Health Facts and Tips

Stroke Prevention Diet, Eat Less Salt, but More Potassium

The standard advice is to reduce salt intake in the diet to help reduce blood pressure and the risk of stroke.

Recent research has confirmed that sodium itself is NOT the major cause of the problem but the balance between sodium and potassium, which are the major electrolytes in the body.

The others Calcium, Chloride, Magnesium and Phosphorus do not contribute as much.

Sodium and potassium, play a major role controlling water retention in the body, the acidity of the blood (pH), blood pressure, muscle and nerve function, and a host of other body processes.

Recent research has shown that eating an additional 2-3 servings of vegetables or fruit that have high levels of potassium helped lower the risk of stroke, boosting the benefits of having a reduced sodium intake.

Having too little sodium in the diet may itself be harmful.

However, people with kidney problems should lower their potassium intake by eating less of these foods.

This article reviews the research and provides list of foods with naturally high levels of potassium.

Potassium in the Diet - How Much?

Getting enough Potassium is essential as it is required to help maintain fluid and electrolyte balance in the body and tissues. The World Health Organisation recommends that adults have an intake of at least 4g (4,000 mg) of potassium (or 90 to 100mmol) per day, which is a lot.

Potassium deficiency can causes irritability, fatigue and hypertension (increased blood pressure).

Excess potassium, taken as a chemical supplement can be harmful. Unless you have kidney disease, or you are on dialysis, overdosing on potassium from eating natural food sources such as fruit and vegetables is virtually impossible.

Potassium helps to control high blood pressure by maintaining more flexible arteries, and assists with the elimination of excess sodium from the body. Excess Sodium in the diet promotes fluid retention and is one cause of higher blood pressure in many people.

Convenience foods, highly processed foods such as bread and even restaurants foods may not provide sufficient potassium. Home cooked foods make also be deficient in potassium. Boiling or even steaming vegetables depletes potassium within foods. For example, boiling a potato rather than baking with skin on means that almost half the potassium is lost to the water. To preserve potassium people are encouraged to more vegetables and fruit raw, or roasted, stir-fried or lightly steamed, rather than boiled. 

Why the Balance between Sodium and Potassium is Important

The results from a meta-analysis of 22 randomised controlled trials in adults, conducted by researchers at Imperial College London confirmed that increased potassium intake reduces diastolic and systolic blood pressure, significantly.

Higher potassium intake was also shown to reduce the risk of incident stroke, but not of cardiovascular disease or coronary heart disease.

These findings confirmed those of previous similar major studies that diets that increased potassium intake by 42 mMol/day was associated with a 20% lower risk of stroke.

Does a Low Salt Diet Really Lower Blood Pressure?

A separate study on the longer affect of lower salt intake on blood pressure supported these findings. Modest lowering of the amount of salt in the diet for four or more weeks produced significant lowering of the in blood pressure. This applied for men and women and for people with normal and elevated blood pressures. 

The current advice from various health organisations, to halve the average salt intake from 9-12 g/day to about 5-6 g/day, was shown to be effective in lowering blood pressure. However lowering salt intake to 25% of current levels, to 3 g/day, was shown to be more effective, and should be promoted as a health target.

The study found that the combination of reducing salt intake and increasing potassium intake in the diets had boosted impact on blood pressure compared with changing just one of them.

Salt and potassium have opposing effects on the body.

So you can lower your blood pressure by simultaneously reducing your salt intake and boosting potassium-rich foods that you east such as beans, green leaf, vegetables bananas and dates that have very low sodium levels.

How to Reduce Salt Intake in Your Diet

Most people believe that they can lower the salt in their diet by reducing the amount of fast food they eat, and avoiding obviously high salt snack foods such as chips, biscuits, sauces and package soups. However studies have shown that most people get their over-burden of salt from common foods such as bread. processed meats, pasta sauces and soups (see the image below). Makers of processed foods load their products with salt, because the consumers who are addicted to salt think they taste better.

The general principle for lowering salt intake are:

Avoid processed foods - not just junk foods but foods such as white bread and sauces which contribute most salt to the diets of people who eat 'healthy foods". See the image below.

Foods with high salt that should be eaten in moderation include:

• White bread and bread rolls.
• All Pre-packaged condiments and sauces including pasta sauces, soy sauce and most commercial tomato based sauces
• Dehydrated or packet foods, such as instant pasta or soups
• Canned vegetables
• Processed meats, such as sausages, salami, hot dogs and luncheon meats
• Most snack foods, such as potato chips
• Most ‘fast’ foods, such as pizza

The best ways to reduce salt intake in the diet are:

Note: sea salt contains just as much sodium as normal table salt

• Replace salt in cooking by using spices and herbs such as garlic, coriander and oregano, juices such as lime and lemon juice to add a sour taste to meals.
• Always choose ‘salt free’ or ‘low salt’ versions of common foods. such as commercial sauces.
• Buy fresh vegetables rather than canned.
• Eat takeaway and fast foods sparingly.
• Cut back on processed and packaged foods.
• Avoid all foods known to have high salt.
• Choose reduced salt bread and breakfast cereals – bread is a major source of sodium in the diet.
• Avoid adding salt to cooking and at the table.

Foods with the Highest and Lowest Levels of Salt (gm/100g)

The two tables below list the foods with the highest and lowest densities of salt. The 'density' refers to the amount of salt in grams, per 100g serving of the food.

Of course, you are unlikely to eat 100g of Soy sauce at a sitting, but knowing the salt content of a variety of foods helps.

The low salt foods can be used as alternatives or replacements for the high salt ones.

Many of the foods with high potassium, such as the fruits and vegetables listed below, also have very low sodium levels, and so they have dual-action in reducing blood pressure and the risk of stroke.

Foods with the Highest Level of Salt (mg/100g)

Foods with the Lowest Level of Salt (mg/100g)

How Can You Boost Your Potassium Intake with Natural Foods?

The two tables below provide a guide to the natural foods that have the highest levels of potassium. The foods are ranked from high to low and the serving sizes are shown.

Some of the best foods are

• Beet Greens
• Beans, white
• Potatoes
• Beans, Lima
• Squash, Winter
• Soybeans
• Spinach
• Bananas
• Mushrooms
• Avocados
• Fish
• Apricots, dried
• Beans, Pinto
• Beans, baked
• Lentils
• Beans, Kidney
• Prune juice
• Black-eyed peas
• Carrot juice
• Squash

See the Tables for full listings and details

Top Ten Foods with the Highest Level of Potassium

Ranked List of Potassium Rich Foods by Serving Size

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