If you take any plant, burn it to ash, throw the ash in a pot of water, stir it around, skim it off and then let the water evaporate, you’ll be left with a white residue at the bottom known as pot ash. It has been used since the dawn of history for everything from making soap, glass, fertilizers, and bleach. It was not until 1807, when a new element was discovered in this so-called “vegetable alkali.” They called it pot ashium—potassium. True story, which I bring up only to emphasize the most concentrated source in our diet, plants.
Every cell in the body requires the element potassium to function. As I detail in my 2-min. video 98% of American Diets Potassium Deficient, for much of the last 3 million years or so, we ate so many plants that we probably got 10,000 mg of potassium in our daily diet. Today, we’d be lucky to get 3,000.
Less than 2% of Americans even get the recommended minimum adequate intake of 4,700 a day. To get even the adequate intake, the average American would have to eat like 5 more bananas worth of potassium a day. 98% of Americans eat potassium deficient diets because they don’t eat enough plants.
Why do we care? A review of all the best studies ever done on potassium intake and it’s relationship to two of our top killers, stroke and heart disease, was recently published in the Journal of the American College of Cardiology. A 1600 mg per day higher potassium intake was associated with a 21% lower risk of stroke. That still wouldn’t get the average American up to the minimum adequate intake, but it might be able to wipe out a fifth of their stroke risk. The paper concludes: “These results support recommendations for higher consumption of potassium-rich foods to prevent vascular diseases.”
What does “potassium-rich foods” mean? Find out in my 2-min. video 98% of American Diets Potassium Deficient. Hint: bananas don’t even make it into the top 50 sources!
People eating plant-based diets are often asked where they get their protein (and have to explain that plants are the preferred source). Maybe they should then ask where people eating conventional diets get their potassium–or their fiber for that matter *see Relieving Yourself of Excess Estrogen). For more on what we evolved to eat, see Paleolithic Lessons.
The banana listing reminds me of a similarly humorous finding about the levels of eyesight-saving nutrients in eggs versus greens. See Egg Industry Blind Spot.
Bananas are also kind of pitiful antioxidant-wise (see Best Berries and Which Fruit Fights Cancer Better?). Is it worth going out of our way to eat plants with the most antioxidants, though? See Anti-Inflammatory Antioxidants to find out.
-Michael Greger, M.D.
Image credit: 24oranges.nl / Flickr
The distinguished neurologist Roy Swank‘s low saturated fat diet remains the “most effective treatment of multiple sclerosis ever reported in the peer review literature.” In patients with early stage MS, 95% were without progression of their disease 34 years after adopting his meat and dairy-restricted diet. Even patients with initially advanced disease showed significant benefit. To date, no medication or invasive procedure has ever come close to demonstrating such success.
To understand one reason why a plant-based diet may be so successful in treating the disabling auto-immune disease, one has to first understand how the immune system works. This was one of the greatest mysteries in all of biology—solved by a brilliant scientist who won the Nobel in 1960 for figuring it out.
As I illustrate in my 3-min. video Clonal Selection Theory of Immunity, each one of our antibody-producing immune cells, called B-cells, produces only one type of antibody. Antibodies are one of the main weapons our immune system uses to attack foreign invaders. And they’re specific. It’s not just like we have one B-cell that covers grass pollen and another that covers bacteria, we have a B-cell in our body whose only job is to make antibodies against the pollen of purple Siberian oniongrass! (whether or not we ever come in contact with it). Another whose only job is to make antibodies against the tail proteins of bacteria that live only in the thermal vents at the bottom of the ocean…
Wait a second. There must be a billion different things in the world. If each of our B cells produces only one type of antibody, then we’d need to have a billion different types of B cells. And we do!
So, let’s suppose one day you’re walking along and get attacked by a platypus (they have poison spurs on their heels you know). And so for your whole life up until that point the B-cell in your body that produces antibodies against duck-billed platypus venom was just hanging around, twiddling its thumbs, until that very moment. As soon as the venom is detected that specific B-cell starts dividing like crazy, making copies of itself, and soon you have a whole swarm of clones specialized for platypus poison protection. Fending off the toxin, you live happily ever after. That is how the immune system works. Aren’t our bodies spectacular?
If we have a billion different types of antibody-producing B cells, each capable of recognizing a different molecular signature, why then do we tend not to attack ourselves? And how can what we eat sometimes undermine this inherent protection from autoimmune disease?
As I describe in my 3-min video Clonal Deletion Theory of Immunity, the reason that we don’t often fall prey to friendly fire is because before we’re even born we kill off each and every B cell that recognizes us. That’s what our thymus gland is for. When we’re still a fetus, our body lines up all our immune cells, holds up a picture of our self and asks them one by one: “do you recognize this person?” And if any of our immune cells says yes, they’re killed on the spot, death by apopotosis (programmed cell death) and good riddance.
Turns out this process of ridding our bodies of self-recognizing immune cells happens throughout our lives, mostly in our bone marrow. If you remember, though, in my video series on IGF-1 (starting with The Answer to the Pritikin Puzzle) animal protein consumption increases the level of a cancer-promoting growth hormone that prevents apoptosis, prevents our body’s killing of cells it wants to get rid—that’s why IGF-1 levels are linked to cancer. So IGF-1 might contribute to the inappropriate survival of self-reactive white blood cells in autoimmune or inflammatory conditions. Maybe that’s why people who eat plant-based diets appear protected from autoimmune diseases, explaining, for example, the extraordinary rarity of most autoimmune diseases among sub-Saharan rural blacks following a traditional plant-based diet. Before they changed their diets, evidently not a single case of MS had been diagnosed among a population of 15 million.
-Michael Greger, M.D.
Image credit: GerryShaw / Wikimedia Commons