Vitamin B12 Rich Diet by Sue Kira

by sue

Vitamin B12 Rich Diet

by Sue Kira, Naturopath & Clinical Nutritionist

About Vitamin B12

Vitamin B12 deficiency

Things that affect the absorption or block B12

Good food sources of B12

Vegan sources of B12

About Vitamin B12

Vitamin B12 is my second favourite vitamin. Why? Because Vitamin B6 is my favourite so B12 has to be the runner up. I like B12 because so many people seem to have more energy when their B12 levels improve, and because this site is all about vitality, what a fit!

Vitamin B12 is also known as cyanobalamin, cobalamin and methylcobalamin, which are great words to use in a spelling test!

B12 is a water-soluble vitamin, and the only vitamin that contains the mineral cobalt. That’s unusual because here we have a vitamin that contains a mineral, whereas normally, vitamins are vitamins and mineral are minerals. Cobalt is considered to help repair the myelin sheath, the membrane that surrounds and protects nerve cells. Cobalt also helps to form haemoglobin (the red in our red cells).

Animal protein is almost the only substantial source of B12, found in liver, kidneys, muscle meats, fish, egg yolks and in smaller amounts in mushrooms, nutritional yeast and algae such as Spirulina. B12 cannot be made synthetically but must be grown like penicillin, from bacteria or moulds.

Vitamin B12 is necessary for the normal metabolism of nerve tissue and is involved in the metabolism of proteins, fats and carbohydrates. B12 helps iron function better in the body and aids folate in the synthesis (making) of choline.

B12 needs what is called an ‘intrinsic factor’, a muco-protein enzyme present in the digestive system, to absorb B12 from our food. Autoimmune reactions in the body can bind the intrinsic factor, preventing proper B12 absorption.

B12 needs to be combined with calcium foods during absorption to be able to properly benefit the body. A properly functioning thyroid and sufficient hydrochloric acid in the stomach is also needed for B12 absorption. Highest concentrations of B12 are found in our liver, kidneys, heart, pancreas, testes, brain, blood and bone marrow.

Injections of B12 are commonly prescribed for B12 deficiency due to poor oral absorption. They are used to treat pernicious anaemia (B12 anaemia) and have also been used to treat fatigue, nervous irritability, poor concentration, insomnia, leg paralysis, atrophy of the brain, lack of balance and to reduce the effects of bruising and black eyes. Strangely, B12 has also been used to diminish the effects of hangovers.

B12 deficiency is commonly linked to conditions such as low energy, mood disorders and inability to cope with stress.

Benefits of B12

Healthy energy levels
One of the main complaints or concerns of my clients in clinic was because they were lethargic and tired most of the time. There are so many reasons for ongoing fatigue, but a major cause was low levels of B12. We need B12 to help us to convert the carbs we eat into energy that we can drive our muscles, mind, and body. Adequate B12 can reverse this situation for many people.

Healthy mood & nervous system
Another common condition that many clients have are mood disorders such as anxiety and depression. Along with B6, zinc and folate, B12 helps to make SAMe (S-adenosyl methionine) which is a valuable support for the nervous system, stress and mood regulation. Surprisingly, it has also been shown to reduce pain sensations (makes us feel pain less) which is good for conditions like fibromyalgia, arthritis and other painful conditions.

Healthy heart and vascular system
Without sufficient levels of vitamin B12 (as well as B6 and folate) you risk getting high levels of homocysteine, which is a substance that can build up in your blood and contribute to heart disease, stroke, vascular disorders and heart attack risk. Normal levels of homocysteine help to keep cholesterol at a healthy level. Elevated homocysteine has also been linked to neurological conditions such as dementia and Alzheimer’s, so keeping homocysteine normal is also a bonus for your brain.

Healthy memory
One of the main indications of low B12 levels (apart from fatigue) is failing memory, especially short-term memory, such as forgetting what you were talking about mid-sentence, or forgetting a dear friend’s name when introducing them to someone. Rather than an embarrassing moment that you might blame on aging, memory loss can be linked to low B12 levels.

Sometimes you can have low B12 even if your blood tests show you are within the range. But is your level optimal? You want your B12 to be near the top end of the reference (which is often written in brackets beside your result).

If you had been taking a supplement containing B12 without having a couple of days off it prior to testing, your blood could show a good, or even excessively high level of B12. But that’s showing what is still floating through your blood from the supplement and is not a true indication of your cellular level of B12.

B12 is needed for more than your memory, but also more serious cognitive decline disorders such as dementia and Alzheimer’s disease. Other issues from low B12 are poor concentration and focus, attention disorders like ADD and ADHD, and decreased learning capacity (especially important for kids’ growing brains at school).

Healthy digestive system
Because B12 is needed to make digestive enzymes and acids, low levels of B12 can result in poor digestion and poor levels of healthy bacteria in the digestive system. Healthy bacteria are needed for the proper breakdown of food to obtain our nutrients, and to also break down harmful bacteria and fungi like candida organisms. A healthy digestive system helps to prevent a host of diseases.

Healthy hair, skin and nails
A good level of Vitamin B12 is needed for cellular division and the growth of new cells. Body parts like skin, hair and nails, as well as the digestive system cells, are what we term ‘quick turn-over’ cells, because they replace themselves very quickly compared to other cells in the body. Therefore, these areas have greater ability to repair quickly, but can also quickly show signs of damage.

So if your skin is dry and rough, then your body is trying to quickly replace these cells to grow new ones, but without enough B12 this can’t happen efficiently. B12 drops or cream can be used topically (applied directly) for skin conditions like eczema, dermatitis or psoriasis.

Healthy pregnancy
B12 and folate (and some other nutrients) are super important to help prevent birth defects such as a cleft palate or lip, apart from other conditions. Vitamin B12 is also needed to create the genetic DNA to build a whole new little body inside of you, so it makes sense to have plenty of B12 in your diet, especially while pregnant.

Healthy blood
There is a type of anaemia called ‘megaloblastic anaemia’ which is related to very low levels of vitamin B12. The ‘mega’ part of the word megaloblastic refers to how your red cells swell up to a ‘mega’ size when the B12 levels are very low, which can mask an iron deficiency where the cells look very small. This is a reason for different types of blood tests to determine if you truly have low vitamin B12 (see below under ‘Testing for a vitamin B12 deficiency’).

Other types of anaemia are pernicious anaemia (low folate) and iron deficient anaemia which many are familiar with. With all types of anaemia, the main symptom is fatigue and weakness. This weakness is a result of insufficient oxygen being carried around the body. Apart from making us feel tired, low oxygen means our muscles don’t work properly – and the most important muscle we have is our heart.

Wow! After seeing all this information, no wonder B12 is such an important vitamin and one of my favourites.

By the way, in case it comes up at a trivia night, or you want to impress someone, the biggest muscles we have are in our buttocks. 🙂

Vitamin B12 deficiency

Those with the greatest risk of deficiency include:

  • the elderly due to less stomach acid to be able to digest meat etc efficiently and assimilate B12
  • those with digestive issues
  • people with auto-immune disorders that affect the absorption of nutrients, such as Hashimotos thyroid and Celiac disease
  • people with inflammatory bowel diseases such as Crohn’s or ulcerative colitis
  • people who genetically don’t have the necessary ‘intrinsic factor’ needed
  • smokers, as nicotine blocks B12 absorption
  • those with poor good bacterial levels in the gut due to bacterial overgrowth or parasitic infections
  • people who consume too much sugar, alcohol or starch.

Symptoms can include:

  • Constant tiredness
  • Bleeding gums or mouth ulcers
  • Nausea, diarrhea, constipation, or cramping
  • Feeling dizzy/lightheaded, low blood pressure
  • Poor memory, concentration & confusion
  • Mood changes, like increased anxiety or depression
  • Muscle aches and weakness or joint pain
  • Difficulty breathing or shortness of breath
  • Heart palpitations or irregular beats (can lead to heart disease)

Testing for a vitamin B12 deficiency

Picking up a B12 deficiency isn’t always easy. Many people get a blood B12 reading that shows normal, but at least 50% of these may still be low in B12 at a cellular level. There are other tests that can help to determine if your B12 is low and these include: checking for homocysteine levels (tied to low B12, folate and B6); and there is a test called ‘Methyl Malonic Acid’ or MMA, which can indicate if B12 is getting into the cells properly.

I’ve had so many clinical experiences where B12 showed as ‘normal’ in standard lab tests but the client had definite signs of low B12 (which appeared to be validated when I saw the size of their red cells under my microscope). I found that these clients responded very well to additional B12.

When someone’s B12 is so low that it is below the reference level, then they have pernicious anaemia. But a problem occurs when many people are told that their levels of B12 are fine when, in fact, their levels are actually only half way, or even under half way, up the reference range.

A typical comment is, ‘they’re a bit low, but within reference’. But results are not the best they can be, unless they are towards the top end of the reference range. That’s where we need our levels to be in order to be healthy, happy and energetically vital. This is called ‘optimal’.

I find this can be the case for many tests done on vitamins, and particularly minerals, and also with thyroid levels, where it may be called ‘Euthyroid’ which means ‘normal’, but it may be sub-optimal for that person. In other words, not as good as it could be.

Things that affect the absorption or block B12

  • Alcohol – uses up B12
  • Smoking – nicotine blocks absorption and uses up B12
  • Antibiotics – reduces ability of the stomach to absorb and use B12
  • Stomach acid controlling drugs (antacids) – affects absorption of B12
  • Potassium supplements – reduce absorption of vitamin B12 (potassium in food is fine)
  • Some drugs – interfere with the ability to absorb, or may block B12
  • Deficiency of the protein called ‘intrinsic factor’ in the stomach which helps us to get the B12 from our food
  • Lack of ‘friendly bacteria’ – certain good bacteria help to convert B12 into its active useable form in the body
  • Certain bad bacteria and parasites rob our body of B12 and other nutrients
  • Digestive disorders – inflammatory bowel conditions affect absorption
  • High stress – uses up B12
  • Lack of sufficient hydrochloric acid (stomach acid) to break down proteins etc to extract the B12 out of our food.

Symptoms of too much B12

Normally it is difficult to have too much B12 because it is a water-soluble vitamin and can be flushed out of the body very easily. As far as I know, it is unheard of to have excessive B12 from food. But some people can be allergic to B12 as a supplement, which could be because of how it is made, or from other excipients in the product. In the rare case that you may have too much, or are allergic to B12, you may experience any of the following symptoms:

  • Anaphylactic shock (very rare)
  • Diarrhea
  • Difficulty swallowing
  • Numbness or tingling in your face, hands or arms
  • Nausea & vomiting
  • Skin rash or eczema

Recommended Daily Amount of B12

Following is the recommended daily allowance (RDA) for vitamin B12. The amounts are expressed in micrograms (mcg). A microgram = 1,000th of a milligram.

  • Infants 0–6mths: need 0.4mcg
  • Infants 7–12mths: need 0.5mcg
  • Toddlers 1–3yrs: need 0.9mcg
  • Children 4–8yrs: need 1.2mcg
  • Children 9–13yrs: need 1.8mcg
  • Men and women 14+: need 2.4mcg
  • Pregnant women: need 2.6mcg
  • Breastfeeding women: need 2.8mcg

As often seen, the RDA is quite low compared to optimal health levels of B12. In my opinion, the RDA for adults should be around 100mcg per day, with some needing as much as 5000mcg (5mg), especially those with certain health conditions. If taking a supplement, the best forms are ‘sublingual’ (dissolve under the tongue) oral suckable tablets or sprays, and preferably for both, in the more active form called Methylcobalamin.

For more advice, contact your doctor or health practitioner.

Good food sources of B12

Following are some foods rich in B12, showing the weight of the food and the quantity of vitamin B12 in micrograms. This list of foods can be used in conjunction with the above RDA’s.

  • Beef and chicken liver: 3.5oz/100g = 90mcg
  • Salmon: 1 fillet 3.9oz/110g = 20mcg
  • Herring: 1 fillet 5.3oz/150g = 19mcg
  • Mackerel: 3oz/85g = 15mcg
  • Sardines: 1 cup = 13mcg
  • Tuna: 3oz/85g = 10mcg
  • Trout 1 fillet: 3.5oz/100g = 10mcg
  • Turkey: 3oz/85g = 1.1 mcg
  • Beef tenderloin: 3oz/85g = 1.0mcg
  • Lamb: 3oz/85g = 0.8mcg
  • Egg (medium): 1 = 0.6mcg
  • Chicken: 1 breast = 0.3mcg
  • Mushrooms: 3.5oz/100g = 0.09mcg

Vegan sources of B12

Mushrooms only have very small amounts of B12 as you can see above. It seems that nutritional yeast only contains B12 if fortified (added). Spirulina and other algae contain what is called Pseudo-B12; many references don’t consider this a reliable source of B12 and suggest that it doesn’t convert to what our bodies use.

However, studies with vegans with high homocysteine levels (a sign of low B12) had their homocysteine levels lowered to normal and their B12 levels within range, using oral supplementation of six capsules per day of Spirulina over a three-month period. This is equivalent to about one heaped teaspoon of the powder if using Spirulina in a smoothie.

More research needs to be done on vegan B12, but I often found that most vegans I treated needed supplemental B12. But then again, so do many meat eaters with poor digestive systems.

Often the vegans who don’t have a B12 deficiency have good digestive systems. Something to ponder on!


Before you commence your diet, see your medical or health care professional for qualified guidance about what foods and supplements are best for your body. While on the diet do not stop any medications or supplements previously prescribed unless advised otherwise by your medical or health care professional.

During the early stages of a new diet, you may experience symptoms such as fatigue, headaches, or body aches, which may occur because your body is detoxifying. However, if you are unsure about a symptom at any time, check immediately with your medical or health care professional.


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