Ein Monat Vegan - Teil 1

At the moment you read and hear a lot in the media about vegan nutrition being the best for the climate. I think there's a lot to talk about on this topic, but to really understand what it means to be vegan, you have to try it yourself. Here I want to tell you about my experiences. After this Updates will continue to be uploaded weekly to the opening blog. Every Friday evening.

Now that I've often found myself in the situation of discussing the pros and cons of a vegan lifestyle with friends or acquaintances, without one of the participants being vegan, I decided to try it out for myself to try. Because you can discuss a lot, even if you actually have no idea what it actually means to live vegan. I made it easy for myself for this experiment and initially limited myself to nutrition and did not extend the vegan lifestyle to all areas of life. Because you have to deal with the topic a lot to find out which products actually contain animal components. Adhesives, e.g. from labels, are often not vegan, for example. Cleaning agents and some cosmetic products also contain non-vegan ingredients.

Is eating vegan even good for the environment?

I asked myself that too, after all it feels like you produce a lot more packaging waste, buy vegetables and fruit with much longer transport routes than, for example, regional milk. When I say "soy," a lot of people start talking about rainforest deforestation. It's kind of gotten into people's heads that vegans eat mostly tofu, which is where the rainforest is cut down, and that's really bad. I don't dispute that at all. Rainforest is important for the climate (and the current situation in Brazil makes my heart bleed, but more on that maybe another time). Another question, what do cows actually eat? Grass?

Soy is mostly imported into Germany and used mainly in meat and milk production as concentrated feed. High-yielding cows that give 40 to 60 liters of milk a day have to eat protein-rich feed made from corn, soya or rapeseed. This soy also comes from the monocultures of South America, is often genetically modified and contaminated with pesticides (Those). So when I buy milk, far more soy has been grown for a liter than for the soy milk I could drink instead. If I also opt for spelled or oat milk or for soy milk and tofu from regionally grown soy beans, the products used come from Germany and Austria. A fairly recent study has shown that the vegan diet can reduce the ecological footprint by up to 73%.

Official positions and recommendations

The Academy of Nutrition and Dietetics (AND, formerly the American Dietetic Association), an association of more than 70,000 nutritionists, researchers and medical professionals, considers the vegan-vegetarian diet - among other nutritional organizations - to be healthy and for all ages - and phases of life suitable:

"It is the position of the Academy of Nutrition and Dietetics that well-planned vegetarian diets, including strictly vegetarian or vegan diets, are healthy and nutritionally appropriate, and may have health benefits in the prevention and treatment of certain health conditions. Well-designed vegetarian diets are appropriate for people at all stages of life, including pregnancy, lactation, infancy, childhood and adolescence, as well as for athletes.« 

The Australian and Canadian nutrition organizations agree with this position, e.g. in their guidelines for a healthy vegan diet with useful tips. The British state health service, the National Health Service, also provides unreserved information and advice.

The German Society for Nutrition (DGE) is (still) reluctant to make such statements, but in 2016 it also published a position paper on vegan nutrition, including helpful tips on healthy vegan nutrition. 

Vegan diet and diseases of civilization

Vegetarians and vegans often have a lower risk of developing so-called “common diseases” such as type 2 diabetes, heart disease and obesity – in contrast to people who consume a lot of meat and meat products such as sausages, etc.

Particularly obvious is the finding that the body mass index (BMI; a value that indicates the ratio of body weight and height) of people with a predominantly or purely vegan diet is significantly more often in the normal range (BMI in the range 20-25) than of people with mixed diets. The diet-related reasons for this are primarily the higher supply of dietary fiber and the lower fat and protein intake in vegetarian diets. Other causes are the often generally healthier lifestyle, such as greater physical activity.

The cholesterol levels in the blood are also significantly lower in people who eat vegan than in people who eat meat. The reason for this is the lower or non-existent supply of animal fats, which provide saturated fatty acids and cholesterol, and the higher supply of monounsaturated and polyunsaturated fatty acids. Rarer obesity and lower cholesterol levels, among other factors, reduce the likelihood of cardiovascular diseases, i.e. diseases affecting the heart and blood vessels, such as high blood pressure, stroke or heart attack.

The risk of developing type 2 diabetes is also reduced. With a vegan-vegetarian lifestyle, patients with type 2 diabetes can improve their levels (e.g. blood sugar and insulin) and reduce their medication dose or even stop it altogether.

Those affected by rheumatoid arthritis can also often relieve symptoms by switching to a vegan diet.

A high consumption of fruit and vegetables, as is often the case with vegan-vegetarian diets, can also increase life expectancy. To that end, a high consumption of red and especially processed meat (sausage and smoked meat) increases the risk of cancer, as an assessment by the WHO shows.

In summary, a well-planned and wholesome vegan-vegetarian diet can reduce the risk of numerous diet-related diseases.

Important nutrients and their occurrence

Studies show that a sufficient supply of nutrients can be easily implemented through a vegetarian or vegan diet. However, you should pay special attention to certain nutrients.


Protein, also known as protein, is primarily used by the body to build tissue (1). Many people are unaware that sufficient amounts of protein are also found in many plant-based foods. In the case of vegetable proteins, it should be noted that all nine indispensable (formerly: »essential«) amino acids are consumed in sufficient quantities. By combining different vegetable protein suppliers throughout the day, this can be implemented and an adequate protein quality can be achieved. A particularly good "biological value" - how well a dietary protein can be converted into endogenous protein - has, for example, the combination of legumes and cereals, e.g. B. Lentils with rice. In addition to legumes, tofu, and other soy products, good plant sources include whole grains, nuts, oilseeds, and potatoes (1). 

Vitamin B12

Vitamin B12 (cobalamin) plays a vital role in cell division, blood formation and the nervous system and is probably the most discussed nutrient in a vegan diet. Natural occurrences in sufficient quantities are only found in animal foods, which is why the supply through food can be critical, especially for vegans and vegetarians who only consume very small amounts of dairy products and/or eggs. But many older people who eat mixed foods also suffer from a vitamin B12 deficiency. Although they absorb enough vitamin B12 through food, their physical absorption capacity is usually reduced. Especially in risk groups such as pregnant women, breastfeeding women, children and older people, care must be taken to ensure an adequate intake, which is best checked regularly in a blood test (see below).

The first non-specific signs of a vitamin B12 deficiency can be tiredness, dizziness, paleness and general weakness. If a vitamin B12 deficiency remains untreated, there will be long-term haematopoietic disorders as well as neurological and psychiatric impairments, such as sensory, coordination and balance disorders, apathy, hallucinations, paralysis and psychoses. These nervous system disorders are potentially irreversible.

Some sources report vitamin B12 occurrences in beer, sauerkraut, seaweed or other plant foods; However, their content is either only marginal or the effect on humans has not yet been proven. Some of these foods contain structurally similar compounds (analogues) to vitamin B12, but they cannot fulfill the vital functions of the vitamin. Therefore, fortified foods, dietary supplements, medical injections, or a vitamin B12 toothpaste are the only ways to safely meet vitamin B12 needs on a vegan diet.

Vitamin B2

Vitamin B2 (riboflavin) is a vitamin that is important for energy production in the metabolism. Apart from animal products, it is mainly found in nuts, seeds, mushrooms, legumes, the outer layers and germs of cereals and thus in whole grain products. Vegetarians and omnivores hardly differ in their intake of vitamin B2 and almost always reach the intake recommendations. In studies with vegans, the riboflavin status was partly found to be sufficient and partly to be too low. In addition to a wholesome food selection, it can be helpful to have your vitamin B2 status checked regularly in blood tests.

Omega-3 fatty acids

Omega-3 fatty acids are essential to life and are particularly important for heart and blood vessel health and as components of the brain and nerve cells. The question often arises as to how the need for omega-3 fatty acids can be met with a purely or predominantly vegan diet. In fact, in addition to fish, many plant-based foods also contain omega-3 fatty acids, particularly alpha-linolenic acid. Good sources are linseed, rapeseed, hemp or walnut oil or walnuts.

The omega-6 fatty acid linoleic acid is also essential. However, vegans and vegetarians in particular take in too much omega-6 and too little omega-3 fatty acids. A 5:1 ratio of omega-6 to omega-3 fatty acids is recommended, but most people don't achieve this. Omega-6 fatty acids can adversely affect the conversion of the omega-3 fatty acid alpha-linolenic acid into the health-promoting long-chain omega-3 fatty acids EPA and DHA.

More and more experts are recommending EPA and DHA supplements for vegan-vegetarian diets. In any case, according to the DGE, pregnant and breastfeeding women should take at least 200 mg DHA daily.


The mineral calcium builds bones and teeth, is important for blood clotting and ensures the excitability of nerves and muscles. About 1 kilogram of calcium is stored in the human body. In industrialized countries, the calcium requirement is largely covered by milk and milk products, but calcium-rich mineral water and many plant-based foods also contribute to an optimal supply. The latter include sesame (also known as sesame butter/tahini), almonds, dark green vegetables such as kale and broccoli, and plant-based drinks fortified with calcium.

The DGE recommends a daily intake of 1,000 mg of calcium for adults. This recommendation is given against the background of Western eating habits; as intake of animal protein and salt increases, so does calcium excretion. In the case of a predominantly or purely vegan diet, an adequate supply of calcium could also be guaranteed with a minimum intake of around 700 mg calcium/day, although absorption can be hampered by oxalic acid and no official recommendation for vegan diets has yet been given. Nevertheless, calcium is a critical nutrient and (not only) vegans should ensure an optimal supply in order to e.g. prevent osteoporosis.

To demand

Iron is particularly important for the transport of oxygen in the red blood cells, but also for energy production and the immune system. A large number of plant-based foods contain iron, e.g. whole grains, legumes, nuts and oilseeds. In the case of iron, however, it is not just the pure amount that is decisive, but also how well the iron contained in a food can be absorbed by the body at all. Vitamin C and other organic acids in particular can significantly improve absorption – just a little lemon juice in a salad or in pasta and cereal dishes, paprika with wholemeal bread or a glass of orange juice with muesli can have this effect.


Zinc is a trace element that plays an important role in metabolism, acid-base balance, the immune system, cell growth and wound healing. A deficiency can impair numerous metabolic processes due to the diverse mode of action. While severe deficiency is rare in industrialized countries, mild zinc deficiency is more common. Children and young people, as well as pregnant women, breastfeeding women and the elderly in particular, should ensure that they are adequately supplied. Studies have found no greater risk of zinc deficiency in adult vegans or vegetarians than in omnivores. Although the zinc intake was lower, the zinc levels in the blood were sufficient on average. Pumpkin seeds, oatmeal and lentils, for example, contain plenty of zinc, as well as whole grains, nuts and legumes in general. 


Iodine is important for the function of the thyroid gland and the associated hormone balance (1). The DGE recommends that adults take in 200 µg of iodine daily. Since our soil is very low in iodine, the food grown on it contains hardly any iodine. The most important source is iodized table or sea salt, which, however, should not cover the entire iodine requirement due to the simultaneous negative effects of excessive salt consumption: 200 µg iodine corresponds to about two teaspoons of salt. However, the DGE advises not to consume more than 6 g of pure salt or salt found in processed products per day. In addition, the iodine supply can be improved by eating seaweed, e.g. B. the moderately iodinated nori seaweed, which is used for sushi. Algae, which contain a lot of iodine, should only be consumed rarely or in very small quantities. These include e.g. Arame, Kombu, Wakame or Hijiki. Excessive iodine intake, like iodine deficiency, can lead to thyroid disorders. Iodine supplements are another safe source. However, they should only be used if the iodine supply from iodized salt and algae is not sufficient - especially during pregnancy and breastfeeding.

Vitamin D

Vitamin D ensures, among other things, that the body absorbs enough calcium and builds up calcium in the bones. It can be produced by the body itself when sunlight hits the skin. Adequate care, however, presupposes that you spend at least 15 to 30 minutes a day in the sun around midday with uncovered arms and no sun protection. In Germany, this is particularly difficult in the months with little sunshine: Most of the UV-B light, a part of solar radiation that is important for vitamin D synthesis, is filtered out by the atmosphere between mid-October and mid-March due to the changed angle of incidence of the sunlight . A vitamin D deficiency not only affects calcium absorption and bone formation (e.g. increases the risk of osteoporosis), but can also increase the risk of numerous diseases such as cardiovascular problems. Few foods contain enough vitamin D to meet human needs. That is why most people who eat mixed foods are not sufficiently supplied with vitamin D in the months with little sunshine.

Therefore, in our latitudes, the vitamin D supply should generally be ensured through fortified foods or dietary supplements in the months between mid-October and mid-March. Vegans should be careful here, because added vitamin D (D3) is often obtained from the wool fat of sheep and is therefore not of vegetable origin. Vitamin D2 and vitamin D3 from lichen, on the other hand, are vegan.

Medical advice and research on vegan diets

In classical medical studies, dietetics and the influence of nutrition on health unfortunately plays only a minor role or not at all. Outdated food pyramids are sometimes taught and students have hardly any opportunities to get to know and deepen the special features of vegan-vegetarian nutrition. So it is hardly surprising that many medical professionals are skeptical about vegan nutrition in particular. The benefits mentioned above, such as disease prevention or the alleviation of certain ailments, are hardly known.

Important values in the blood test

The most important values for vegans and vegetarians are various vitamin B12 parameters (see below). Irrespective of their diet, women of childbearing age should have their iron levels (hemoglobin, ferritin) checked regularly.

The determination of the vitamin B12 supply is usually not covered by health insurance and must therefore be paid for by yourself. It is best to talk to your doctor's office about this. Since a deficiency can have serious consequences, regular blood tests should be carried out on a vegan or predominantly vegan diet. It is important to ensure that the holo-transcobalamin value, the so-called holo-TC or "active vitamin B12", is measured, because this is the only way to assess the body's vitamin B12 supply. For detailed clarification of a low holo-TC, the status of the methylmalonic acid (MMA) can be determined - ideally during the same blood test or in a second step. You can find more information on this on our practical information sheet on checking the vitamin B12 status to take with you to the practice.

Some experts recommend checking every two to three years, other sources recommend annual tests. Since the necessity and frequency of such checks and blood tests as well as any therapy depends on your own values, supplementation and state of health, please always discuss this with your doctor in confidence.

It also makes sense to check your vitamin D levels, especially in autumn, since the body can only produce it with the help of sufficient exposure to the sun (see above). This is often not covered by health insurance, but can be included in the blood count if desired. The occasional examination of the supply of zinc (zinc level in the blood), vitamin B2 (EGRAC; Erythrocyte Glutathione Reductase Activation Coefficient) and iodine (excretion in the 24-hour urine) is useful for vegetarians and vegans.


According to the findings of numerous scientific studies, statements from well-known institutions and, last but not least, many personal experience reports, a balanced vegan or predominantly vegan diet represents a health-promoting diet. With a varied, wholesome selection of foods, the intake of all nutrients can be ensured (exceptions: vitamin B12 must be consumed in general and Vitamin D should be supplemented in the winter months). It makes sense to regularly check potentially critical nutrients. If you pay attention to these points, nothing stands in the way of a vegan diet - on the contrary, it can help to prevent and alleviate diseases.

literature sources

  1. Leitzmann, C. & Keller, M. (2013). Vegetarian Diet (3rd ed.). Publisher Eugen Ulmer: Stuttgart.
  2. Schumann, L., Martin, H.H. & Keller, M. (2014). Calcium, milk and bone health - claims and facts. Nutrition Focus 14 (11-12), 326-31. Also: written exchange with Dr. Markus Keller (2014).

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