THE EVOLUTION DIET

THE EVOLUTION DIET

Or, more accurately, what evolution can tell us about diet, started in my mind as a semi-humorous post that soon evolved into one with some serious messages.  It was triggered by a conversation I overheard discussing someones weight problem and the persons lack of knowledge of what I thought were bits of information one could not overlook if they kept up with the news and opinion over the past few dozen years.

The evolutionary aspects of diet

We are a product of a long evolutionary history.  One would think our more recent ancestors had a more direct impact on our genetic heritage.  That is probably true, but more remote ones often leave their imprint on our genetic code.  Many fundamentals of our biochemistry go back to one-celled ancestors common to both plants and animals.  So it is not surprising that vegetation has a store of nutrients useful for a healthy diet.

We may worry about exposure to foreign organisms, especially bacteria.  When our ancestors left that primordial soup in which they evolved they were accompanied by a varied flora and fauna.  So today, after a course of antibiotics that kill off useful members of those organism inhabiting our gut, it is a good idea to eat yogurt and perhaps other things that will reintroduce those useful organisms back in to the gut.  Doing so can lead to rapid return of comfortable intestinal function.

Even our skin may benefit from the presence of useful organisms that compete with pathogens trying to establish themselves on or in our skin.

Fast forward to the present and we see diets that rely on excessive distortion, not truly natural diets based on our evolutionary history.

A fatal diet

A few decades ago, a liquid protein diet worked wonders in providing rapid weight loss.  But some died when they reached their desired weight and tried to resume a normal diet to prevent further weight loss.  It was thought the lack of carbohydrates and/or fats in their diet had fostered the deterioration of the parts of their biochemical cellular features which could not be retooled quickly enough to preserve life.

A balanced diet

Is balanced on a tray carried by the waitperson?  No, it is one that should contain all needed nutrients such as vitamins, minerals, proteins, fats, carbohydrates as well as fiber and some less easily characterized nutrients.  Would an egg diet be a balanced diet, it has all the nutrients needed to form the systems of a bird?  No, most adults need a larger supply of energy. But some eggs are probably beneficial.  Fats are food having the most calories (stored energy), about 9 calories per gram, carbohydrates and proteins each have about 4 or 4 1/2 calories per gram, and alcohol has about 9 calories per gram.  So, if you are serious about a diet, reduce the alcohol consumption to the equivalent of a small glass of wine; none is far better than too much.

Nutrients do not all provide energy.  For example-  Our need for vitamin C in our diet is almost certainly a result of having tree-dwelling primate ancestors that had so much vitamin C laden fruit in their diet that random mutations destroying the ability to make vitamin C did not get eliminated by natural selection.  Non-primates ancestors such as your pets retained the ability to make vitamin C from earlier common ancestors we share.

Fat was the most efficient material to use for storing energy.  Not only for its high energy content, but it has very low impact on the aqueous based metabolic processes of cells.  Thus enough can be more easily stored to get an animal through seasons of low food supply.  We don't have that need now so our natural tendency to stock up does not get followed by a season to use up the excess reserves.  We still need fats and/or oils in our diet to aid uptake of fat soluble vitamins in our food.

Because we cannot digest fiber it does not provide dietary calories.  We lost that ability sometime way back in our evolutionary history.  Our appendix is thought to be a vestigial organ representing the cecal sac of an ancestor that could use it as a location to use microorganisms to break down fiber and otherwise indigestible plant parts, like cellulose, into usable carbohydrates.

High protein diets may put an excessive load of breakdown products on the excretory system.  More details of protein metabolism can be found in [ http://evolutioninsights.blogspot.com/2014/04/evolution-of-proteins.html ] a post which also indicates the important role protein break-down products had in adaptation for animals emerging from water to occupy terrestrial habitats.  The views count for the protein post is zero.  The views count for carbohydrates [  http://evolutioninsights.blogspot.com/2014/04/evolution-of-carbohydrates.html ] was one.  The views count for fats [  http://evolutioninsights.blogspot.com/2014/04/evolution-and-fats.html ] was two.  But the next post on macromolecules was more than an order of magnitude more popular [ http://evolutioninsights.blogspot.com/2014/05/evolution-of-macromolecules.html ].

Teeth

Our teeth include biting (incisors), piercing and tearing (canines), and chewing or grinding (molars), a combination of forms characteristic of omnivores.  That could suggest that our transition from one diet to another was fairly rapid in an evolutionary sense; it also makes us more adaptable to a variety of diets.

Evolution of diet

Our earliest animal like ancestors fed on small microorganisms like bacteria.  That method of nutrition can still be seen in us as the white blood cells that go around ingesting bacteria that invade our body.  Things go awry when disease causing bacteria get too good a start in our body.

The large eggs, part of the diet of many of us, developed in part because birds and reptiles were able to form them with a shell because the waste products of protein metabolism could be largely in the form of nearly insoluble uric acid.  Before that ammonia that was the first nitrogenous waste product of protein metabolism could diffuse in to the water.  We have partially gotten away from uric acid by using urea as a soluble nearly non-toxic alternative.  But for most of us, too much protein can lead to gout and other problems of excess uric acid accumulation.  Egg, dairy, and meat eaters face other problems from cholesterol and saturated fats although most of us can use moderate amounts if adequate vegetable, fruits, and whole grain fiber gets to our diet.  Some fish, not all types of fish, each week seems to have a beneficial role in nutrition.

Trans-fats, refined sugars and refined grains were not part of our remote ancestors diets, and we would probably be better off without them.  But even if we could study middens or other evidence of diet of distant ancestors it does not necessarily mean that roots, leaves, fruits, and berries form an essential diet.  We do not know the health and disease problems of those ancestors in sufficient detail to know that we should try to be like them.

My wife tells me that if I eat like my grandparents did on the farm, then I should work like them too.

An important consequence of a vegetarian diet is better avoidance of toxic chemicals we have introduced into our environment.  Animal protein can accumulate heavy metals, the animal fats can accumulate organic toxins when animals get food or medicines that contain those compounds.  Fortunately, the scary numbers are partly due to our ability to often identify pollutants in parts per billion amounts, a few generations ago when tests identified parts per million amounts, we didn't know they were there.  The bad thing is that some can poison at extremely low concentrations if they mimic or interfere with hormones or their functions.

Part of the bureaucracy many complain about is doing its best to see that we get safe food, drugs, air, and water.  That is not to say that improvements cannot be made.

Joe Engemann    Kalamazoo, Michigan       July 21, 2015

EVOLUTION OF CARBOHYDRATES

EVOLUTION OF AMAZING CARBOHYDRATES

The Stuff of Life

Plants and animals utilize a variety of basic materials to make the specialized parts that are so different in some ways.  Carbohydrates, proteins, and fats make up most of the volume of organic molecules and structures in the watery bath inside and/or outside the membrane bounded cells of living organisms.  Minerals make up a major part of vertebrate skeletal structures and of shells of some invertebrates.  Very important in proper functioning, and often controlling aspects of development and function, are vitamins, hormones, minerals, and trace elements in very small amounts. 

The hereditary material has a central role in perhaps most aspects of life, but little will be said about it in today’s blog.  DNA, RNA, and enzymes and the feedback mechanisms used are modified along with evolution of the things they control.

Glucose in plants versus animals

Glucose has an important role in utilization of stored energy in plants and animals.  But only a small amount can be tolerated in the cells of plants or animals.  Animals and plants can both burn it up as they metabolize it to produce energy by the same chemical pathways.  But too much in the cell would result in the cell bursting from water absorption that occurs by its diffusion into the cell from the watery bath around it.  Cells that survived are those that evolved to convert excess glucose into other compounds, especially large polymers such as cellulose in plants and glycogen in animals.

Plants can also store large amounts of glucose as starch as well.  Both cellulose and starch molecules are so large that only a few molecules can store hundreds of glucose molecules.  The generic name for such a large compound molecule is polymer.  Plants make glucose in abundance by the process of photosynthesis.  Glucose polymerized into cellulose makes a useful structural material, typically as the major part of the cell walls of plants. 

Cellulose processing was lost in the early cells that gave rise to the animal kingdom.  But animals developed a modified form of storage called glycogen that functions, as starch may do in plants at night, to quickly replace glucose when it becomes depleted in the cell from activity.

Glucose is a six carbon sugar.  Disaccharides are twelve carbon sugars such as sucrose, maltose and lactose; they are formed from particular combinations of two monosaccharides, such as glucose and fructose.  A five carbon sugar is part of the linking mechanism, for the chains forming DNA and RNA, along with one of the four purines and/or pyrimidines (adenine, cytosine, guanine, and thymine).  Each link of the chain with one of the four purines or pyrimidines uses three links at a time to code the hereditary processes of life.

A hypothesis about a balanced diet

We know that insulin helps the body in regulating blood glucose by somehow helping balance the role of storage and utilization between blood sugar and storage or release from fats and other stores.  Plants do not have insulin to my knowledge, but many of the chemical processes involved in storage and release of glucose may be similar. Varied grains, fruits, and vegetables in the diet are likely to provide some necessary substances involved in the process that are not fully known.  They and the fiber associated also provide a valuable role in maintaining the proper gut flora and fauna needed for healthy functioning of the lower digestive tract.

The first organic molecules

Organic molecules are commonly thought of as originating in living organisms.  But a few simple ones can form when lightning passes through a gaseous atmosphere containing water vapor, carbon dioxide, methane, and nitrogen.  Similar simple compounds can form in sea water exposed to red hot lava.  Both may have been important in contributing to the dissolved nutrients of seawater in early seas when the first life evolved.

Among those compounds formed in such circumstances are glucose, glycine, and adenine.  We have already discussed some of the role of glucose above.  Glycine and adenine are among simple amino acids utilized to make polymers, called proteins.  Additionally, adenine has an important role basic in ATP (adenosine tri-phosphate) for energy transfer processes in cellular metabolism.

The big picture

The above is just a rudimentary look at a portion of the processes and materials of life.  How they interact here is probably identical to how they have acted (and are or will act) in other comparable planets scattered throughout the cosmos.  Natural selection would probably produce great similarity of results through these remarkable chance directed processes that could only be controlled by an infinitely intelligent and powerful being.  It should be truly humbling to see that such a being has promised so much to us through his Son two thousand years ago.

Joseph G. Engemann      April 25, 2014