Facts About Vitamins

This page will guide you through the facts about vitamins - substances that your body needs to develop and function properly.

This information will help you make well-informed decisions about what vitamins, from what sources and in what doses are the best to keep your immune health in top shape. So, let's get started...

vegetable salad in a glass bowl Vitamins can be either fat-soluble or water-soluble - this characteristic defines whether a vitamin absolutely has to be consumed daily, or can be stored in the body to be used as needed.

Fat-soluble vitamins (A, D, E and K) can be stored in the body, some up to several years, and are used when needed. It doesn't mean that you don't need to consume these vitamins daily - it means that it takes longer to develop deficiency.

Water-soluble vitamins (C and the B vitamins) do not get stored as much and circulate in the bloodstream, whatever your body does not use comes out with the urine.

Water-soluble vitamins need to be consumed with food or supplements daily to replenish supply and avoid deficiency. Only the water-soluble B12 vitamin can be stored for a very long period of time in the liver.

By clicking on the link of a vitamin below, you will find a brief review of each of the listed vitamins, useful facts about vitamins: what it is responsible for, information on the vitamin's deficiency symptoms, its toxicity, recommended intake and the best food sources for each vitamin:

Vitamin A

Vitamin B complex

Vitamin C

Vitamin D

Vitamin E

Vitamin K

I have put together a table which lists some of the most common foods and their quantities to meet daily recommended amounts (RDA) for each vitamin. You can find this table here:

Table of Selected Food Sources of VITAMINS to meet the minimum RDA.


  • Vitamin D is the only vitamin that, through a series of processes in the skin, then liver and kidneys, becomes a powerful steroid hormone calsitriol. In fact, it is the most powerful steroid hormone in your body - it turns genes on that are making proteins essential to fighting cancer, and turns genes off that are making proteins promoting cancer. This is an amazing property of vitamin D that is limited only by how much we go into the sun with unprotected skin or how much vitamin D (in D3 form) we take as a supplement.

  • Too much vitamin A as pre-formed retynol prevents vitamin D from being produced in your body, greatly reducing the immuno-enhancing benefits of vitamin D. Stick with beta-carotene as your main source of vitamin A instead.

  • Not enough magnesium in your diet means no vitamin D production in your body, no matter how much time you spend in the sun or how much vitamin D3 you take as a supplement. Green leafy vegetables, nuts and seeds (pumpkin, sunflower and sesame) take care of this problem.

  • All B vitamins are very interrelated - B2 is necessary for the activation of B6; B6 and B2 are necessary for the conversion of tryptophan (an essential amino acid) to vitamin B3; B12 is necessary to convert folic acid to its active form; B6 deficiency reduces vitamin B12 absorption and so on. That is why B vitamins are often referred to as the Vitamin B Complex. Taking any one separate vitamin B supplement is almost useless.

  • Vitamin C, vitamin E and beta-carotene form of vitamin A are also antioxidants - that is they are able to neutralize dangerous free radicals and thus reduce oxidative stress.

  • Vitamin C has been shown to temporary increase the levels of Glutathione (GSH) - most powerful antioxidant, detoxifier and immune booster produced by your own body.

  • Your body can produce only vitamin D and vitamin K. The rest of the vitamins enter your body only with the food, both of plant and animal origin. That is why it is very important to make healthy and varied food choices.

  • The best sources of vitamins are fresh, ripe fruits and vegetables, and minimally processed foods.


carrot and pills

  • The first thing to determine is whether you need vitamins as supplements or not.

    If you don't eat 9-12 servings of fresh fruits and vegetables a day, often eat canned ones instead and other processed and prepackaged meals - you, most likely, need vitamin supplementation.

  • Most important fact of all the facts about vitamins - a multi-vitamin should never be a substitution for fresh fruits and vegetables, or balanced minimally processed meals.

  • A balanced multi-vitamin is a better choice than several single vitamin supplements because vitamins and minerals are very interrelated and dependant on each other for proper balance of all nutrients.

  • What is better to drink with a multi-vitamin? Is it ok to take it with morning tea or coffee? Water is the best when taking a multi-vitamin. Polyphenols in teas, coffee and fresh fruit juices may interfere with proper absorption of vitamins and minerals.

  • It is better to take a multi-vitamin with a meal to minimize nausea or heartburn that can be caused by vitamins taken on an empty stomach. Also, digestive juices being produced during the meal help break down vitamin supplements so that they are better absorbed.


vitamins bottle

  • Most of the vitamins and nutrients in a high quality multi-vitamin should come from natural, not synthetic sources.

    Check the label for such ingredients as concentrates of alfalfa, watercress, parsley, dehydrated spinach, carrot pulp, etc. If not sure, don't be shy to contact the manufacturer and ask what the sources of vitamins are.

  • A well-balanced multi-vitamin has all vitamins and minerals listed in the range of 50% - 150% of recommended daily amount. Such extremes as 1,000% of RDA (as often the case with vitamins A, C, E and B complex) should be avoided. There is no scientific evidence proving that such high doses of these vitamins are beneficial or can prevent any disease.

  • All vitamin A should be in beta-carotene form. Retinol acetates (pre-formed vitamin A) block the metabolism of vitamin D that is crucial to your immune health. Large doses of retinol (more than 2,500IU) can also be toxic, especially during pregnancy as it may cause birth defects.

  • All multi-vitamins don't have enough calcium in them. You might want to supplement with calcium if you don't eat dairy or plenty of green leafy vegetables. Most calcium supplements are from sources that I consider unnatural for human consumption - shells, coral, limestone rock, chalk, or animal bones. If we, the humans, were to eat these we would have a completely different set of teeth! Plant, algae and milk sources of calcium are what our digestive system can process, safely and effectively. Milk calcium is safe for lactose intolerant people because lactose and all allergens have been removed.

  • Most multi-vitamins don't have enough vitamin D in them. Government issued RDA of 400IU is ridiculously low in light of recently published scientific research as a result of which the new minimum RDA should be 1,000IU. Dr. John Cannell of Vitamin D Council recommends as much as 5,000IU a day for people with no exposure to sun.

  • Choose a multi-vitamin with folate (folic acid) content at no more than 50% of RDA. You get plenty of additional folate from fortified breads, cereals and pastas (if they are included in your menu). Too much folate can mask vitamin B12 deficiency and lead to permanent nerve damage. Only pregnant women need larger doses of folate because folate deficiency leads to neural tube defects in fetuses.

  • Last but not the least. In our quest to learn the facts about vitamins we have to rely on the information on purity and potency provided by manufacturers. If you want to be sure your multi-vitamin is not contaminated with harmful substances and contains all ingredients in stated quantities check vitamin reports at Consumer Lab - an independent laboratory testing vitamins and other nutrition supplements (there is a $29.95 annual fee for unlimited access to all reports).

Discuss these facts about vitamins with your family doctor before introducing any multi-vitamin or supplement into your diet, especially if you have a medical condition.

In addition to this Facts About Vitamins page you might find the following useful:

Foods That Boost Immune System

Ways to Boost Your Immune System

How to Raise Your Glutathione Levels Safely And Naturally

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