Why No Grains and Legumes? Part 1: Lectins

grains-legumes-300x198.jpgRecently my boyfriend has been straying from his normal Paleo ways because he feels that grain-laden cookies are more important than his overall health and longevity.  In the meantime, I’m faced with a gluten-free cookie and candy explosion every time I open our cupboard. The smell of them in their consumer-enticing packaging is sometimes more than I can bear when I’m reaching past them to get to my (sigh) bag of nuts and seeds. “Wait, why am I not eating grains again?” The question pops into my head and I suddenly can relate to all of my family and friends who think I’m crazy for eating Paleo. What’s wrong with grains again? Well, this post is dedicated to everyone out there who has the same formidable temptations in their cupboards, and to me, because I need the reminder.

I wonder sometimes if the aroma of boiling rice, the doughy texture of a doughnut and the satisfying squish of a black bean are so tantalizing because I grew up smelling, eating and enjoying them, or because of some genetic predisposition. It’s confusing to me that grains and legumes (all beans – black, pinto, soy, peanuts, etc.) would be so pleasing to us, since they’re basically poisonous, having heavily contributed to the current, overwhelming predominance of heart disease, digestive disorders and obesity rates in this country. There are a lot of reasons for this – grains and legumes contain a sordid collection of “anti-nutrients”.  Some of them strip away your minerals and some cause intestinal damage and immune problems.  We’ll start with the little anti-nutrient proteins called lectins, and in future posts I’ll move on from there.

What Are Lectins?
Lectins are proteins found in animals (including you) and plants – they’re everywhere, especially in grains, legumes (especially soy), nuts and seeds.  They have many protective functions in the human body – everything from recognizing pathogens to controlling protein levels in the blood.  Their function in plants is thought to be protective, too, to the plant, that is.

Lectins are found in the seeds of plants and they’re thought to have something to do with the survival of the seed.  The way they’re believed to protect the seed is that they can cause considerable intestinal distress (diarrhea, nausea, bloating, vomiting, even death) to those who eat the seeds, in hopes of deterring the predator from coming back for more.

Immune Response
Wheat contains a lectin called wheat germ agglutinin, or WGA.  Lectins are sticky little buggers and the WGA goes into your small intestine and gloms onto the brush border.  It then tricks your body into taking it across the border of your intestine intact, where it is seen as a foreign invader by your immune system.  Antibodies are created in response to the lectins, and unfortunately, lectins often look a lot like other parts of your body.  They may look like cells in your brain, pancreas, etc., so the same antibodies that were created to attack the lectin will actually go launch attacks on your own body.  This is where autoimmune issues arise, like diabetes type 1, celiac disease, lupus and multiple sclerosis.

Leaky Gut
To make things worse, on their way into your body, lectins damage the walls of your intestines, helping to create “leaky gut”, so that other large particles can cross the intestinal barrier, enter your blood stream and begin other immune cascades. This is basically how food sensitivities start. Something goes in (like the WGA) and makes some holes in your gut that lets big particles of food into your blood stream. Then your immune system gets VERY overwhelmed and confused and starts attacking things at random – gluten, blueberries, asparagus, olive oil, etc. Symptoms can range from migraine headaches to eczema to weight gain and depression.

Can’t you cook the lectins out of the foods?
Cooking, sprouting or soaking your grains, legumes, nuts and seeds all helps to decrease the number of lectins they contain, but none of those processes completely eliminates the lectins, except for pressure cooking.  Lectins are really heat stable.  They’re also resistant to enzymatic activity, which is partly why they’re so difficult for us (and your dog, etc.) to digest.

Should you not eat nuts and seeds?
You may be wondering (as I did) why we’re told to eat seeds and nuts on the Paleo diet when they, too, house these vicious little molecules. The truth is that it’s always better to soak or sprout your nuts and seeds, and that you should really eat them in moderation.  Think about it: our ancestors probably didn’t have access to a whole bunch of nuts and seeds every day, much less almond butter and other goodies that take a whole lot of nuts and seeds to produce.  I think the reason that nuts and seeds are allowed on the diet but not grains and legumes is that grains and legumes contain a whole host of other “anti-nutrients” beyond just lectins.

To be continued…

References:
http://thepaleodiet.blogspot.com/2010/05/paleo-diet-q-sprouted-legumes.html
http://en.wikipedia.org/wiki/Lectin
http://www.krispin.com/lectin.html
http://jcem.endojournals.org/cgi/content/abstract/88/10/4857