As I have written before there are many theories about what makes a proper human diet. And, what makes it more confusing is that you can always find a study to support each theory. One of the main arguments is whether or not humans should eat meat. From my personal experience and that of my clients I believe that we should. Yet at the same time I believe that a vegan or vegetarian or plant based diet can be very good for someone for a particular period of time. It can be healing.

But, here are some key questions. What is the plant based diet being compared to? What did the person eat before? Is the diet in and of itself healthy and providing all the nutrients or is it just cleaning up what was there? The answer could be yes, no, or maybe. Will this same diet provide long term health? What is the significance of the age the diet is started?

When we discuss animal product the most important question is the source. It is a healthy animal raised in a healthy manner? Or, is it a factory farmed animal raised in confinement on hormones, antibiotics, and food that it would not eat in nature? All of this makes a huge difference.

From my own personal experience I was a vegetarian for five years before studying nutrition. Yes, on that diet I certainly became healthier. I got my weight down from over 180 pounds to 150. However, I still suffered from seasonal asthma and needed an inhaler; I had virgin teeth that cracked; I could not get my weight below 150; I had high triglycerides levels; and less than optimal cholesterol levels . Once I started to consume animal products from healthy sources my weight got down to 140, I don’t have the seasonal asthma, and my triglycerides and cholesterol are in healthy ranges.

At the end of the day diet is a personal choice. My personal belief and from my studies and experience I believe that we need food that has animal origin. Some of this will be explained below. Also, there are many definitions of “vegetarian” and what that specific person will or will not eat. This is beyond the scope of this article. The purpose of this article is informational and to explain possible nutrient deficiencies that may occur in some vegetarians from not eating sufficient animal product.

As we begin to explore these specific nutrients you will notice one underlying theme. Vitamins come in many forms. I’ll explain using theoretical Vitamin X. While we may call it Vitamin X (and the government allows it to be labeled as Vitamin X), this Vitamin X has different chemistry in animals and plants. Since we are an animal, the animal form is more bioavailable to us. The plant form needs to be converted in our body into the animal form. Often times that process is not very efficient and that is where potential deficiencies can begin.

Also, I will not detail the functions of the various nutrients in this article. I will provide links to other articles for that information.

Vitamin A

Vitamin A is also known as Beta-carotene. But, it gets confusing because they are not the same substance! Vitamin A (more specifically called Retinol) is found only in animal products, such as butter, egg yolks, liver, organ meats and shellfish. Beta-carotene is found in plant food, such as carrots, red bell peppers, sweet potatoes, winter squash, and leafy greens (collard greens, kale, spinach, Swiss chard, turnip greens). For the animal product to be a good source of Vitamin A, the animal needs to be eating green foods, such as cows eating green grass.

When we consume Beta-carotene from plants (or vitamin supplements) our body has to convert it into Vitamin A. And guess what – we aren’t that efficient in doing that. A variety of conversion ratios have been found based on different populations and experiments. The bottom line is that some people convert better than others. In fact, it may be nearly impossible to eat the amount of vegetables required to actually get what we need on daily basis.

It has also been found that large doses of beta-carotene supplements have led to increases in cancer mortality and total mortality in human trials. It was found that these massive doses increased oxidative stress and stimulated the production of enzymes that degraded true vitamin A. This caused a cellular vitamin A deficiency and the resulting cancer.

Vitamin D

Vitamin D – the “vitamin du jour” as I like to say. It certainly is in the news almost every day and it even has its very own “council” (The Vitamin D Council). I don’t think any other vitamin has achieved that status! Let me cut through the clutter for you – Vitamin D is very important and most of us don’t get enough of it – meat eaters and vegetarians!

When we discuss Vitamin D we need to understand there are two main forms. Humans and animals synthesize vitamin D3 in their skin from exposure to the Sun. Vitamin D2 is found in some plant foods, especially mushrooms that have been exposed to ultraviolet light. Studies have shown that Vitamin D2 may be five to ten times less effective at supporting long-term nutritional status.

In addition, Vitamin D is “fat soluble.” That means you need fat for it to be properly utilized by the body. Many vegetarian diets are low in fat diet. This may impact their ability to effectively utilize the Vitamin D.

Where do we get Vitamin D? The number one source is the Sun. It is also found in eggs, fatty fish (mackerel, salmon, sardines, tuna, and trout), liver, and milk products.

Vitamin K2

Vitamin K also comes in two forms: K1 and K2. Vitamin K1 is found in green plants, while vitamin K2 is found in animal fats and fermented foods. One of these fermented foods is natto, a soy food commonly consumed in Japan, but not elsewhere. Therefore, the vegetarian not eating natto may be at risk for a deficiency of Vitamin K2.

Vitamin K – easy to remember – K is for “clotting”, well there is actually lots more to it! Vitamin K1 is known for activating blood clotting. Vitamin K2 is used for all of vitamin K’s other functions, primarily bone mineralization. Therefore, these two K vitamins are not interchangeable.

For more information on Vitamins A, D, and K please click here

Vitamin B12

Vitamin B12 may be one of the most important of all the B vitamins, particularly because only true bioavailable B12 comes from animal sources. There is no such thing as “vegan” or “vegetarian” B12 as far as your body goes. Most supplements supply cyanocobalamin and call it B12. In this chemical each molecule of B12 is attached to a molecule of cyanide. Since vitamin B12 detoxifies cyanide by binding it and causing its excretion in the urine, this form has poor bioavailability in most people.

Vitamin B12 needs along with it what is known as “intrinsic factor” which comes from animals. Fortunately B12 (as other B vitamins) will store in the body, but over time you can become deficient. In fact, a good friend of mine, after years of being a vegetarian has reintroduced more animal product into her diet after seeing a live blood analysis showing a lack of B12 and a move towards anemia.

B12 is available from animal products such as fish (halibut, salmon, scallops, shrimp, and snapper are best sources), lamb, beef, organ meats, and yogurt. It is important for the blood, digestive, hepatic, and nervous systems.

Vitamin B6

Vitamin B6 occurs in three forms: pyridoxine, pyridoxamine and pyridoxal. Plant foods contain pyridoxine, while animal foods contain pyridoxal and pyridoxamine. The human body requires pyridoxal for most functions, pyridoxamine for a few others. Pyridoxine has no role in the human body but can be converted into the other two forms in the liver using vitamin B2.

Therefore, the plant form of vitamin B6 in order to be useful to the body depends upon the status of vitamin B2. Also, as you would likely expect vitamin B2 levels tend to be higher in animal foods so again the vegetarian is at risk with their plant based diet. Another issue with plant foods is that much of their B6 is bound up with sugars that make it difficult or impossible to absorb. So we have both B2 and B6 risks.

Vegetarians should select plant foods that have the least amount of their pyridoxine bound up in sugar complexes. Bananas are an excellent source because the sugar-bound form is low, their total content is comparable to many meats, and they are typically eaten raw. Most plant foods are relatively poor sources, however, and B6 intake would be much higher on a mixed diet including muscle meats, seafood and organ meats.

The best plant sources are bananas, mushrooms, nutritional yeast, and wheat germ. The best animal sources are fish (cod, halibut, snapper, salmon, and tuna), lean beef, organ meats, and poultry.

To read more about the B Vitamins click here


Zinc is one of the most important minerals for the body. Essentially it is involved with enzymes and enzymes control every reaction in the body. Enough said? To read more about zinc click here

Zinc is present in both animal and plant foods. As is the theme of this article it all comes down to its bioavailability once in the human body. While zinc is present in grains, legumes, fruits and vegetables, it is found in much lower concentrations compared to animal foods. In addition, zinc absorption in the body is inhibited by plant compounds such as phytate, oxalate, polyphenols and fiber, and enhanced by compounds present in meat. It is possible for a well planned vegetarian diet to escape zinc deficiency, it is difficult to maintain a truly healthy zinc status without eating animal foods.

Zinc we are often told is good for the immune system. True, but apparently viruses like it too! What does that mean? Taking that zinc lozenge may not always be the best idea if it is a virus you are fighting.

Animal sources of zinc are Cheddar cheese, lamb, lean beef and pork, liver, milk, poultry, seafood (crabs, oysters, shrimp), and yogurt. Plant sources of zinc are almonds, beets, carrots, cashews, green peas, mushrooms, peanuts, pumpkin seeds, sesame seeds, spinach, wheat germ, and whole grains.

Essential Fatty Acids

The essential fatty acids are better known as the “omega” family, featuring the 3’s, 6’s, and 9’s. These are polyunsaturated fats and whenever we hear the word “essential” in nutrition it means that we must eat these nutrients, as our body does not manufacture them. We need all the essential fatty acids. The issue here again is balance. Omega 6’s are considered “pro-inflammatory” while Omega 3’s are “anti-inflammatory.” And you guessed it – the vegetarian diet is more prone to Omega 6’s.

Our body was designed to consume the Omega 3’s and 6’s in relatively equal amounts (you’ll see anywhere from 1:1 to 2:1 Omega 6’s to 3’s in the nutrition literature), most Americans are in the 20:1 to 50:1 ratio. Why? Omega 6’s are found heavily in grains – the foods featured in many vegetarian diets. Omega 3’s are found in cold water wild fish, something not too prevalent in most vegetarian diets. In fact, vegetarians have 30 percent lower levels of EPA and DHA than omnivores, while vegans have over 50 percent lower EPA and almost 60 percent lower DHA.

Plant sources of the essential fatty acids include: black current seed oil, evening primrose oil, flaxseed, lecithin, linseed oil, sesame seeds, sunflower seeds, walnuts, wheat germ, and winter squash. Animal sources include seafood (halibut, salmon, scallops, shrimp, snapper, and tuna) and grass-fed beef.

There are a few things you should know about flax seeds. First, beware of the marketing hype! If the flax seed is whole your body can not break it down. We can only work with flax seed in the form of meal or oil. If you buy flax seeds grind them up in a coffee grinder and store them in the refrigerator. As a polyunsaturated fat they go rancid very quickly, so only grind up a small amount. The ground flax you get in the store likely has preservatives added to keep it “fresh”, but the oils are likely already rancid.

Second, we are told that flax seed contain Omega 3’s. This is true. However it is not DHA or EPA meaning the body has to convert it. And guess what – once again this is not a very efficient process in the body.

To read more about the Essential Fatty Acids click here

Bernard Rosen, PhD is a Nutrition Consultant and Educator. He works with individuals, groups, and at corporations to create individualized nutrition and wellness programs. His office is in Coeur d’Alene, ID. To learn more or to schedule an appointment, e-mail at, call (208) 771-6570 or go to