High potassium foods provide a diet that is complete in all nutrients. If you restrict the diet to just certain types of food groups however, you can have deficiencies. There are several types of diet that have unique potential deficiencies that can be guarded against if you know about them.
Multiple reports have examined the potential deficiencies in a vegan diet. There is no one single vegan diet, but all the vegan diets avoid animal food sources. The major potential deficiencies include Vitamins D and B12, various amino acids, iron, selenium and some other trace elements, and iodine.
One study found vegans to only get about 40% of the recommended iodine intake (Eur J Clin Nutr. 2003 Aug;57(8):947-55.). Findings were similar in other studies, including one done in the U.S. (J Clin Endocrinol Metab. 2011 Aug;96(8):E1303-7.)
The high potassium diet is not a vegan or vegetarian diet, but does include a lot of fruits and vegetables. There are a great many plants and plant products that are high in potassium. But if the diet is limited solely to plants, attention must be given to getting enough of other nutrients that are commonly deficient in vegan diets. Some individual reports of iodine deficiency in vegans have shown pregnant or lactating women and young children on a vegan diet are especially prone to iodine deficiency.
There are several ways to avoid deficiency. Iodine has been added to some common foods. In the U.S., table salt is iodized, but the salt added to processed food is not. Those vegans who do not add salt to their dishes need another source of iodine.
For omnivores, the simplest way to avoid iodine deficiency is to eat food that has come from the sea. Most omnivores can simply eat fish, especially those from the ocean. However, this is not open to vegans. The alternative often resorted to by vegans is to eat vegetables from the sea, usually a variety of seaweed.
The problem with seaweed is that the iodine content is variable. The recommended daily intake of iodine for an adult is 100 to 150 micrograms. The upper limit is 1100 micrograms (1.1 milligrams). Most seaweeds, such as kelp or kombu, only require a fraction of a gram of the seaweed to deliver the recommended amount of iodine, and thus present the risk of getting too much iodine. One species, hijiki (hiziki), should be totally avoided since it also has too much arsenic.
Additionally, some seaweeds have too much sodium. But raw lavar and agar have good ratios of potassium to sodium, as well as a good amount of potassium. There are also commercial products made from these seaweeds, but the processing changes the ratios of potassium to sodium. Check the label for the amount of each element.
The commercial products do retain the iodine though. Eden Foods Agar-Agar, for example, provides 80 mcg (80% of RDA) of iodine in a tablespoon of agar flakes, which will make a cup of agar gel. The gel can be used similar to gelatin for thickening, pie fillings and custards or Jello type desserts.
Alternative solutions for most vegans are to get iodine in a supplement, or to eat vegetables that are grown in soil with adequate iodine, such as land that is seaside. The iodine will be taken up by the plants and thus will be transferred to anyone who eats the plants.
You can find other nutrient values for lavar and agar in the vegetables table, and look for other tables of nutrient values in various food categories in the List of Posts.