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A little history of Vitamin D

If you do some research online, and offline, as I did, you’ll find a lot of slightly different tales depicting the history of Vitamin D. My personal favourite is that found on Wikipedia about the American researchers Elmer McCollum and Marguerite Davis, who in 1914 (a time when the bone deformity, rickets, was rife in north-eastern USA and northern Europe) discovered a substance in cod liver oil which was named, “vitamin A”. Then it seems a British doctor by the name of Edward Mellanby somehow noticed that dogs fed with cod liver oil didn’t develop rickets and concluded that vitamin A, or a closely associated factor, could prevent the disease. In 1922, Elmer McCollum tested modified cod liver oil in which the vitamin A had been destroyed. The modified oil cured the sick dogs, so McCollum concluded that the factor in cod liver oil which cured rickets was distinct from vitamin A. He called this factor vitamin D, because it was the fourth vitamin to be named. There lies the birth of vitamin D.


Vitamin D plays an important role in bone health, as well as in immune, nerve and muscle function. In addition, it may play a role in protecting against cancer, heart disease, stroke, diabetes, auto-immune diseases, and depression.

Vegan Sources

In 1971, vitamin D was reclassified as a “vitamin D hormone,” meaning that it can act as both a vitamin and a hormone. In people that live near the equator and who are constantly exposed to sunlight throughout the year, vitamin D is a hormone that their bodies can build in sufficient amounts for them. Yet people that live far from the equator, where sunlight is limited, or those that have an indoor lifestyle, where there is a significantly lower exposure to sunlight, an alternative becomes necessary. This would  come in the form of fortified foods, or by supplement intake. The Recommended Dietary Allowance (RDA) is 15 mcg for adults under 70. So my advice is to sit outside in the sunshine every day whilst eating your breakfast of grilled mushrooms with cereal, orange juice, coffee with soy milk, and you’ll be just fine. However, if you feel this will fall short on your RDA, then grab some supplements to top up.


As always, I hope you have enjoyed reading this as much as I’ve enjoyed writing it. Tomorrow we’ll look at Omega 3 Fatty Acids (DHA & DPA), their function, and how we can get more of them.


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vegan supplements

There’s two ways to tackle this subject, I can either dip in, offer the facts, and then jump out. Or, I can dive in deep, swim around for ages, and probably never surface again ……….. let’s see how long I can hold my breath for.

My main reason for spending time on this subject is selfish, it’s self-education, but if I can prick the ears of a few of you, then all to the good. It’s a fascinating subject, and one that I believe will be touched upon in nearly every conversation that I have with a meat-eater. It seems to be their opening line, my lack of this, and my lack of that. So it’s best I prepare myself with some solid vegan apologetics.

Although a plant-based diet will deliver most vitamins in abundance, vegans (and many non-vegans) do need to pay special attention to their Vitamin B12, Vitamin D, Omega 3 Fatty Acids (DHA & DPA), Iodine, Zinc, Selenium and finally K2 intakes.

What are Vitamins ?

Vitamins are essential to life, but cannot be synthesised by the body in adequate amounts. Therefore, outside sources must be obtained. Although the total amount of vitamins the body needs is tiny – only 0.5 gram per day – the functions they perform are vital. Some, such as vitamin D, have hormone-like functions as regulators of mineral metabolism, or regulators of cell and tissue growth and differentiation (such as some forms of vitamin A). Others can function as antioxidants (e.g., vitamin E and sometimes vitamin C). The largest number of vitamins, the B complex vitamins, function as enzyme cofactors (coenzymes) or the precursors for them; coenzymes help enzymes in their work as catalysts in metabolism. In this role, vitamins may be tightly bound to enzymes as part of prosthetic groups: For example, biotin is part of enzymes involved in making fatty acids. They may also be less tightly bound to enzyme catalysts as coenzymes, detachable molecules that function to carry chemical groups or electrons between molecules. For example, folic acid may carry methyl, formyl, and methylene groups in the cell. Although these roles in assisting enzyme-substrate reactions are vitamins’ best-known function, the other vitamin functions are of equal importance.

Although a plant-based diet will deliver most vitamins in abundance, vegans (and many non-vegans) need to pay special attention to their vitamin B12, and D intake. Let’s take a look at B12.

Vitamin B12

Vitamin B12 has the largest molecular structure of any vitamin, with the mineral cobalt at it’s centre. It’s a water-soluble vitamin that has a key role in the normal functioning of the brain and nervous system via the synthesis of myelin, and the formation of red blood cells. It is one of eight B vitamins, and is involved in the metabolism of every cell of the human body, especially affecting DNA synthesis, fatty acid and amino acid metabolism.


Vitamin B12 deficiency can offer a range of symptoms such as fatigue, lethargy, depression, poor memory, breathlessness, headaches, and pale skin, among others, especially in elderly people (over age 60) who produce less stomach acid as they age, thereby increasing their probability of a deficiency. Vitamin B12 deficiency can also cause symptoms of mania and psychosis in more severe cases. 

Recommended intake

The body requires vitamin B12 in tiny amounts; the official Recommended Dietary Allowance (RDA) for adults is 2.4 mcg per day. However, recent reports are suggesting that this be more akin to between 4 to 7 mcg per day. Ingestion options for the current RDA are :

  • Consume fortified foods 2-3 times per day to get at least 3 micrograms of vitamin B12
  • or take 10 micrograms of B12 as a compliment once per day
  • or take 2000 micrograms of B12 as a compliment once per week

Fortified foods include some common breakfast cereals, soy milks, almond milks, coconut milks, other plant milks, nutritional yeast, vegan mayonnaise, tofu, and various types and brands of vegan deli slices, burgers, and other veggie meats.

In conclusion

There’s so much data out there that suggests average vegan intakes of vitamin B12 to be far below the RDA, with numbers suggesting up to a 25 percent shortfall in intake. Vegans who don’t include a reliable source of vitamin B12 will eventually become deficient. This could take months for some, and years for others, but it will happen, with damage ranging from the dramatic, to the irreversible.


I hope you have enjoyed reading this, I’ve certainly enjoyed writing it. Tomorrow we’ll look at Vitamin D, it’s function, and how we can get more of it.

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