Water Retention: What Is It and How Can I Avoid Water Retention?

Water retention, also known as fluid retention refers to an..

Water Retention: What Is It and How Can I Avoid Water Retention?

Water retention, also known as fluid retention refers to an excessive build up of fluid in the circulatory system, body tissues, or cavities in the body.

Up to 70% of the human body consists of water – water exists both inside and outside our body’s cells. Blood is mostly made up of water, as are our organs and muscles.

A complex system of hormones and prostaglandins (hormone-like substances) is used by the human body to regulate water levels.

This means that excess water intake can be resolved by the kidneys quickly excreting the excess fluid in the form of urine.

Likewise, reduced hydration on another day can result in a decreased urine output than usual.

Up to 70% of our body is water:

  • Muscle is made up of approximately 75% water
  • Fat consists of about 50% water
  • Bones are made up of about 50% water.


Causes of water retention

Water retention can occur in many different areas of the body and for differing reasons. We will look at these individually.


Fluid (liquid) rich in nutrients, vitamins and oxygen continuously passes from tiny blood vessels (capillaries) into surrounding tissues – this fluid is known as interstitial fluid (tissue fluid). Interstitial fluid nourishes cells and eventually makes its way back to the capillaries.

Water retention may occur if pressure inside the capillaries changes.

Water (fluid) retention is also possible if something occurs that makes the capillary walls too leaky.

If something goes wrong with capillary pressure or capillary wall permeability (wall becomes too leaky), excess liquid (fluid) will be released into the tissue spaces between cells.

If too much fluid is released more and more of it will remain in the tissues, rather than returning to the capillaries, resulting in swelling and water logging (water retention).

The lymphatic system

The lymphatic system, which consists of a network of vessels throughout the body, drains lymph (a fluid) from tissues and empties it back into the bloodstream.

However, if too much fluid is released in the first place the lymphatic system can be overwhelmed – it is unable to return fluid fast enough, and it accumulates around the tissues (fluid retention).

Sometimes, if the lymphatic system is congested, there may be something wrong with the rate at which fluid is returned back into the bloodstream.

This means that fluid can remain in the tissues, causing swelling in various parts of the body, including the abdomen (ascites) or ankles, legs and feet (edema).

Diagram of the lymphatic system
The lymphatic system is a network of vessels that carry a clear fluid called lymph.

The heart

Normal pressure within blood vessels is partly maintained by the pumping force of the heart. However, if the heart starts to fail (congestive heart failure), there will be a change in blood pressure, which often results in serious water retention.

Typically, the legs, feet and/or ankles will swell. Fluid will also build up in the lungs, giving the patient a chronic (long-term) cough.

Congestive heart failure can eventually cause breathing problems, as well as excessive stress on the heart. The patient will probably be prescribed diuretics.

A diuretic is anything that promotes the formation of urine by the kidney – in other words, anything which helps the body shed water.

The kidneys

Our kidneys carry out the complex system of filtration in our bodies – excess waste and fluid material are removed from the blood and excreted from the body.

Our kidneys get their blood and oxygen supply from the renal arteries, which are branches of the abdominal aorta (another artery).

When it enters the kidneys, blood goes through smaller and smaller blood vessels – the smallest ones being the glomeruli (tiny capillary blood vessels which are arranged in tufts).

It is in the glomeruli that blood is filtered – waste, fluids and other substances are extracted and cross into miniscule tubules, from which the bloodstream reabsorbs what the body is able to reuse.

What the body cannot reuse – waste – is excreted in our urine.

In most cases our kidneys are able to eliminate all waste materials that our body produces.

However, if the blood flow to the kidneys is affected, or the tubules or glomeruli are not working properly because of damage or disease, or if urine outflow is obstructed, problems can occur.

Including kidney failure – then waste material, including fluids, cannot be eliminated (shed) from the body properly, resulting in fluid retention.


The weight of the uterus on the major veins of the pelvis can cause a buildup of fluid in the body during pregnancy.

In most cases it is nothing to worry about and generally resolves after the baby is born.

Physical inactivity

Physical activity (exercise) helps the leg veins return blood to the heart (against gravity).

If the blood does not travel fast enough it will begin to accumulate in the legs, resulting in higher pressure in the capillaries.

Fluid will leave the capillaries at a higher rate because of the higher pressure.

The higher pressure also makes it harder for fluids to come back later on.

Eventually, some capillaries may break; leaving small blood marks under the skin, and the veins can become swollen and distorted (varicose veins).

Long haul flights can increase your risk of water retention.

Exercise is also needed to stimulate the lymphatic system to fulfill its function of regulating overflow – bringing fluids back into the bloodstream at rates which may regulate body water levels.

Very long periods of physical inactivity, such as a long-haul flight, increase the risk of water retention.

During a long-haul flight, even minor physical movements, such as standing on tiptoes and down a few times, rotating the ankles and wiggling the toes can help reduce fluid retention.


Humans require a certain level of proteins for effective water balance.

An individual with severe protein deficiency may find it harder to get the water from the tissue spaces back into the capillaries.

The enlarged abdomens of seriously malnourished and/or starving people are mainly caused by a lack of protein in their diet.


When an inflammation is present in the body, histamine is released.

Histamine causes the gaps between the cells of the capillary walls to widen, making them more leaky.

The aim is to make it easier for infection-fighting white cells to quickly get to the site of an inflammation (infection).

However, if the inflammation persists for a long time, water retention can become chronic (long-term).


Some medications can cause water retention, including:

  • Estrogen-containing drugs, such as the combined oral contraceptive pill, or HRT (hormone replacement therapy).
  • NSAIDs (non-steroidal anti-inflammatory drugs) – medications with analgesic (pain reducing), antipyretic (fever reducing) effects. In high doses they are actually effective in reducing inflammation. Examples include aspirin, ibuprofen and naproxen.
  • Beta-blockers – used to treat abnormal heart rhythms and prevent tachycardias.


Pre-menstrual water retention

This causes bloating and can cause breast tenderness.

Experts say it is due to hormone imbalances, and also some nutritional factors.

Premenstrual refers to the second half of the woman’s menstrual cycle (during the days or the week or so before her period begins).

Salt (sodium)

Sodium-rich foods may cause water retention.

Malnutrition and/or bad diet

Dieticians say low consumption of thiamine (vitamin B1), as well as insufficient vitamins B6 and B5 may contribute toward fluid retention.

Low levels of albumin levels may also play a part – low albumin levels can also be caused by kidney disease.


Some foods and insect bites may cause edema in susceptible people.

Thyroid disease

People with a disorder of the thyroid gland can commonly experience water retention.

6 Simple Ways to Reduce Water Retention

Water retention occurs when excess fluids build up inside the body.

It is also known as fluid retention or edema.

Water retention occurs in the circulatory system or within tissues and cavities. It can cause swelling in the hands, feet, ankles and legs.

There are several reasons why it happens, many of which are not serious.

Some women experience water retention during pregnancy or before their monthly period.

People who are physically inactive, such as when bedridden or sitting through long flights, may also be affected.

However, water retention can also be a symptom of a severe medical condition like kidney disease or heart failure.

If you’re having sudden or severe water retention then seek medical attention immediately.

But in cases where the swelling is mild and there is no underlying health condition, you may be able to reduce water retention with a few simple tricks.

Here are 6 ways to reduce water retention.

1. Eat Less Salt

Salt is made of sodium and chloride.

Sodium binds to water in the body and helps maintain the balance of fluids both inside and outside of cells.

If you often eat meals that are high in salt, such as many processed foods, your body may retain water. These foods are actually the biggest dietary source of sodium.

The most common advice for reducing water retention is to decrease sodium intake. However, the evidence behind this is mixed.

Several studies have found that increased sodium intake leads to increased retention of fluid inside the body.

On the other hand, one study of healthy men found that increased sodium intake did not cause body fluid retention, so this may depend on the individual.

2. Increase Your Magnesium Intake

Magnesium is a very important mineral.

In fact, it is involved in more than 300 enzymatic reactions that keep the body functioning.

Moreover, increasing your magnesium intake may help reduce water retention.

One study found that 200 mg of magnesium per day reduced water retention in women with premenstrual symptoms (PMS).

Other studies of women with PMS have reported similar results.

Good sources of magnesium include nuts, whole grains, dark chocolate and leafy, green vegetables. It is also available as a supplement.

3. Increase Vitamin B6 Intake

Vitamin B6 is a group of several related vitamins.

They are important for the formation of red blood cells, and they also serve many other functions in the body.

Vitamin B6 has been shown to reduce water retention in women with premenstrual syndrome.

Foods rich in vitamin B6 include bananas, potatoes, walnuts and meat.

4. Eat More Potassium-Rich Foods

Potassium is a mineral that serves several important functions.

For example, it helps send the electrical signals that keep the body running. It may also benefit heart health.

Potassium appears to help reduce water retention in two ways, by decreasing sodium levels and increasing urine production.

Bananas, avocados and tomatoes are examples of foods that are high in potassium.

5. Try Taking Dandelion

Dandelion (Taraxacum officinale) is an herb that has been used as a natural diuretic in folk medicine for a long time.

Natural diuretics may help reduce water retention by making you pee more often.

In one study, 17 volunteers took three doses of dandelion leaf extract over a 24-hour period.

They monitored their fluid intake and output during the following days, and reported a significant increase in the amount of urine produced.

Although this was a small study with no control group, the results indicate that dandelion extract may be an effective diuretic.

6. Avoid Refined Carbs

Eating refined carbs leads to rapid spikes in blood sugar and insulin levels.

High insulin levels cause the body to retain more sodium by increasing re-absorption of sodium in the kidneys.

This leads to more fluid volume inside the body.

Examples of refined carbs include processed sugars and grains, such as table sugar and white flour.

Other Ways To Reduce Water Retention

Reducing water retention is something that hasn’t been studied much.

However, there are a few other potentially effective ways to reduce water retention.

Keep in mind that some of these are only supported by anecdotal evidence, not studies.

  • Move around: Simply walking and moving around a bit can be effective at reducing fluid build-up in some areas, such as the lower limbs. Elevating your feet can also help.
  • Drink more water: Some believe that increasing water intake can paradoxically reduce water retention.
  • Horsetail: One study found that the horsetail herb has diuretic effects.
  • Parsley: This herb has a reputation as a diuretic in folk medicine.
  • Hibiscus: Roselle, a species of hibiscus, has been used in folk medicine as a diuretic. A recent study also supports this.
  • Garlic: Well known for its effect on the common cold, garlic has historically been used as a diuretic.
  • Fennel: This plant may also have diuretic effects.
  • Corn silk: This herb is traditionally used for the treatment of water retention in some parts of the world.
  • Nettle: This is another folk remedy used to reduce water retention.
  • Cranberry juice: It has been claimed that cranberry juice can have diuretic effects.

Daniel Messer, RNutr, CPT

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