How much evidence is there for harmful effects from legumes and grains?

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?

I’m not familiar with this particular wad of theory, but anytime purveyors of a diet or other money-making scheme start talking vaguely about “allergens”, “irritation” and “inflammation”, my “crap-O-meter” starts pinging like mad.

Never heard of it. However Richard Dawkins states in one of his books (The Ancestors Tale) that early humans were intolerant of grains and that over millennia we have developed the ability to digest them without discomfort. He goes on to say that there are populations in Africa which continue to be gluten intolerant today, and (I stand to be corrected) Asian people are sensitive too.

If so then we, the vast majority of humans who can happily eat grains (don’t know where legumes stand), are mutants of the original human strain. :wink:

He probably said Asians tend to be lactose intolerant.

As usual, the diet is a bunch of crackpot nonsense. But it will be replaced by different crackpot nonsense next year when a whole new crop of books are released. Maybe I’ll write one that says you are healthier if you don’t read crackpot’s book.

Here is a list off the top of my head of stupid health fads:

High colonics, candida, hypoglycemia, sugar makes kids hyper, vaccinations cause autism, cell phones radiation, environmental illness, sensitivity to electric fields, locavorism, raw foods, irradiated foods, GM food, diet based on blood type, macrobiotics, organic food, apple cider.

Bwuh? :confused: 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.

Eating and buying locally is also better for your local economy. The only health-related claim I’ve ever heard related to locality was the notion that local honey provides an immune benefit to pollen-allergy sufferers.

None at all that I have seen, and it also contradicts everything that we know about mammallian physiology. So it’s really up to the person postulating this to present their evidence.

Lectins certainly exist. They certainly exist in high concentrations in some legumes. I have never heard of high concentrations of lectins in cereals. Lectins can cause gut irritation if legumes are incorrectly cooked and eaten in large quantities.

But lectins are proteins. So first off, how how can a protein pass through the gut wall. I can’t think of any mechanism that would allow this to happen. Even if it could pass through, how does a foreign protein circulate throughout the body and cause these inflammation effects without provoking the most obvious effect, which is anaphylactic shock? Foreign proteins can;t just float around in the bloodstream without major ill effects.

I doubt Dawkins said that.

Savanna chimpanzees regularly eat grains with no signs of discomfort. It’s kinda hard to imagine that both we and our closest relatives independently evolved this ability to tolerate grains.

It’s in “The Farmer’s Tale,” page 35 of the hardcover. The key lines,

Page 33, that is.

Either you mean opposition to these things is idiocy, or you’re gravely misinformed.

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.

Nobody has yet pointed to any evidence of any problem with legumes and grains. Even if the Dawkins speculation is exactly on point, that just means that the fundamental premise of a “paleo” diet is misguided; the ideal diet for our pre-agricultural ancestors didn’t include grains, but we’re not quite the same animal as they.

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.

I will say that regardless of whether the lectin claims are correct or not, the diet is inarguably healthy – you end up eating lean meat, a lower level of complex carbs, and a ton of vegetables.

Here is an article that references some studies that the Paleo folk feel supports their claims that lectins can be responsible for inflammation in other parts of the body:

The article mentions a “really disturbing finding came with the discovery in 1989 that some food lectins get past the gut wall and deposit themselves in distant organs” and references a couple of studies.

I have never heard this as a part of the original Paleo diet theories. Could you provide cites about who is saying this and what connection they have to the Paleo Diet?

I don’t know what you’re trying to say or who you’re criticizing here so I’m just contribute some real science.

As a matter of definition (i.e. not having the mutation on chromosome 2 that allows for the continued production of the lactase enzyme as an adult) most Asians (near 100% for east Asians, moving toward 50% for Middle Easterners) are hypolactasic, a condition that has a wide variety of names in the literature, including lactase non-persistence, lactase deficiency, lactose malabsorption, or lactose intolerance.

Most medical studies tend to use lactose intolerant for the clinical state of having tested positive to a lactose load, i.e. developing symptoms when given lactose to eat or drink. However, lactose intolerance is overwhelmingly used popularly to mean either the clinical condition or the underlying genetic condition or both. Almost anybody writing popular science would say that Asians tend to be lactose intolerant, even if an insignificant minority of them has ever been formally tested. And in fact, everybody writing popular science about LI says exactly that.

I was finally convinced that I require only one food to sustain life because everyone always tells me, “Hey you, eat shit.”

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.

Reading the linked Allergist article reinforces the view that it’s a big jump from “some diseases may have dietary links in genetically susceptible people” to “everyone should eat like cavemen”.

As I have read through much of this stuff, I note a strong dependence on anecdotal
evidence and a lack of controlled studies. There doesn’t seem to be any need for real evidence. When I first heard of holistic, I thought it derived from whole. It is spelled more like holy, where belief is more important than solid fact.

OK, that caused me to lose respect for Dawkins.

He states that humans can’t have been eating large amounts of cereals in the past, with no evidence at all for the claim. We have found grindstones 40 ,000 years old a grindstone that had been used to grind grass seeds. So we know that we have been eating large amounts of cereals for at least 40, 000 years. chimpanzees eat large amounts of grass seeds. Presumably hominids have always eaten large amounts of grass seeds.

Yet Dawkins makes a claim that we could not have done so based upon nothing at all that I can see. And he then supports that by pointing out that he has never seen any studies that do support such a claim. :dubious:

Consider me unconvinced. Dawkins may be a good biologist, but his knowledge of anthropology and logic leaves a little to be desired.

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: The FAQ section describes the theory.