Sugar

I have some hopefully good, deep stuff I am working on, but in the meanwhile, here is a quick, VERY SPECULATIVE thread on my theory for why refined sugars are probably bad for you:

First, refined sugars are evolutionarily novel. Unless you’re a Hazda, your ancient ancestors never had this much sugar.

Pick up a piece of raw sugar cane and gnaw on it. Raw sugar cane has such a high fiber to sugar content that you can use it as a toothbrush after chewing it for a bit.

According to the internet, a stick of raw sugar cane has 10 grams of sugar in it. A can of Coke has 39. Even milk (whole, skim, or fat-free) contains 12 grams of natural milk sugars (lactose) per glass. Your body has no problem handling the normal amounts of unrefined sugars in regular foods, but to get the amount of sugar found in a single soda, you’d have to eat almost four whole stalks of sugarcane, which you certainly aren’t going to do in a few minutes.

It’s when we extract all of the sugar and throw away the rest of the fiber, fat, and protein in the food that we run into trouble.

(The same is probably also true of fat, though I am rather fond of butter.)

In my opinion, all forms of heavily refined sugar are suspect, including fruit juice, which is essentially refined fructose. People think that fruit juice is “healthy” because it comes from fruit, which is a plant and therefore “natural” and “good for you,” unlike, say, sugar, which comes from sugar cane, which is… also a plant. Or HFCS, which is totally unnatural because it comes from… corn. Which is a plant.

“They actually did studies on the sugar plantations back in the early 1900s. All of the workers were healthy and lived longer than the sugar executives who got the refined, processed product.”

I don’t know if I agree with everything he has to say, but refined fructose is no more natural than any other refined sugar. Again, the amount of sugar you get from eating an apple is very different from the amount you get from a cup of apple juice.

Now people are talking about reducing childhood obesity by eliminating the scourge of 100% fruit juice:

Excessive fruit juice consumption is associated with increased risk for obesity… sucrose consumption without the corresponding fiber, as is commonly present in fruit juice, is associated with the metabolic syndrome, liver injury, and obesity.

Regular fruit is probably good for you. Refined is not.

Here’s another study on the problems with fructose:

If calcium levels in the blood are low, our bodies produce more parathyroid hormone, stimulating the absorption of calcium by the kidneys, as well as the production of vitamin D (calcitriol), also in the kidneys. Calcitriol stimulates the absorption of calcium in the intestine, decreases the production of PTH and stimulates the release of calcium from the bone. …

… Ferraris fed rats diets with high levels of glucose, fructose or starch. He and his team studied three groups of lactating rats and three groups of non-pregnant rats (the control group).

“Since the amounts of calcium channels and of binding proteins depend on the levels of the hormone calcitriol, we confirmed that calcitriol levels were much greater in lactating rats,” said Ferraris.  … “However, when the rat mothers were consuming fructose, there were no increases in calcitriol levels,” Ferraris added. “The levels remained the same as those in non-pregnant rats, and as a consequence, there were no increases in intestinal and renal calcium transport.”

You then have two options: food cravings until you eat enough to balance the nutrients, or strip bones of calcium. This is what triggers tooth decay.

Sugar not only feeds the bacteria on your teeth (I think), it also weakens your teeth to pay the piper for sugar digestion. (Also, there may be something about sugar-fed bacteria lowering the pH in your mouth.)

The second thing that happens is your taste buds acclimate to excessive sugar. Soon “Sweet” tastes “normal.”

Now when you try to stop eating sugar, normal food tastes “boring” “sour” “bitter” etc.
This is where you just have to bite the bullet and cut sugar anyway. If you keep eating normal food, eventually it will start tasting good again.

It just takes time for your brain to change its assumptions about what food tastes like.
But if you keep sweetening your food with “artificial” sweeteners, then you never give yourself a chance to recalibrate what food should taste like. You will keep craving sugar.
And it is really hard to stop eating sugar and let your body return to normal when you crave sugar.

If artificial sweeteners help you reduce sugar consumption and eventually stop using it altogether, then they’re probably a good idea, but don’t fall into the trap of thinking you’re going to get just as much cake and ice cream as always, just it won’t have any consequences anymore. No. Nature doesn’t work like that. Nature has consequences.

So I feel like I’ve been picking on fructose a lot in this post. I didn’t mean to. I am suspicious of all refined sugars; these are just the sources I happened across while researching today.

I am not sure about honey. I don’t eat a lot of honey, but maybe it’s okay. The Hadza of Tanzania eat a great deal of honey and they seem fine, but maybe they’re adapted to their diet in ways that we aren’t.

So what happens when you eat too much sugar? Aside from, obviously, food cravings, weight gain, mineral depletion, and tooth decay…

So here’s a theory:

Our bodies naturally cycle between winter and summer states. At least they do if you hail from a place that historically had winter; I can’t speak for people in radically different climates.

In the summer, plant matter (carbohydrates, fiber,) are widely available and any animal that can takes as much advantage of this as possible. As omnivores, we gorge on berries, leaves, fruits, tubers, really whatever we can. When we are satiated–when we have enough fat stores to last for the winter–our bodies start shutting down insulin production. That’s enough. We don’t need it anymore.

In the winter, there’s very little plant food naturally available, unless you’re a farmer (farming is relatively recent in areas with long winters.)

In the winter, you hunt animals for meat and fat.This is what the Inuit and Eskimo did almost all year round.

The digestion of meat and fat does not require insulin, but works on the ketogenic pathways which, long story short, also turn food into energy and keep people alive.

The real beauty of ketosis is that, apparently, it ramps up your energy production–that is, you feel physically warmer when running entirely off of meat and fat than when running off carbs. Given that ketosis is the winter digestive cycle, this is amazingly appropriate.

By spring, chances are you’ve lost a lot of the weight from last summer. Winters are harsh. With the fat gone, the body starts producing insulin again.

At this point, you go from hyperglycemia (too much sugar in your bloodstream if you eat anything sweet, due to no insulin,) to hypoglycemia–your body produces a lot of insulin to transform any plants you eat into energy FAST. (Remember the discussion above about how your body transforms fructose into fat? Back in our ancestral environment, that was a feature, not a bug!)

This lets you put on pounds quickly in the spring and summer, using now-available plants as your primary food source.

The difficulty with our society is we’ve figured out how to take the energy part out of the plants, refine it, and store up huge quantities of it so we can eat it any time we want, which is all the time.

Evolution makes us want to eat, obviously. Ancestors who didn’t have a good “eat now” drive didn’t eat whatever good food was available and didn’t become ancestors.

But now we’ve hacked that, and as a result we never go into the sugar-free periods we were built to occasionally endure.

I don’t think you need to go full keto or anti-bread or something to make up for this. Just cutting down on refined sugars (and most refined oils, btw) is probably enough for most people.

Note: Humans have been eating grains for longer than the domestication of plants–there’s a reason we thought it was a good idea to domesticate grains in the first place, and it wasn’t because they were a random, un-eaten weed. If your ancestors ate bread, then there’s a good chance that you can digest bread just fine.

But if bread causes you issues, then by all means, avoid it. Different people thrive on different foods.

Please remember that this thread is speculative.

AND FOR GOODNESS SAKES DON’T PUT SUGAR IN FRUIT THINGS. JAM DOES NOT NEED SUGAR. NEITHER DOES PIE.

IF YOU ARE USING DECENT FRUIT THEN YOU DON’T NEED SUGAR. THE ONLY REASON YOU NEED SUGAR IS IF YOUR FRUIT IS CRAP. THEN JUST GO EAT SOMETHING ELSE.

 

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Neanderthal DNA–hey!–what is it good for?

Quite a bit.

First, a bit of history:

neanderthalmap
map of Neanderthal DNA in humans

It appears that there were (at least) 3 main cross-breeding events with Neanderthals. The first event most likely happened when one small band of humans had left Africa and ventured into the Middle East, where Neanderthals were living. The DNA acquired from that partnership can be found in all modern non-Africans, since they are all descended from this same group. (Since there has also been back-migration from the Middle East into Africa sometime in the past 70,000 years, many African groups also have a small amount of this DNA.)

Soon after, the group that became the Melanesians, Papuans, and Aborigines split off from the rest and headed east, where they encountered–and interbred with–the mysterious Denisovans, a third human species that we know mostly from DNA. Various sources claim this happened before the second neanderthal inter-breeding event, but just looking at the amount of admixed neanderthal in Oceanans suggests this is wrong.

Meanwhile, the rest of the non-African humans, probably still living in the Middle East or Eurasian Steppe, encountered a second band of Neanderthals, resulting in a second admixture event, shared by all Asians and Europeans, but not Melanesians &c. Then the Asians and Europeans went their separate ways, and the Asians encountered yet a third group of Neanderthals, giving them the highest rates of Neanderthal ancestry.

nature-siberian-neanderthals-17.02.16-v2

During their wanderings, some of these Asians encountered Melanesians, resulting in a little Denisovan DNA in today’s south Asians (especially Tibetans, who appear to have acquired some useful adaptations to Tibet’s high altitude from ancient Denisovans.)

There were other interbreeding events, including a much older one that left homo sapiens DNA in Neanderthals, and one that produced Denny, a Neanderthal/Denisovan hybrid. There were also interbreeding events in Africa, involving as-yet unidentified hominins. (In the human family tree to the right/above, Melanesians are included within the greater Asian clade.)

Who married whom? So far, we’ve found no evidence of Neanderthal mitochondrial DNA–passed from mothers to their children–in modern humans, so the pairings most likely involved Neanderthal men and human women. But we have also found extremely little Neanderthal DNA on the Y chromosome–so it is likely that they only had female children, or any male children they had were infertile.

Anthropogenesis-DenisovaAlleleMapInterestingly, we find higher amounts of Neanderthal DNA in older skeletons, like the 40,000 year old Tianyuan Man, or this fellow from Romania with 10% Neanderthal DNA, than in modern humans. Two potential explanations for the decrease: later mixing with groups that didn’t have Neanderthal DNA resulted in dilution, or people with more Neanderthal DNA just got out-competed by people with less.

Given the dearth of DNA on the Y chromosome and the number of diseases linked to Neanderthal DNA, including Lupus, Crohn’s, cirrhosis, and Type-2 diabetes, the fact that morphological differences between Sapiens and Neanderthals are large enough that we classify them as different species, and the fact that Neanderthals had larger craniums than Sapiens but Sapiens women attempting to give birth to hybrid children still had regular old Sapiens pelvises, gradual selection against Neanderthal DNA in humans seems likely.

However, the Neanderthals probably contributed some useful DNA that has been sorted out of the general mix and come down the ages to us. For example, the trait that allows Tibetans to live at high altitudes likely came from a Denisovan ancestor:

Researchers discovered in 2010 that Tibetans have several genes that help them use smaller amounts of oxygen efficiently, allowing them to deliver enough of it to their limbs while exercising at high altitude. Most notable is a version of a gene called EPAS1, which regulates the body’s production of hemoglobin. They were surprised, however, by how rapidly the variant of EPAS1spread—initially, they thought it spread in 3000 years through 40% of high-altitude Tibetans, which is the fastest genetic sweep ever observed in humans—and they wondered where it came from.

Modern humans have Neanderthal DNA variants for keratin (a protein found in skin, nails, hair, etc.,) and UV-light adaptations that likely helped us deal with the lower light levels found outside Africa. There’s circumstantial evidence that microcephalin D could have Neanderthal origins (it appeared about 37,000 years ago and is located primarily outside of Africa,) but no one has found microcephalin D in a Neanderthal, so this has not been proven. (And, indeed, another study has found that Neanderthal DNA tends not to be expressed in the brain.)

Yet on the other hand, Neanderthal admixture affected sapiens’ skull shapes:

Here, using MRI in a large cohort of healthy individuals of European-descent, we show that the amount of Neanderthal-originating polymorphism carried in living humans is related to cranial and brain morphology. First, as a validation of our approach, we demonstrate that a greater load of Neanderthal-derived genetic variants (higher “NeanderScore”) is associated with skull shapes resembling those of known Neanderthal cranial remains, particularly in occipital and parietal bones. Next, we demonstrate convergent NeanderScore-related findings in the brain (measured by gray- and white-matter volume, sulcal depth, and gyrification index) that localize to the visual cortex and intraparietal sulcus. This work provides insights into ancestral human neurobiology and suggests that Neanderthal-derived genetic variation is neurologically functional in the contemporary population.

(Not too surprising, given Neanderthals’ enormous craniums.)

Homo sapiens also received Neanderthal genes affecting the immune system, which were probably quite useful when encountering new pathogens outside of Africa, and genes for the “lipid catabolic process,”[19] which probably means they were eating new, fattier diets that Neanderthals were better adapted to digest.

Even Neanderthal-derived traits that today we cast as problems, like Type II Diabetes and depression, might have been beneficial to our ancestors:

“Depression risk in modern human populations is influenced by sunlight exposure, which differs between high and low latitudes, and we found enrichment of circadian clock genes near the Neanderthal alleles that contribute most to this association.”

Why would we find an association between Neanderthal DNA and circadian clock genes? Neanderthals had thousands of years more exposure to Europe’s long nights and cold winters than homo Sapiens’; it is unlikely that they developed these adaptations in order to become less well-adapted to their environment. It is more likely that Neanderthals downregulated their activity levels during the winter–to put it colloquially, they hibernated.

No problem for furry hunter-gatherers who lived in caves–much more problematic for information age workers who are expected to show up at the office at 9 am every day.

Type II diabetes affects digestion by decreasing the production of insulin, necessary for transporting converting carbs (glucose) into cells so it can be transformed into energy. However, your body can make up for a total lack of carbs via ketosis–essentially converting fats into energy.

Our hunter-gatherer ancestors–whether Neanderthal or Sapiens–didn’t eat a lot of plants during the European and Siberian winters because no a lot of plants grow during the winter. If they were lucky enough to eat at all, they ate meat and fat, like the modern Inuit and Eskimo.

And if your diet is meat and fat, then you don’t need insulin–you need ketosis and maybe some superior lipid digestion. (Incidentally, the data on ketogenic diets and type II diabetes looks pretty good.)

In sum, Neanderthal and Denisovan DNA, while not always useful, seems to have helped Homo sapiens adapt to colder winters, high altitudes, new pathogens, new foods, and maybe changed how we think and perceive the world.