Vitamin a daily intake
Pro Research Analysisby 
Searched over 200M research papers
Understanding Daily Vitamin A Intake: Recommendations and Sources
Recommended Daily Intake of Vitamin A
Vitamin A is a crucial fat-soluble micronutrient essential for various bodily functions, including vision, immune function, and cellular communication. The recommended daily intake (RDI) for vitamin A varies by demographic factors such as age, sex, and physiological status. For adult men, the RDI is generally around 700 micrograms (µg) of retinol equivalents (RE), while for adult women, it is approximately 600 µg RE . These values are designed to maintain an adequate body pool of vitamin A, ensuring sufficient reserves for periods of low intake or physiological stress .
Global Variations in Vitamin A Intake
Africa, South America, and Asia
Recent studies have highlighted significant discrepancies in vitamin A intake across different regions. For instance, the estimated daily per capita intake in Africa, South America, and Asia is significantly lower than the recommended levels, with values of 371, 372, and 258 µg RE, respectively. These figures are well below the recommended 600 µg RE for adult males, indicating a widespread deficiency that necessitates new strategies to combat vitamin A deficiency .
China
In China, the average daily intake of vitamin A is also below the recommended levels, with an average intake of 460.56 µg retinol activity equivalents (RAE) per day. This is significantly lower than the recommended dietary reference intake of 800 µg RAE/day for adult men and 700 µg RAE/day for adult women . Vegetables are the primary source of vitamin A in the Chinese diet, contributing approximately 54.94% of the total intake .
Korea
In Korea, the average dietary vitamin A intake is 864.3 µg RE/day for men and 715.0 µg RE/day for women. Despite these figures, a significant portion of the population still consumes less vitamin A than the Estimated Average Requirement (EAR), with 42.9% and 70.6% of the population falling below the EAR based on RE and RAE, respectively .
Spain
In Spain, the average dietary intake of vitamin A is 716.4 µg RE/day, with retinol contributing 57.9% and provitamin-A carotenoids contributing 42.1% of the total intake. The primary sources of provitamin-A carotenoids in the Spanish diet are red and orange-colored fruits and vegetables .
Sources of Vitamin A
Animal Sources
Animal-derived foods are rich in preformed vitamin A (retinol), which is readily absorbed and utilized by the body. Common sources include liver, fish oils, milk, eggs, and meat. In Western countries, where animal products are more commonly consumed, preformed vitamin A accounts for nearly 65% of the total vitamin A intake .
Plant Sources
Provitamin A carotenoids, such as beta-carotene, are abundant in plant-based foods and are converted into retinol in the body. Key sources include dark green leafy vegetables, carrots, sweet potatoes, and red and orange fruits. In China, dark and light vegetables and fruits are major contributors to carotene intake, accounting for 84.2% of the total . Similarly, in Korea, the major food sources of vitamin A include Korean radish leaves, carrots, red pepper, and laver .
Challenges and Recommendations
Bioavailability and Conversion
The bioavailability of provitamin A carotenoids and their conversion to retinol can be overestimated. It is proposed that instead of 6 µg from a mixed diet, 21 µg of beta-carotene are required to provide 1 µg of retinol or 1 RE of vitamin A . This adjustment significantly impacts the estimated daily intake and highlights the need for accurate dietary assessments.
Fortification and Dietary Adjustments
To address vitamin A deficiencies, especially in regions with low intake, fortification of commonly consumed foods such as vegetable oils and increasing the vitamin A content of staple vegetables are effective strategies. These measures can help populations meet the recommended dietary guidelines .
Conclusion
Ensuring adequate vitamin A intake is crucial for maintaining optimal health. While the recommended daily intake varies, many regions fall short of these guidelines, necessitating public health interventions and dietary adjustments. By understanding the sources and bioavailability of vitamin A, effective strategies can be implemented to combat deficiencies and promote better health outcomes globally.
Sources and full results
Most relevant research papers on this topic