Do alkaline diets really work?

According to alkaline nutrition theory, you would have to eat about four times the amount of vegetables or fruits to balance out the acid load from digesting a steak. — dpa

We're constantly questioning what kind of diet is best for our health.

Sometimes, the focus is on the harmful effects of too much sugar or fat, or on the amount of animal products we should or shouldn’t eat.

Something that usually doesn’t get much attention is how, if at all, diet affects our body’s acid-base balance.

But some nutritionists maintain that the typical diet in many societies causes an overacidification of the body that can lead to health problems.

Nutritionist and author Juergen Vormann, founder and head of the Munich-based Institute for Prevention and Nutrition in Germany, calls this latent acidosis, i.e. a non-measurable degree of overacidification in which blood pH, kept slightly alkaline by the body in a process known as acid-base homeostasis, becomes less so than normal.

The culprit, according to Vormann, is our protein-rich diet, as foods with a high protein content form acids when metabolised.

We counter this acidity with alkaline-forming foods such as vegetables and fruit, but unfortunately eat too little of them, he explains, so our kidneys have to excrete the excess acids.

”Kidney function begins to decline at about the age of 30,” he says, adding that the kidneys lose about 1% of their capacity to excrete acids per year thereafter.

The body has no problem excreting excess alkalis though, he says.

Meat, fish and dairy products are metabolised into acids, as are noodles and other grain products.

Cheese, particularly hard cheeses such as cheddar and Parmesan, as well as processed cheese, are particularly acid-forming.

Oils and fats are neutral in their metabolic reactions.

Vegetables and fruit are among the foods that are alkaline-forming.

Fennel and spinach, for example, stand out in this regard.

As for fruit, the alkaline effect is greatest from dried figs and raisins, as well as bananas, black currants and kiwi fruit, says German Nutrition Society (DGE) spokeswoman Antje Gahl.

”We don’t recommend a special alkaline diet since the body’s acid-base balance is regulated automatically and healthy people have no cause to worry about serious disorders from eating certain foods,” she says.

She adds that the DGE does, however, recommend a plant-rich diet, which incidentally will help reduce acid formation.

DGE guidelines call for five portions of vegetables and fruit daily, and no more than 300g to 600g of meat and meat products weekly.

Not only is latent acidosis non-measurable, according to Vormann, its symptoms are also nonspecific, including fatigue, pain for no apparent reason, or changes to the skin or nails.

So all that you can do is to see if your wellbeing improves by eating more vegetables and fruit, instead of meat, dairy products and grains, which would entail a fundamental change of diet for many people.

”When you eat 100g of steak, your body needs 400g of vegetables to neutralise the acid load,” remarks Vormann, who has authored a book on alkaline foods.

He says it doesn’t matter whether you eat vegetables raw or steamed so long as you don’t cook them “to death”.

”We need protein, there is no question about that,” he emphasises.

”But we should eat plenty of alkali-forming foods to offset it.” – By Elena Zelle and Tim Obojski/dpa