Vitamin B12

The daily requirement for vitamin B12 is 2.5 μg/day, and it increases during pregnancy, rising to 4.5 μg/day.

Vitamin B12 is found mainly in foods of animal origin. Among the best sources are offal, in particular liver: lamb liver (around 60 μg/100 g), veal liver (52.6 μg/100 g), and chicken liver (16.9 μg/100 g). To limit retinol intake, chicken liver is recommended, with a cooked portion of 75 g per week considered safe after the first trimester of pregnancy. 

Animal hearts, such as those of beef or lamb, are also rich in B12, with around 11 μg per 100 g. Among seafood, cooked shellfish, such as clams, can contain up to 39.5 μg/100 g, octopus 36 μg/100 g, and oysters 28.6 μg/100 g. Among fish, mackerel is the richest (19 μg/100 g), followed by anchovies (15.3 μg), sardines (13.6 μg), and herring (13.4 μg).

Certain seaweeds, such as nori, also provide vitamin B12, with around 39 μg/100 g, and dulse with 9.81 μg/100 g. Dairy products contain more modest amounts, such as parmesan with 2.64 μg/100 g and soft cheeses around 2.5 μg/100 g.

It all depends on the individual. 

Vitamin B12 deficiency can be due to absorption difficulties, particularly if the body is unable to release vitamin B12 from food in the intestine. This situation occurs notably in people who lack intrinsic factor, a protein necessary for B12 absorption (as in pernicious anaemia), or who have undergone gastrointestinal surgery or taken certain medications (for example, metformin for diabetes). Low dietary intake of B12, often seen in people following vegan or vegetarian diets, can also lead to deficiency.

The groups most at risk of vitamin B12 deficiency include: 

People with pernicious anaemia: This autoimmune condition prevents the production of intrinsic factor, making it impossible to absorb vitamin B12 despite an adequate diet.

People with gastrointestinal disorders: Conditions such as coeliac disease or Crohn's disease can prevent adequate absorption of vitamin B12.

People with low gastric acid: Reduced acidity in the stomach prevents the release of vitamin B12 bound to food, limiting its absorption.

People following vegetarian or vegan diets: Natural sources of vitamin B12 come predominantly from animal products, which puts vegans and vegetarians at increased risk of deficiency. In this case, taking a women's food supplement containing it may be essential. 

A vitamin B12 deficiency can lead to various symptoms, such as megaloblastic anaemia (characterised by large, abnormal red blood cells), a reduction in white blood cells and platelets, inflammation of the tongue, fatigue, palpitations, pale skin, memory loss, and weight loss. Neurological effects, such as numbness and tingling in the hands and feet, are also common, and can even extend to cognitive disorders such as dementia.

Vitamin B12, or cobalamin, encompasses four different compounds distinguished by the molecular group bound to the cobalt atom. Among them, methylcobalamin and adenosylcobalamin are the active forms used directly by the body. The other two forms, cyanocobalamin and hydroxocobalamin, require conversion to become active.

Cyanocobalamin: Although it can increase B12 levels, cyanocobalamin must first be broken down into cobalamin and cyanide before being converted into active forms (methylcobalamin or adenosylcobalamin). This process is less efficient in certain people with genetic mutations, and the release of cyanide, even in small quantities, is not without consequence.

Hydroxocobalamin: It is as effective as the other forms at raising B12 levels, but it can inhibit nitric oxide synthase, an enzyme essential for the production of nitric oxide, which plays a role in blood pressure regulation and placental development during pregnancy. Consequently, taking it during pregnancy could pose risks of hypertension.

Methylcobalamin: This form is directly integrated into the methylation cycle without any further conversion, allowing the body to conserve energy. 

Adenosylcobalamin: Naturally ready to use, it can also be converted into methylcobalamin without involving the MTHFR gene, which is important for folate metabolism. As such, even people with variations of the MTHFR gene can use it effectively.

Here are the main nutrients at risk of deficiency for people following a vegan diet:

Vitamin B12: Deficiency in vitamin B12 is almost inevitable for vegans, as this vitamin is found exclusively in animal-derived foods. It is essential for neurological function and the formation of red blood cells.

Vitamin D: Although the body can synthesise vitamin D through sun exposure, dietary intake is also necessary. Deficiency affects calcium metabolism, a mineral that also requires monitoring on a vegan diet. Our vitamin D in pregnancy is vegan and suitable for everyone.

Iron: Haem iron, which is more readily absorbed by the body, is found only in animal-derived foods. Plant foods contain non-haem iron, which is absorbed less efficiently. Our iron supplement for pregnant women contains a dose tailored to women's needs. 

Omega-3: Essential for brain health, particularly during pregnancy and breastfeeding, omega-3s are found in vegetable oils in the form of ALA, but conversion to DHA and EPA (the active forms) is inefficient. Our supplement omega-3 in pregnancy is vegan.

Choline: Crucial for the development of the baby's brain during pregnancy and breastfeeding, choline is often insufficient in a vegan diet, hence the need for supplementation. Our supplement choline in pregnancy vegan helps to meet your needs. 

Iodine, zinc and selenium: These minerals are found in plant foods, but in insufficient quantities. A varied and balanced diet is essential to avoid deficiencies.

Proteins, which are found in abundance in plant-based foods, but if the sources of protein intake are not combined correctly, it is possible to consume insufficient amounts of essential amino acids. Animal proteins are indeed more readily absorbed. 

These risks can be managed with supplements or strategic dietary choices to maintain optimal nutritional balance.