"How To Avoid Lectin Poisoning"
In the 1800s, a compound was discovered in castor beans,
which we would come to know as the first of a class of lectin proteins,
natural compounds found throughout the food supply,
but concentrated in beans, whole grains, and certain fruits and vegetables.
Every decade or two, in the popular literature, and the medical literature,
a question is raised whether dietary lectins are causing disease.
It’s easy to raise hysteria about lectins;
after all, that first one, found back in 1889,
went by the name Ricin, known to be a potent homicidal poison,
used by the Kremlin to assassinate anti-communist dissidents,
or by rogue chemistry professors for that matter.
And, ricin is a lectin.
Thankfully, however, many lectins are non-toxic,
such as those found in tomatoes, lentils, and other common foods.
And, even the ones that are toxic— like those found in kidney beans—
are utterly destroyed by proper cooking.
But, you can’t eat raw kidney beans.
If you do, you’ll be doubled over with nausea, vomiting, and diarrhea
within hours, thanks to the lectins,
which would otherwise be destroyed by adequate cooking.
How do you even eat raw kidney beans, though?
The only way they’re sold uncooked is as dried beans,
and they’re like little rocks.
Well, in the first reported outbreak, an impromptu supper was made
with a bag of beans dumped in a skillet and soaked in water overnight,
but never cooked.
You can’t even just throw dried beans in a slow cooker.
Dried kidney beans have to be boiled.
Kidney beans should be soaked in water for at least 5 hours
and then boiled for at least 10 minutes.
Ten minutes?
Kidney beans wouldn’t be done after just 10 minutes.
Exactly.
Yeah, cooking presoaked beans for a couple minutes
can destroy the lectins, but it takes like an hour of boiling
before they’re edible, before you could flatten them easily with a fork.
So, the lectins would be long gone before they’re palatable.
Without presoaking, it takes 45 minutes in a pressure cooker
to get rid of all the lectins, but an hour to make kidney beans edible.
So basically, it appears that cooking beans to the point
where they might be considered edible is more than sufficient
to destroy virtually all lectin activity.
Even 12 hours at 65 Celsius won’t do it, though,
which is like the temperature of a cup of hot tea.
But, you can tell they weren’t done, still firm and rubbery,
though you could imagine someone putting those in some “raw” vegetable salad,
and that could make people sick.
And, it has, with dozens of incidents reported over the years,
all of which could have been easily prevented
had the beans been soaked overnight, drained, and then boiled
for at least 10 minutes.
Or, if they would have just eaten canned beans.
Canned beans are cooked beans;
the canning process is a cooking process.
None of the confirmed incidents were due to canned beans.
We’ve known since the early ‘60s that conventional cooking methods
can effectively destroy lectins in beans.
Therefore, it is possible to ignore any human problems
that could be associated with lectins from properly processed legumes.
So yeah, you can show that feeding lectins to rats isn’t good for them,
or to cell tissues in a petri dish,
but in these articles that claim dietary lectins
may be disease causing toxicants,
the only negative effect they can find on humans
are those raw and undercooked kidney bean incidents.
Do dietary lectins cause diseases of affluence?
How about we test that hypothesis?
So, they performed a trial on 24 domestic pigs,
and a paleo pig diet beat out cereal-based swine feed.
Could they not find any people willing to eat paleo?
In response to one such review of the evidence based
largely on laboratory rodents, one peer reviewer cautioned
that we should not draw conclusions about the involvement of dietary lectins
in the cause of diseases “without definite and positive proof.”
That was written more than a quarter century ago,
and no, such clinical proof has yet to materialize.
What we do have, however, is ever growing evidence that legumes—
beans, split peas, chickpeas, and lentils--are good for us,
associated with a longer lifespan,
a significantly lower risk of colorectal cancer,
a leading cancer killer, considered part of a natural,
cost-effective, and free-from-side-effects solution
for the prevention and treatment of type 2 diabetes.
Randomize people who eat five cups of lentils, chickpeas, split peas,
and navy beans a week, and you can see the same benefits
in terms of weight loss and metabolic benefits
that you do with caloric restriction portion control.
And, the whole lectins theory is based on lectin-containing foods
being inflammatory, but prescribe 4 servings a week of legumes,
packed with lectins and get a significant drop in C-reactive protein-
In fact, a 40% drop in this leading indicator
of systemic inflammation, eating more beans.
The purported “plant paradox” is that on one hand,
whole healthy plant foods are the foundation of a good diet,
yet we supposedly need to avoid beans and whole grains
and certain fruits and vegetables because of the evil lectins.
But, if you look at the actual science, all whole plant foods are associated
with decreased mortality, meaning the more of them people ate,
the longer people tended to live.
And, this includes lectin-filled foods, such as whole grains and beans.
So maybe, there’s really no paradox after all.