Leisha What Urine and Live Blood Might Tell Us About How the Body Cleans Itself
There is a place where the textbooks go quiet, and I have always been drawn to it. Medicine is very good at telling us what can be measured, yet traditions have been noticing things in the body for centuries, long before anyone could name a compound or build a microscope. The more I practice looking in a microsope at soil, blood or urine (new for me), the more I realize we can make assessments by putting things together and not separating them. I want to hold both: the measurements and the noticing the bird’s eye view.
I suppose this is my itch. When I look at live and dried blood, I see the plasma and everything floating in it, red and white blood cells, platelets, fibrin strands, crystal-like shapes, undigested protein, uric acid and fermentation.
I’ve started doing some research in urinalysis and how to read the urine with the microscope. The question I have is how does the body clear the debris, and what shows up in the urine and how can this be compared to or compared to live blood analysis?
Medical orthodoxy has answers for some of that, but I think I can learn by going looking myself and comparing this to live and dried blood analysis as this is not a recognized “medical” testing. So I am following this trail, and the trail begins with a stream most of us flush without a second glance.
I get asked often what I think about drinking your own urine. I studied Ayurveda many years ago and understand the tradition and why this was recommended 1000s of years ago. A thousand years ago, in the tradition, the picture was very different. Diets were different, and so was the exposure to chemicals, toxins and poisons. So the argument for it today isn’t the same as the argument then.
Our kidneys filter out waste, excess salts and whatever medications and chemicals we have been exposed to, and all of it leaves through the urine. What made sense in a very different world doesn’t automatically carry over into our time and situation today.
What’s Actually in the Bottle?
Urine is about 95% water, warm and roughly isotonic, which means its salt concentration sits in the same ballpark as our own body fluids, so it doesn’t strongly pull water out of cells or push water in, although urine does swing from dilute to concentrated through the day. The rest is whatever the kidneys have filtered out of the blood. Urea makes up about 2%, roughly 20 grams per litre, and is the main solute. Urea is how the body safely carries nitrogen away. When we break down protein, the leftover nitrogen becomes ammonia, which is toxic, so the liver converts it into urea, a far gentler molecule that rides in the blood to the kidneys. It is also a wonderful water magnet and skin softener, which is a story I’ll come back to in a moment.
Alongside Urea it we find allantoin, a breakdown product of uric acid, and uric acid itself, a strong antioxidant, plus salts, ammonia, amino acids and trace minerals. That leaves me with a question. If I see uric acid in the blood, is it there as an antioxidant? I always thought of it as a waste product, and now I am questioning it. The answer seems to be both. Uric acid is the end product of purine breakdown in humans, because unlike most mammals we lack the enzyme uricase that would break it down further. Yet in the blood it is also one of our main antioxidants, mopping up reactive molecules, and in doing that job it can be oxidised into allantoin, which may be part of why allantoin turns up in urine. So it is a waste product that does useful work on its way out. The trouble starts when there is too much of it, because at high levels it can crystallise in the joints and kidneys.
Every day the kidneys filter roughly 180 litres of fluid, reabsorb most of it and send the remaining 1 to 2 litres on to the bladder, which is a rather remarkable cleaning system.
Creatinine deserves a special mention, because it is easily confused with creatine, the supplement bodybuilders take and is very popular today. They are related, but they are not the same thing. Creatine is made in the liver and kidneys from amino acids and stored mostly in muscle, where it helps regenerate the quick energy needed for short, powerful efforts. Creatinine is what is left over. A small, fairly steady fraction of the body’s creatine breaks down each day, and the kidneys filter the resulting creatinine out into the urine.
So creatine is the fuel store and creatinine is the waste product. Because creatinine reflects muscle mass and kidney filtration, it is a useful marker, and someone taking creatine supplements can show slightly higher creatinine simply because there is more creatine to break down.
Then my garden brain took over, because urea is also one of the most widely used nitrogen fertilisers, and soil microbes break it down with an enzyme called urease. In the garden it is a mixed blessing. When urease breaks it down, ammonia and ammonium are released in a sudden surge. Some of that is lost to the air, some is converted by microbes into nitrate that washes away, and that conversion makes the soil more acidic over time. Repeated heavy doses of easy nitrogen also favour fast-growing microbes that burn through the soil’s organic matter, and they can weaken the partnership between plant roots and mycorrhizal fungi, because plants stop trading with fungi when nitrogen is handed to them for free. Year after year, the soil food web can end up poorer for it. Same molecule: waste in our bodies, fertiliser in the garden and a remedy on our skin….
Urea is a keratolytic, which means it loosens the bonds holding dead keratin together and pulls water into tissue, and the concentration decides what it does. Think of the outer layer of skin as a brick wall of dead cells held together by tough keratin. Urea is a water magnet that pulls moisture into that wall and swells it, and it also interferes with the hydrogen bonds that keep keratin proteins packed tightly together, so the structure loosens and the dead cells let go and shed. At low strengths the water-holding wins and skin feels soft. At high strengths the loosening wins, enough to dissolve thickened skin and dead tissue.
At 5 to 10% it moisturises and sits in most good foot creams, at 20 to 30% it softens calluses and cracked heels, and at 40% it breaks down dead tissue, which is why prescription products at that strength are used to clear wounds so the living tissue underneath can close. Allantoin turns up in commercial skin and wound creams too, as a protectant that encourages cell turnover. Two compounds from urine, sitting on a chemist’s shelf.
The tradition got there first. The yogic practice of amaroli, described in the Shivambu Kalpa, a section of the Damar Tantra with 107 verses framed as a conversation between Shiva and Parvati, uses a person’s own urine as medicine. Nobody could name urea back then, yet the tradition found it by feel. It is a pattern I keep running into: a tradition works out over centuries that something helps, science isolates the compound, patents a cream and sells it back, and then laughs at the tradition that found it.
Sterile? Not Quite
For a century, medical orthodoxy held that fresh urine from a healthy person is sterile, and modern sequencing has shown that to be wrong. The bladder has its own microbiome, and adult urine is not sterile. Standard urine cultures miss most of what lives there, which is why the old belief lasted so long. Catheter samples that bypass the outside still grow bacteria, so the organisms are coming from the bladder itself, and on the way out urine passes through the urethra and over the skin, picking up more. That caught my attention, because it is the lesson the soil keeps teaching me: wherever we look, there is a living community we didn’t know about. For intact skin it barely matters. For an open wound it matters a great deal, because the wound is a direct route into tissue.
So why did it work on the battlefield? Because of what it was being compared against. A soldier with a wound and no clean water had ditch water, river water, a dirty rag or his own urine, and against those, urine wins. It is warm, roughly the right salinity, carries urea and hasn’t been sitting in mud. It was never being compared with saline and a sterile dressing, because he had neither. The same reasoning sits behind the jellyfish sting and athlete’s foot folklore. In these cases, the person had no alternative.
For hard skin, cracked heels, calluses, fungal nails and psoriasis plaques, a urea cream gives a known strength with no smell, no mess and no bacteria. I would use 10% for maintenance and 20 to 40% for hard skin. For an open wound, clean water and proper wound care come first, and if dead tissue needs removing, 40% urea exists for exactly that and is sterile in the tube. If you are in a survival situation with nothing else, the old answer still applies, because urine is the cleanest fluid you have. Get proper treatment as soon as you can, and remember that tetanus, not the fluid you washed with, is what kills people in that scenario. So take the urea and leave the bacteria.
Reading the Signals
So what is that stream telling us day to day? Color is the first clue. Pale yellow to straw is the sweet spot, dark yellow or amber means it is time for water, and completely clear means we could ease off. Orange, pink, red or brown can be carrots, vitamins, medications or beets, but if nothing we ate explains it, get it checked. Smell works the same way. Strong ammonia is usually dehydration and asparagus is harmless, while a foul smell, a sweet fruity smell, persistent foam or cloudiness deserves some attention.
Where Does It All Go?
Back to the question that has been nagging at me. If I can see fibrin, platelets, crystals and what looks like leftover protein floating in the plasma, where does it all go? My first guess was that it simply gets flushed out through the kidneys. It turns out the kidneys are far choosier than that, and the real story is less like a drain and more like a garden’s recycling system.
Think of the kidney as a bouncer at a very exclusive club. Water, salts, urea, creatinine and dissolved uric acid are small enough to get in and head for the urine. Blood cells, platelets and big proteins get turned away and stay in the bloodstream. That is why protein showing up in the urine is worth noticing. It means something got past the bouncer that should have stayed in.
So who deals with everything the bouncer won’t let out? A crew of decomposers, and this is where my soil brain gets excited. In the garden, dead plant material is eaten and recycled by bacteria, fungi and protozoa. In the body, the recyclers are macrophages, a name that literally means “big eaters.” They patrol the spleen, the liver and the lymph, swallowing worn-out or damaged material and breaking it into parts the body can reuse.
Take a platelet. It is a tiny fragment of a cell, made in the bone marrow, that lives for only about 7 to 10 days. When it is spent, macrophages in the spleen and liver engulf it. Nothing goes out in the urine. It gets composted.
Fibrin is even more fun. When we are injured, the blood weaves a net of fibrin threads to plug the gap, a bit like a fishing net. Once the repair is done, the body calls in an enzyme called plasmin, a pair of molecular scissors that cuts the net into small fragments for the liver and spleen to mop up. Labs can actually measure some of those fragments, one of them called D-dimer, which gives us a measurable marker for what I may be glimpsing under the microscope.
Uric acid is the one most obviously headed for the toilet, and even it takes two routes. About two thirds leaves through the kidneys, and about a third goes out through the gut, where intestinal bacteria help break it down. That made me smile, because it ties my microscope straight back to the microbiome. Crystals aren’t permanent either. If hydration, pH or concentration shift, they dissolve back into the fluid, rather like sugar stirred into tea. If they don’t, macrophages try to eat them, and that tussle between the big eaters and the crystals is how the inflammation of gout begins.
Then there is the gut, the garden gate. Long dietary proteins are chopped into single amino acids and short chains called peptides before they are absorbed, so whole undigested protein shouldn’t be wandering around the bloodstream. Everything absorbed from the gut travels by the portal vein straight to the liver, which works like a checkpoint. Kupffer cells, the liver’s own big eaters, and detox pathways screen the arrivals. A healthy gut lining, fed by butyrate from fibre fermentation, keeps most unwanted material out in the first place. Fermentation isn’t waste either. It produces short-chain fatty acids that the body burns as fuel.
So it is less a drain and more a team: the kidneys, liver, gut, spleen, lymph and the big eaters, all working together. Many traditional systems described cleansing in much the same way, and I love how neatly the biology fits.
Urine Under the Microscope
A typical urine test starts with a look at color and clarity, then dips a strip into the sample to check concentration, pH, protein, glucose, ketones, blood, bilirubin and a couple of markers that hint at infection. Then comes the part I find most exciting. A drop of the spun-down sediment goes under the microscope. I am looking to purchase that spinner machine.
So, what is in that drop is a little village of characters. There are red and white blood cells, cells shed from the lining of the urinary tract, bacteria and yeast, tiny tube-shaped moulds called casts that form inside the kidney, and crystals in all sorts of shapes. Uric acid crystals are yellow to reddish-brown rhomboids, barrels and rosettes, and they love acidic, concentrated urine, so they turn up after purine-rich meals like red meat, shellfish or beer, or when a sample cools before anyone looks at it. Calcium oxalate crystals look like tiny envelopes, and triple phosphate crystals look like coffin lids.
I see many of the same characters in live blood, so can the parts and pieces be compared? I am learning and I think the answer is yes, and partly. Red cells, white cells, yeast-like forms and bacteria are the shared cast, and watching how they look in both fluids is a wonderful way to learn. The catch is that the two fluids are very different stages. Blood is living tissue held at a tightly controlled pH of around 7.4, so what we see is mostly the cells themselves. Urine is a collecting bin that swings from acidic to alkaline and from very dilute to very concentrated, so much of what appears, especially crystals, tells us about the urine itself, its pH, its concentration, its freshness and what we ate yesterday. Even red cells change shape in urine, swelling when it is dilute and shrinking when it is concentrated. And a uric acid crystal in urine isn’t automatically a clue about uric acid in the blood, where it is mostly dissolved and tends to crystallise only where it concentrates, such as in the joints or kidneys.
A drop of blood also starts clotting the moment it meets the slide, so fibrin strands and crystal-like shapes can form on the slide itself as it cools and dries. That makes me want to watch the same drop at different times, right away, after five minutes and after fifteen, to see which shapes belong to the body and which are made by the slide. Then I want to go further and look at fresh urine and live blood from the same person on the same day, noting the urine’s pH and concentration, and see what changes after hydration, after a purine-rich meal and after a fast. If the pattern shifts in step with something we can measure, like urine pH or a blood uric acid test, we have learned something real. Live blood interpretation is more of an art than a lab standard, so I would treat any match as a clue rather than an answer.
When I get the time (ya right!), this is where I am heading. I want to go beyond what orthodoxy tells us, but with one foot always in what we can measure, so the microscope earns its place. Urine isn’t glamorous, but it is honest, and I keep finding that the things we overlook, whether it is the dirt under our feet or the stream we flush away, are full of information once we start paying attention.
