Micronutrients Missing In Vegan Diets: What You Need To Know

A vegan diet can be deficient in several micronutrients, including vitamins B12 and D, iodine, calcium, iron, and zinc. Vitamin B12 is almost exclusively found in animal-sourced foods, and vegans who don't take supplements are at a higher risk of deficiency than vegetarians. Vitamin D can be obtained from sunlight, but vegans may still be deficient if their sun exposure is limited. Iodine, calcium, and zinc are also typically found in animal-based foods and can be deficient in a vegan diet. Iron is present in plant-based foods but is poorly absorbed, so vegans may need twice the recommended amount to meet their daily needs.

Vitamin B12

Lacto-ovo-vegetarians can get adequate amounts of this nutrient from dairy products and eggs, but it is much more challenging for vegans. Vegans who don't take supplements are at a higher risk of vitamin B12 deficiency than vegetarians.

To get sufficient amounts of vitamin B12, people following a vegan diet must take supplements or eat food that has been fortified with this nutrient. These include enriched yeast extracts, nori seaweed (a type of marine algae), and tempeh (a fermented soy product). However, seaweed may not provide a sufficient amount on its own, and raw or freeze-dried nori may be better than conventionally dried types as some vitamin B12 is destroyed during the drying process.

Vitamin D3

Sources of Vitamin D3

The best sources of vitamin D3 are fatty fish and egg yolks. Other sources include supplements, cod liver oil, or enriched foods like milk or cereals.

Since the main dietary sources of vitamin D3 are not plant-based, vegetarians and vegans may be at a higher risk of deficiency, especially during the winter in countries north or south of the equator.

Symptoms of Vitamin D Deficiency

Deficiency in vitamin D is linked to an increased risk of various adverse conditions, including osteoporosis, with an increased risk of fractures in older adults, multiple sclerosis, impaired brain function, and muscle wasting and reduced strength, especially in older adults.

Supplements

Vegan vitamin D3 supplements made from lichen are available to purchase online.

DHA (Docosahexaenoic acid)

DHA, or Docosahexaenoic Acid, is an essential omega-3 fatty acid that is important for normal brain development and function. It is a structural component of the skin, eyes, and brain, and plays a critical role in brain tissue growth and function, especially during development and infancy. DHA is crucial for the formation of structures in the brain and eyes during pregnancy and early life.

DHA is mainly found in seafood, such as fish, shellfish, and fish oils, as well as certain types of algae. While it can also be found in meat, dairy, and eggs, the amounts are much smaller. Because DHA is not sufficiently produced by the body, it is important to obtain it through diet or supplements.

Deficiency in DHA can have adverse effects on mental health and brain function, especially in children. In addition, inadequate DHA intake in pregnant women may negatively impact fetal brain development. Low levels of DHA have been linked to an increased risk of memory complaints, dementia, and Alzheimer's disease. DHA also plays a role in eye and vision health, and a deficiency may cause vision problems, especially in children.

Vegans are at risk of DHA deficiency due to the limited sources of this nutrient in a plant-based diet. However, vegans can supplement their DHA intake by consuming algal oil, which is derived from certain microalgae. These supplements are available in specialty stores and online.

Iodine

The body does not produce iodine, so it must be obtained from the diet. The recommended daily amount of iodine for adults is 150 mcg. Iodine deficiency can lead to hypothyroidism, with symptoms such as an inability to tolerate colder temperatures.

Studies have shown that vegans are at risk of iodine deficiency. A 2019 study in Norway found that vegans had a median urinary iodine concentration (MUIC) of 43 mcg/L, indicating moderate iodine deficiency. Another study from 2020 in the same country reported similar results, with 55% of vegans having iodine levels below the recommended cut-off for sufficient status.

Strategies for Vegans

To ensure adequate iodine intake, vegans should include iodine-rich plant-based sources like seaweed in their diet. However, due to the variable iodine content in seaweed, it is important to monitor intake to avoid excessive levels. Iodine-containing supplements can also help vegans meet their daily requirements.

Iron

• Dried fruits, such as raisins
• Iron-fortified cereals
• Beans, such as kidney beans, soybeans, and lima beans
• Dark green leafy vegetables, such as spinach and swiss chard
• Tofu and tempeh
• Blackstrap molasses

Frequently asked questions