Legumes linked to better diet quality

Australian cohort links between legume consumption and overall diet quality

Article written by Joanna Russell, Associate Lecturer in the Faculty of Social Sciences at the University of Wollongong.  Her research interests focus on assessing diet and health outcomes in large cohorts.

The range of benefits from eating legumes regularly includes a good, inexpensive dietary source of plant protein and dietary fibre. In addition, they are a low glycaemic index food and also provide small amounts of iron, zinc, magnesium and calcium(1). Evidence to date suggests that legumes may play a role in reducing the risk of cardiovascular disease in adults due to their ability to improve serum total cholesterol and LDL cholesterol concentrations, but additionally they could have other health benefits(2, 3). 

Legumes are one of the main food types which make up the Mediterranean type diet, a diet that is high in fruit, vegetables, legumes and fish as well as olive oil being the main source of fat. The research has constantly reported the benefits of consuming this type of diet such as reducing the risk of mortality as well as reducing the risk of developing diabetes and obesity(4). Indeed, high legume consumption was found to be consistent with higher diet quality when adhering to the Mediterranean Diet. Tortosa et al (5) investigated the incidence of Metabolic Syndrome in a cohort of university graduates and reported the incidence of Metabolic Syndrome increased with decreasing adherence to the Mediterranean Diet.

However, the Mediterranean type diet is not commonly consumed outside of this European region although Greek migrants are reported to retain this type of diet after settling in Australia(6). In other countries such as Australia, suggested diets beneficial to health are provided through published dietary guidelines(7). These recommendations include regular consumption of legumes as part of a healthy diet either as a vegetable or as a meat alternative. Although the most recently published Australian Dietary Guidelines(8) do not provide specific recommendations for the amount of legumes to consume a week, the Grains and Legumes Nutrition Council suggest eating legumes 2-3 times a week as part of a healthy diet.

With the new dietary guidelines in mind, the quantified recommendations from the Grains & Legumes Nutrition Council legume consumption has been explored in a cohort of older adults and their overall diet quality in terms of adhering to the published Australian dietary guidelines. Preliminary findings will be presented at the Nutrition Society of Australia’s Annual Scientific Meeting in early December that suggest, similar to previous evidence, adults aged 49 years and over are not eating adequate amounts of legumes as recommended by the published guidelines. However, individuals who did consume at least two serves per week also had higher diet quality scores(9). These findings require further investigation, particularly as we have previously found in this cohort that individuals with higher total diet scores had a reduced risk of mortality, a reduced risk of impaired fasting glucose as well as better quality of life and functional ability (10-12). 

Future research is necessary to determine whether legumes, although a small component of the overall diet, play a role in the health benefits derived from eating a healthy diet as recommended by published dietary guidelines.

References

1. Bazzano La HJOLG, et al. Legume consumption and risk of coronary heart disease in us men and women: Nhanes i epidemiologic follow-up study. Archives of Internal Medicine. 2001;161(21):2573-8.
2. Jukanti AK, Gaur PM, Gowda CLL, Chibbar RN. Nutritional quality and health benefits of chickpea (Cicer arietinum L.): a review. British Journal of Nutrition. 2012 Aug;108:S11-S26.
3. Bazzano LA, Thompson AM, Tees MT, Nguyen CH, Winham DM. Non-soy legume consumption lowers cholesterol levels: A meta-analysis of randomized controlled trials. Nutrition, Metabolism and Cardiovascular Diseases. 2011;21(2):94-103.
4. Schröder H. Protective mechanisms of the Mediterranean diet in obesity and type 2 diabetes. Journal of Nutritional Biochemistry. 2007;18(3):149-60.
5. Tortosa A, Bes-Rastrollo M, Sanchez-Villegas A, Basterra-Gortari FJ, Nũnez-Cordoba JM, Martinez-Gonzalez MA. Mediterranean diet inversely associated with the incidence of metabolic syndrome: The SUN prospective cohort. Diabetes Care. 2007;30(11):2957-9.
6. Kouris-Blazos A, Gnardellis C, Wahlqvist M, L., Trichopoulos D, Lukito W, Trichopoulos A. Are the advantages of the Mediterranean diet transferable to other populations? A cohort study in Melbourne, Australia. British Journal of Nutrition. 1999;82:57-61.
7. National Health and Medical Research Council. Dietary Guidelines for Australian Adults. Canberra: National Health & Medical Research Council; 2003.
8. National Health and Medical Research Council. Australian Dietary Guidelines. Ageing DoHa, editor. Canberra: Department of Health and Ageing; 2013.
9. Russell J, Flood V, Broome M, editors. Do older Australians eat enough legumes? Nutrition Society of Australia's Annual Scientific Meeting; 2013 3-6 December 2013; Brisbane, Queensland.
10. Russell J, Flood V, Rochtchina E, Gopinath B, Allman-Farinelli M, Bauman A, et al. Adherence to dietary guidelines and 15-year risk of all-cause mortality. British Journal of Nutrition. 2013;109:547-55.
11. Gopinath B, Rochtchina E, Flood VM, Mitchell P. Diet quality is prospectively associated with incident impaired fasting glucose in older adults. Diabetic Medicine. 2013;30(5):557-62.
12. Gopinath B, Russell J, Flood VM, Burlutsky G, Mitchell P. Adherence to Dietary Guidelines Positively Affects Quality of Life and Functional Status of Older Adults. Journal of the Academy of Nutrition and Dietetics. 2013:http://dx.doi.org/10.1016/j.jand.2013.09.001.