Swollen ankles in the evening, rings that feel tight, that feeling of “holding water”. Fluid retention is one of the most common complaints, especially among women. Most of the time it is caused by everyday habits, such as salt and standing for long hours. Sometimes, however, it is a sign that needs a doctor. In this guide you will find the most common causes, what helps in your diet and 7 things worth knowing.
What fluid retention is
Fluid retention (or oedema) is the build-up of fluid in the tissues, which causes swelling. It usually appears in the ankles, feet and lower legs, more rarely in the hands or face. It is often mild and goes away on its own.
Fluid retention at a glance
| Question | Answer |
|---|---|
| Where does it show? | Usually in the ankles, feet and lower legs. |
| Common causes | Too much salt, many hours standing or sitting, heat, hormonal changes, certain medicines. |
| Salt | The WHO recommends less than 5 g of salt a day (about one teaspoon). |
| Water | Don't cut it out. EFSA considers about 2 litres of water a day in total, from drinks and food, adequate for women. |
| When to see a doctor? | If the swelling is sudden, severe, in one leg only or comes with shortness of breath (see below). |
The most common causes
| Cause | What happens |
|---|---|
| Too much salt | Sodium “pulls” water. Most salt does not come from the salt shaker but from processed foods, bread, cold cuts, snacks and sauces. |
| Standing or desk job | When we stay still for many hours, fluid collects in the legs. |
| Heat | Blood vessels dilate and the legs swell more easily. |
| Hormones | Many women feel swollen in the days before their period. It also happens in pregnancy. |
| Medicines | Some blood pressure medicines, contraceptives, hormone therapy, cortisone and some antidepressants. |
| Medical causes | Varicose veins, thyroid, heart, kidney or liver problems, a blood clot. These need a medical assessment. |
What helps in your diet
- Less salt: cook with herbs, lemon and spices. Check labels for sodium.
- More fruit and vegetables: they are natural sources of potassium.
- Pulses, yoghurt, potatoes, tomatoes, bananas, leafy greens: they provide potassium and magnesium.
- Enough water: the idea “I drink less so I don't retain water” is not true.
- Fewer ready meals: they are the biggest “hidden” source of salt.
Electrolytes: potassium and magnesium
Potassium and magnesium are electrolytes, i.e. minerals involved in fluid balance and muscle function. There are authorised health claims for them (EU Regulation 432/2012):
| Nutrient | Authorised claim |
|---|---|
| Magnesium | Contributes to electrolyte balance, to normal muscle function and to a reduction of tiredness and fatigue. |
| Potassium | Contributes to the maintenance of normal blood pressure and to normal muscle function. |
| Vitamin B6 | Contributes to normal energy-yielding metabolism, to normal functioning of the nervous system and to the regulation of hormonal activity. |
Their first source is always your diet. For more, see our article on magnesium.
The Water Away is a food supplement in plant-based capsules with potassium, magnesium, vitamin B6 and 10 plant ingredients, such as alfalfa, dandelion, parsley and celery seed. Take 1 capsule with each main meal, up to 3 capsules a day. Its authorised claims relate to magnesium, potassium and vitamin B6, as shown in the table.
Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle.
7 things worth knowing
| What to know | Why |
|---|---|
| 1. Raise your legs | When you can, rest your legs on a chair or cushion. |
| 2. Walking | Movement helps circulation. Take breaks if you work standing or sitting. |
| 3. Comfortable shoes and clothes | Avoid tight shoes, socks and clothes. |
| 4. Salt is hidden | Bread, cold cuts, cheese, snacks and sauces provide most of it. |
| 5. Don't cut down on water | The body needs fluids. Dehydration does not solve the problem. |
| 6. Scales vs body fat measurement | “Water” changes the scale reading from day to day. A body fat measurement shows water, fat and muscle separately. |
| 7. Don't stop medicines | If you suspect a medicine is to blame, talk to your doctor first. |
When to see a doctor
- Immediately: if the swelling comes with shortness of breath, chest pain or tightness, palpitations or dizziness, call 166 or 112.
- Soon: if only one leg is swollen for no known reason, if the swelling is severe, painful or sudden, if the area is red and warm or you have a fever, if your face or abdomen is also swollen, or if you have diabetes.
- Scheduled appointment: if both legs are swollen and you don't improve after a few days, or if you already have a heart, kidney or vein problem.
Read also
Find out more about magnesium, metabolism and probiotics and prebiotics. For a personalised programme, you can book an online appointment or start with the Digital Diet.
Frequently asked questions
What causes fluid retention?
Usually too much salt, many hours of standing or sitting, heat and hormonal changes. More rarely it is due to medicines or a health problem.
If I drink less water, will I retain less fluid?
No. The body needs enough fluids. The most important thing is to reduce salt.
Which foods help?
Fruit, vegetables, pulses and yoghurt, which provide potassium and magnesium, and fewer processed foods.
Why do I swell before my period?
The hormonal changes of the cycle affect fluid balance. It usually passes once the period starts.
When should I worry?
When the swelling is sudden, severe, in one leg only or comes with shortness of breath, chest pain or fever.
Do supplements solve fluid retention?
No supplement replaces cutting down on salt, moving more and a medical assessment when needed. Supplements with potassium and magnesium have authorised claims only for what is listed in the table.
Sources
- Regulation (EU) 432/2012 – List of authorised health claims.
- NHS. Oedema (swelling).
- World Health Organization. Sodium reduction – Fact sheet.
- EFSA NDA Panel. Scientific Opinion on Dietary Reference Values for water. EFSA Journal, 2010.
This article is for information purposes and is not a medical diagnosis, nor does it replace a doctor’s advice.
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