All About Vitamins

Vitamin D
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Why vitamin D is good for you

Vitamin D’s most important role is to regulate how much calcium is absorbed from the food that is eaten and to ensure that levels of calcium are regulated properly in the body.

The immune system also needs vitamin D to function effectively.

To get enough vitamin D, a general rule of thumb is: in winter, get about 20-30 minutes a day of sunlight directly on the face and in summer, 10-20 minutes (but not in the hottest part of the day).

The ultraviolet light in sunshine makes a type of cholesterol that is found just under the skin, into cholecalciferol (or vitamin D3). The vitamin D3 gets carried to the kidneys, where it becomes even more active. Some of the vitamin D stays in the liver and kidneys, where it helps to reabsorb calcium from the blood. Some goes to the bones to help them hold onto their calcium. The rest goes to the intestines to help absorb calcium from food.

Vitamin D is found naturally in some foods, in a slightly different form, called ergocalciferol or vitamin D2. The body can use this form of vitamin D just as well as the other type from sunshine.


Important vitamin D facts

  • Vitamin D is also classified as a hormone
  • There is a receptor for vitamin D on every cell in the body, which means that it is important for metabolic processes on a cellular level
  • People who have adequate to high levels of vitamin D in the body outlive people with low to deficient levels


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Groups at risk of vitamin D deficiency

Deficiency can occur in individuals that do not get enough sunlight.

People that may be deficient in vitamin D include:

Talk to a medical professional about vitamin D supplements BEFORE taking them.


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Symptoms of vitamin D deficiency

Children who do not get enough vitamin D develop rickets – their bones do not grow and do not harden properly. Luckily, most children do get enough vitamin D in their diet and rickets is very rare today in the West, but it does still occur in developing countries.

Vitamin D deficiency in older adults shows up as a condition called osteomalacia – soft, weak and painful bones.


Vitamin D and health

Talk to a medical professional about vitamin D supplements BEFORE taking them.


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Vitamin D in food

Vitamin D (mcg)
Cod liver oil
1 Tbsp
Sardines, canned
Mackerel, fresh
Salmon, fresh
Herring, fresh
Prawns (shrimp)
1 cup
Beef liver
1 large
1 Tbsp
Cheddar cheese
1 pat


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Vitamin D recommended daily intake (RDI)

RDA lifestage age amount
  INFANTS 0-12mths 200IU (5mcg)
  CHILDREN 1-8yrs 200IU (5mcg)
  CHILDREN 9-18yrs 200IU (5mcg)
  ADULTS 19-50yrs 200IU (5mcg)
  SENIORS 51-70yrs
400IU (10mcg)
600IU (15mcg)
  PREGNANT   200IU (5mcg)
  LACTATING   200IU (5mcg)
TOLERABLE UPPER LIMIT lifestage age amounT
  INFANTS 0-12mths 1000IU (25mcg)
  CHILDREN 1-8yrs 1000IU (25mcg)
  CHILDREN 9-18yrs 2000IU (50mcg)
  ADULTS 19-50yrs 2000IU (50mcg)
  SENIORS 51+yrs
2000IU (50mcg)
  PREGNANT   2000IU (50mcg)
  LACTATING   2000IU (50mcg)
TOXIC LEVELS >10,000IU per day

The tolerable upper limits should only be taken for short periods and only under medical supervision.


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Vitamin D works best with


Overdosage, toxicity and cautions for vitamin D

Too much Vitamin D from supplements is dangerous! Do not exceed 2,000IU (50mcg) daily - for adults and 1,000IU (25mcg) - for infants and children!

Symptoms of having too much vitamin D are:

A long-term effect of too much vitamin D is the deposit of calcium in soft tissues of the body including the blood vessel walls and kidneys where it can cause serious damage.

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Last reviewed: 1 August 2020 || Last updated: 1 August 2020


NOTE: Mega doses of vitamins, minerals, amino acids, or other supplements cannot cure illnesses and in fact can be very dangerous and produce toxic side effects and interfere with medicine you are taking. Always ensure you consult your doctor before taking any type of nutrient supplement.
Disclaimer: This guide is not intended to be used for diagnostic or prescriptive purposes. For any treatment or diagnosis of illness, please see your doctor.


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