Frequent consumption of legumes has been reported to provide health benefits and reduce the risk of certain diseases. In particular, legume rich diets have been shown to reduce the blood pressure of subjects with hypertension and insulin resistance. Legumes may also aid in weight loss, and prevent weight gain, when consumed as part of a high quality diet. This weight loss effect of legumes may relate to the high fibre content, which is thought to slow digestion and thus decrease the glycaemic effects of carbohydrate foods. Adding legumes to a diet high in refined carbohydrates may therefore decrease some of the negative metabolic effects and prevent the deleterious weight gain associated with such low quality food. There is therefore interest in assessing the nutritional intakes of those who regularly consume legumes. Beans is one form of legumes that has been repeatedly reported to offer potential cardioprotective effects.
Researchers1 have investigated the associations between legume consumption and various nutrient intakes using data taken from the National Health Examination Survey (NHANES (1999-2002) in the United States. In particular, the researchers looked at the consumption of beans using 24-hour dietary recall, with consumers divided into baked bean, other bean or baked and other bean groups. Bean consumers had higher intakes of dietary fibre when compared to non-bean consumers, as might be expected. In addition, bean consumers also had high intakes of potassium, magnesium, iron and copper, when compared to non-bean consumers. Those individuals who regularly consumed beans had a lower body weight and a smaller waist circumference, as well as a 23% reduce risk of increased waist size and a 22% reduced risk of being obese. Baked bean consumption, but not other bean consumption was also associated with a reduced systolic blood pressure.
These results support previous studies that show bean consumption is associated with a lower body weight and reduced risk of cardiovascular disease. Interestingly, the sodium intake of baked bean consumers was higher than the sodium intake of non-baked bean consumers, yet bean consumers had lower blood pressure. This adds more evidence to the growing body of research that indicated the sodium hypothesis of high blood pressure is false (here), and that sodium only affects the blood pressure of a small number of sodium sensitive individuals (here). In this study, the bean consumers had elevated potassium levels compared to non-consumers. Some evidence suggests that the potassium to sodium ratio in the diet is important in blood pressure regulation and this may be another reason why bean consumption is associated with a reduced blood pressure. The high fibre content of beans may explain their weigh loss benefits.
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