VITAMINS – Dosage and Toxicity

Vitamin Maximum permissible dosage Toxic signs and symptoms

Vitamin A Infants 10,000iu Appetite loss, headache,

Adults 50,000iu blurred vision, unusual bleeding, dry cracked skin, loss of hair, muscular stiffness and pain

Vitamin B group See individual compounds below

Niacin 100mg Flushing, headaches, cramps, nausea, vomiting and burning or itching skin

Niacinamide 100mg As above

Pantothenic acid Not tested Occasional diarrhoea

Pyridoxine 200mg Numbness, tingling and other sensory nerve effects

Riboflavin No toxic effects

Thiamine No toxic effects

Vitamin B12 No toxic effects

Beta-carotene No toxicity recorded up to 250mg per day

Biotin No toxic effects reported

Vitamin C 10g per day, except under supervision Nausea, diarrhoea, flatulence

Vitamin D 1,000iu/kg of body weight Nausea, vomiting, appetite loss, diarrhoea, headache, excessive urination, constipation, pallor

Vitamin E 800iu Severe weakness and fatigue, may worsen hypertension

Folic acid 15mg Abdominal distension, appetite loss, nausea and vivid dreams

Vitamin K No side effects if given orally

There is controversy about this dosage and legal guidelines may state that 10mg or more is toxic. This continues to be a contentious issue.


Vitamins are a group of organic compounds that are present in variable, minute quantities in natural foodstuffs and are required for normal growth and maintenance of life. As a rule the human is unable to synthesize these compounds, thus encouraging the term Vital’ to be part of the name. Vitamins are generally needed only in small amounts and have no calorific value, therefore they do not furnish energy but are essential for transformation of nutrition into energy and the regulation of most, if not all, biochemical processes in the body.

It is not necessary for the individual to have much of an understanding of vitamins despite what the popular press and complementary medical journals might suggest. A balanced diet containing five portions of fruit or vegetables, not overcooked, in association with non-refined carbohydrates, protein and a small amount of the right sort of fats will not lead people into deficiencies. The body is remarkably good at absorbing what it needs from the most unlikely sources and if food is eaten by instinct, most vitamins will be taken in as required. For that reason, no more is mentioned in this section on this vast and fascinating subject. Every condition that would benefit from vitamin supplementation will have recommended dosages or guidelines within this site. The recommendations are based on ‘natural’ products that, sadly, tend to separate individual supplements from their coenzymes and other compounds that help their absorption. I therefore strongly recommend the use of natural food-state vitamins. These are available and are made by extracting all the nutrients from a natural source and not separating them.

Vitamin toxicity

As more knowledge filters through to practitioners of complementary medicine concerning the beneficial effects of high-dose vitamin therapy, it is necessary for practitioners and individuals to be aware of possible side effects or toxicity.

Principally, it is difficult to overdose on a vitamin, especially if it is a natural food state vitamin as mentioned above. I have listed here the maximum permissible amounts that can be taken on a daily basis and some of the signs and symptoms to watch out for if taking vitamin supplements.