“Drink adequate water to keep your kidneys healthy!” — Now that’s a piece of time-tested health advice, right? But then how does it work?
The internet and medical literature, in general, is filled with ample advice on drinking adequate water for good kidney health. Usually, you will find pearls of advice urging you to drink at least 8 glasses of water daily for optimum health benefits. To be factually correct, it is your total liquid intake throughout the day that matters. This could be in the form of water, juices, smoothies, milk or other non-alcoholic beverages or even soups and broths that you take throughout the day (We specify the term “non-alcoholic” here because although liquid, alcohol is a major dehydrator).
However, we all know how plain, drinking water always forms the mainstay of retaining an optimum hydration status.
So, what is it about plain water that makes it the “drink of choice” to quench thirst in the truest sense?
And how exactly does drinking more water keep your kidneys healthy?
Hint: It has got nothing to do with “flushing” your kidneys
Can increasing water intake slow down the progression of chronic kidney disease? What does the latest research suggest?
These are the areas that this article today aims to delve into.
But first things first.
WHY DOES PLAIN WATER “DOMINATE” THE “HYDRATION SCENE”
We have mentioned above how it is about your overall daily fluid intake (and not just water), that matters when it comes to hydration. However, drinking water will always remain the best way to quench your thirst. And it has a good enough biochemical basis for it too.
You see, all liquids are designated a number representing it’s “osmolality“, that is basically a measure of how particle-loaded, a certain liquid is. By this logic, both blood plasma (the liquid part of the blood), as well as beverages, have their Osmolality numbers.
The closer the osmolality number of a consumable liquid to that of blood plasma, the better it is to quench our thirst. Plain drinking water has an osmolality ranging between 290-310 milli-Osmols per kg. This is pretty close to the corresponding number for Blood Plasma 275-295 milli Osmol/kg.
Hence Water helps quench thirst most efficiently.
The more particles come in, such as Sodium & Sugar in your average Soda or say fruit sugars and minerals in juices, the higher their Osmolality numbers climb and the poorer their “true hydration capacity” becomes. In a nutshell, 1 glass of Water would hydrate you more efficiently than 1 can of Soda or fruit juice.
Now that we understand this part, let’s dissect how improving your hydration status could prove to be “Tender Loving Care” for your Kidneys.
HOW DOES WATER HELP KIDNEY HEALTH?
1. PREVENTS DIRECT “MECHANICAL” DAMAGE TO DELICATE KIDNEY FILTERS
Whatever we take in anything by our mouth, it enters the bloodstream. So, when you drink more water than your usual intake, the water content in your blood increases proportionately too. As the picture above shows, a well-hydrated bloodstream allows your blood cells and other particle components to flow freely. This prevents the mineral salts, proteins and other tiny particles normally present in the bloodstream to “jostle for space”, make the blood flow sluggish and cause any potential “mechanical” micro-damages to the delicate filtration units of kidneys! Nobody likes the “Rush Hour” at King’s Cross (London) anyway, right?
2. PREVENTS THE FORMATION OF KIDNEY STONES
Dehydration or low water content in the bloodstream relatively increase the “overall load” from all the blood cells, mineral salts and blood proteins normally floating in the bloodstream. This makes the blood flow relatively sluggish. As a direct impact, when such blood filters into the kidney for urine formation, it courses through our tiny kidney tubes “lazily” as well. In such a scenario, the mineral salts in the urine get ample time to decide on a “fine piece of real estate” within our kidney tubes and tend to “settle down” along with the various twists and turns of our kidney tubes. Over time, these can solidify and form kidney stones.
Increasing water intake literally “flushes” even the remotest areas of the kidney tubes & removes the possibility of these minerals clumping together. Hence, it serves as an effective means to ward-off those painful kidney stones from forming.
Further, even if tiny kidney stones do form, increasing your water intake can help you pass those in your urine without any additional meds PROVIDED these stones are less than 0.5 centimeters in diameter. Stones larger than that would additionally require stone-dissolving treatments or in some cases, surgery.
3. PROTECTS AGAINST URINARY TRACT & KIDNEY INFECTION
Dehydration turns our blood overtly Acidic. This increases the propensity of mineral salts normally floating in the bloodstream to clump together. As a result, blood acidity serves as a “biochemical boost” for kidney stone formation by precipitation. (Read more here)
Further, abnormally acidic blood also increases our susceptibility to bacterial Urinary Tract Infection (UTI). Wondering how? Well, normal health & a good hydration status ensures a healthy Urine pH range as well. This allows for the production and activity of a protein called “Siderocalin” to guard us against bacterial UTI. High Blood Acidity during Dehydration “spills over” to the Urine making it a lot more Acidic than it should be. This inhibits the formation of new Siderocalin protein and also renders the existing stock inactive. Essentially, this lets bacteria grow and multiply in the urinary tract uninhibited! Such UTI can easily spread upwards to the kidneys via tubes called the Ureters connecting the kidneys with bladder. (Image below)
4. CAN POTENTIALLY EVADE KIDNEY DAMAGE DUE TO HIGH BLOOD PRESSURE
Drinking more water than you usually do curbs the release of a hormone called Vasopressin (also called Anti-Diuretic Hormone) from the brain. This is the precise hormone that normally serves to absorb any excess water from the urine forming within kidney filters to ensure that blood retains just the right amount of “fluidity” that’s optimum for all body functions. Obviously, this is need-based. If the blood feels thinner than necessary, the brain lowers the secretion Vasopressin hormone levels to allow all excess water out of the body via urine. This delicate system makes maintaining the fluidity of blood, a tamper-proof business!
Now, as an adjunct effect, Vasopressin normally causes a transient rise in blood pressure values (certainly within the permissible range) by temporarily narrowing blood vessels. The higher the Vasopressin hormone levels, the greater the BP-raising effect.
With prolonged dehydration, your bloodstream goes desperate for more water from wherever possible. The brain perceives this urgency and secretes Vasopressin hormone by “heaps” to suck-in water from the urine forming within kidney filters. However, if the body is dehydrated, the urine will lack any excess water that can be “loaned” to the bloodstream in need. As a result, all this Vasopressin hormone diverges from its mission to extract water from urine & ends up raising the blood pressure instead. If this goes on for a continuous period of weeks to months, especially with simultaneous kidney disease in place, it will only aggravate the kidney damage and hasten kidney failure. That is obviously undesirable!
Something as simple as drinking more water beyond our usual intake makes our blood more free-flowing than necessary. So, it basically signals our brain to keep a leash on Vasopressin hormone, allows all of the excess water out of the body via urine and also ultimately tones-down the BP-raising effect of Vasopressin hormone. This could potentially offset the development of kidney disease due to sustained, high blood pressure.
So, make sure you drink ample water throughout the day!!
But wait. What counts as adequate water intake in the first place?
Let the illustration below take you through how doctors decide adequate daily water intake for you.
BREAKING THE (WATER) “ADEQUACY CODE”
If you are not already on designated daily water intake limits set by your physician, then the water intake that’s good enough to keep kidney stones away should be your target water intake adjusted to your daily activity levels, the geographical area where you reside and individual general health requirements.
CAN DRINKING MORE WATER IMPROVE DECLINING KIDNEY FUNCTION
We explained above how good hydration is critical to keeping your kidneys healthy. But can it help with slowing down the progression of kidney disease? A million-dollar question, right?
An interesting research study published in the Journal of American Medical Association (JAMA) in 2018 looked at the exact prospect on whether increasing water intake has any positive effect in slowing down kidney disease progression or not.
Going by how water intake and Vasopressin hormone work, this ”Watery Intervention” looked promising as well. In sync with the hopes, a section of healthy volunteers with kidney disease on greater-than-normal water intake did show better BP numbers over the years too. However, the exact number of volunteers who showed this positive effect did not turn out to be significant by statistics to be called a clinical success.
In a nutshell, increasing water intake can potentially keep kidney disease due to renal-induced high blood pressure from setting-in. But if you already have established Chronic Kidney Disease, it is unlikely to become a standalone treatment to effectively slow down kidney failure in the future. However, because we now understand how drinking more water can help retain good BP numbers, it certainly doesn’t harm to ensure good hydration.
Hence, if you are a CKD patient, your doctor would recommend you drink at least 2 Liters of water daily.
This is UNLESS you are:
- Already on Dialysis
- A heart patient or any medical condition that warrants reducing water intake
- On Water Pills
These conditions listed above would require you to tweak your water intake as recommended by your medical team based on individual water retention & general health status.
So, that is how significant something as simple as increasing your daily water intake could prove for your kidney health. It’s relatively inexpensive, DIY and effective too! These are the best kind of health interventions right?!
But just like with all things simple, things that lack fanfare, it is commonplace for many of us to not be sufficiently motivated to actively pursue our daily water intake goals.
🔊 Which is why Team ATK chose to DISSECT why staying well-hydrated can be a boon for kidneys.
Hope reading the article helps you stay motivated about maintaining your daily hydration goals!
Ooh, I’m all thirsty after typing all this heavy-weight water stuff. Gonna go and replenish my beautiful bloodstream with one, no two full glasses of plain drinking water.
And what are you waiting for? Unless you have designated daily water intake limits set by your physician, go get that refreshing drink of water too! Take care all of you.
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