In recent years, the traditional Greek Mediterranean diet and vegan diets have become two of the most popular plant-based diet patterns in the health movement.
In some corners of the nutrition industry it has become general accepted dogma that vegan diets are nutritionally superior to virtually every diet in the world including the likes of omnivorous diet patterns such as the Mediterranean diet.
However, this isn’t supported or based on an understanding of nutritional science, the basic fact will always be that omnivorous plant-based diets are significantly more nutritionally adequate than strict vegan diets naturally.
Strict vegan diets are so nutritionally inadequate that they cannot even reliably provide virtually any dietary intake of basic essential nutrients such as Vitamin B12 or Vitamin D, without resorting entirely to synthetic supplements and/or fortified foods.
Nor do vegan diets often provide any direct intake of long-chain forms of Omega-3 fatty acids for example. This is just a few examples of the problematic nature of vegan diets.
There are a whole host of other nutrients that vegan diets either do not reliably provide or are lacking in.
I truly believe the poor nutritional adequacy of vegan diets is entirely why they are so poorly sustained long-term by the majority of individuals who try them and why omnivorous plant-based diets are significantly better for adherence.
Both the Mediterranean and vegan diets are heralded for their potential cardiovascular health benefits, however many nutrients that vegan diets can be lacking in such as Vitamin B12, Vitamin D, long-chain Omega-3 fatty acids, conditional essential nutrients such as taurine and carnitine, might actually end up having negative and adverse consequences on cardiovascular function in certain at-risk groups who are already functionally depleted in these nutrients and/or have issues with methylation capacity/homocysteine metabolism.
Let’s take a look at five reasons why I believe a traditional Greek style Mediterranean diet is significantly nutritionally superior to strict vegan diet patterns.
1. Vitamin B12
It is for this reason that vegans are required to supplement with synthetic vitamin b12 supplements in order to compensate for the lack of natural dietary vitamin b12 intake.
A number of studies have now found that vegans have the lowest levels of vitamin B12 and highest rates of clinical deficiency out of all dietary groups as a consequence.
Vitamin B12 deficiency can have profound consequences on health, especially if left untreated including irreparable nervous system damage and even spinal-cord degeneration and increasing cardiovascular disease risk through inadequate remethylation of homocysteine.
The Mediterranean diet on the other hand provides ample dietary intake of Vitamin B12 from foods such as oily fish/seafood, lean poultry, occasional red meat and dairy foods.
A single portion of oily fish such as sardines can provide over 100% of the DV(daily value) for Vitamin B12.
The lack of a reliable Vitamin B12 dietary source with vegan diets is one of the chief reasons why I believe the likes of a Mediterranean diet is significantly nutritionally superior.
Following a diet that may provide no direct intake of active forms of cobalamin such as methylcobalamin, adenosylcobalamin is potentially risky and not surprisingly the research is confirming that many vegans are not maintaining healthy Vitamin B12 status as a consequence.
2. Long-Chain Omega-3 Fatty Acids(EPA/DHA)
Vegan diets typically rely purely on the short-chain form of Omega-3 fatty acids known as ALA (Alpha-linolenic acid), which has to first convert to EPA (eicosapentaenoic acid) and then finally to DHA (docosahexaenoic acid) in the body.
Studies have found that conversion of ALA to DHA may be unreliable and restricted in humans.
The research has also shown that vegetarians and vegans have lower levels of DHA in the body(plasma, serum, erythrocytes, adipose, and platelet) compared to omnivores.
Unlike vegan diets, the Mediterranean diet provides generous intake of both the short-chain form of Omega-3 in ALA from plant-foods such as nuts, leafy greens and seeds, along with good intake of the long-chain form of Omega-3 fats in the form of EPA and DHA from foods such as oily fish and other seafood.
Any diet for supporting cardiovascular health should be perfectly capable of providing good intake of both the short-chain and long-chain omega-3 fatty acids for optimal cardiovascular protection.
The only way vegans can once again obtain direct intake of long-chain Omega-3 fatty acids is by including Algae DHA Oil Vegan Supplements into their diets.
DHA (docosahexaenoic acid) has been shown to significantly reduce triglyceride levels, which are an independent cardiovascular disease risk factor. Many high carb/low fat vegans end up with increased triglycerides levels, due to the excessive consumption of carbohydrates and lack of healthy fats in their diets.
3. Vitamin D
Another basic essential nutrient that vegan diets typically fail to provide any natural reliable dietary intake of is Vitamin D, aside from those who regularly eat sun-dried edible mushrooms, which have shown to be a source of Vitamin D.
Vegan diets typically rely purely on fortified foods and synthetic Vitamin D supplements in order to boost dietary Vitamin D intake.
The Mediterranean diet on the other hand provides an extremely important and valuable dietary boost of Vitamin D3 from the regular consumption of Oily fish such as sardines.
Oily fish such as sardines are a rare dietary source of Vitamin D3 and a single can portion can provide around 50% of the DV(daily value) for Vitamin D.
Dietary intakes of Vitamin D appear to be low in vegans who don’t obtain adequate sun exposure. Although since the introduction of various Vegan-Derived Vitamin D3 Supplements things have improved slightly.
4. Conditional Essential Nutrients (Taurine, Creatine, Carnitine, Carnosine etc)
Vegan diet proponents often like to make out that the only nutrients of concern that individuals need to worry about when it comes to vegan diet patterns are the likes of Vitamin B12, Vitamin D, Calcium, Iron and maybe zinc and iodine if you are lucky.
However, whilst this might be true as a general rule of the thumb for the majority of healthy individuals, it is far from true for those with complex chronic illnesses who may have genetic driven health problems that can even cause deficiencies in conditional essential nutrients such as taurine, carnitine and so on.
Vegan diets don’t typically provide direct dietary intake of conditionally essential nutrients such as taurine or carnitine, relying purely on precursor amino acids for their synthesis, which can often also be poorly provided by vegan diets, especially those restricting protein intake.
Omnivorous diets that contain the likes of meat, poultry and fish such as the Mediterranean diet pattern provide direct dietary intake of conditional essential nutrients such as taurine, carnitine, creatine, carnosine and many others.
Research once again indicates that vegetarian and vegan diets reduce muscle creatine stores.
Similar to muscle creatine levels, evidence also indicates that vegetarians have lower levels of muscle carnosine compared to omnivores. 
The form of iron found in plant-foods is known as non-heme iron and is considered to be significantly less bioavailable than the heme-iron form found in animal foods.
It is for this reason that the iron status of vegans and vegetarians has received huge interest over the years from the nutritional community, amongst many complaints especially from vegan women struggling and unable to maintain healthy iron levels.
Studies have found that the absorption of non-heme iron can be significantly enhanced by pairing non-heme iron rich plant-foods with foods rich in Vitamin C.
Vegan diets can also contain very high intake of “anti-nutritional” factors such as phytates found in grains/legumes and polyphenolic tannins found in the likes of cocoa products, tea, coffee, fruits and other plant-foods.
These “anti-nutritional” factors may exacerbate and slightly affect iron status in individuals with existing iron-deficiency anemia and/or poor dietary intake of iron.
The Mediterranean diet as you can guess due to the inclusion of a variety of animal foods and plant-foods contains good intake of both forms of iron.
The information in this article has not been evaluated by the FDA and should not be used to diagnose, cure or treat any disease, implied or otherwise.