Alkaline Foods: The Big List at a Glance

In nutritional science, alkaline foods are considered to be above all plant-based foods such as vegetables, salads, many types of fruit, potatoes, herbs, mushrooms as well as some nuts and seeds. The term refers to how a food acts arithmetically in the metabolism, and not to its taste. A predominantly plant-based diet with plenty of vegetables and fruit is regarded as the basis of the so-called alkaline diet. This overview shows you the most important alkaline foods, classifies the concept honestly and gives practical everyday tips.

What is meant by alkaline foods

Behind the division into alkaline and acid-forming is the idea that foods leave different residues in the metabolism depending on their mineral and protein content. Plant-based, mineral-rich foods are mostly classified as alkaline, while protein- and phosphate-rich foods such as meat, cheese and cereal products are rather classified as acid-forming. The thought behind this is that alkaline minerals such as potassium, calcium and magnesium are present in abundant amounts in vegetables and fruit, while sulphur-containing amino acids from protein-rich foods act arithmetically in an acid-forming way. This model calculation is a useful ordering principle, but should not be confused with a direct, measurable effect on the blood pH value. Important for classification: the body keeps the acid-base balance of the blood constant itself within narrow limits via the lungs and kidneys. The food classification is therefore above all an orientation grid for a plant-based diet.

Alkaline foods at a glance

The following foods are listed as alkaline in common tables and are at the same time rich in vitamins, minerals and fibre.

• Vegetables: spinach, broccoli, courgette, carrots, fennel, celery, cucumber, peppers
• Leafy salads: lamb's lettuce, rocket, lettuce, endive
• Potatoes and sweet potatoes
• Fruit: bananas, apples, berries, apricots, melon, grapes
• Herbs: parsley, basil, chives, dill
• Mushrooms such as button mushrooms and chanterelles
• Nuts and seeds: almonds, flaxseed (in moderation)
• Dried fruit such as figs and dates (in moderation)

It is striking that the list corresponds at its core to what is recommended anyway as the basis of a vegetable- and fruit-rich diet. To classify the values, the specialist literature sometimes uses so-called PRAL values, which estimate the arithmetic acid- or base-forming effect of a food. A negative PRAL value stands for a rather alkaline effect, a positive one for a rather acid-forming effect. For everyday life you do not need to know these values: the simple rule of thumb "plenty of fresh vegetables and fruit, plus potatoes and herbs" leads in practice to the same result as the study of individual tables. A common misunderstanding here concerns taste: lemons and other citrus fruits taste sour, but are nevertheless listed as alkaline in many alkaline tables, because what matters is not the taste but the minerals and the arithmetic metabolic effect. Conversely, mild-tasting foods can be classified as acid-forming. Anyone who is guided by such tables should therefore not be misled by the taste.

These foods are considered acid-forming

For orientation, it helps to look at the other side. Frequently classified as acid-forming are meat, sausage, fish, eggs, cheese and other dairy products, cereal and whole-grain products, pulses as well as sugar and heavily processed foods. Many of these foods are nevertheless valuable suppliers of nutrients. An alkaline-based diet therefore does not mean cutting out acid-forming foods completely, but shifting the ratio in favour of vegetables and fruit. Some tables additionally distinguish between "good" and "bad" acid-forming foods: whole-grain products, pulses and nuts provide many valuable nutrients and fibre despite their slightly acid-forming classification, while heavily processed products, sugar and white flour are less favourable in many respects. This distinction shows that a blanket demonisation of whole food groups falls short.

What the concept can achieve and what it cannot

The practical value of an alkaline diet lies less in the pH value than in the result: anyone guided by alkaline tables automatically eats more vegetables, salad and fruit and fewer heavily processed products. There is much to be said, from a nutritional science point of view, for a plant-based diet with plenty of vegetables and fruit. At the same time, the widespread thought that one has to actively de-acidify the body is to be viewed critically from a professional point of view, since healthy kidneys and lungs reliably take on this task. The benefit therefore lies in the dietary pattern, not in a theory of over-acidification. The term "over-acidification" is often used differently in everyday life than in medicine, where a genuine disturbance of the acid-base balance in the blood is a serious, clearly defined clinical picture with medical causes and has nothing to do with the everyday diet of a healthy person. For healthy people the practical consequence is simple and positive: bringing more plant-based variety onto the plate, without having to worry about complicated pH calculations.

Putting alkaline eating into practice in everyday life

A practical rule of thumb is to fill the plate to a larger extent with vegetables, salad and potatoes and to cut back a little on meat and heavily processed products. Include a plant-based component in every meal, reach for fruit or a handful of nuts for snacks and drink enough water or unsweetened tea. As for drinks, water and unsweetened herbal or fruit teas are a good choice, while heavily sugary lemonades and soft drinks should rather take a back seat. A practical idea is the plate rule: about half the plate with vegetables and salad, a quarter with a filling side such as potatoes or whole grains and a quarter with a protein source. Anyone who also shops seasonally and regionally often gets vegetables and fruit fresher and more aromatic, which makes the switch to more plant-based food pleasant. It is not about strict prohibitions, but about a sensible shift of the overall picture towards more plant-based variety.

An alkaline-based day as an example

What this feels like concretely is shown by a simple example day. For breakfast a fruit salad of apple, banana and berries with a few almonds. For lunch baked potatoes with a large colourful salad of leafy greens, cucumber, peppers and carrots, plus a dressing of olive oil and fresh herbs. In the afternoon a handful of grapes or a piece of melon. For dinner a vegetable pan with courgette, fennel, broccoli and mushrooms, supplemented by a smaller portion of whole grains or pulses. Water or unsweetened herbal tea is drunk. Such a day is neither strict nor complicated, but an appetising, filling way of eating that fits well into everyday life and can be varied at will. On this day, plant-based, mineral-rich foods are clearly in the foreground, while acid-forming components keep their place in moderation. It is precisely this weighting that is the practical core of the concept, entirely without complicated calculations.

When a professional classification makes sense

For healthy people, a plant-based diet oriented towards alkaline foods is harmless and fits well with general recommendations. Caution, on the other hand, is advised with commercial offers that present expensive alkaline powders, special alkaline salts or elaborate courses as necessary. Such products are usually not required for a healthy diet, because the beneficial effect comes from the foods themselves and not from a powder. The money is usually better invested in fresh vegetables, fruit and high-quality oils. Very strict alkaline courses or the permanent omission of whole food groups, on the other hand, can lead to one-sidedness. Anyone who has a kidney disease, takes medication or plans a strict course should have this clarified by a doctor beforehand, in order to ensure the supply of all important nutrients. Even with existing metabolic diseases, professional guidance is advisable, rather than relying on blanket alkaline promises. For most healthy people the message remains simple and positive: more vegetables, fruit and herbs on the plate, fewer heavily processed products, and the rest almost takes care of itself.

Frequently asked questions (FAQ)

Which foods are alkaline?

Considered alkaline are above all plant-based foods such as vegetables, leafy salads, potatoes, many types of fruit, fresh herbs, mushrooms as well as some nuts and seeds. They are at the same time rich in vitamins and minerals.

Which foods are acid-forming?

Frequently classified as acid-forming are meat, sausage, fish, eggs, cheese, cereal products, pulses as well as sugar and heavily processed foods. Many of them, however, remain valuable suppliers of nutrients.

Can you de-acidify the body through diet?

Healthy kidneys and lungs keep the acid-base balance of the blood within narrow limits by themselves. The benefit of an alkaline diet therefore lies more in the plant-based pattern than in an active de-acidification.

Is an alkaline diet healthy?

Since it provides plenty of vegetables, salad and fruit and few processed products, it largely coincides with general dietary recommendations. Very strict alkaline courses, however, can lead to one-sidedness.

Do you have to avoid acid-forming foods entirely?

No. It is not about prohibitions, but about shifting the ratio in favour of plant-based foods. Protein sources and whole-grain products remain part of a balanced diet.