How you prepare high potassium foods is important in determining how much potassium in the food will get into your body. It is no good to have 4700 mg of potassium in the food you would consume, and then lose a large amount of it during the preparation.
Most methods of cooking make it easy to keep the potassium in the food. But one method in particular frequently pulls potassium out of the food.
Plant Food Products
Eating the raw food is the easiest method to keep all the potassium in the food. It is a good method for most vegetables, fruits, and spices. But do not use it for animal products. Animal products are more easily contaminated, and more easily grow harmful organisms.
Occasionally plants harbor harmful organisms. But if you pick plant foods fresh, consume them fresh, and wash them prior to eating, they have a low likelihood of having harmful organisms. If you know the producer of the plant food, you can determine the possibility of chemical contamination. And if you know what to look for, you can determine if the fruit or vegetable is spoiled.
Animal Food Products
Contamination of animal products is often invisible, though. Even the most careful farmer can have meat, dairy or eggs with harmful organisms. Almost all eggs have salmonella on the shell surface. You should assume all poultry has salmonella on the surface. Meats can have organisms that will not show up like spotted or softened produce does. Likewise, unpasteurized dairy can have microorganisms that don't show.
When handling animal products, you should not use the same utensils with the raw product and the cooked product, unless thoroughly washed before using with the cooked product. You should wash your hands, dishes and utensils thoroughly after using them with raw food before using them with cooked product.
Although some knowledgeable producers and consumers have used raw animal products safely, I feel it is too difficult. Some of my friends and I have had contaminated raw animal products from sources we trusted. So I feel you should cook all meat and egg products, and pasteurize all dairy.
For high potassium foods, you have a multitude of choices for preparation. You can eat it raw after washing. You can steam it, bake it (without baking soda or powder), fry it, grill it, roast it or broil it. These methods will lose none or minimal amounts of potassium. And you can use these methods with most dishes. Many BBQ enthusiasts already have tried various vegetables grilled. To mention just a few – peppers, potatoes, onions, and zucchini are great sliced and grilled.
The main preparation method that loses potassium from many foods is boiling in water. It pulls potassium into the water. If you consume the water though, you will consume all of the potassium. You commonly consume the water with soups, chilies and stews. But if you discard the water, you will reduce the amount of potassium you get from the food. Combine that with the common method of adding salt to the water the food is boiled in, and you will have ruined the health advantage of high potassium foods. You will have increased the sodium and lowered the all important potassium to sodium ratio.
A good method for preparing intact grains, such as rolled oats or quinoa, is to add just enough water to soak into the grain and then microwave the dish. This heats the grain and destroys any organisms, while making the grain soft enough to eat. This method drives water into the grain. The method does not leach potassium from the grain like boiling does. So you consume all the potassium in the grain. You can also use this method with dry lentils and beans, although the soak time is longer.
Of course, you can add spices at any time. And this will increase the potassium content of the dish, while adding flavor.