Another food group composed of functional foods is whole, intact grains that are high in potassium. Many whole grains are high potassium foods. Thus they contribute to lower blood pressure, less osteoporosis and fewer kidney stones. Many of the beneficial qualities of whole grains are because of their high potassium content. But other aspects of the whole grains also contribute to health. These aspects can slow insulin secretion, reduce unfavorable LDL cholesterol, and reduce inflammation throughout the body.
Differences Between Intact And Refined Grain
What are the differences between intact grains and refined grains that contribute to these effects? Whole grains include more nutrients and have less sodium. And if the grains are intact (not simply the ground up whole grain) they are more slowly digested. Thus they contribute to lower mortality.
Many of the processes involved in refining grains destroy nutrients in the grain. For example, heating destroys the heat labile nutrients. Also, chemicals added to preserve or change texture have other effects beyond the preservation or texture change. And adding sodium for longer shelf life destroys the favorable potassium to sodium ratio of intact grains.
Functional Metabolic Effects
By grinding the grain into a fine powder, the carbohydrates in the food are more quickly absorbed than carbohydrates in the intact grain. Thus, blood sugar rises more quickly and insulin spikes, leading to a rapid fall in blood sugar and a tired feeling 2 hours later. And when blood sugar rises and falls quickly, hunger returns within 2 hours. As a result, people eat more often, leading to more calories absorbed in a day. Ultimately, this results in more obesity and insulin sensitivity (1).
Including the intact, whole grain retains the insoluble and soluble fiber. As a result, the soluble fiber contributes to lower LDL cholesterol, and thus lower amounts of plaque buildup in the blood vessels, including the heart vessels. And the insoluble fiber speeds passage of food through the intestines, giving less time for harmful waste products to buildup in the intestines. In addition, the fiber from intact grain, but not from refined grain is associated with reduced mortality (2).
Furthermore, several studies have shown lower amounts of inflammatory markers in the body after meals composed of whole grains (3). This may be related to the slower rise in blood glucose, since there is a higher amount of reactive oxygen (free radicals) generation with a high blood glucose level. However, another possible explanation is that the phytochemicals present may be able to blunt the free radicals.
Tables Of High Potassium Foods
A table of high potassium grains with potassium and sodium content can be found by clicking the links on the “Links to Food Potassium Tables” tab at the top of the page.
1. N. M. McKeown, J. B. Meigs, S. Liu, P. W. F. Wilson, and P. F. Jacques, “Whole-grain intake is favorably associated with metabolic risk factors for type 2 diabetes and cardiovascular disease in the Framingham Offspring Study,” American Journal of Clinical Nutrition, vol. 76, no. 2, pp. 390–398, 2002.
2. D. R. Jacobs, M. A. Pereira, K. A. Meyer, and L. H. Kushi, “Fiber from whole grains, but not refined grains, is inversely associated with all-cause mortality in older women: the Iowa Women’s Health Study,” Journal of the American College of Nutrition, vol. 19, no. 3, pp. 326S–330S, 2000.
3. P. L. Lutsey, D. R. Jacobs, S. Kori et al., “Whole grain intake and its cross-sectional association with obesity, insulin resistance, inflammation, diabetes and subclinical CVD: the MESA Study,” British Journal of Nutrition, vol. 98, no. 2, pp. 397–405, 2007.