Vegetarianism – types, what to eat, vitamins B12 and D, iron deficiency

Vegetarianism has many faces, but regardless of the extent to which certain products are eliminated, the diet should always be balanced. Vegetarians should pay special attention to eating foods rich in calcium, iron and zinc. To meet the demand for vitamin B12, it is worth using fortified foods or supplementation (after consulting a doctor). We advise you how to compose a diet.

How to switch to a vegetarian diet?  What can you replace meat with in your diet?How to switch to a vegetarian diet? What can you replace meat with in your diet?

{getToc} $title={Table of Contents}

Types of vegetarianism

Its varieties differ in the extent to which groups of animal products are eliminated. In the case of more restrictive forms, restrictions may also apply to selected plant foods, e.g. their thermal processing. 

A group of products of plant origin
A type of vegetarian dietVegetables fruitsNuts and seedsDry legume seeds
FlexitarianYes Yes Yes 
Semi-vegetarianYes Yes Yes 
PescovegetarianYes Yes Yes 
Lacto-ovo vegetarianYes Yes Yes 
Ovo-vegetarianYes Yes Yes 
Lacto-vegetarianYes Yes Yes 
VeganYes Yes Yes 
Fruitarian*Yes Yes NO
Raw foodyes, only uncooked and unprocessed**


A group of products of animal origin
A type of vegetarian dietMilk and dairy productsEggs and egg-based productsFishes and seafoodPoultryRed meat
FlexitarianYesYeswith meat restriction, without complete elimination
Semi-vegetarianYes Yes Yes Yes NO
PescovegetarianNONOYesNO NO
Lacto-ovo vegetarian Yes Yes NONONO
Ovo-vegetarianNOYes NONONO
Lacto-vegetarianYes NONONONO

* is based only on fresh and dried fruit, seeds and some vegetables

**except short heat treatment

***is based mainly on minimally processed products: whole grains, cereal products (approx. 60% of the diet), especially brown rice, vegetables and fruits – preferably from a local supplier (approx. 20-30%, dry plant seeds legumes, soy-based products and seaweed (approx. 5-10%); occasionally allows the consumption of white meat, including fish (once or twice a week).

Semi-vegetarianism is not considered a vegetarian diet by some because it allows for the occasional consumption of poultry. This variety also includes a new approach to the vegetarian diet – flexitarianism – occasional consumption of meat.

It should be emphasized that the classification of diets is subject to frequent modifications.

Advantages of vegetarianism

Plant-based diets usually contain a lot of fiber, “good” fatty acids, minerals and vitamins, so they can help control body weight, lipid profile, glucose levels and blood pressure. 

Potential benefits of the diet:

  • obesity prevention  ,
  • heart disease prevention  ,
  • hypertension prevention  ,
  • prevention  of type 2 diabetes ,
  • environmental Protection,
  • lower cost.

Not every diet is healthy – if it still contains a lot of added sugar, salt, saturated fatty acids and trans fats, it may be as unfavorable as a mixed diet with a similar composition.

Regardless of your diet, you should limit the consumption of highly processed foods, e.g. sweetened drinks, French fries and chips.

How to become vegetarian?

Before starting such a diet, especially a more restrictive type (e.g. veganism), it is worth consulting a doctor and finding out whether you should take dietary supplements – if so, what preparation and in what dose. 

The American Academy of Nutrition and Dietetics has stated that a balanced vegetarian diet, including vegan, is safe at all ages – i.e. it meets the need for energy and nutrients, and what’s more, it may bring health benefits in the prevention and treatment of certain diseases. 

On your own, without appropriate knowledge, it is difficult to plan a plant-based diet (especially more restrictive types). A dietitian will help you balance your diet to prevent possible nutritional deficiencies and dispel any doubts about your diet. It is worth starting your adventure with a diet by consulting a specialist who will teach you how to create properly composed meals. 

If you have decided to become a vegetarian, consult your doctor and find out what to replace meat with and what products you need to add to your menu so that it contains all the microelements and essential ingredients.If you have decided to become a vegetarian, consult your doctor and find out what to replace meat with and what products you need to add to your menu so that it contains all the microelements and essential ingredients.

Vegetarianism: what to eat

Contrary to appearances, plant-based diets, despite eliminating a number of products, offer a wealth of dishes and flavors. It is worth drawing inspiration from cultures where the diet is largely based on plant products – e.g. Indian, Middle Eastern, Chinese and Thai.

It’s a good idea to start by reviewing your favorite recipes to see if you can replace an animal product with a plant-based equivalent. Instead of meat,  in many cases you can add soy and soy-based products, or other legumes (e.g. chickpeas, beans).

Every vegetarian should pay special attention to products rich in protein and  calcium . Below is an example of a plant-based diet plate and an explanation of what foods fall into each of the food groups on it. 

Food groupSample foods in each group(scope of elimination to be taken into account)
Foods rich in proteinsoy and soy-based productslegumes other than soy (e.g. chickpeas, lentils, beans)meat analogueseggsmilk and dairy productspoultryfish
Vegetablesbreadbreakfast cerealspastagroats, rice
Fruitraw/cooked/dried fruitfruit juice (100 percent)
Fatsoil, olive oil, margarinean avocadonuts, peanut butterbutter, mayonnaise
Nuts and seedsnutsseeds (e.g. sesame, sunflower, pumpkin seeds)peanut butter
Foods rich in calciumsoy-based products (e.g. fortified soy drink, tofu)high calcium waterfortified plant drinks (watch out for sugar content)nuts, seedsvegetables low in oxalates and phytates (e.g. kale, broccoli, bok choy and dried figs)
Foods rich in omega-3 fatty acidslinseed oil, linseedchia seeds (Salvia hispanica)Italian nutsseaweed
Supplementation of vitamins D and B12 as indicated.

∗ Own study based on: Academy of Nutrition and Dietetics. VegPlate: a mediterranean-based food guide for italian adults, pregnant, and lactating vegetarians. Journal of the Academy of Nutrition and Dietetics 2018; 118(12): 2235-2243.

Vegetarianism and vitamins

Vitamin B12

Vitamin B12 is found only in products of animal origin, so diets based solely on plant products are almost doomed to its deficiency. People on a vegetarian diet should take an appropriate vitamin B12 supplement or consume an appropriate amount of it with fortified foods.

In lacto-ovo vegetarians, the availability of this vitamin depends on the amount and type of animal products consumed (i.e. milk and dairy products, and eggs), as well as fortified foods.

Seaweed (e.g. nori, spirulina, chlorella), yeast and fermented foods (e.g. tempeh) contain vitamin B12, but unfortunately its biologically inactive form, so they should not be treated as a source of this vitamin in a vegetarian diet.

Vitamin B12 deficiency usually takes years to develop due to the body’s stores of the vitamin. There are no indications for routine determination of vitamin B12 concentration in people on a plant-based diet without clinical symptoms of its deficiency. The decision on the appropriateness of such a marking is made by the doctor. The diagnosis of vitamin B12 deficiency is based on the interview, clinical symptoms, blood counts and other diagnostic tests ordered by a doctor.

Symptoms of vitamin deficiency may include:  fatigue , pale skin and even jaundice (due to  anemia ), but also gastrointestinal symptoms (e.g.  abdominal pain ,  diarrhea ) and neurological and psychiatric changes (e.g. cognitive disorders,  insomnia , vision, irritability, low mood and  depression ). They are not very specific, so the occurrence of any of the symptoms mentioned does not necessarily indicate a deficiency of this vitamin.

  • What is vitamin B12 responsible for? What are the indications for the test? Check! 

Vitamin D

Vitamin D deficiency depends little on diet. The concentration of vitamin D in the blood depends mainly on exposure to sunlight and the angle of sunlight in a given latitude at a given time of year, as well as the supplementation of this ingredient. 

In the period from May to September, every healthy person should spend at least 15 minutes “under the sun” without sunscreen (between 10 a.m. and 3 p.m.) to ensure the appropriate level of vitamin D synthesis (except for children under 3 years of age, people at risk of skin cancer, people with type 1 skin – i.e. pale, fair complexion, or people with skin burns in the past).

Currently, preventive supplementation is required from September to the end of April in an appropriate dose (in healthy adults: 800-2000 IU) and appropriate sun exposure in the summer.

In the absence of sufficient exposure, supplementation is recommended throughout the year. It is worth consulting a doctor to determine the preparation and the appropriate dose of the vitamin.

Symptoms of vitamin D deficiency include: fatigue, bone pain, muscle weakness, and osteoporotic fractures. However, fatigue is not an absolute indication for determining the concentration of this vitamin in the blood. The decision about the validity of this test is made by the doctor.

  • Check your vitamin D level. What are the norms and when is it worth doing the test?

Products rich in calcium 

People starting their adventure with a vegetarian diet should pay special attention to good sources of calcium, i.e. soy-based products (e.g. fortified soy drink, tofu), water with a high calcium content, nuts, seeds and vegetables low in oxalates and phytates. (e.g. kale, broccoli, bok choy and dried figs).

To provide the body with the appropriate amount of calcium, it is also important to consume products fortified with calcium, e.g. plant drinks (be careful about the sugar content), soy drinks, juices and breakfast cereals.

For people following a less restrictive type of diet, a particularly large amount of calcium is found in a portion of: sardines (100 g), milk (250 ml), natural yogurt (150 g), buttermilk (200 g), mozzarella cheese or yellow Gouda/cheddar cheese ( 1 slice) and salmon (about 100 g).

Calcium and phytates

Phytates are found in cereal products, especially wheat and rye flakes and bran, legume seeds (e.g. white and red beans, chickpeas, lentils), seeds (e.g. sesame, flax, sunflower) and nuts and peanuts.

Phytates strongly bind calcium, phosphorus, potassium, magnesium, manganese and  zinc , forming insoluble complexes with them, thus limiting their absorption. Phytates can form compounds with minerals not only in the food itself, but also in the intestine.

There are a number of solutions to reduce the content of phytates in food – i.e. grinding grains, soaking seeds (resulting in the partial transfer of these compounds to water) and cooking, but these treatments may simultaneously cause the loss of many valuable minerals and vitamins.

It is easy to notice that many foods containing phytates are subjected to heat treatment or other processes before consumption, which significantly reduce the activity of phytates. It seems that in developed countries, when following a balanced diet, the content of phytate compounds in the diet is not a major problem.

Calcium and oxalates

Oxalates, like phytates, also limit calcium absorption. These anti-nutritional compounds are particularly rich in: spinach, sorrel and other dark green leafy vegetables, beets and beetroot, rhubarb, wheat flakes, dry legumes, nuts, seeds, soy products, chocolate, strawberries, but also strong tea and coffee.

Limiting oxalates in the diet is particularly important in supporting the treatment of kidney stones and preventing recurrence, but also in preventing the formation of kidney stones.

Adequate fluid intake and/or simultaneous consumption of foods containing a lot of calcium may limit their adverse effects (but at the same time help reduce calcium absorption).

Iron in a meatless diet

Iron is found in both animal and plant products. However, non-heme iron contained in plant foods is characterized by poorer absorption.

Foods of plant origin rich in iron include: cereal products (it is worth paying attention to those fortified with iron), green leafy vegetables (e.g. kale), fruits (especially dried ones, e.g. apricots) and dry legumes. 

  • In the case of bread, it is worth choosing sourdough bread – the fermentation process causes some of the phytates that limit the absorption of iron to be broken down (see:  Calcium and phytates ). Similarly, in the case of soy-based products, it is worth choosing fermented ones (e.g. tempeh).
  • Simultaneous consumption of products rich in vitamin C (e.g. peppers, parsley, lemon, orange, broccoli, tomatoes) increases the absorption of this element.
  • Coffee and tea may additionally limit the absorption of iron from plant foods.

Iron deficiency causes  anemia , which manifests itself, among others, in: fatigue, poorer concentration, weakened cognitive functions, impaired immune system functions and poorer physical performance.


It is estimated that up to 56 percent zinc in a mixed diet comes from animal foods. Good sources of zinc for vegetarians are: cereal products, nuts and seeds, and dry legumes. These groups of products also contain phytates, which may limit the absorption of this element (see :  Calcium and phytates ).

Soaking and fermenting foods and choosing sourdough bread are steps you can take to reduce the phytate content of foods.

Organic acids from fruits may increase the absorption of zinc. For people who allow the consumption of certain animal products, good sources of zinc are: milk and dairy products, fish, seafood and eggs.

Zinc deficiency may manifest itself in: loss of appetite, impaired immune system function, and in case of severe deficiency also diarrhea, hair loss, poorer wound healing and taste disorders. These symptoms are not very specific, so they do not necessarily indicate a deficiency of this vitamin.

Omega-3 fatty acids

The diet should include 250 mg of long-chain omega-3 fatty acids (DHA, docosahexaenoic acid and EPA, eicosapentaenoic acid) per day.

They are important because they affect the functioning of the nervous system and vision, but also the immune and circulatory systems. Over 50 percent brain mass consists of fats, one of the dominant ones is DHA acid.

EPA and DHA acids can be supplied directly with food (fish, seafood, fish oil and seaweed) or converted in the body from other omega-3 acids (ALA, alpha-linolenic acid). Sources of ALA acids are: linseed, linseed oil, chia seeds and walnuts.

If the intake of DHA and EPA acids in the diet is too low, supplementation with an appropriate preparation (based on fish oil or algae – in the case of vegans) is recommended. If you have a cardiovascular risk or have had a heart attack, your doctor may recommend a higher fish intake or a dose of supplementation.

Is meat healthy?

Meat, especially red meat, has for some time been considered a food whose consumption should be limited. Is it right? In its 2016 recommendations, the Food and Nutrition Institute recommends limiting the consumption of red meat and processed meat products to 0.5 kg/week – among products rich in protein, it is recommended to choose fish, dry legumes and eggs.

Red meat  refers to beef, veal, pork, lamb, horse and goat meat, and sheep meat.

Processed meat  refers to meat that has been subjected to salting, fermentation, smoking or any other process to enhance flavor or preserve it. This group includes, among others: hot dogs, sausages, ham, and dried beef.

It has been found that when meat is processed at high temperatures, carcinogenic substances are produced (e.g. N-nitroso compounds, heterocyclic aromatic amines).

However, it has not yet been confirmed whether specific meat preparation methods have a different impact on cancer risk.

Processed meat has been classified by the International Agency for Research on Cancer (IARC) as carcinogenic to humans, based on sufficient scientific evidence from epidemiological studies demonstrating an association between its consumption and the development of colon cancer.

Meat - do we have to avoid it?Meat – do we have to avoid it?

In turn, red meat has been classified as a probably carcinogenic food, i.e. the link between its consumption and the development of cancer has so far been based on limited scientific evidence.

The estimated risk associated with red meat consumption is mainly for colon cancer, but there have also been reports of pancreatic and  prostate cancer .

It has been estimated that daily consumption of 50 g of processed meat increases the risk of colon cancer by approximately 18 percent, and probably by 17 percent. in case of daily consumption of 100 g of red meat.

A bit of confusion was caused by a work published in 2019, characterized by high methodological quality (without any conflict of interest).

The authors showed that a diet limiting red meat may have a beneficial effect on reducing overall death, death due to cardiovascular diseases, stroke, myocardial infarction and breast cancer, as well as cancers in general – but the strength of this evidence is very weak. /weak.

In short, in this review of the studies analyzed, the effect of a high-red meat diet was unclear, small, or not observed. It seems that due to these results, recommendations limiting the consumption of red meat may be liberalized soon. 

Impact on the environment

A diet based on plant-based products has a lower impact on the increase in greenhouse gas emissions (by up to 45% per year per capita), land use (by as much as 55%), water consumption (by about 37%) and the decline in biodiversity in compared to a diet rich in animal foods, especially red meat.

Learn more about the role of diet in climate change in our article on  the planetary diet . 

Advantages and disadvantages of a vegetarian diet

  • AdvantagesDisadvantagesIt is beneficial for the environment (including lower greenhouse gas emissions).
  • It may be helpful in controlling body weight and constipation, preventing cardiovascular diseases, type 2 diabetes and some cancers. 
  • Provides a large amount of vegetables and fruit (makes it easier to provide five portions of vegetables and fruit a day).
  • It contains a lot of vitamins, minerals and fiber.
  • It has a high content of antioxidants.
  • It may be cheaper.
  • It may be associated with the risk of deficiency of: vitamin B12, calcium, iron, zinc, long-chain fatty acids (EPA and DHA).
  • It may be necessary to supplement vitamin B12 if it cannot be obtained through the diet.


  • Agnoli C., Baroni L., Bertii I. et al.,  Position paper on vegetarian diets from the working group of the Italian Society of Human Nutrition . Nutrition, Metabolism & Cardiovascular Diseases. 2017; 27(12): 1037-1052.
  • Patient education: Vegetarian diet (The Basics) . UpToDate, Topic 121349 Version 2.0.
  • Jamrozik P. Vegetarian diet. Practical Medicine for Patients,,dieta-wegetarianska (access: December 30, 2019).
  • Schrier SL,  Clinical manifestation and diagnosis of vitamin B12 and folate deficiency . UpToDate, Topic 7155 Version 47.0.
  • Ankar A., ​​Kumar A.,  ​​Vitamin B12 Deficiency (Cobalamin ), (access: 2019.05.13).
  • Langan RC, Goodbred AJ,  Vitamin B12 Deficiency: Recognition and Management . American Family Physician 2017; 96(6): 384-389.
  • Rusińska A., Płudowski P., Walczak M. et al.,  Vitamin D Supplementation Guidelines for General Population and Groups at Risk of Vitamin D Deficiency in Poland – Recommendations of the Polish Society of Pediatric Endocrinology and Diabetes and the Expert Panel With Participation of National Specialist Consultants and Representatives of Scientific Societies – 2018 Update . Front Endocrinol 9:246, doi: 10.3389/fendo.2018.00246.
  • Dawson-Hughes B.,  Vitamin D deficiency in adults: Definition, clinical manifestations, and treatment . UpToDate, Topic 2022 Version 46.0.
  • Curhan GC,  Risk factors for calcium stones in adults . UpToDate, Topic 7375 Version 25.0.
  • Finkielstein VA, Goldfarb DS,  Strategies for preventing calcium oxalate stones . CMAJ. 2006;174(10):1407–1409. doi:10.1503/cmaj.051517
  • Wnęk D.,  Diet for kidney stones . Practical Medicine for Patients,,dieta-w-kamicy-nerkowej (access: December 30, 2019).
  • Schlemmer U., Frochlich W., Prieto RM et al.,  Phytate in foods and significance  for humans: food sources, intake, processing, bioavailability, protective role and analysis. Mol Nutr Food Res 2009; 53: 330-375.
  • Bohn L., Meyer AS, Rasmussen SK,  Phytate: impact on environment and human nutrition. A challenge for molecular breeding . J Zhejiang Univ Sci B. 2008;9(3):165–191. doi:10.1631/jzus.B0710640
  • Demory-Luce D., Motil KJ,  Vegetarian diets for children . UpToDate, Topic 5353 Version 15.0.
  • World  Health Organization. Q&A on the carcinogenicity of the consumption of red meat and processed meat ,  (accessed: December 30, 2019).
  • Zeraatkar D., Johnston BC, Bartoszko J. et al.,  Effect of lower versus higher red meat intake on cardiometabolic and cancer outcome: a systematic review of randomized trials . Ann Intern Med 2019, doi: 10.7326/M19-0622.
  • Academy of Nutrition and Dietetics. VegPlate: a mediterranean-based food guide for italian adults, pregnant, and lactating vegetarians . Journal of the Academy of Nutrition and Dietetics 2018; 118(12): 2235-2243.
  • Calder P.,  Docosahezaenoic Acid . Ann Nutr Metab 2016; 69 (suppl 1): 8-21.
  • EAT -Lancet Commission. Summary Report of the EAT-Lancet Commission. Healthy Diets From Sustainable Food Systems . Food Planet Health. 2019.
  • Kushi LH, Cunningham JE, Hebert JR, et al.,  The macrobiotic diet in cancer . The Journal of Nutrition 20011; 131(11): 3056-3064.
  • National Institutes of Health. Zinc. Fact sheet for health professionals ,  (accessed: January 2, 2019).
  • National Institutes of Health . Fact sheet for health professionals ,  (accessed: January 2, 2019).
The presented medical information should not be treated as guidelines for medical treatment for each patient. The medical procedure, including the scope and frequency of diagnostic tests and/or therapeutic procedures, is decided individually by the doctor, in accordance with medical indications, which he determines after reviewing the patient’s condition. The doctor makes the decision in consultation with the patient. If the patient wants to perform tests that are not covered by medical indications, the patient has the option of having them performed for a fee.
Previous Post Next Post

نموذج الاتصال