If you’re looking for a much-needed boost to your immune system, most of us are familiar with the benefits of ‘probiotics’ in foods that help balance the good bacteria in our guts. What is less understood are ‘pre-biotics’ in foods.
This is despite emerging evidence that prebiotics – including resistant starch found in whole grain, high fibre grain foods and legumes – have the potential for the same effects, acting in a similar way to probiotics, according to the Grains and Legumes Nutrition Council™ (GLNC).
As we enter the autumn months, building our immune system to guard against common infections like colds and the flu becomes more important to us all.
The science is clear that diet plays a significant role in our ability to resist infections(1), but many of us don’t understand why, and what foods are going to effectively help our immunity to ward off illness.
‘Enjoying a balanced diet including foods rich in prebiotics helps to feed our immune system to fight and avoid common infections like cold and flu,’ explains Chris Cashman, Nutrition Project Officer at GLNC – the authority on the nutrition and health benefits of grains and legumes.
‘In the same way as regularly consuming probiotics, enjoying a range of whole grain or high fibre grain foods, legumes and a variety of vegetables may also enhance immune health,’ Chris adds. ‘This is through a prebiotic effect – an increase in the balance of beneficial bacteria in the digestive system which provide a range of health benefits including improved immune responses.’
Here’s how nutrition can support immune health.
Protect against infection with probiotics
It’s well known that the balance of bacteria in the digestive system – the gut – is important to protect against infection. A top-up of live beneficial bacteria, probiotics, can be achieved by consuming lactobacilli and bifidobacteria strains of probiotics in fermented foods, such as yoghurts and some fermented milks. These have been found to support the immune system. It’s now emerging that prebiotics have the potential for the same effects.
Boost your immunity with prebiotics
Prebiotics are special types of dietary fibres, which ferment in the digestive system. This fermentation helps to feed the beneficial bacteria in the gut, improving the composition and/or activity of lactobacilli, bifidobacteria and other bacteria species (probiotics) that produce protective components and deliver health benefits(2). One interesting prebiotic is resistant starch, with studies promising that this type of dietary fibre has greater potential to ferment in the digestive system, and so may have greater potential to enhance immune responses and protect the digestive system(3).
Create balance with foods containing prebiotics
A range of common foods recommended in the Australian Dietary Guidelines4 contain an array of prebiotic fibres. These foods include legumes such as peas, chickpeas, lentils and beans, as well as whole grain and high fibre grain foods containing wheat, rye, barley, oats, brown rice and certain fruits and vegetables(5 6). Enjoying these within a balanced diet may support the balance of bacteria and potentially improve immune function(7 8).
For more facts about immune health visit www.glnc.org.au
FOUR FACTS ON IMMUNE HEALTH
1. Prebiotics can enhance good bacteria in our guts. Prebiotics, including resistant starch found in whole grain, high fibre grain foods and legumes, have the potential to induce the same sorts of immune enhancing effects as probiotics, acting through similar mechanisms(2, 5, 7).
2. Immune responses are fuelled by diet. There is increased demand for energy and essential nutrients to produce the cells required for a specific immune response. Ultimately the foods we eat are the source of the essential amino acids, essential fats, vitamins and minerals required for the immune system to function on a day to day basis and to respond optimally to an insult(7, 9).
3. A balanced diet helps to resist infection. Enjoying a balanced diet, as recommended by the Dietary Guidelines, provides the nutrition the immune system requires to work effectively and resist infection. An inadequate diet impairs immune defences, increasing the risk of infection.1, 9 This can be due to insufficient intake of energy and macronutrients (protein, essential fats, carbohydrates) and/or due to deficiencies in specific vitamins and minerals such as vitamin A, D, E, and B vitamins, zinc, iron, iodine and selenium(7, 9).
4. Grains and legumes contain a range of valuable nutrients. Grain foods and legumes are leading contributors of a range of nutrients which play an essential role in immune function including folate, thiamine, niacin, magnesium, iron, zinc and protein(9, 10).
1. Katona P, Katona-Apte J. ‘The Interaction between Nutrition and Infection’. Clinical Infectious Diseases. 2008;46(10):1582-8.
2. Gibson GR, Probert HM, Loo JV, Rastall RA, Roberfroid MB. ‘Dietary modulation of the human colonic microbiota: updating the concept of prebiotics’. Nutrition Research Reviews. 2004;17(2):259-75.
3. Bird AR, Conlon MA, Christophersen CT, Topping DL. ‘Resistant starch, large bowel fermentation and a broader perspective of prebiotics and probiotics’. Beneficial Microbes. 2010;1(4):423-31
4. National Health and Medical Research Council. Australian Dietary Guidelines. 2013. Canberra: National Health and Medical Research Council.
5. Dr Jane Muir, J et al. Conference Presentation: ‘What are the risks/benefits of fermentable carbohydrates?’ The FODMAP Story. Accessed online http://www.glnc.org.au/4th/events/ilsi-presentations/ 4th April 2013
6. Landon. S, Colyer. CGB, and Salman, H. ‘The Resistant Starch Report. An Australian update on health benefits, measurement and dietary intakes’. Food Australia Supplement 2013. Accessed online 17 Dec 2013: http://foodaust.com.au/wp-content/uploads/2012/04/Hi_Maize-supplement_web.pdf
7. Calder PC. ‘Feeding the immune system’. Proceedings of the Nutrition Society. 2013;72(03):299-309.
8. Lomax AR, Calder PC. ‘Prebiotics, immune function, infection and inflammation: a review of the evidence’. The British Journal Of Nutrition. 2009;101(5):633-58.
9. Calder PC. ‘The Importance of Nutrition to Healthy Immune Function. Wellmune; 2013. Accessed online 10/12/2013. http://www.fibebiotics.eu/index.php/videos
10. McLennan WP, A. National Nutrition Survey. ‘Nutrient intakes and physical measurements’. Australia 1995. ABS Cat No 48050 Canberra: Australian Bureau of Statistics. 1998.