Kidney Disease And Hydration

Kidney disease occurs when the kidney loses its ability to properly filter blood. Damage to the kidneys disrupts their filtration capacity, causing waste and fluid to build up in the body. 

Staying hydrated is important for proper kidney function as drinking water helps the kidneys remove excess waste through urination. Insufficient fluid intake can therefore adversely affect the kidneys’ filtration function. Frequent dehydration may eventually lead to serious, permanent kidney damage.

What is kidney disease?

The kidneys consist of millions of specialised filtration units called nephrons, which help eliminate body waste and excess fluid. The kidneys also create hormones to control blood pressure and maintain a healthy balance of water and electrolytes in the bloodstream. 

When the kidneys are damaged, the body’s fluid and electrolyte balance is significantly altered. This can lead to the accumulation of  fluids and other toxic substances inside the body.  

Kidney diseases can be progressive and they are more common than one may expect. According to Kidney care UK, nearly 3.5 million people in the UK are affected by chronic kidney disease.

Kidney disease is categorised into two main types:

• Acute kidney injury: Also known as acute renal failure, which involves a sudden loss of kidney function. The injury is generally short-term with chances of full recovery. However, if the damage is extensive, it may lead to a higher risk of developing lifelong chronic kidney disease.¹

• Chronic kidney disease (CKD): Here there is gradual loss of kidney function. The condition progresses over time, reducing the kidney’s filtration ability and damaging renal tissues in an irreversible manner. A study showed that CKD affects more than 10% of people worldwide. It is more prevalent in older individuals, people assigned female at birth, and people with other risk factors such as family history of kidney disease, diabetes, and high blood pressure.²

Other common kidney diseases include:

• Polycystic Kidney Disease (PKD): This is an inherited condition characterised by the formation of clumps of fluid-filled cysts within the kidneys, resulting in kidney enlargement. PKD cysts slowly progress to damage most of the kidneys, leading to renal failure. One study found that increased supplemental fluid intake reduced the rate of renal cyst growth in PKD animal subjects.³

• Kidney stones: Also called renal calculi are the tough deposits of minerals and salts that accumulate inside the kidneys. There are several causes of kidney stones, including poor diet, obesity, and certain medications. Severe dehydration can predispose to kidney stone formation because it enables minerals to crystallise and clump together.

• Kidney infections: Medically known as pyelonephritis, this is a type of urinary tract infection (UTI) that can occur in any part of the urinary tract. Such infections can affect the kidneys if they travel upwards from the urinary bladder or urethra to the kidneys.

• Kidney Cyst: A simple kidney cyst is a fluid-filled pouch. These cysts differ from those in PKD, where numerous cysts  damage the kidneys. The exact cause of simple kidney cysts is still unknown. However, many researchers believe that kidney damage or injury may be one of the causes.

• Kidney cancer: Also called renal cancer, is when kidney cells become malignant and start to proliferate in an abnormal way. The World Cancer Research International Fund statistics showed kidney cancer (renal cell adenocarcinoma) as the 14th most common cancer worldwide.

Symptoms of kidney disease

The symptoms of kidney disease may include:

• Swelling of the ankles, feet, and/or face – due to extra fluid build-up.
• Shortness of breath or chest pain – if excess fluid builds inside lungs.
• Changes in urine output.
• High blood pressure.

Uremia, which literally means urine in the blood is caused by the kidney’s inability to excrete toxic substances. Uraemia is responsible for the following symptoms of kidney disease:

• Upset stomach or vomiting.
• Loss of appetite.
• Extreme fatigue and weakness.
• Muscular spasm.

Why is staying hydrated so important?

Like all other organs, the kidneys also need water to function properly. They play a vital role in keeping the blood clean and chemically balanced. They efficiently filter waste material through tiny specialised tubes called renal tubules, which help to retain necessary substances such as vitamins, minerals, salts, and other nutrients by reintroducing them into the bloodstream and eliminating the residues from the renal tubules in the form of urine.

Sufficient water intake can aid the kidneys in stabilising the pH and salt composition, which is necessary for the effective functioning of all body cells and potentially lowers the risk of developing kidney diseases.

Staying hydrated with kidney disease

Drinking plenty of water is one of the healthiest choices you can make. Water aids in the elimination of waste, and ensures adequate renal blood flow. It can also prevent the formation of kidney stones and urinary tract infections (UTIs).

If you have already been diagnosed with kidney disease, speak to your healthcare provider about how much fluid you require; as some kidney conditions require fluid restriction.

Recommended daily water intake

One of the best ways to keep your kidneys healthy is to maintain hydration. Drinking sufficient amounts of water on a regular basis is an important factor in kidney health. Dehydration  can worsen kidney disease due to buildup of toxic substances.

It is recommended to drink at least ten glasses of water for people assigned male at birth and 8 glasses of water (200 mL each) for people assigned female at birth on a daily basis. However, there are no set rules, since daily intake may vary depending on various environmental and physical conditions. 

Benefits of staying hydrated

Staying well hydrated can improve kidney function, reducing the risk of further complications.

Good hydration is essential for preventing kidney stones and urinary tract infections. Drinking plenty of water can flush out small kidney stones and help eliminate toxic waste. Water ensures increased urine production and reduces urine concentration, both of which aid in eliminating infection-causing bacteria.

The kidneys produce more concentrated urine under low hydration conditions, which may contribute to kidney damage. Sufficient water intake is therefore beneficial to the kidneys.⁴

Conclusion

Kidney disease can be a progressive and serious condition. Any damage to the kidneys can disrupt renal function and the body’s chemical balance. Hydration is essential for normal kidney function; it aids in removing toxic waste through the urine. 

Dehydration can cause fatigue, and impaired kidney function. Severe dehydration may lead to kidney failure. For optimal kidney health, it is recommended that you drink sufficient amounts of water.  

One way to tell if you are drinking enough water is by monitoring the appearance of your urine, dark urine may be a pointer towards insufficient fluid intake. Speak to your healthcare provider today about how much water you should be drinking.