vigor.2 Similarly, an Australian study showed positive effects of an arabinogalactan and glucomannan plant derived blend of polysaccharides on cognitive and mood outcomes in middle-aged adults. This study showed that after 12 weeks, compared to placebo those that had received the 4g dose of NPS report improved mood outcomes, as reduced tension and improved outlook, and better memory recall.3 These emerging studies point to the potential of NPS’s to improve cognitive health.
 
The brain requires nutrition for optimal structure and cellular function. Emerging studies suggest that NSP’s have a direct impact on the electrical activity of the brain. Administration of NSP’s derived from lichens and barley, in animal models, shows that these complex polysaccharides increase the electrical activity of cells within the hippocampus, an area of the brain associated with learning and memory.4,5 These findings provide a clue about potential mechanisms that might underpin memory effects seen in human studies.
 
In addition, NPS effects on cognitive function may be through mechanisms related to cognition and mood, such as blood glucose regulation and gut function. Whilst a vast majority of NPS’s are considered indigestible by the human digestive tract, some are known to have prebiotic effects that could benefit the gut microbiota. Excitedly, new research has began to demonstrate how changes within the gut can affect changes in learning and memory in animal models.6,7 It may be that complex interactions between NPS and gut microbiota impact mechanisms that result in cognitive benefit.
 
It is important that NSP’s in cereal seeds, grains, legumes, plants and fungi are included as part of a healthy diet, as they make a significant contribution to human health and nutrition. Understanding the benefits for cognitive function and the mechanisms underlying the nutritional significance of dietary NSP for brain health is an exciting area for researchers, industry and consumers to explore.


 
References:
  1.  Kumar, V., et al., Dietary roles of non-starch polysaccharides in human nutrition: a review. Critical reviews in food science and nutrition, 2012. 52(10): p. 899-935.
  2. Talbott, S. and J. Talbott, Effect of beta 1,3/1,6 glucan on respiratory tract infection symptoms and mood state in marathon atheletes. Journal of Sports Science and Medicine, 2009. 8: p. 509-515.
  3. Best, T., E. Kemps, and J. Bryan, Saccharide effects on cognition and well-being in middle-aged adults: A randomised controlled trial. Developmental Neuropsychology, 2010. 35: p. 66-80.
  4. Hirano, E., et al., P B-2, a polysaccharide fraction from lichen Flavoparmelia baltimorensis, peripherally promotes the induction of long-term potentiation in the rat dentate gyrus in vivo. Brain Research, 2003. 963: p. 307-311.
  5. Edagawa, Y., et al., Systemic administration of lentinan, a branched β-glucan, enhances long-term potentiation in the rat dentate gyrus in vivo. Neuroscience Letters, 2001. 314(3): p. 139–142.
  6. Lyte, M., Microbial endocrinology and nutrition: A perspective on new mechanisms by which diet can influence gut-to-brain communication. PharmaNutrition, 2013. 1(1): p. 35–39.
  7. Heijtz, R.D., et al., Normal gut microbiota modulates brain development and behavior. Proceedings of the National Academy of Sciences of the USA 2011. 108(7): p. 3047-3052.
  
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Weapons of Mass Reduction

The latest on grains & legumes and higher protein weight loss diets

With around 62.8% of Australian adults overweight or obese our nation’s battle against the bulge rages on.1 Alarmingly, it appears young Australian women are gaining weight at the fastest rate with an average increase of 0.6 kilograms per year according to a recent survey.2 Here we discuss some of the latest research on higher protein weight loss diets and give you guidance on how you can enjoy a variety of foods while defending your waistline.

Higher protein benefits – But how much?

With young women gaining weight more rapidly than other groups it is not surprising they are searching for effective weight loss strategies. Higher protein diets are popular with this group and there is good scientific evidence supporting the short term weight loss benefits of energy restricted higher protein (moderate carbohydrate) diets.3 Studies indicate that eating a relatively higher intake of protein helps to preserve muscle mass during weight loss. This is beneficial as our muscles are metabolically active (meaning they burn energy) and so minimising losses in muscle mass during weight loss can result in an overall greater reduction in body fat.4

So the science supports a ‘higher protein diet’, but in the effort to lose weight the important message of a balanced diet gets lost. So a key question is how much protein do we need each day to get these weight loss benefits? The good news is that a study published last month investigated this very question. Researchers from the US found that eating beyond twice the recommended level of protein intake (i.e. greater than 1.6 grams per kilogram body weight of protein each day) while following an energy restricted weight loss diet had no further benefits for fat loss in the young men and women.5 This finding supports the current level of protein recommended in many balanced higher protein (moderate carbohydrate) weight loss diets including the CSIRO total wellbeing diet.

So let’s put this ‘higher’ level of protein intake into real food and a whole diet perspective. In 2011-12 the average Australian woman weighed 71.1 kg6 and so to achieve a higher protein intake of twice the recommended level (similar to this recent study) an average woman could simply aim to eat three serves of protein foods like meat, poultry, fish, nuts or legumes as well as a couple of serves of dairy. This leaves room for a range of other foods including vegetables, fruit and grain (preferably half whole grain or high fibre) foods (which also contribute small amounts of plant protein) to nutritionally balance out your diet as well as give you the variety you need to sustain your diet and achieve your weight and/or waist related goals.

Room for nutrient rich grain foods (portion size matters)
 
The Grains & Legumes Nutrition CouncilTM (GLNC) is concerned that while young women are gaining weight the most rapidly, they are also the group most likely to be cutting out core grain foods from their day with the belief that this will help them lose weight.7 To help young women understand nutrient rich carbohydrate foods have an essential role within higher protein diets, the GLNC recently undertook a six month online campaign; Grains & Weight loss - the whole story. This campaign guides women on which grain foods and how many serves to eat each day to achieve their short term weight loss goals. An added bonus of eating whole grain and high fibre grain foods each day is that this dietary habit is associated with less weight gain in the long term.8,9
  
The key message of the campaign is based on a recent study of young overweight women where they followed a higher protein (moderate carbohydrate) eating plan that including 4 serves of nutrient rich grain foods, like whole grains or high fibre grain foods, each day.10 By six months, women who sustained this healthy approach to weight loss were able to achieve an average of 9kg weight loss (almost 10% of their body weight) which they were able to maintain over the full 12 months. Based on this Australian study here are two examples of what a normal day of a higher protein moderate carbohydrate diet looks like: Day 1 and Day 2. Once you have had a chance to check out these online resources, GLNC would appreciate your feedback and so welcome you to complete a brief 2 minute survey to assist us improve the quality of current and future campaigns.

Secret Weapons of Mass Reduction… A word on legumes

Are you one of the 80% of Australians who miss out on the nutritional benefits and belly busting potential of legumes? If you are looking to add a new weapon against weight to your diet look no further than legumes, such as beans (e.g. kidney, berlotti or navy), chickpeas, lentils and dried split peas. Studies indicate that people who eat legumes regularly are more likely to have lower waist size and lower risk of obesity.11.12 Eating legumes more often is an excellent habit to boost you nutrition, contribute to improvement in health and assist you achieve you weight related goals. Why not start this healthy habit now and aim to eat a variety of legumes at least 2-3 times each week as part a balanced diet. To help, check out our family friendly legume cookbook.

References:
  1. Australian Bureau of Statistics. Australian Health Survey: Biomedical Results for Chronic Diseases, 2011-12. August 2013. http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/4364.0.55.005Chapter1002011-12
  2. Popkin. (2010). "Australian Longitudinal Study of Women’s Health Weight Gain (g/year) 1996-2003." from http://www.alswh.org.au/.
  3. Wycherley, T. P., et al. (2012). "Comparison of the effects of 52 weeks weight loss with either a high-protein or high-carbohydrate diet on body composition and cardiometabolic risk factors in overweight and obese males." Nutrition & Diabetes 2(8).
  4. Phillips, S. M. (2008) Higher protein during an energy deficit: muscle’s guardian and fat’s enemy? Med. Sci. Sports Exerc. 40, 503–504
  5. Pasiakos, S et al. Effects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial. The FASEB Journal. 2013:27(9): 3837-3847. http://www.fasebj.org/content/27/9/3837.abstract
  6. Australian Bureau of Statistics. Australian Health Survey: Biomedical Results for Chronic Diseases, 2011-12. August 2013. http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/4338.0main+features212011-13
  7. Project Go Grain, Colmar Brunton 2011
  8. Williams PG,Grafenauer SJ, and O’Shea JE. Cereal grains, legumes,and weight management: a comprehensive review of the scientific evidence. Nutrition Reviews. 2008;66(4):171-82
  9. Du H et al. Dietary fiber and subsequent changes in body weight and waist circumference in European men and women. Am J Clin Nutr 2010;91:329-36.
  10. Griffin, H. J., et al. (2013). "Higher protein diet for weight management in young overweight women: a 12-month randomized controlled trial." Diabetes Obes Metab 15(6): 572-575.
  11. McCrory MA, et al. Pulse Consumption, Satiety, and Weight Management. Adv Nutr (Bethesda). 2010;1(1):17-30. http://advances.nutrition.org/content/1/1/17.full
  12. Papanikolaou Y, Fulgoni V. Bean consumption is associated with greater nutrient intake, reduced systolic blood pressure, lower body weight, and a smaller waist circumference in adults: results from the National Health and Nutrition Examination Survey 1999-2002. J Am Coll Nutr. 2008;27:569-576. http://www.ncbi.nlm.nih.gov/pubmed/18845707
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