Recommendations for vitamin A, as well as other nutrients, are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board at the National Academies of Sciences, Engineering, and Medicine. Dri is a term for a set of reference intakes that are used to plan and assess the nutrient intakes of healthy people. These values, which vary by age and sex, include:
Recommended Dietary Allowance (RDA): The average daily level of intake that is enough to meet the nutrient needs of nearly all (97% to 98%) healthy people.
Adequate Intake (AI): This level is established when there is not enough scientific research evidence to develop an RDA. Dietary reference intakes for vitamin A:
Infants (AI)
0 to 6 months: 400 micrograms per day (mcg/day)
7 to 12 months: 500 mcg/day
The Recommended Dietary Allowance (RDA) for vitamins is how much of each vitamin most people should get each day. The RDA for vitamins may be used as goals for each person.
Contents
A, also known as retinol, has several important functions. These include: helping your body’s natural defence against illness and infection (the immune system) work properly
helping vision in dim light
keeping skin and the lining of some parts of the body, such as the nose, healthy.
Function
These values, which vary by age and sex, include:
Recommended Dietary Allowance (RDA): The average daily level of intake that is enough to meet the nutrient needs of nearly all (97% to 98%) healthy people.
Adequate Intake (AI): This level is established when there is not enough scientific research evidence to develop an RDA. It is set at a level that is thought to ensure enough nutrition. Children (RDA)
1 to 3 years: 300 mcg/day
4 to 8 years: 400 mcg/day
9 to 13 years: 600 mcg/day
Adolescents and adults (RDA)
Males age 14 and older: 900 mcg/day
Females age 14 and older: 700 mcg/day (for females aged 19 to 50, 770 mcg/day during pregnancy and 1,300 mcg/day during breastfeeding)
The best way to get the daily requirement of important vitamins is to eat a wide variety of fruits, vegetables, fortified dairy foods, legumes (dried beans), lentils, and whole grain.
What Is Vitamin A?
Carotenoids are pigments responsible for plant’s red, yellow and orange colours, which our bodies can absorb and convert to vitamin A. One of the most well-known and abundant carotenoids in nature is beta-carotene. There are also other types of carotenoids in foods, such as lycopene, lutein and zeaxanthin, which are not converted to vitamin A in our bodies but have other health benefits.
Our bodies absorb vitamin A from animal products better than vitamin A from plant-based foods.
Sources Of Vitamin A
There are two main sources of vitamin A: animal sources and plant sources. All the sources of vitamin A need some fat in the diet to aid absorption.
In animal sources, vitamin A is found as retinol, the ‘active’ form of vitamin A. Liver, including fish liver, is a very good source. Other animal sources are egg yolk (not the white) and dairy products such as milk (including human breast milk), cheese and butter. Meat, from the animal’s muscles, is not a good source.
Carotenoids are the pigments that give plants their green colour and some fruits and vegetables their red or orange colour. (Note: if these oils are boiled to remove their colour the vitamin A is destroyed.). Mashing these vegetables up after cooking makes them easier to digest.