We often hear about “functional food.” But what does that mean? And how do high potassium foods fit in? Functional foods are those with health benefits beyond the basic nutrition they provide. The term is used a lot in marketing, but often the health benefit is not as definite as the advertisement claims. Among the most well established groups of functional food are the high potassium foods.
There are a number of studies showing the reduction of hypertension, cardiovascular disease, osteoporosis and kidney stones in populations on a high potassium foods diet. There have been epidemiological studies to show populations on high potassium diets have less of these conditions. There have been multiple experimental human and animal studies showing this improvement. And there are multiple studies shedding light on the way these conditions are improved. There have been a great number of laboratory studies showing the metabolic pathways that give these results. This is really the amount of work that needs to be done for a type of food to be considered functional. One or two limited studies showing good results are not enough.
Food Component Versus Food
Many studies have been based on the speculation that a single component of the diet is responsible for a particular favorable or unfavorable effect. One that has been shown to be unfavorable in a very strong way is the studies on saturated fat. But the problem with the studies that show the harm a food can do is that such studies just result in the recommendation of eliminating a food from the diet. What most people want to know is what they should eat. This is more important than what to avoid.
Many of the food components that have been studied are found in only a small selection of food, such as resveratrol or each vitamin. Often when the component is separated from the food it is found in so it can be given as a supplement, the supplement does not give the anticipated effect. Many vitamins and antioxidants fall into this category. But that does not mean that the food component has no effect. There is a big difference between failing to show an effect and showing no effect.
Some Studies' Shortcomings
The researchers' suspicions are often based on good evidence, but the bench top procedures, or the procedures for data analysis, are not adequate to show the effect. For antioxidants, the ORAC test did not correlate with what was happening in the cell. It was not the right bench top procedure for what people want to know about these foods. So the conclusion should not be that antioxidants are useless. It should be that the jury is still out. We discussed this antioxidant problem in a prior post.
There are a great many metanalyses being done now. Many of these are failing to show the same effect for a food component that smaller studies showed. Although the metanalyses include methods to correct for the differences in the studies used in the metanalysis, the failure to show an effect may be because the statistical procedure for data analysis may not be the right one. We discussed an interesting set of metanalyses here.
Cardiovascular disease is the leading cause of death globally. A great many studies have been done to find functional foods to reduce the amount of cardiovascular disease. High potassium foods are the major component of diets designed to reduce this disease. There are other factors to consider besides just potassium, but none are more important than the potassium sodium ratio.
Just taking in a supplement containing a large load of potassium does correct some aspects of cardiovascular disease, but there are other factors to also consider. By getting potassium from several food groups rather than from a pill of potassium salt, those other factors are dealt with. In upcoming posts we will discuss functional food considerations of high potassium foods, and what else each of the high potassium food groups can provide beyond the favorable effect of potassium.
The “Links to Food Potassium Tables” on the tab at the top of the page has links to all the tables of nutrient and potassium values on this site.