I’m not here to convince you of anything. I’m not here to debate things with you. And I’m not here to share and discuss views or opinions. I am here to talk about physiology, biochemistry, and what these can teach us about optimal health. In fact, I’m not even going to tell you anything about what you should eat and not eat, or drink and not drink. Instead, I’ll leave you to deduce that for yourselves.
The truth is that nothing we believe or think has any bearing or relevance to how things actually are: how the body works; how it responds to water or orange juice; to starch, protein and fat; to stress and relaxation; or to exercise and sleep. Everything about how the bodymind functions is determined by physiology and biochemistry.
We certainly do not know or understand everything—far from it. But we do understand quite a lot, and what we do know and understand is enough to show us how to live in optimal health without suffering from any of the aches and pains, and ills and ailments that today plague modern societies throughout the world.
Thirty minutes is not long enough for me to tell you everything I would like to. So, we’ll restrict this talk to those basic points that I feel are most fundamental in beginning to understand the effects on the bodymind of what we eat and drink: we’ll talk about water, sugar, protein and fat.
So, you have the choice now to take the blue pill, get up, go back to your office, and believe whatever you want to believe. Or, to take the red pill, stay here, and see what I can show you of how things happen in the body when we eat or drink certain things.
You’re all ready, so let’s start.
Water, as you will see, is extremely important. And so, I will spend quite a bit of time on it.
Some people drink a lot of water, some drink less, and some drink hardly any. Why is that? Do you think some people need more water than others: that some need a lot and other don’t need much?
Have you ever wondered what happens when you drink a glass of water? Where does it go? What does it do? How long does it stay there?
What’s the connection between the water we drink and the urine we pee? How does the water go from our glass to our pee? Why do we pee? What do we pee? When do we need to pee? How does that work?
How much should we drink? When should we drink? Is it important to drink at certain times and not at others? What happens when we don’t drink? Is any of this important?
Well, to start, a new born baby is about 90% water by weight. An old person on their death bed is about 50% water. And a healthy teenager or adult is around 73%. It has always been like this, and looking at this picture very simply, we can say that we should strive to remain around 73% for as long as we are alive, and the closer we get to 50%, the closer we are to death.
In the digestive system
You pick up a glass, fill it with fresh, pure water, raise it to your lips, and drink. The water goes straight into the empty stomach. There, it first hydrates the specialised cells that make up the stomach’s lining and the layer of mucus that covers it, and then hydrates the pancreas. The water then moves into the intestine where it also hydrates the cells that form the lining, and the leftover starts to permeate through the intestinal wall into the bloodstream, which then carries it throughout the body. This takes about 30 minutes.
The amount of water needed to hydrate the digestive system in preparation for a meal is one to two glasses or 200-500 ml, meaning that of the first two glasses you drink on the empty stomach in the morning or before a meal, little will make it to the bloodstream, because it is most important for the body’s self-preservation to ensure, first and foremost, that the digestive system is well hydrated.
You can check this for yourself: get up in the morning, go pee, drink one glass of plain water, and then wait and see how long it will take, and how much you will pee out; the next morning drink two glasses and see; and on the third morning, drink a whole litre instead, and see what happens.
Why is the hydration of the digestive system so important? Because it is on it that the organism as a whole relies for its survival:
If there is dehydration, the mucus layer of the stomach is thin and dry, and thus cannot protect the lining from the corrosive hydrochloric acid that is secreted to breakdown protein. The stomach wall gets damaged, and over time, this leads to stomach ulcers, and a stomach that simply doesn’t work properly anymore, incapable of digesting protein into the essential amino acids most importantly needed for proper brain function, but for many other things as well.
If there is dehydration, the pancreas cannot produce its alkaline bicarbonate solution needed to neutralise the acidic chyme that goes from the stomach into the first part of the small intestine. This leads to pH imbalance and damage to the intestinal wall, which over time also leads to ulcers, leaky gut, malabsorption, poor elimination, bacterial and fungal overgrowth, and systemic toxicity.
In the blood
OK. Now, what happens in the blood? Our blood is made of red blood cells (45%) and white blood cells and platelets (0.7%) floating in blood plasma (54.3%). Blood plasma shuttles nutrients to cells around the body, and transports wastes out: it consists of 92% water, 8% specialised (mostly transporter) proteins, and trace amounts of solutes (things dissolved or floating in it).
Although in trace amounts, the solutes, and especially sodium, are vital. The concentration of solutes in blood plasma is around 300 mmol/l (don’t worry about the units). In the highest concentration of all is sodium at 140, and in the second highest is chloride at 100. The sum of these is 240, and so from these numbers alone, we see that blood plasma is more or less just salty water.
Amazing isn’t it? We’re told to avoid salt because it supposedly causes high blood pressure and heart disease, but when we look at our own blood, among all the solutes, it is sodium and chloride—the salt—that are and need to be in the highest concentrations!
Alright, what keeps everything in balance, what keeps tabs on the water content, on the sodium content, on the chloride, on the bicarbonate, and on every other electrolyte or solute? It’s the kidneys. What keeps a very close watch on blood pressure, and adjusts and controls the blood’s consistency, thickness and viscosity? It’s the kidneys. And what excretes the toxic metabolic wastes urea, uric acid and creatinine, produced more or less continuously in a normal functioning body? It’s the kidneys: so important, yet so under-appreciated, and so rarely considered or given the importance and attention they deserve.
You have 4-5 litres of blood in your body (I have about 4, and Uwe over here has about 5). One quarter of all the blood coming out of the heart flows through the kidneys: this is on average 1.2 litres per minute, which amounts to more than 1700 litres per day. And thus, every drop of blood goes through the kidneys about 400 times each and every day!
To maintain flow and pressure more easily, only 20% of the blood flowing through the kidney is filtered (that’s 240 ml or about a cup per minute, and thus 340 l/day). Because half of the blood’s volume is water, this amounts to a total of 850 (1700/2) litres of water; filtering 20% means that 170 litres of water are filtered each day.
Therefore, if one litre of urine is produced in 24 hours (that’s unfortunately pretty typical), then close to 169 out of 170 of these litres of water are reabsorbed: a reabsorption efficiency of 99.4%! Drinking a bit more and producing two litres of urine eases this down to a nonetheless remarkable efficiency of 98.8% (168/170). Think about it for a second: 99% reabsorption efficiency. That’s high efficiency.
But what does ‘filtering the blood’ actually mean and how is this done exactly? In each kidney there are about 1 million miniature filters called nephrons. It is in the nephron that the blood is filtered and the urine produced in five stages, first through Bowman’s capsule (1) and into the proximal convoluted tubule (2), then along the loop of Henle (3) and into the distal convoluted tubule (4), and finally out through the collecting duct (5) and into the ureter to the bladder. That’s how pee is made and where it comes from. What’s in it? Well, mostly water, of course, some extra solutes, but more importantly, it contains urea, uric acid and creatine, those toxic metabolic wastes resulting from protein digestion, that the body needs to excrete.
And what about blood pressure regulation? Blood pressure is intimately related to blood volume, i.e., the amount of water in it, and blood osmolarity, i.e., the concentration of solutes, mainly sodium as we’ve seen, and to a lesser extent the other electrolytes, but also glucose. Maintaining these in balance is essential for proper function of everything in the body. For this reason, there are pressure sensors throughout every blood vessel, and osmolarity sensors in the hypothalamus of the brain, as well as highly sensitive sensors of both kinds in the kidney itself.
A drop in volume sensed by the pressure sensors in the blood vessels, or a rise in solute concentration sensed in the hypothalamus, will trigger the release of vasopressin from the pituitary gland. Vasopressin will signal the kidney to release more water for reabsorption into the bloodstream to make up for the drop in volume and rise in solute concentration.
Vasopressin will make the blood vessels constrict and tighten to maintain the blood pressure constant. It will also stimulate the secretion of glucose from the liver in case fast reaction times become necessary, as well as clotting factors and platelets to make the blood thicker and stickier, and prevent excessive blood losses in case of injury. All of these are part of the standard stress response. Vasopressin will also stimulate the secretion of the stress-induced adrenocorticotropic hormone or ACTH that will act to reinforce all of the above and make things even worse than they already are.
What does this mean? It means that even mild dehydration triggers a full stress response in the body with all associated effects and consequences.
How much water:
The minimum requirement for survival is 1.2 litres in 24 hours. The minimum for proper kidney and metabolic function is 2 litres per day. But the amount required for optimal function and health is 4 litres, together with 2 teaspoons of unrefined sea salt to replenish and maintain sodium levels in order to maximise hydration.
Conclusion for water:
Here’s my long one line conclusion about water: Water is life, and the absence of it is death; not enough water in the digestive system leads to damage of the stomach and intestines, to bad digestion, malabsorption and nutritional deficiencies, to systemic toxicity, and generalised bacterial and fungal infections; not enough water in the bloodstream leads to a full blown, textbook stress response with all the terribly negative consequences this entails, and maybe most importantly, severe damage to the arteries, and thus to the formation of arterial plaques which lead to cardio and cerebrovascular disease, i.e., heart attack and stroke; the optimal is around 4 litres of water over the course of the day, drank on an empty stomach, matched with 2 teaspoons of salt either with the water or the meals.
With this general overview of several important systems and functions, let’s move on to food: to what happens when we eat something. And to make things as simple and clear as possible, we’ll consider each macronutrient separately, and we’ll start with the undisputed favourite of them all: sugar.
What happens when we have a fruit: a tart apple, a juicy orange, or a sweet date? What happens when we eat a biscuit, a piece of bread or a plate of pasta? How is sugar digested? How are starches digested? What happens to it in the body?
In the digestive system
Drinking a glass of orange juice on an empty stomach, will deliver 20 g of sugar to the blood in as little as a few minutes. The sugar goes from the mouth and into the stomach, which if empty, allows it to move directly to the small intestine. In a matter of minutes the sugar will have passed through the intestinal wall and made it into the bloodstream.
If the stomach is not empty, but instead contains some amount of protein, then the sugar will remain in there, because the contents of the stomach will only be emptied into the small intestine when the protein has been broken down, a process that takes around 3-4 hours. And in the meantime, the sugar will ferment, causing aches and bloating, and impair digestion.
In the blood
As soon as the sugar is in circulation and sensed by the pancreas, insulin will be secreted in an amount that is proportional to the concentration of sugar. Insulin’s primary role is storage of “excess” nutrients, and regulation of fat storage and fat burning: when insulin is high, there is fat storage; when insulin is low, there is fat burning. It’s that simple. And it also means that insulin is the primary regulator of energy balance, and therefore of metabolism.
From an evolutionary perspective, the importance of insulin is perfectly clear. Firstly, it is a mechanism that is common to all living creatures, from the simplest to the most complex, because all these living creatures depend for their survival on a mechanism that allows them to store nutrients when they are available for consumption but not needed by their metabolism, in order to live through periods where food is not available. This is why the role of insulin is so fundamental and why it is a master hormone to which most others are subject. But when glucose levels are higher than a minimum functional threshold, what insulin is trying to do, is to clear away the circulating glucose.
The body does not want large amounts of glucose in circulation. It wants blood glucose to be low—as low as possible—and beyond this minimum glucose concentration of 60 to 80 mg/dl, it always tries to store it away and clear it from the bloodstream. It tries to store what it can in the muscles and liver as glycogen, and stores the rest (i.e. most of it) as fat.
All simple and starchy carbohydrates end up as glucose in the blood, and stimulate the secretion of insulin from the pancreas. Very small amounts of glucose in the bloodstream is essential for life; large amounts of glucose in the bloodstream is toxic.
Chronically elevated glucose levels lead to chronically elevated insulin levels. Like for any kind of messenger mechanism—as is insulin—if there are too many messengers repeating the same message over and over again, very soon they are not heard because their efforts at passing on the message becomes more like background noise.
Frustrated that they are not taken seriously, the messengers seek reinforcements in numbers to be able to transmit the message more forcefully. This, however, leads to even more annoyance on the part of the listeners—the message recipients—that now start to simply ignore the message and the messengers altogether.
This process continues to gradually escalate up to the point where the terrain is completely flooded by messengers yelling the same thing, but no one listening because they have insulated their windows and doors, and closed them tightly shut.
Here, the messengers are the insulin molecules; the message recipients are our cells—muscle, liver and fat cells; and the message is “take this sugar from the bloodstream, and store it away. We cannot have this circulating around for long.” The desensitisation—the not-listening—to different, progressively higher degrees over time, is called insulin resistance. Finally, the complete ignoring by the cells of the message and the messengers is called type II diabetes.
Furthermore, insulin resistance, not in the muscle, liver and fats cells, but in the brain cells, leads to neurological degradation identified as cognitive impairment, dementia or Alzheimer’s. Because beyond the fact that type II diabetes and Alzheimer’s disease are both increasing together at an alarming rate in the US and other western countries, and beyond the fact that diabetics are at least twice as likely to develop Alzheimer’s compared to non-diabetics, the basic condition of insulin resistance inevitably leads to chronically elevated glucose concentrations simply because the cells do not allow the glucose to enter.
And glucose staying in the bloodstream damages the lining of the arteries, which then leads to plaque formation: the body’s repair mechanism for the damaged cells underneath, just like a scab on the skin. Thus, as are the coronary arteries of advanced atherosclerotic heart disease sufferers (and diabetics) are riddled with plaques, so are the arteries and blood vessels in the brains of dementia and Alzheimer’s sufferers (and diabetics).
Here are two quotes from metabolic scientists:
Inflammation causes our cells (specifically our mitochondria) to increase production of free radicals. Free radicals are like mini roadside bombs that interfere with normal cellular functions. So … : 1) dietary carbohydrate raises serum insulin; 2) insulin promotes inflammation … ; 3) inflammation increases cellular free radical generation; 4) free radicals attack any convenient nearby target; 5) ideal targets for free radicals are [cell] membrane polyunsaturated fats; 6) membrane polyunsaturated fats are important determinants of cellular function … (p. 82).
Carbohydrate ingestion and … hyperglycemia activate a host of inflammatory and free radical-generating pathways. Some of these include: … activation of NF-kB which regulates the transcriptional activity of over 100 pro-inflammatory genes. (The art and science of low carbohydrate living by Volek and Phinney, p.186).
If you drip insulin into the femoral artery of a dog, … , the artery becomes almost totally occluded with plaque after about three months; the contra lateral side remains totally clear. [So, it’s the] contact of insulin in the artery [that] causes it to fill up with plaque. That has been known since the 70s and has been repeated in chickens and in dogs; it is really a well-known fact that insulin floating around in the blood causes a plaque build-up.
Insulin also causes the blood to clot … and causes the conversion of macrophages into foam cells, which are the cells that accumulate the fatty deposits. […] It fills the body with plaque, it constricts the arteries, it stimulates the sympathetic nervous system, it increases platelet adhesiveness and coaguability of the blood. (p. 7)
And for the last quote:
Insulin regulates lifespan. If there is a single marker for lifespan, as they are finding in centenarian studies, it is insulin, specifically insulin sensitivity. How sensitive are your cells to insulin? When they are not sensitive, the insulin levels go up. Insulin resistance is the basis of all of the chronic diseases of ageing. Cardiovascular disease, osteoporosis, obesity, diabetes, cancer, all the so-called chronic diseases of ageing and auto-immune diseases, those are symptoms, [the cause is insulin]. (Insulin and Its Metabolic Effects by Ron Rosedale, p. 3)
What happens if we eat complex carbohydrates like the starches found in grains and grain products, starchy vegetables like potatoes, or giant grasses like corn. Well, firstly, they take quite a bit longer to digest. Just as for simple sugars, their digestion does not take place in the stomach, but instead in the small intestine, where the enzymes work to break down the long sugar chains into glucose. During this time, glucose is released into the bloodstream as it becomes available, little by little, and therefore stimulates the secretion of insulin in smaller amounts, but over a longer period of time.
However, although the breakdown of starches takes place in the alkaline environment of the intestine, the breakdown process itself leads to acidic residues that acidify the intestine as well as the blood. Over time, this leads to exactly the same problems caused by the digestive system made dysfunctional from dehydration, and from the inability of the pancreas to alkalise the small intestine. What do we get? Intestinal inflammation and damage, ulcers, leaky gut, malabsorption, poor elimination, bacterial and fungal overgrowth, and systemic toxicity.
Conclusion for sugar
So, my one-line conclusion about sugar: On an empty stomach, sugar goes straight through to the intestine and into the bloodstream within minutes; starches are digested into sugar in several hours by pancreatic enzymes in the alkaline environment of the intestine, but produce acidic residues that impair and damage the intestinal tract and digestive system; insulin is secreted by the pancreas in response to the presence of glucose in the blood; and insulin-sensitivity is the best universal marker for health and longevity, while insulin-resistance is the best universal marker for all the chronic degenerative diseases, as well as premature ageing and death.
How are proteins digested? How much do we need? What happens if we eat too little or too much?
In the digestive system
Protein provide the body amino acids needed for countless functions throughout the organism. However, in order to make these amino acids available, the large and very tightly wound protein molecules need to sit in an highly acidic bath for several hours. This is done in the stomach, and is only necessary for the digestion of protein. As soon as protein enters the stomach, it’s presence is detected by sensor cells, and the acidic hydrochloric solution needed for the breakdown is secreted.
It’s important to keep in mind that if the stomach is unable to secrete the required amount of hydrochloric acid, then the protein will be only partially broken down, and the animo acids will not be available in the bloodstream. This, besides the bad digestion, stomach aches and cramps, gas and bloating, will consequently lead to amino acid deficiency, for which the gravest consequences will be on the central nervous system: brain function and moods.
Metabolic wastes in the blood
Protein metabolism, although essential for survival, produces the highly toxic byproducts as metabolic wastes that need to be excreted. As we saw, this is the primary excretory role of the kidneys, and it is very important that these all-important work horses stay in perfect condition to ensure proper elimination of these wastes.
Production of these wastes is inevitable, but the amount is proportional to the quantity of protein that is ingested and metabolised. Therefore, it is best to have as much protein as we need, but not more; how much depends mostly on muscle mass and activity, but is between 0.75 and 1.5 g of protein per kg of lean mass per day.
I’m 58 kg, 8.5% fat which makes 5 kg, and therefore have 52 kg of lean mass, which gives 40-52 g of protein per day. That’s not much: a couple of large handful of almonds and a couple of eggs or a small piece of meat or fish (remember that both raw meat and fish are about 70% water by weight).
Conclusion for protein
My one-line conclusion: a well-functioning and abundant supply of hydrochloric acid from the stomach is absolutely essential for complete protein digestion; protein, in order to be properly broken down and digested, must be eaten either by itself, with fat or with green vegetables, but never with either simple or starchy carbohydrates, and always on a well hydrated digestive system; to minimise the amount of toxic wastes produced by protein metabolism, the amount consumed should not be excessive.
Fat, fat, fat. How much do we need? How much can we eat? How is it digested? Where does it go? How is it stored? How is it burned? When is it stored and when is it burned? So many important question about fat.
Firstly, I think it is crucial to start by saying that fat is the most important nutrient for humans. To state a few of these essential functions: fat is needed by every cell, especially in the brain, most of it of which is pure fat; it is needed for absorption and fixing of minerals; it is needed for absorption of proper usage of all fat-soluble vitamins, the most essential of which as vitamin A and vitamin D, without which we cannot live; it is needed to support healthy cholesterol synthesis and metabolism, and cholesterol is what all hormones and nerve synapses in the body are made from.
These things alone should be enough to convince anyone that fat is indeed the most important nutrient for us. Let’s look at a few more details.
In the digestive system
Fat, eaten alone on an empty stomach, goes straight into the small intestine. As sugar, it does not require to remain in the stomach because it does not need an acidic environment to be broken down and digested; it needs the alkaline environment of the intestine.
Unlike sugar or starches, however, fat can remain in the stomach with protein for hours without any problem. Also unlike sugar and starches, most fats need an additional element for digestion: bile, manufactured by the liver, but stored and secreted into the small intestine by the gall bladder, when there’s fat. The bile emulsifies the fat into droplets so that it can be transported through the intestinal wall and then circulated into the bloodstream.
As cellular fuel
Probably every cell in the body can use glucose as a source of fuel. Actually, probably every cell of every living organism can use glucose as a source of fuel. This is an evolutionary trait that comes from the fact that we, and all living creatures, are descendants of the first, extremely simple living organisms that found a way to use glucose as fuel.
A molecule of glucose that enters a normal cell will be burned up by the mitochondria with oxygen and produce 36 molecules of ATP (the currency or unit of energy for living organisms). If the glucose is used without oxygen (anaerobically) it will give only 2 ATP. Glucose usage produces a waste by-product, lactic acid or lactate, which can remain in the tissue, or be partially or fully excreted into the bloodstream for elimination by the kidneys, as is normal for acidic wastes.
More importantly though, is that almost every cell in the body can also use fat as a source of fuel. And in fact, cells of living organisms like ourselves much prefer fat over glucose for the very simple reason that the oxidation of a fatty acid by a cell’s mitochondria produces a lot more molecules of ATP (the amount depends on the kind of fatty acid, and more specifically on the number of carbon atoms), and in addition, does not produce acidic waste by-product—no lactic acid or any other kind of acid—and thus no acid that requires excretion and elimination, and no acid that accumulates in the tissues.
For those relatively few cells that cannot use fat directly, the body manufactures ketone bodies, which are just simple, fat-derived molecules intended as fuel, mostly for the brain. But ketones have a whole array of wonderful, health-promoting properties, especially for the brain, like stimulating the healing and clearing out of plaques in the cerebral arteries and arterioles. This fact is the basis for many therapeutic treatments of people suffering from central nervous system disorders like epileptics, young or old, and Alzheimer’s patients.
Very importantly, fatty acids in circulation will not be stored into fat cells unless insulin is elevated: the fat will remain in circulation for hours, no matter how much of it there is, slowly being used up by working cells as fuel, and continue to signal satiety and suppress hunger until it is used up and gone.
If insulin is elevated, however, the insulin will store everything away, the glucose, the protein, and the fat, also no matter how much of it there is, and most of it in fat cells. Remember, insulin’s role here is to store away excess nutrients for use during future times of scarcity. It doesn’t care that we already have dozens kilos of stored fat for future times of scarcity. It just clears the bloodstream of nutrients and promotes fat storage.
Conclusion for fat
That’s it, that’s the last topic I’m going to talk about for now, and here’s my final one-line conclusion for fats: Fats are needed for building and repairing cells, for mineral absorption, for cholesterol synthesis, for hormonal balance and brain function; fats are digested in the alkaline intestine, where they are emulsified by the bile made in the liver and secreted by the gall bladder; unlike sugar, it can remain in the stomach together with protein for hours without causing problems; fat is the ideal cellular fuel, because the oxidation of a fatty acid in the cell produces 24 units of ATP, twelve times more than glucose, and does not produce any acidic by-products such as lactic acid in the case of glucose. Fat-derived ketones are not only fuel for a few specialised cells like some of those in the brain, but have many health-promoting and healing therapeutic effects.
Thanks for listening. I’m open for questions.
This talk was given to a group of colleagues at the European Space Astronomy Centre of the European Space Agency, in Villanueva de la Canada near Madrid in Spain, on August 6, 2013.