Legumes and chronic disease

Evidence of the health benefits of legumes builds

The science supporting the health benefits of legumes is stacking up with two large intervention studies indicating the importance of eating legumes regularly for older people and people with diabetes. Only one in five Australians eat legumes regularly and so with rising rates of chronic disease, Australian’s stand to benefit more than ever from the health benefits associated with increasing legume intake.

Legumes and Cardiovascular Disease

Cardiovascular disease is one of Australia's largest health problems and is the term used for heart, stroke and any disease of the blood vessel. The Heart Foundation estimates that this disease accounts for approximately 33% of deaths each year, “killing one Australian every 11 minutes”.1 A recent study compared risk factors for cardiovascular disease for individuals aged 50 years and older following their regular diet versus a legume based diet. The legume based diet included 150g dry weight (250g wet weight) per day of foods prepared with lentils, chickpeas, beans and peas. The authors concluded that a legume based diet reduced total and LDL-cholesterol in individuals aged 50 years and older, an age at which the risk of cardiovascular disease is elevated. These observations were estimated to reduce coronary heart disease by 17-25%.2

Legumes provide a range of essential nutrients including protein, carbohydrates, dietary fibre, minerals and vitamins. The component in legumes which may account for their cholesterol-lowering effects may be dietary fibre, through its action of binding bile acids in the intestine and preventing their reabsorption. This recent study found that participants ate approximately 36% more fibre during the pulse based diet compared with the regular diet.2

Legumes and Diabetes

Nearly one million Australians have diabetes, surprisingly it is estimated that about half of those are not aware that they have the condition. As poorly controlled diabetes is a strong risk factor for cardiovascular disease it is no surprise that around 75% of Australian’s with diabetes die from cardiovascular disease.3

Legumes are among the lowest glycemic index (GI) foods. Low GI foods are digested slowly and they have been shown to improve blood glucose control in people with diabetes. A recent Canadian study compared a low GI diet which encouraged individuals to eat at least one cup (around 190g) of cooked pulses per day with a high wheat fibre diet were whole wheat cereals, breads and brown rice were emphasised. The authors concluded that eating legumes as part of a low GI diet improved blood glucose control and reduced risk of coronary heart disease in individuals with diabetes.4

These findings support current recommendations for individuals with diabetes to include legumes to decrease the overall GI of their diet. The mechanism behind improved blood glucose with higher legume intake may not only be accounted for by the low GI of legumes. Legumes contain soluble fibre and vegetable proteins which may contribute to improved blood glucose control observed with higher intake of legumes.

How much should we eat?

In the studies discussed the participants were encouraged to eat around 250g & 190g of cooked legumes daily, respectively. On average Australians only eat 18.5 grams of legumes per week.5 This average is deceptive because actually most Australian’s are not eating any legumes regularly. Aiming for at least two serves of legumes a week is a good start, but keep in mind the health benefits associated with higher intakes of legumes.

One serve = 75g or ½ cup cooked beans, peas or lentils.

For more information on legumes visit our website to download copy of ‘Lifting the Lid on Legumes’ and ‘Tips and Tricks to enjoying legumes more often’ as well as our recently developed fact sheet “Heart Health with grains and legumes”. While you’re there pick up some ideas from our legume recipe pages. www.glnc.org.au

References:

1. The Heart Foundation. Accessed online 13th November 2012. www.heartfoundation.org.au
2. Abeysekara, S et al. A pulse based diet is effective for reducing total and LDL cholesterol in older adults. British Journal of Nutrition 2012, 108, pp S103- S110
3. Diabetes Australia. Accessed online 13th November 2012. www.diabetesaustralia.com.au
4. Jenkins, D et al. Effect of legumes as part of a low glycemic index diet on glycemic control and cardiovascular risk factors in Type 2 Diabetes Mellitus: a randomized controlled trial. Archives of Internal Medicine 2012. Published online.
5. Project Go Grain, Colmar Brunton 2011