Why haven’t humans evolved beyond gluten sensitivity?

I’ve done a lot of reading about gluten sensitivity, and because there’s so much research and data on both sides of the gluten is ok/gluten is the devil fence, it seems to me I just need to go with my gut (pun intended) and believe the research that seems more legit to me. Therefore, I have limited my gluten intake for about 2 years now, and while I haven’t been perfectly gluten-free, I have gone for short stints with no gluten, and I honestly don’t think I am gluten-sensitive. I still see, from a logical if not physical perspective, the benefits of avoiding gluten, so I still avoid it, much to the irritation of my spouse. His argument has repeatedly been, “If gluten is a real problem, why haven’t humans evolved to process gluten properly?” I have not been able to answer that question to my satisfaction, so here we are.

This article from Doctor Auer gives a quick history of grains in human diets, from ancient Egypt to present day, possibly correlating with the rise of osteoporosis, diabetes, and later cancer and various degenerative diseases. Modern production methods strip out most of the grains’ nutrients, add chemicals, and leave behind naturally occurring toxins that cause gut inflammation. To sum up:

We must remember that evolutionarily speaking, we have been around for almost two million years, but we have only been eating grains for a few thousand. As such, our bodies have not had the time to adapt to this “new” food in our diet. Furthermore, modern farming, harvesting, and processing methods have stripped grains of their nutritional integrity, decreasing their digestibility, and making them highly toxic and inflammatory food to our bodies.

Here’s more, from Science 2.0:

“Only for the past ten thousand years have we had wheat-based foods in our diets, which in evolutionary terms makes wheat almost a novel food. If you put that in context to the 2.5 millions years that mankind has been on earth, it makes sense that our bodies are still adapting to this food, and more specifically, the gluten that it contains.”

But the best answers come from this Paleo Mom article. She explains the role of evolutionary pressure, or factors that reduce reproductive success, in adaptation, and states that while humans have had enough time to adapt to grains, there has not been sufficient evolutionary pressure to do so, because health issues related to grain consumption do not generally affect reproduction rates. (There’s an interesting reader comment at the bottom about gut flora that’s worth researching, but not for this post.)

So the answer I will give to Spouse and anyone else is: Humans are adapting to process grains, but have not yet fully adapted because eating grains does not interfere with reproduction enough to select out grain-intolerant genes at a high rate.

Why do horses drool?


It has always cracked me up: ponies who get into clover and drool like leaky faucets. Until recently, I did not know the reason they drool is because of a toxic fungus that grows on the clover. (And I did not know its comical names: Saliva Syndrome! Slobbering Horse Syndrome!)

The Rhizoctonia leguminicola fungus, also called “black patch” because of the (sometimes microscopic) black spots that form on affected leaves, grows on white and red clover, and alfalfa. It produces the toxin slaframine, which can increase horses’ salivary gland output. In more extreme cases, it can also cause increased tear production and urination, difficulty breathing, and–rarely–even abortion. Some horses have have allergic reactions on facial skin that comes in contact with the fungus.

Horses that are more affected than others can either be especially sensitive to the toxin, or just prefer clover, so consume a larger quantity of slaframine.

“Black patch” prefers humid weather, so it is most prevalent in Spring and Summer. To control growth of the fungus, keep your pastures healthy. Clover thrives in stressful conditions, such as droughts, extended wet periods, poor soils, and over-grazing, so rotate your pastures to minimize stress. Use chemical treatments carefully to avoid harming your animals. Note that the fungus can also be present in hay containing affected clover or alfalfa.






Frog or toad?

frog or toad

Frog or toad?

Toad or frog?

Here’s how to tell:

Think about where they live and how they behave. Frogs live in or near water, they’re good jumpers, and they swim. Toads are born in water, but mostly live on land and walk more than jump. So,

frogs have slimy skin (moist environment), long legs (jumping), webbed feet (swimming), and bulging eyes on top of their heads (peeking above water while their bodies are submerged);

toads have dry, bumpy skin (dry environment), shorter legs and toed feet (walking), and flatter eyes (no need to peer out from underwater). Toads are also generally wider than frogs.

Other cool things to know: touching a toad won’t give you warts, and toads have fewer predators than frogs, because their skin tastes bad.

If you like frogs, visit Save the Frogs, a really cool website frog conservation. It has news, events, and froggy facts.

So, what do you think this guy is? Frog or toad?




What is melatonin, exactly?

What is melatonin?

Melatonin is a hormone naturally produced by the body in response to darkness. A control center in the hypothalamus handles signaling related to processes that make us feel sleepy or awake, and when it’s dark (and only when it’s dark), the control center tells the pineal gland to produce melatonin. Natural melatonin production decreases with age, and people who have trouble sleeping are typically low in melatonin.

Should I take a melatonin supplement?

Study results are mixed regarding the effectiveness of melatonin as a sleep aid, and for its use in the treatment of all sorts of other physical and mental issues. It’s recommended that if you try it, you use it as a short-term supplement, for up to two months. The most common side effects are daytime sleepiness, dizziness, and headaches; there have been no reports of overdoses or toxicity.

Warnings: Melatonin could interfere with lots of different medications, so talk to your doctor if you’re medicating. It is the only hormone approved for sale in the US, and it is sold as a supplement, so it’s not regulated. Choose commercial supplements made in a lab, as those made from animal sources could contain contaminants.


What’s the deal with fireflies?

Why do they flash?

Romance. Adult fireflies use flash patterns to identify members of same species and opposite sex. Females of two species have been shown to prefer males with higher flash rates and stronger flash intensity, but otherwise not much is known about the flash patterns.

How do they flash?

A chemical reaction in the firefly’s light organ causes bioluminescence when oxygen can reach the photocyte cells. The photocytes are deprived of oxygen by neighboring mitochondria, which consume all the oxygen present, leaving the light cells dark. When a nerve signal instructs cells to produce nitric oxide, the mitochondrial respiration is halted and the oxygen present is free to be used in the bioluminescence reaction.

(Fun fact: I was first introduced to mitochondria as a child in the book A Wind in the Door.)

What else is cool about fireflies?

  • There’s a place in the Smokies where a species called synchronous fireflies flash at the same time. It’s not known why they’re synchronous: it could be competitive — if I flash first, the girls will notice me; or it could be collaborative — if our group flashes together, we have a better chance of getting the girls’ attention. Here’s a video. It’s a little bit creepy. Peak flashing in the park is late May to mid June.
  • Adults fireflies only live about 21 days, and don’t eat.
  • One species has a bluish light.
  • Females flash too but don’t usually fly.

Fireflies and lightning bugs are the same critters. Which do you say? I say both, but probably more often use “lightning bug.”


Scientific American

National Park Service

Tufts Journal