Do fruits and vegetables have potassium for a different reason than animals? If mammals need potassium & sodium for, among other things, keeping their nerves in balance do fruits and vegetables need them for a totally different reason and that explains why there is such an imbalance of high potassium/low sodium in plants? Example, an orange has almost 200mg of potassium and 0mg of sodium. What purpose does the potassium serve in fruits and vegetables?
I have been under the impression that a lot of the nutrients and micro-nutrients found in plants are actually, as far as the plant is concerned, just environmental toxins that the plant picks up and then concentrates in their fruit or leaves or wherever, or else they are waste products of the plants’ own biochemical processes.
Well, the ocean is contaminated with predominately sodium chloride.
rock is basically equal amounts of Ca Na and K … there’s no point saying that there is more of one over another, what is true at one area is not true at the other…but basically they are never far apart…
I think that the basic idea is that while the cell has to be fussy about absorbing Na+, its loving the uptake of K+. The cell can then use osmotic pressures to assist in respiration.
How ? The Na ion channel in the cell is just big enough to let Na through,
but block K+. The cell uses the Na ion channel to pump out Na+ and maintain salt levels…
So therefore, the largest contaminant is repelled.
And it is NOT contamination, the Na is expelled for a reason. the 2nd suitable ion for controlling metabolism is K+ and there is are channels for that too. They are used for a huge variety of purposes, so basically it is because its just a little bigger than Na+ and a little smaller than Ca++ that its kept inside the cells … Ca is less soluble and has more insoluble forms, so its not the one…
Do vegetables actually contain more K than Na? My impression is that we require Na in gram amounts, but K in mg quantities, plants only seem to have more of the one than the other. In fact, hyponatremia (too little Na) can be fatal and can be brought about by just drinking too much H2O.
Good question. Here’s what I got from a little Googling:
[ul][]Banana: 1 mg Na, 422 mg K[]Apple: 2 mg Na, 195 mg K[]Orange: 0 mg Na, 174 mg K[]Mango: 3 mg Na, 564 mg K[]Kiwifruit: 2 mg Na, 215 mg K[]Tomato: 6 mg Na, 292 mg K[]Corn: 58 mg Na, 476 g K[]Carrot: 42 mg Na, 195 mg K[]Celery: 42 mg Na, 104 mg K[]Lettuce: 10 mg Na, 70 mg K[*]Broccoli: 49 mg Na, 468 mg K[/ul]So it seems that most (edible) plant tissues do have more potassium than sodium in them; and that fruits are particularly low in sodium compared to leaves, stalks, seeds, roots, etc.
[Moderating]
That’s pretty much wrong. When posting in GQ, it’s best to stick to facts you actually know rather than “impressions,” especially as a first response.
From the GQ rules:
Colibri
General Questions Moderator
Here’s a good summary of the functions of potassium in plants. It is used in many enzymes and physiological processes. Potassium is one of the most vital nutrients for plant growth. In contrast, sodium is not an essential element for plants but may be used in small quantities.
Both sodium and potassium are essential for animals, especially for electrical processes in nerve and muscle function. Since plants lack such tissues, they don’t need sodium like animals do.
Herbivorous animals normally get much less sodium from their diet than they need, which is why they must frequent salt licks or other sources of such elements. Carnivores and omnivores usually can obtain enough sodium from the meat in their diets.