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Which supplements should vegetarians and vegans take?

Vegetarians and vegans are at risk of certain nutritional deficiencies. Discover which nutrients they could easily be missing out on and the key supplements they should be taking.
Vegans and vegetarians eating
Vegetarians and vegans, watch out for deficiencies!
Rédaction Supersmart.
2022-04-26Comments (0)

Vegetarianism, veganism: definitions and differences

With the increase in recent years in the number of diet options (paleo, raw-food, etc), it’s worth taking a moment to clarify some terms which often get misused or mixed up.


Vegetarian and vegan diets

Irrespective of the type of diet, the most important thing (and this applies to omnivores too), is to ensure a varied and balanced intake of food!

And if this is slightly more of a challenge for vegetarians and vegans, it’s simply because plant protein sources are almost always sources of carbohydrates too, and even fats.

In addition, and most importantly, it’s necessary to consider not just protein intake but essential amino acid intake: to provide the body with all the amino acids it needs, it’s important to achieve a balance between pulses and grains (2).

To ensure an adequate intake of protein (between 0.8g/kg of bodyweight and 2g/kg of bodyweight for body-builders, for example) and essential amino acids, lacto- and ovo-vegetarians sometimes choose to take powdered whey protein, which contains all the essential amino acids and provides a significant amount of protein.

Also important is a high intake of raw fruits and vegetables (especially those rich in vitamin C to promote absorption of plant-source iron which is less well-absorbed than that from animal sources), wholegrains, various legumes and pulses (not just tofu), and spices: by varying your range of foods in this way, and including colour and diversity in your meals, you should be able to give your body what it needs … to some extent, at least (3).

The fact is that, despite all these efforts, there are some nutrients that are difficult – if not impossible - to find in sufficient amounts in a vegan diet. Let's explain....

Vitamin D: essential for everyone, whatever their diet!

This is explored in detail in our article on vitamin D: according to doctors, scientists and health organisations, modern lifestyles in the West make it impossible to obtain enough vitamin D, whatever the diet.

So this applies to vegans, vegetarians, and omnivores alike: it’s advisable to take a vitamin D supplement, at least in autumn, winter and the beginning of spring (for example, the vegan vitamin D product Vegan D3) (4).

Vitamin B12: an essential supplement for vegetarians and vegans

There are many misconceptions surrounding the issue of vitamin B12 for vegans and vegetarians. So to clear up any confusion: no plant-source food can provide the body with the amount of vitamin B12 it needs, not even spirulina. Even though this algae does contain vitamin B12, it is not absorbed by the body (5-6).

Vitamin B12 is actually produced from the fermentation of plants by bacteria, for example, in the stomachs of ruminant animals. It is also produced in the stools of certain coprophage herbivores (such as rabbits which eat their own faeces in order to obtain nutrients not directly provided by their digestion) (7).

And since we human beings are not ruminants, we are unable to produce vitamin B12 by consuming plants.

That’s why vegetarians need to supplement with vitamin B12 (with, for example, the product Methylcobalamine). And to be suitable for vegans it must be produced from bacterial fermentation.


Iodine and low-salt diets

While almost all table salt available in Europe is enriched with iodine to prevent cretinism, vegetarians and vegans following a low-salt diet should watch their iodine intake.

Iodine supports normal energy metabolism, mental and nervous system function, thyroid hormone production and thyroid function, as well as normal skin, but can be lacking in a diet that’s too low in salt.

In such cases, iodine supplementation should be considered (with, for example, the product Potassium Iodide) (9).

Iron: for vegetarians and vegans with diagnosed deficiency

As mentioned, iron from plant sources, known as ‘non-haem iron’, is less bioavailable: in the region of 5% compared with 25% for haem iron, the kind obtained from meat (10).

However, plant-source iron can be made more bioavailable by eating a diet rich in vitamin C. In winter, this means regularly eating foods such as red cabbage and/or kiwi and/or lamb’s lettuce and/or spinach leaves, etc. It’s obviously easier in spring and summer when most seasonal fruits and vegetables contain significant amounts of vitamin C (11).

In the case of diagnosed anaemia in vegetarians or vegans, it may therefore be wise, under medical supervision, to take an iron supplement, for example, Iron Bisglycinate).

Zinc and selenium supplements: if in doubt

Let’s now consider zinc and selenium deficiency. A diet that contains a lot of pulses and grains can lead to excess levels of phytate or phytic acid in the body (12).

Even though phytate is a powerful antioxidant and may help combat osteoporosis, it’s often also described as an ‘anti-nutrient’.

Abundant in pulses, grains and nuts (and all seeds, in fact), it’s thought to impair intestinal absorption of minerals and trace-elements (13).

In order to reduce intake of phytates when eating a diet rich in legumes, nuts and grains, it’s therefore strongly recommended to soak these foods in water for several hours and rinse them before cooking thoroughly.

If in doubt, or if you have symptoms of zinc and selenium deficiency, consider supplementing with zinc (such as with the product Zinc Orotate) and selenium (L-Selenomethionine).


  1. MATHIEU, Sasha et DORARD, Géraldine. Végétarisme, végétalisme, véganisme: aspects motivationnels et psychologiques associés à l’alimentation sélective. La presse médicale, 2016, vol. 45, no 9, p. 726-733.
  2. MARIOTTI, François et GARDNER, Christopher D. Adéquation de l’apport en protéines et acides aminés dans les régimes végétariens. Cahiers de Nutrition et de Diététique, 2020, vol. 55, no 2, p. 66-81.
  3. MESSINA, Mark et MESSINA, Virginia. The dietitian's guide to vegetarian diets: issues and applications. Aspen, 1996.
  4. Rapport de l’Académie nationale de médecine. Statut vitaminique, rôle extra osseux et besoins quotidiens en vitamine D. Bull Acad Natle Med. 2012, 196, 1011.
  5. PAWLAK, Roman, PARROTT, Scott James, RAJ, Sudha, et al.How prevalent is vitamin B12 deficiency among vegetarians?. Nutrition reviews, 2013, vol. 71, no 2, p. 110-117.
  6. DAGNELIE, Pieter C., VAN STAVEREN, Wija A., et VAN DEN BERG, Henk. Vitamin B-12 from algae appears not to be bioavailable. The American journal of clinical nutrition, 1991, vol. 53, no 3, p. 695-697.
  7. ALLEN, Lindsay H. Vitamin B-12. Advances in Nutrition, 2012, vol. 3, no 1, p. 54-55.
  8. HUNT, Alesia, HARRINGTON, Dominic, et ROBINSON, Susan. Vitamin B12 deficiency. Bmj, 2014, vol. 349.
  9. DELANGE, Francois. Risks and benefits of iodine supplementation. The Lancet, 1998, vol. 351, no 9107, p. 923-924.
  10. HUNT, Janet R. Bioavailability of iron, zinc, and other trace minerals from vegetarian diets. The American journal of clinical nutrition, 2003, vol. 78, no 3, p. 633S-639S.
  11. MONSEN, Elaine R., et al.Iron nutrition and absorption: dietary factors which impact iron bioavailability. Journal of the American Dietetic Association, 1988, vol. 88, no 7, p. 786-790.
  12. DE BORTOLI, Maritsa Carla et COZZOLINO, Silvia Maria Franciscato. Zinc and selenium nutritional status in vegetarians. Biological trace element research, 2009, vol. 127, no 3, p. 228-233.
  13. REDDY, N. R., SATHE, S. K., et SALUNKHE, D. K. Phytates in legumes and cereals. Advances in food research, 1982, vol. 28, p. 1-92.


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