A Bowl and a Green
Eating this way for years shouldn't cost you your health. This page covers only what vegetarian diets most often miss, each point with its source.
First, this one
Plant foods contain no vitamin B12 naturally. On a vegetarian diet it has to come from a supplement or fortified food. There is no third way.
A B12 deficiency damages nerves, and folate can mask it early on — blood work looks fine while you are already short. By the time your hands tingle, some of the damage does not come back. It is the one thing here with no room to improvise.
What gets missed
vitamin B12
Must supplementHematopoiesis and nerves depend on it. Absence begins with fatigue, numbness in hands and feet, and poor memory; neurological damage may not return for a long time. The trouble is that taking too much folic acid will cover up blood images. Blood tests look normal, but there is already a shortage of people.
Where it comes from
- supplements
- Fortified foods: breakfast cereals, fortified soy milk, nutritional yeast
What actually works
Adults 2.4 mcg per day, 2.6 during pregnancy and 2.8 during breastfeeding. Plant-based foods naturally contain no B12 — only fortified ones. There is no maximum tolerable intake of B12, the toxicity is extremely low, and the health is not healthy, so there is no need to panic if you take more. People who take metformin or antacid drugs for a long time will have lower absorption and should be checked regularly.
NIH Office of Dietary Supplements · Vitamin B12
ironed
Worth watchingThere is non-heme iron in plants, and the absorption rate is inherently lower than in meat.
Where it comes from
- Beans and soy products
- dark leafy vegetables
- pumpkin seeds, sesame
- Fortified muesli
- dried fruit
What actually works
Eating the same meal as vitamin C boosts absorption — bell peppers, broccoli, and tangerines are all good. Don't drink tea or coffee before or after meals. The polyphenols in them will block iron and be separated for an hour.
UK National Health Service · Vegan Diet
calcium
Worth watchingAfter not drinking milk, calcium should be collected from elsewhere.
Where it comes from
- Tofu with brine or gypsum
- Calcium-added soy milk
- tahini
- broccoli, kale, cabbage
What actually works
Spinach and amaranth seem high in calcium, but they are also high in oxalic acid, so you can't actually absorb much. Don't count them in the calcium of the day. Tofu depends on the ingredient list — use brine or gypsum to supplement calcium, not gluconolactone.
UK National Health Service · Vegan Diet
vitamin D
Worth watchingI ate calcium, and I can't use it without D.
Where it comes from
- Bask in the sun
- Fortified soy milk, fortified cereal
- supplements
What actually works
Eating and sunbathing alone is not enough in autumn and winter. In particular, cities at high latitudes — London, Berlin, Seattle, and Toronto — can't get out the sun for less than half a year. There are two types of supplements: D2 is vegan; most D3 comes from lanolin, so be sure to identify lichen (lichen) sources if you are vegan.
UK National Health Service · Vegan Diet
omega-3 fatty acids
Worth watchingThe eyes and brain need EPA and DHA, and plants provide ALA.
Where it comes from
- Flaxseed, chia seed, hemp seed
- walnuts
- Linseed oil, perilla oil
What actually works
The body can convert ALA to EPA and DHA, but the efficiency is very low, and the expected conversion is not reliable. If you eat ground flaxseeds, the whole grains will be removed as they are. If you want to directly supplement DHA, algae oil is the only source of nutrients — DHA in fish originally comes from eating algae.
UK National Health Service · Vegan Diet; Dietary Guidelines for Chinese Residents (2022) For Vegetarians
iodine
Worth watchingtubular thyroid gland. Both insufficiency and overdose have happened.
Where it comes from
- iodized salt
- kelp, seaweed
What actually works
Don't use kelp as a daily source of iodine — its iodine content fluctuates greatly, and you may be overdosed after one meal. Iodized salt is much more stable. People who use non-iodized salt or low sodium salt should take care of themselves.
UK National Health Service · Vegan Diet
zinc
Worth watchingPhytic acid in whole grains and beans binds zinc and makes it unable to absorb it.
Where it comes from
- Beans, soy products
- Whole Valley
- pumpkin seeds, cashew nuts
What actually works
Soaking, sprouting, and fermentation can remove some of the phytic acid — soaking and cooking beans, steamed buns, and tempura are all better absorbed than those that have not been treated.
UK National Health Service · Vegan Diet
proteins
Rarely a problemIt's said the most, but it's actually the least likely to go wrong.
Where it comes from
- Soy beans and products: tofu, soy milk, tempura, yuba
- Other legumes
- nuts, seeds
- Whole Valley
What actually works
Vegetarian adults are 50 to 80 grams of soy and products and 25 to 60 grams of ghee daily. You don't have to pack every meal into “complete protein” — you can change the variety of foods in a day, and the amino acids will fill up on their own.
Dietary Guidelines for Chinese Residents (2022) For Vegetarians
About fermented soybean products and algae
The Dietary Guidelines for Chinese Residents (2022) recommend that vegetarians eat 5 to 10 grams of fermented soy products every day, in part because they contain B12. The US National Institutes of Health clearly stated that plant-based foods naturally do not contain B12.
That's not a difference in wording. Most of the tests found in fermented milk, tempeh, seaweed, and spirulina are inactive analogues — they can't be used by humans, and they can also take up blood tests, making the results easy to see. So this page separates the two things: fermented soy products should be eaten; they are good for the intestines and other nutrients; however, B12 only recognizes supplements and fortified foods.
US National Institutes of Health Office of Dietary Supplements · Vitamin B12; Dietary Guidelines for Chinese Residents (2022) Vegetarians
Sources
- US National Institutes of Health Office of Dietary Supplements · Vitamin B12 Instructions
- UK National Health Service · Vegan Diet
- Chinese Nutrition Society · Dietary Guidelines for Chinese Residents (2022) Dietary Guidelines for Vegetarians
This page summarises published guidance; it is not medical advice. For doses, whether to get tested and what to test, ask a doctor — especially if you are pregnant, breastfeeding, raising a child on this diet, or taking metformin or acid-reducing medication long term.