# How much evidence is there for harmful effects from legumes and grains? **URL:** \ **Category:** Factual Questions\ **Created:** [February 21, 2011, 6:32pm UTC](https://boards.straightdope.com/t/how-much-evidence-is-there-for-harmful-effects-from-legumes-and-grains/572135 "2011-02-21T18:32:52Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![misterW](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@misterW](https://boards.straightdope.com/u/misterW)\ **Post date:** [February 23, 2011, 10:42pm UTC](https://boards.straightdope.com/t/how-much-evidence-is-there-for-harmful-effects-from-legumes-and-grains/572135/21 "2011-02-23T22:42:41Z")
> [@Jackmannii](#): > > No doubt the “paleo” diet is _the_ diet to follow for health and long life since our paleolithic ancestors lived such long and healthy lives. :dubious: > > There’s a comparatively recent fascination with the idea that our more primitive forebears and people in current Third World/less developed societies know something we don’t about health. Mostly it seems they have known how to die prematurely. The diet may not do what is claimed, certainly, but your argument seems to be missing the point. Wouldn’t that be like dismissing a fitness program practiced by boxers by pointing to the brain damage that is common among its practitioners? The idea seems to be simply that the body evolved to process foods that were available. Newer foods were not around long enough for such an evolution to take place and result in some health problems. Now, whether or not this is true is clearly something else altogether, but pointing to early deaths from childbirth, predators, or disease is irrelevant. Why is it shocking that useful information might be gotten from primitive forbears or less developed cultures? While I wouldn’t expect a society without our scientific knowledge to have any idea of the mechanism involved, sometimes groups simply hit on things that work and stick with it. ---
**Author:** ![purplehorseshoe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/purplehorseshoe/32/2996_2.png) [@purplehorseshoe](https://boards.straightdope.com/u/purplehorseshoe)\ **Post date:** [February 24, 2011, 12:00am UTC](https://boards.straightdope.com/t/how-much-evidence-is-there-for-harmful-effects-from-legumes-and-grains/572135/22 "2011-02-24T00:00:06Z")
> [@marshmallow](#): > > Man, what _are_ you supposed to eat? Can’t eat potatoes, wheat, rice, pasta, red meat, pork, eggs, dairy, and now legumes? I guess it would be hard to get fat if you consumed nothing but fish, fruits, vegetables, and water. Nope, sorry, fish is out, too, if you’re talking about what you’re “supposed” to each. Mercury levels, y’know, plus the rape and pillage of our planet’s oceans. Eggs cycle on and off the “(not) supposed to eat” list faster than any other single item! They have cholesterol! They’re a good source of protein! Adults! Kids! Adults! Kids! ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [February 24, 2011, 12:58am UTC](https://boards.straightdope.com/t/how-much-evidence-is-there-for-harmful-effects-from-legumes-and-grains/572135/23 "2011-02-24T00:58:46Z")
> [@purplehorseshoe](#): > > Bwuh? 😕 I’ve never heard anyone claim local food is healthier or that it treats symptoms of diseases. It’s just supposed to be better for the environment - less fossil fuels to transport food, etc. Local food is often claimed to be _fresher_, as in just harvested recently. And there are certainly some foods that taste better when really fresh (local Minnesota-grown sweet corn, for instance). But I’m not sure that anyone can actually prove that such local foods are healthier to any significant degree. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [February 24, 2011, 1:02am UTC](https://boards.straightdope.com/t/how-much-evidence-is-there-for-harmful-effects-from-legumes-and-grains/572135/24 "2011-02-24T01:02:03Z")
> [@misterW](#): > > Maybe it isn’t part of the original. I came across it and assumed it was the general theory but I now see there a million different advocates and variations of the diet. This particular version was put forth by Robb Wolf. Here’s the web site: [http://robbwolf.com/](http://robbwolf.com/). The FAQ section describes the theory. And it ends with explaining it all by leaky gut syndrome, which is a deal-breaker if you believe in science. ---
**Author:** ![misterW](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@misterW](https://boards.straightdope.com/u/misterW)\ **Post date:** [February 24, 2011, 2:17am UTC](https://boards.straightdope.com/t/how-much-evidence-is-there-for-harmful-effects-from-legumes-and-grains/572135/25 "2011-02-24T02:17:57Z")
In an interview, I heard Robb Wolf talk mainly of reducing inflammation within the gut. i think he did mention the leaky gut business, but the main focus seemed to be reducing inflammation within the digestive system. Since Blake stated above that lectins are known to cause irritation within the gut, would reducing lectins in the diet be likely to yield any measurable health benefits? ---
**Author:** ![fumster](https://avatars.discourse-cdn.com/v4/letter/f/e9c0ed/32.png) [@fumster](https://boards.straightdope.com/u/fumster)\ **Post date:** [February 24, 2011, 4:03am UTC](https://boards.straightdope.com/t/how-much-evidence-is-there-for-harmful-effects-from-legumes-and-grains/572135/26 "2011-02-24T04:03:50Z")
> [@misterW](#): > > Perhaps the idea of lectins causing bodily inflammation is incorrect, but I am looking for evidence and arguments, not just dismissal because it reminds you of other fad diets. Who has the burden of proof again? ---
**Author:** ![misterW](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@misterW](https://boards.straightdope.com/u/misterW)\ **Post date:** [February 24, 2011, 2:18pm UTC](https://boards.straightdope.com/t/how-much-evidence-is-there-for-harmful-effects-from-legumes-and-grains/572135/27 "2011-02-24T14:18:35Z")
> [@sh1bu1](#): > > Who has the burden of proof again? Of course, the burden of proof is on those making the claim. I wouldn’t expect anyone to “prove” it otherwise. But it is possible to make strong arguments against the claim that are also very informative (ie see Blake’s and Exapno Mapcase’s posts). It certainly may be New Age bullshit, I’m just looking for reasons that is likely to be the case. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [February 24, 2011, 4:54pm UTC](https://boards.straightdope.com/t/how-much-evidence-is-there-for-harmful-effects-from-legumes-and-grains/572135/28 "2011-02-24T16:54:44Z")
> [@misterW](#): > > Of course, the burden of proof is on those making the claim. I wouldn’t expect anyone to “prove” it otherwise. But it is possible to make strong arguments against the claim that are also very informative (ie see Blake’s and Exapno Mapcase’s posts). It certainly may be New Age bullshit, I’m just looking for reasons that is likely to be the case. Just going to quote the OP real quick so we are all reminded of what the original question was: > [@](#): > > A big part of the “Paleo” diet is the idea that certain foods (legumes and grains are the big ones) contain lectins – allergens that not only irritate the digestive system but pass through it and cause inflammation in other parts of the body as well. > > How much evidence is there to support this position? Let’s take grain, first. The big “evidence” for grains causing these sorts of problem is probably gluten intolerance, also known as celiac disease or celiac sprue. Gluten is a protein found in wheat, rye, and barley (there’s a related protein in oats that may or may not cause problems for a particular person with celiac). It is a definite fact that, in those with gluten intolerance, gluten causes irritation in the digestive tract. In fact, it can cause so much irritation that the intestines no longer function well, leading to problems like malnutrition because the body is no longer able to absorb nutrients well or properly. This can have effects on the entire body. Now, the “allergen” (not really an allergen, but whatever) does not actually pass into the blood stream, but it _does_ cause effects all over the body if the situation isn’t fixed. I could see where someone who isn’t really medically literate could conflate “gluten” with “allergen” and somehow conclude that the system-wide effects are due to gluten sneaking in through the intestines and wandering around the body. That’s not what is actually happening, but to my mind that’s a likely explanation for the story and it’s not made out of whole cloth. Now, on to the legumes. Many legumes contain substances that aren’t good for you in a raw state. I’m guessing the worst offender is phytohaemagglutinin, which is a lectin. It’s toxic in the raw state, a half dozen raw kidney beans can induce nausea, profuse vomiting, and diarrhea. Thorough cooking destroys the lectin, rendering the beans safe to eat. But - and this is very important - _undercooking INcreases the amount of phytohaemagglutinin_ before the levels drop. Undercooked beans in that case are _worse_ raw. I think this is a case where incorrect preparation makes people very sick and then they use this as a basis to say legumes are bad for you. Again, it’s not made up entirely of pixie dust, but it’s not the truth, either. So… if you don’t have gluten intolerance grains should be OK for you. If you cook beans thoroughly and at a proper temperature (at least 100 C for 10 minutes is what I see all the time) they shouldn’t be a problem. Outside of an additional small group who has genuine allergies to a grain or a legume, there’s nothing wrong with these foods for the rest of humanity. There aren’t evil little proteins twiddling Snidley Whiplash mustaches as they sneak between the cells of your intestines, intent on wreaking havoc in the rest of the body. I could situations in the past where people didn’t know about these things and after an unfortunate meal with undercooked beans, or a village family genetically prone to celiac, they swear off these foods. I could see raw foodists getting into trouble with the beans, too (fermentation of beans can also detoxify them but you have to know how to do it properly). Way back in the stone age (which is what the “paleo” part of all of these means) I could see such things happening more often, but that shouldn’t apply to modern folks with access to [del]reliable sources of fire[/del] ovens, stoves, and other cooking appliances, not to mention food thermometers, cooking timers, and the rest. [Previous page](https://boards.straightdope.com/t/how-much-evidence-is-there-for-harmful-effects-from-legumes-and-grains/572135.md?page=1)