I have here a bottle of V8 Low Sodium Original 100% Vegetable Juice (from concentrate with added ingredients) of which, according to the label, one 8 oz (240 mL) serving provides:
[ul]
[li]Sodium: 140 mg (6% DV)[/li][li]Potassium: 900 mg (25% DV)[/li][/ul]
Prune Juice is high-K stuff too. I have a generic store-brand bottle that doesn’t mention it on the label, but a certain major brand name, OTOH, does. Apparently it’s natural, not an additive.
What I always found hard-to-get is the B vitamins. All the foods that are allegedly high in B vitamins tend to have %DV in the high one-digit range. That’s high?
B Vitamins are found in small amounts, but you only need small amounts. Your body can store extra B12 in the liver, so you don’t have to necessarily eat it every day. Most cereals are fortified with the B vitamins as well. All of the B vitamins are in the food supply in fortified products, but even so, every single B vitamin is pretty easy to get plenty of if you eat a balanced diet. As I said before, most Americans are short on veggies, fruits and dairy which are excellent sources for these vitamins.
BTW, I’m majoring in Nutrition Science and studying this stuff right now. I don’t know everything, obviously, but I will try to find answers and give you correct information based on current science and my course studies.
Do note that a lot of tracking apps are “crowd sourced” and the entries are made by regular folks who may not put in values for potassium when they enter a food into the database. People sometimes just put in the values they’re interested in (fat, carbs, protein) and share it with the rest of the world and we all think we’re eating sodium-free pretzels!
Supposedly it is limited because potassium can damage the stomach and gastrointestinal lining.
As an electrolyte K is not really anymore dangerous than sodium. The LD50 is similar, and excess is generally removed by the kidneys unless you have kidney disease.
I have been adding a few hundred mg of potassium to orange juice and drinking that a couple times a day, I hope that isn’t causing stomach damage.
Potassium salts are also available in tablets or capsules, which for therapeutic purposes are formulated to allow potassium to leach slowly out of a matrix, as very high concentrations of potassium ion (which might occur next to a solid tablet of potassium chloride) can kill tissue, and cause injury to the gastric or intestinal mucosa. For this reason, non-prescription supplement potassium pills are limited by law in the US to only 99 mg of potassium.