What is an alkaline diet?

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An alkaline diet is built on vegetables, fruit, potatoes and legumes and reduces processed food, salt and large amounts of meat. This guide explains what it can do for your health, where its limits are and how to put it into practice. 

Alkaline nutrition: the key to a long life and the fight against chronic diseases?

Nowadays, many people eat in very different ways - some diets are good, others rather bad. The alkaline diet puts fresh plant foods at the center of the plate. 

In 2012, a review published in the "Journal of Environmental and Public Health" looked at the research on alkaline diets, covering topics such as bone health, muscle, back pain and vitamin D. Its author concluded that an alkaline diet may be of value in reducing illness and deaths from chronic diseases and that further studies are warranted (Schwalfenberg, 2012).

How does an alkaline diet work? Eating plenty of fresh vegetables, fruit and unprocessed plant proteins lowers the acid load of the diet and leads to a higher pH value in the urine; the calculated acid load of the day's food predicts the urine pH well (Remer & Manz, 1995). Doctors also use this effect in the diet of people prone to recurrent kidney stones. An alkaline diet also supplies potassium and magnesium, two minerals that many people do not get enough of.

→ You can find our 7-day alkaline fasting plan here (PDF, in German).

What is an alkaline diet?

An alkaline diet focuses on foods that leave few acids behind once the body has broken them down, above all vegetables, fruit, potatoes and legumes. Whether a food has an acid-forming or an alkalizing effect depends mainly on four nutrients: protein, phosphorus, potassium and magnesium (Remer et al., 2003). How sour a food tastes plays no role: fruit and fruit juices taste sour, yet on balance they have an alkalizing effect (Remer & Manz, 1995). All living organisms on earth depend on a certain pH value .

The basic principles of the acid ash hypothesis form the framework of the alkaline diet. According to a study published in the Journal of Bone and Mineral Research, the acid-ash hypothesis states that "protein and grain-rich foods with low potassium intake lead to dietary acid load and net acid excretion (NAE) with elevated urinary calcium levels. Calcium is removed from the skeleton, which leads to osteoporosis." The alkaline diet attempts to prevent precisely this by taking into account the pH value of individual foods in order to limit acid intake through food.

Even if not all experts agree with this hypothesis, all agree that a stable pH value in the blood is vital for us humans. It lies between 7.35 and 7.45 and is kept within this narrow range by the lungs, the buffer systems of the blood and the kidneys, which play the main role in balancing out acids from food (Hamm et al., 2015). The authors of Forbes magazine write: "Our bodies go to great lengths to ensure a balanced pH level." In a healthy person, food cannot push the blood pH out of this range. What diet does change is the amount of acid the kidneys have to excrete. Naturopaths call a lasting high acid load latent acidosis or hyperacidity. Acidosis in the medical sense, where the blood pH falls below 7.35, is something different: it is caused by illnesses such as kidney failure or uncontrolled diabetes and is a medical emergency.

What is the "pH value"?

The abbreviation "pH" stands for "pondus Hydrogenii", which translates roughly as "weight of hydrogen". It is a measure of how acidic or alkaline certain body fluids or tissues are. The scale of values ranges from 0 to 14. The more acidic a solution is, the lower the pH value. The more alkaline a solution is, the higher the value. A pH value of around 7 is considered neutral. The optimum pH value for humans is 7.4, i.e. slightly alkaline. The pH value fluctuates depending on the body region and organ. It is most acidic in the stomach.

Even the smallest changes in the pH value can cause serious problems. This applies not only to us humans, but to all organisms. For example, the pH value of the oceans has fallen from 8.2 to 8.1 due to environmental problems, such as the increasing uptake of CO₂. Various forms of life that live in the ocean are suffering as a result. The pH value is also important for the growth of plants and therefore also affects the mineral content of the food we consume. Minerals in the ocean, the soil and the human body act as a buffer to maintain an optimal pH level. As soon as the acidity increases, the mineral content decreases.

How an alkaline diet works

Below is some background information on acids and bases in the human diet as well as important explanations on how an alkaline diet can be beneficial.

Background information on acids and bases:

• Scientists believe that there have been "significant changes in the overall acid load in the human diet from the time of hunter-gatherers to the present day." Following the agricultural revolution and the mass industrialization of our food supply over the last 200 years, the food we eat has significantly less potassium, magnesium and fiber and significantly more sodium and chloride than it used to.
• Normally, the kidneys ensure a balanced electrolyte balance (calcium, magnesium, potassium and sodium). If we expose our body to excessively acidic substances, these electrolytes are used to regulate the acidity.
• According to the aforementioned article in the Journal of Environmental Health, the ratio of potassium to sodium has changed dramatically for most people. The ratio of potassium to sodium used to be 10:1; today it is 1:3! People who eat a standard diet now consume on average three times as much sodium as potassium.
• Many children and adults eat a diet that is extremely high in sodium and low in magnesium and potassium as well as antioxidants, fiber and essential vitamins. In addition, the standard diet in industrialized countries consists of too many refined fats, simple sugars, sodium and chloride.
• All these changes in the human diet have led to a higher acid load. Researchers describe this as a mild, diet-related acid load; the blood pH itself stays within its normal range. In addition, many people take in too few nutrients and suffer from a lack of potassium and magnesium, for example.
• To buffer a high acid load over many years, the body draws on alkaline minerals. This is why a good supply of potassium, magnesium and calcium matters on an acid-rich diet.

Can food change your body's pH?

Only partly. The blood pH stays stable whatever you eat, but the urine pH changes noticeably with your diet. Researchers calculate the potential renal acid load (PRAL) of foods for this purpose: certain hard cheeses have the highest acid load, fats and oils are neutral, and fruit, fruit juices and vegetables have an alkalizing effect (Remer & Manz, 1995).

Latent acidosis, a lasting but mild acid load without any change in blood pH, is a concept from naturopathy. It has been suggested as one factor behind complaints such as chronic back pain (Vormann et al., 2001).

If there are not enough vegetables and fruit on the plate every day, alkaline minerals can fill the gap. Our Alkaline Balance Powder contains potassium citrate together with magnesium, calcium and zinc citrate, and it is free from sodium. Zinc contributes to normal acid-base metabolism, and potassium contributes to the maintenance of normal blood pressure; both are authorised EU health claims (Regulation (EU) No 432/2012).

6 possible benefits of an alkaline diet

1. protection of bone density and muscle mass

The intake of minerals plays an important role in building and maintaining healthy bone structures. According to the 2012 review, eating more fruit and vegetables as part of an alkaline diet may benefit bone health and reduce the loss of muscle mass (sarcopenia) as people get older.

Alkaline mineral salts have been studied directly: in a meta-analysis of 14 studies, potassium citrate and potassium bicarbonate lowered the excretion of calcium and acid in the urine and reduced a marker of bone breakdown (Lambert et al., 2015). The authors see this as a potential benefit for bone health.

2. reduced risk of high blood pressure and stroke

Vegetables, fruit, potatoes and legumes are rich in potassium, and potassium is the best-studied reason why an alkaline diet is good for the heart and blood vessels. In a meta-analysis, a higher potassium intake lowered systolic blood pressure by 3.49 mmHg and diastolic blood pressure by 1.96 mmHg; the effect was seen in people with high blood pressure. A higher potassium intake was also linked to a 24% lower risk of stroke (Aburto et al., 2013). Many people who eat an alkaline diet for their heart also look into antioxidants with anti-ageing effects such as R-alpha lipoic acid.

3. relief of chronic pain and inflammation

A lasting acid load is discussed as one of several factors behind chronic pain, for example in the back, the muscles and the joints (joint pain ).

In a study published in the journal of the Society for Minerals and Trace Elements (GMS), 82 patients with chronic low back pain took 30 g of an alkaline multimineral supplement every day for four weeks in addition to their usual medication. On the Aarhus Low Back Pain Rating Scale, their pain score fell by 49% on average, from 41 to 21 points, and 76 of the 82 patients achieved a reduction (Vormann et al., 2001).

4. prevention of magnesium deficiency

Magnesium is required for the function of hundreds of enzyme systems and bodily processes. Many people suffer from a magnesium deficiency and suffer from heart problems, muscle pain, headaches, sleep problems and anxiety as a result. Magnesium is also needed to activate vitamin D and prevent vitamin D deficiency. This is important for general immune defense and endocrine function. Green leafy vegetables, legumes and seeds, which are staples of an alkaline diet, are good sources of magnesium.

5. immune defense and cancer: what is known

Vegetables and fruit supply vitamin C, and a varied alkaline diet also provides zinc and selenium. All three contribute to the normal function of the immune system.

Whether an alkaline diet protects against cancer has hardly been studied. A systematic review found only one suitable study, which showed no link between the acid load of the diet and bladder cancer; no study at all has examined an alkaline diet or alkaline water for cancer treatment (Fenton & Huang, 2016). An alkaline diet is therefore no substitute for medical cancer treatment. You can read about the research on turmeric in our guide on turmeric and cancer prevention .

6. healthy weight

An alkaline diet can support a healthy weight because it replaces many processed, energy-dense foods with vegetables, fruit and legumes. These are rich in fiber and water and fill you up with relatively few calories. Eating more alkalizing foods and fewer processed products makes it easier to eat the amount of calories your body actually needs.

Alkaline nutrition in practice

Here are some tips on how you can eat an alkaline diet:

Fresh vegetables and fruit are the basis. According to the 2012 review, it is worth considering what type of soil produce was grown in, as this may significantly influence its mineral content. Research shows that the quality of the soil has a significant effect on the vitamin and mineral content of the plants. This means that not all alkaline foods are created equal.

The ideal pH value for the general availability of essential nutrients for plants is between 6 and 7. Acidic soils with a pH value of less than 6 provide less calcium and magnesium; alkaline soils with a pH value of more than 7 provide unutilizable iron, manganese, copper and zinc.

If you want to determine your pH value before trying out the following tips, you can get pH test strips to determine your pH value in urine. You will get the most meaningful value with the second urine after getting up. Compare the colors on the test strip with the color scale that comes with the packaging. It is best to test your pH value during the day one hour before a meal or two hours after. Urine pH changes over the course of the day and with every meal, so several readings show the trend better than a single one.

The best alkaline foods:

• Fresh fruit and vegetables promote alkalinity best. Some of the best include mushrooms, citrus fruits, dates, raisins, spinach, grapefruit, tomatoes, avocado, black summer radish, alfalfa, barley grass, cucumber, kale, jicama, wheat grass, broccoli, oregano, garlic, ginger, green beans, endive, cabbage, celery, beet, watermelon, figs and ripe bananas.
• Raw and gently cooked foods: Eat part of your vegetables and fruit raw. Boiling washes some of the potassium and magnesium out into the cooking water, so steaming vegetables or using the cooking water for soups keeps more of the minerals.
• Vegetable proteins: Almonds, white beans, lima beans and most other beans are a good choice.
• Water: Plain tap water or mineral water is the best choice for everyday drinking. Mineral waters rich in bicarbonate are popular on an alkaline diet, and a squeeze of lemon or lime juice adds flavor. Distilled water is not suitable as your main drinking water because it contains no minerals. Do not add baking soda to your water regularly without medical advice, as it contains a lot of sodium.
• Green drinks: Juice from green vegetables and grasses in powder form contain many alkaline foods and chlorophyll. Chlorophyll is similar in structure to haem, the red pigment in blood, but it does not change the pH of the blood; the benefit of green drinks comes from their potassium and magnesium.
• Other foods that you can consume as part of an alkaline diet are: Sprouts, wheat grass, kamut, fermented soy such as natto or tempeh and seeds.

Acid-forming foods and habits that contribute to hyperacidity:

• High-salt foods: Industrially processed foods contain large amounts of sodium chloride - table salt - which can raise blood pressure and adds chloride to the diet.
• Cold cuts and conventional meat
• Industrial cereals (such as cornflakes)
• Eggs
• Caffeinated drinks and alcohol
• Oats and whole grain products: Cereal products are mildly acid-forming. Whole grains still supply valuable fiber and magnesium, so there is no need to cut them out; combine them with plenty of vegetables. 
• Hard cheese: Certain hard cheeses have the highest acid load of all the foods analyzed (Remer & Manz, 1995). Milk and yogurt, on the other hand, remain good sources of calcium for the bones and do not need to be avoided.
• Peanuts and walnuts
• Pasta, rice, bread and packaged cereal products

Other behaviors that lead to acidification of the body:

• Alcohol and drug consumption
• High caffeine intake
• Chronic stress
• Declining nutrient content in our food due to industrial agriculture
• Low-fiber diet
• Lack of exercise
• Meat-rich diet (meat not from pasture farming)
• Very intense exercise without enough recovery
• Poor eating habits and inadequate chewing of food
• industrially processed and refined foods

Alkaline diet vs. paleo diet

• The Paleo diet and the alkaline diet have many things in common and offer similar health benefits, such as a lower risk of nutrient deficiencies, reduced inflammation, better digestion, weight loss or weight maintenance, etc.
• With both diets, the intake of added sugar and inflammation-promoting omega-6 fatty acids is reduced. Cereals and processed carbohydrates are removed from the diet and the consumption of milk and dairy products is restricted. At the same time, more fruit and vegetables are consumed.
• However, there are some important things to bear in mind if you want to follow the rules of the Paleo diet. The Paleo diet eliminates all dairy products from the diet, including yogurt and kefir, an important source of probiotics and minerals for many people. Often not enough emphasis is placed on organic food and pasture-raised meat (and only to a limited extent).
• In addition, the Paleo diet recommends eating a lot of meat, pork and seafood, all of which also have disadvantages.
• Eating too many animal proteins increases the acid load and does not promote alkalinity. When the sulfur-containing amino acids in beef, poultry, cold cuts, seafood and pork are broken down, sulfuric acid is formed, which the kidneys have to excrete. Always try to eat the highest quality animal products and vary your protein sources. This is the best way to balance your pH. 

Precautionary measures in relation to the alkaline diet

It may come as a surprise that some foods are on the list of acidic foods, such as eggs or walnuts. These have an acidic effect on the body. However, this should not stop you from eating them. They contain extremely healthy antioxidants and omega-3 fatty acids and are therefore very valuable for our diet.

Ultimately, it is important that you achieve a healthy balance. A healthy body keeps its blood pH stable, so healthy acid-forming foods such as eggs, fish or whole grains have their place in an alkaline diet. But usually the problem is that we don't eat enough alkaline foods instead of consuming too much acid from healthy whole foods. Eat lots of healthy, real whole foods (especially vegetables and fruit) and limit your intake of packaged foods. Then you will be on the right track.

Downsides and risks of an alkaline diet

For most healthy adults, an alkaline diet is safe as long as it stays varied. These are the main pitfalls:

• Lists that are too strict: Leaving out all dairy products, eggs, fish and grains makes it harder to get enough protein, calcium, iodine and vitamin B12.
• Kidney disease and certain medicines: The benefits of more potassium apply to people whose kidneys handle potassium normally (Aburto et al., 2013). People with kidney disease or who take medicines that raise potassium levels, such as some blood pressure drugs, should talk to their doctor before greatly increasing their potassium intake from food or supplements.
• Baking soda: Taking sodium bicarbonate regularly without medical advice adds a lot of sodium to the diet.
• Serious symptoms: A diet cannot cure serious illnesses. Persistent pain, tiredness or digestive problems should always be checked by a doctor.

Concluding remarks on alkaline nutrition

• An alkaline diet contains lots of healthy whole foods, which lower the acid load of the diet and raise the pH value of the urine; the blood pH stays stable.
• The best-studied benefits come from more potassium: lower blood pressure and a lower risk of stroke. Alkaline mineral salts have also reduced calcium losses and back pain in studies.
• Alkaline foods include fruit and vegetables, raw foods, green juices, beans and almonds.
• Acidic foods that should be limited include high-sodium foods, processed cereals, too much meat and animal protein, added sugar and hard cheese.

Frequently asked questions

Is there science behind the alkaline diet?

Yes, in part. Studies show that diet changes the acid load and the urine pH, while the blood pH stays stable. The strongest evidence concerns the potassium in vegetables and fruit, which lowers high blood pressure, and alkaline mineral salts have reduced calcium losses in the urine and back pain in studies.

What are some downsides to an alkaline diet?

Very strict versions cut out valuable foods such as dairy products, eggs, fish and whole grains, which can lead to gaps in protein, calcium or vitamin B12. People with kidney disease or who take medicines that raise potassium levels should check with their doctor first. An alkaline diet also cannot cure serious illnesses.

What is the 80/20 rule in the alkaline diet?

It means that about 80% of what you eat comes from alkalizing foods such as vegetables, fruit, potatoes and legumes, and about 20% from acid-forming foods such as meat, fish, eggs, cheese and grains. The rule is a practical guideline from alkaline cookbooks rather than a fixed scientific value, but it leads to a varied diet rich in plants.

Can I combine an alkaline diet with a nut free diet?

Yes. Nuts are not essential for an alkaline diet, and walnuts and peanuts are even among the acid-forming foods. Vegetables, fruit, potatoes, legumes and, if tolerated, seeds such as pumpkin or sunflower seeds provide the minerals and plant protein instead.

What foods are allowed on an alkaline diet?

All foods are allowed, but the focus is on vegetables, fruit, potatoes, legumes, herbs and salads. Acid-forming foods such as meat, fish, eggs, cheese and grain products are eaten in smaller amounts and combined with plenty of vegetables, while highly processed foods, a lot of salt, sugar and alcohol are best limited.

Sources (in English):

Schwalfenberg, G. K. (2012, October). The Alkaline Diet: Is There Evidence That an Alkaline pH Diet Benefits Health?  Journal of Environmental and Public Health, 2012: 727630, doi: 10.1155/2012/727630 

Fenton, T. R., Lyon, A. W., Eliasziw, M., Tough, S. C. & Hanley, D. A. (2009, November). Meta-analysis of the effect of the acid-ash hypothesis of osteoporosis on calcium balance. Journal of Bone and Mineral Research: the Official Journal of the American Society for Bone and Mineral Research, 24(11):1835-40, doi: 10.1359/jbmr.090515 

Bonjour, J. P. (2011, March). Protein intake and Bone Health. International Journal for Vitamin and Nutrition Research, 81(2-3):134-42, doi: 10.1024/0300-9831/a000063 

Vormann, J., Worlitschek, M., Goedecke, T. & Silver, B. (2001). Supplementation with alkaline minerals reduces symptoms in patients with chronic low back pain. Journal of Trace Elements in Medicine and Biology: Organ of the Society for Minerals and Trace Elements (GMS), 15(2-3):179-83, doi: 10.1016/S0946-672X(01)80064-X 

Remer, T. & Manz, F. (1995). Potential renal acid load of foods and its influence on urine pH. Journal of the American Dietetic Association, 95(7):791-7, doi: 10.1016/S0002-8223(95)00219-7

Remer, T., Dimitriou, T. & Manz, F. (2003). Dietary potential renal acid load and renal net acid excretion in healthy, free-living children and adolescents. The American Journal of Clinical Nutrition, 77(5):1255-60, doi: 10.1093/ajcn/77.5.1255

Hamm, L. L., Nakhoul, N. & Hering-Smith, K. S. (2015). Acid-Base Homeostasis. Clinical Journal of the American Society of Nephrology, 10(12):2232-42, doi: 10.2215/CJN.07400715

Lambert, H., Frassetto, L., Moore, J. B., Torgerson, D., Gannon, R., Burckhardt, P. et al. (2015). The effect of supplementation with alkaline potassium salts on bone metabolism: a meta-analysis. Osteoporosis International, 26(4):1311-8, doi: 10.1007/s00198-014-3006-9

Aburto, N. J., Hanson, S., Gutierrez, H., Hooper, L., Elliott, P. & Cappuccio, F. P. (2013). Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses. BMJ, 346:f1378, doi: 10.1136/bmj.f1378

Fenton, T. R. & Huang, T. (2016). Systematic review of the association between dietary acid load, alkaline water and cancer. BMJ Open, 6(6):e010438, doi: 10.1136/bmjopen-2015-010438

European Commission (2012). Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods. Official Journal of the European Union, L 136:1-40