Nutrient Deficiency in Vegan & Vegetarian Diets

Whether it’s for ethical, religious, or environmental reasons, most people know at least one friend or family member who has ditched animal products and taken up a purely plant-based diet. Though it may seem like a common fad, in the United States, 5% of the population is estimated to be vegetarian, along with 3% for vegans. Despite being labeled a “healthy” diet, there are multiple nutrients that one cannot obtain from a purely plant-based diet, these include: vitamin B-12, creatine, carnosine, taurine, vitamin D3, heme-iron, the omega-3 fat DHA, and sulfur. Here’s how that happens and why it matters, along with what you can do to improve your consumption and overall health.

Vitamin B-12

In terms of health risks from eating a vegetarian or vegan diet, most people think of vitamin B-12 deficiency. Vitamin B-12 (cobalamin) is present in natural form only in animal sources of food, such as meat, fish, dairy products, and eggs. Your body requires it for several vital functions. Signs of a deficiency include impaired brain function, weakness, and fatigue. Health risks associated with this deficiency include neurological and psychiatric disorders, damage to the nervous system, and an increased risk of heart disease.

You can increase your intake through supplements and foods containing B-12. Some of the best sources of vitamin D are: clams, organ meats such as liver, eggs, sardines, beef, and salmon. Unfortunately, many of these  fortified cereals, certain energy bars, eggs, and dairy products are also good sources of Vitamin B-12. To help prevent B-12 deficiency, don’t rely on one source of vitamin B-12 in your diet. Instead, eat a variety of fortified foods. Including probiotics, which may assist with better absorption of B-12.


Creatine is an amino acid found in animal foods that is important for muscle energy, proper function of your central nervous system, and brain health. A trio consisting of creatine, animal-based omega-3 fats, and Coenzyme Q10 is essential for proper mitochondrial function. Insufficiencies of these may play a role in multiple sclerosis(MS) and other nerve degenerative disorders.

Creatine is not essential in the diet, since it can be produced by the liver. However, vegetarians have lower amounts of creatine in their muscles. Because creatine is not found in any plant foods, vegetarians and vegans can only get it from supplements.


Carnosine is a dipeptide composed of two amino acids: beta-alanine and histidine. It’s a potent antioxidant, the highest concentrations of which are found in your muscles and brain. If you’re a vegetarian, you will have lower levels of carnosine in your muscles. This is one reason why many strict vegans who do not properly compensate for this and other nutritional deficiencies tend to have trouble building muscle.

A more efficient alternative to carnosine supplements, is its primary precursor, beta-alanine. Foods containing beta-alanine are known to efficiently raise carnosine levels in your muscles, and studies looking at increasing athletic performance with carnosine have found beta-alanine to be more effective of the two.

Vitamin D3

Vitamin D is a steroid hormone that you get primarily from sun exposure and certain foods. In recent years, the importance of vitamin D sufficiency for optimal health and chronic disease prevention has become increasingly well recognized. In a recent interview with researcher Dr. Robert Heaney, while sun exposure is the primary and likely ideal way to get your vitamin D, researchers are also finding that a number of foods contain vitamin D3 (cholecalciferol) in biologically meaningful quantities.

Even if you ate animal foods you would most likely resemble almost 90 percent of the population and be deficient in vitamin D. Since most of your vitamin D is produced when your skin is exposed to sunlight, shunning animal foods does not equate to a direct threat of vitamin D deficiency. However, if you’re also shunning the sun then it would definitely be wise to consider a vitamin D3 supplement, as deficiency is virtually guaranteed at that point.

When supplementing, keep the following considerations in mind: 

  1. Use supplemental vitamin D3, not D2. They are not interchangeable, and vitamin D2 may do more harm than good when taken as a supplement.
  2. Increase your vitamin K2 along with D3. They work in tandem to reduce arterial calcification. Vitamin K2 deficiency is actually what produces the symptoms of vitamin D toxicity, which includes inappropriate calcification that can lead to hardening of your arteries.
  3. It’s important to maintain balance between vitamin D, vitamin K2, calcium, and magnesium. Lack of balance between these nutrients is why calcium supplements have become associated with increased risk of heart attack and stroke.

Animal-Based Omega-3 DHA

Docosahexaenoic acid (DHA) is an essential omega-3 fat found in marine animals such as fish and krill. It’s important for normal brain function and heart health. In the body, DHA can also be made from the omega-3 fatty acid ALA, which is found in high amounts in flaxseeds, chia seeds, and walnuts. However, the conversion of ALA to DHA is inefficient. For this reason, vegetarians and vegans are often lower in DHA than meat eaters.

Most of the health benefits linked to omega-3 fats are linked to the animal-based EPA and DHA, not the plant-based ALA. That said, plant-based omega-3 fats are NOT inherently harmful and should by no means be avoided. Ideally, you’d get a combination of both. For example, you could combine flax and hemp in your diet with an animal-based omega-3 in the form of krill oil, which has an antioxidant potency that is 48 times greater than fish oil. From an environmental perspective, krill harvesting is also a far more sustainable and eco-friendly choice compared to fish oil.


Iron is found in both plant and animal foods, but the type of iron differs. Heme-iron is found only in meat, primarily red meat. Non-heme iron is found in plants, but this type of iron is more poorly absorbed by your body. Moreover, heme-iron helps with the absorption of non-heme iron from plants, thus vegans and strict vegetarians have an elevated risk of anemia, even though they’re getting plant-based iron.

Iron serves many functions in your body, but one of the most important is to bind to the hemoglobin molecule and serve as a carrier of oxygen to your tissues. Without proper oxygenation, your cells quickly start dying. So anemia is not to be taken lightly. The best source of iron is high-quality red meat, preferably grass-fed and organic. Unless you are a premenopausal woman or child or have iron deficiency from a recent or chronic blood loss, then you likely don’t need to be at all concerned about iron supplementation.

If you do need supplementation, then a strong word of caution is in order. Ferrous sulfate, a form of iron found in many multivitamins, is a relatively toxic inorganic metal that can lead to significant problems. A safe form of supplement is carbonyl iron.


Taurine is another dietary component that appears to play an important role in brain and heart health. It’s also important for muscle function, bile salt formation, and antioxidant defenses. Together with magnesium, it has a calming effect on your body and mind. Taurine is a byproduct of the sulphurous amino acids cysteine and methionine (a sulfonic acid), and is only found in animal foods. Examples include seafood, red meat, poultry, and dairy products. It’s also available in supplement form.

It is not essential in the diet since small amounts are produced by the body. However, dietary taurine may play a major role in the maintenance of taurine levels in the body, especially since levels of taurine are significantly lower in vegans and vegetarians than in meat eaters.


Derived almost exclusively from dietary protein, such as fish and high-quality (organic and/or grass-fed and pastured) beef and poultry. Meat and fish are considered “complete” as they contain all the sulfur-containing amino acids you need to produce new protein. When you abstain from animal protein you significantly increase your risk of sulfur deficiency and related health problems.

Sulfur plays a vital role in the structure and biological activity of both proteins and enzymes. If you don’t have sufficient amounts of sulfur in your body, this deficiency can cascade into a number of health problems, as it can affect the bones, joints, connective tissues, metabolic processes, and more.

Areas where sulfur plays an important role include:

  • Your body’s electron transport system, as part of iron/sulfur proteins in mitochondria, the energy factories of your cells
  • Vitamin-B thiamine (B1) and biotin conversion, which in turn are essential for converting carbohydrates into energy
  • Synthesizing important metabolic intermediates, such as glutathione
  • Proper insulin function. The insulin molecule consists of two amino acid chains connected to each other by sulfur bridges, without which the insulin cannot perform its biological activity

Vegans and vegetarians are at increased risk of cardiovascular diseases. Low intake of sulfur amino acids by vegetarians and vegans explains the origin of hyperhomocysteinemia (high blood levels of homocysteine). Which may lead to blood clots in your arteries and can also lead to heart attack and stroke. If you don’t eat meat you can get sulfur from coconut oil and olive oil.

Other plant-based sources that contain small amounts of sulfur — provided the food was grown in soil that contains adequate amounts of sulfur — include wheat germ, legumes, garlic, onions, Brussels sprouts, asparagus, and kale. As for supplements, methylsulfonylmethane, commonly known by its acronym MSM, is an option. MSM is an organic form of sulfur and a potent antioxidant, naturally found in many plants.

In Conclusion…

Most nutrient deficiencies will make you susceptible to health complications. Due to this, regardless of your dietary restraints, it is highly important to supply your body with the nutrients you’re not getting from day-to-day meals. By doing so, you prevent, and also reduce your risk of a number of conditions that could arise with time. Take the necessary steps to ensure that you’re getting a sufficient intake of minerals and nutrients from your diet and supplementation. Trust us, it will go a long way!