Cereal grains have a great potassium to sodium ratio. Almost all of them have greater than the Institute of Medicine's recommended 3 to 1 ratio. This ratio has been shown in multiple studies to give the health benefits of reduced blood pressure, heart disease and stroke, increased bone density and reduced chance of kidney stones. These high potassium foods also have a great many other characteristics that make them healthy foods.
Before grinding, the whole grains are slow to digest, giving them a low glycemic index and reducing the spike in blood sugar that occurs after a high glycemic index meal. After grinding into flour, they lose this characteristic, but still have a favorable 3 to 1 ratio of potassium to sodium. They are low in saturated fat, making them favorable for your blood cholesterol. This effect is in addition to the favorable effects of the potassium on blood pressure, heart disease and stroke. These high potassium foods are high in fiber, aiding intestinal health by speeding the passage of food through the system. And they have plenty of vitamins and other minerals besides potassium.
A problem in reading about whole grain is that whole grain has 2 meanings, depending on who is writing about it. It can mean the intact grain as it comes off the stem, or it can mean the flour made from grinding up the intact grain. Grinding the grain has no effect on the potassium content of the grain. The only effect of the grinding on health effects is the increased access of the body to what is in the grain. The stomach acids and enzymes of the body can penetrate the food more quickly. This means the carbohydrates are absorbed more quickly, contributing to the increased glycemic index. On the plus side, for some foods it may mean that the vitamins come out of the grain to be absorbed more readily, and thus help prevent vitamin deficiency.
The table in the immediately preceding post shows a number of interesting facts about these grains. We mentioned some in the post accompanying the table. But some we didn't discuss are the relative amount of potassium you can get from a serving of the cereal as a whole, intact grain, or how these high potassium cereals should be eaten to maximize their favorable, healthy characteristics. Another aspect is that, for almost all the grains, bran has more potassium than the remainder of the grain. The only exception is corn, whose bran is low in potassium. Wheat has the most potassium in the germ, but a great deal is nontheless present in the bran.
White rice is low in potassium, but its bran is loaded with potassium. When the bran is left on, it is brown rice, and the rice is far richer in potassium, and B vitamins. Parboiled rice is rice that has been steamed while the bran is still on the grain. This process drives many of the nutrients into the endosperm (white portion) making it a healthier choice.
Here is a short list of the cereal grains with the very highest potassium content (including pseudo grains like amaranth and quinoa), highest amount to lowest – rice bran, wheat germ, amaranth, quinoa, rye, hulled barley, and wheat. Even whole grain corn has a terrific amount of potassium, having 476 mg in a serving.
The flour of most of the grains, especially if whole grain flour, is high in potassium. However, when a product is made from the flour, almost always sodium is added in the form of baking soda or baking powder to get the dough to rise. Sodium counters many of the health effects of potassium, by its actions affecting aldosterone and some of the paracrine hormones, such as the prostaglandins.
Cooking itself has little effect on potassium. How a grain is cooked has a great effect, though. The potassium ion is water soluble. If cooked in water and the water is discarded, much of the potassium is lost in the water because the potassium is leached into the water. However, if just enough water is added to soak and be absorbed by the grain, and then the grain is cooked, the water is not thrown out. The potassium stays in the food. Since you consume the water that was simply absorbed by the grain, you will get all the potassium that is in the grain.
A great way to have oats is based on this method of just adding enough water to soak the grain prior to cooking. A quick and nutritious breakfast can be made from whole (old fashioned, not instant) oats. By adding enough water to just cover the oats in the bowl, mixing it with the oats, and then cooking in the microwave, you can have a nutritious, high potassium breakfast in 2 1/2 minutes. Oat bran can be mixed in to give its favorable effects, if desired. I like it plain, but you can add fruit or cinnamon for flavor.
Quinoa can make a great meal if prepared in a similar fashion. Just add a cup of water to 1/2 cup of whole grain (not ground up flour) and cook in the microwave.
The health value of the pasta products depends on how much sodium is added. For many types of pasta, sodium is added in the form of baking soda. The ratio of potassium to sodium shifts so much that many pastas are not listed in the table in the previous post. Those that have a favorable potassium to sodium ratio are listed in that table. Another consideration beyond the potassium benefits is the effect on blood sugar by the pasta. The grinding of the whole grain means the carbohydrates in the grain are absorbed faster, and thus a pasta, bread or cake has a higher glycemic index, indicating a higher blood sugar spike than the actual intact whole grain.