·
Vitamin A is a type of fat-soluble vitamin. It is not a single
structure. It is composed of a group of similar molecules, including retinol
and beta-carotene, the precursor of vitamin A.
·
Is the most common. Note 6
·
In the human body, vitamin A is mainly related to cell growth
and differentiation, embryonic development, organ formation, immune function,
and visual development.
·
Vitamin A benefits and side effects
Table of contents
· What are the proven
effects (benefits) of Vitamin A?
· It is beneficial for
children as they suffer from inflammation
· Useful for pigmentary
infections
· The occurrence of
diabetes
· Promoting the health
of young children
· Cataracts, including
age
· Are there any side
effects of vitamin A supplements?
· Safety precautions (8
taboos for use)
· What are the food
sources of vitamin A?
· Is there any blood in
vitamin A supplements for pregnant women?
· What are its vitamin A
components?
What are the proven
benefits of vitamin A?
1. Useful for children with
pneumonia
Pneumonia
is defined as an acute infection of lung tissue caused by one or more
associated pathogens, excluding specific bronchiolitis.
Respiratory
syncytial virus is the major viral agent, found in 15% to 40% of pneumonia
cases, followed by influenza A and B viruses, parainfluenza viruses, human
pneumoniae viruses, and adenoviruses.
Childhood pneumonia is the single leading cause of death in
children under five years of age. It is estimated that the incidence rate in
this age group is 0.29 per year in developing countries and 0.05 per year in developed
countries. Major risk factors include malnutrition, low birth weight, decreased
immunity to measles, and indoor air pollution.
A meta-analysis of the literature (including 15 randomized
controlled trials with a total of 3021 pneumonia patients) indicated that
although vitamin A supplementation in addition to regular treatment cannot
reduce mortality from childhood pneumonia, they improve the overall clinical
response rate and shorten the treatment duration. It improves the duration of
fever and cough, the time to clear signs, and reduces abnormal chest X-ray
findings and length of hospital stay. Note 1
*Conclusion: Additional vitamin A supplementation in the
treatment of pediatric pneumonia can help reduce clinical symptoms and signs
and shorten hospitalization time.
2. Beneficial
for retinitis pigmentosa
Retinitis pigmentosa is a familial hereditary disease
characterized mainly by the progressive degeneration of sensory cells in the
retina. Early symptoms are mainly slow adaptation to darkness and night
blindness, gradually affecting peripheral and central vision. In more severe
cases, it can lead to blindness.
A double-blind trial (4 to 6 years in 601 patients with
retinitis pigmentosa) found that vitamin A supplementation (15,000 IU per day)
reduced deterioration of retinal function by 32% compared with placebo, as
measured by electroretinography). Note 1
However, given the toxicity of large doses and incomplete
research methods, further confirmation is needed.
3.
Prevent diabetes
Diabetes is a complex metabolic disease associated with high
blood sugar and impaired insulin action, mainly caused by poor diet and
living habits and it is estimated that by 2030, more than 400 million adults
will be affected worldwide.
Animal and human experiments have found that vitamin A can
affect pancreatic beta cell production and insulin resistance, and its
deficiency is positively associated with diabetes.
A retrospective study (193,803 Danes) found that eating more
vitamin A (self-fortified dietary foods) in youth not only reduces the risk of
diabetes in midlife and old age, but also reduces the incidence of diabetes in
offspring. Note 2
The author stated that this finding is very important for low-
and middle-income countries suffering from undernutrition, and is a simple and
affordable nutritional intervention method.
4.
Promoting the health of young children
According to a survey conducted by the World Health
Organization, pneumonia, diarrhea and malaria top the list of causes of death
among children under the age of five after the postnatal period. Diarrhea alone
kills 500,000 children every year.
Malnutrition is the main cause of these diseases (45%), and is
mainly linked to poor economic and health conditions, parasites, and chronic
infections, especially in low- and middle-income countries.
The Cochrane Database of Systematic Reviews (Cochrane Database
of Systematic Reviews, including 47 studies including 1,223,856 children over 6
months and under 5 years) indicated that vitamin A supplements could help
reduce morbidity and mortality among young children. (Especially
in reducing diarrhea and diarrhea). Measles events). Note 3
5.
Reduce the risk of cataracts (age-related cataracts)
According to the World Health Organization, there are currently
more than 37 million blind people in the world, and cataracts are the leading
cause of blindness.
Although cataracts can be treated by intraocular lens replacement,
some patients are still unable to receive appropriate treatment due to factors
such as disparate medical resources and high cost. Therefore, it is important
to take the right precautions
A meta-analysis of the literature (including 22 studies) indicated
that higher intakes of vitamin A and beta-carotene could actually help reduce
the risk of cataracts. Note 4
However, the author stated that since potential biases and
interfering factors were not eliminated, the results still need to be confirmed.
6. Reducing the incidence of pancreatic cancer
Pancreatic cancer is one of the most difficult cancers of the digestive system and ranks fourth among the causes of
cancer death, and about three-quarters of cases occur after the age of 65
years.
Because the early symptoms of pancreatic cancer are non-specific
(such as loss of appetite, mild pain, nausea, and weight loss), people often
lose their alertness. When they are diagnosed, about 80% of them are in the
more severe intermediate and advanced stages and cannot be treated with
surgery.
A meta-analysis of the literature (including 11 studies)
indicated an inverse association between vitamin A intake and the incidence of
pancreatic cancer. People who eat larger amounts can reduce their risk by about
16% (compared to those who eat larger amounts) less. ). Note 5
Are there any side effects of vitamin A supplements?
For most healthy people, taking vitamin A in moderation from
food is safe and has no side effects. If you use health supplements, you should
pay attention to the dosage to avoid overdose and long-term poisoning.
In general, toxicity is typically associated with long-term use
of more than 10 times the Recommended Dietary Allowance (RDA), approximately
25,000 to 33,000 IU per day.
Symptoms of acute and chronic vitamin A poisoning include
nausea, headache, hair loss, fatigue, loss of appetite, dizziness, dry skin,
peeling, cerebral edema, hepatosplenomegaly, bone and joint pain, etc. Severe
cases can lead to liver damage, bleeding and coma.
Safety precautions (8 contraindications for use)
There is evidence that some groups are more susceptible to
vitamin A toxicity when taken orally, even at lower doses, including the
elderly, long-term alcoholics, and patients with familial hyperlipidemia.
Long-term use of high doses may increase osteoporosis and hip
fractures, especially in older adults
Pregnant women, children, and people with poor liver and kidney
function who wish to take additional supplements should inform medical staff
first to ensure safe use.
Please be careful if you have low blood pressure or are taking
antihypertensive medications as they may cause low blood pressure
It may have an anticoagulant effect, so please be careful if you
have blood-clotting disorders or are taking anticoagulants.
Concurrent use of high-dose vitamin A and tetracycline
antibiotics may increase the risk of intracranial hypertension.
Orlistat (obesity medication) and cholesterol-lowering
medications (bile acid sequestrants) may inhibit vitamin A absorption.
Do not use it with omeprazole (Prilosec, a gastrointestinal
drug) or the chemotherapy drug doxorubicin (Doxorubicin), because it may affect
the effect of the drug.
What are the food
sources of vitamin A?
Natural vitamin A (retinyl palmitate form) is commonly found in
beef, animal liver, eggs, cod liver oil, dairy products, whole milk, and
cheese.
In addition, beta-carotene is the precursor to vitamin A.
Vitamin A content can also be increased by consuming foods rich in related
carotenoids (such as dark green vegetables, yellow or orange vegetables and
fruits): common foods such as spinach, papaya, sweet potatoes, carrots,
pumpkin, peaches, mango, etc.
Are there any risks in taking vitamin A supplements for pregnant
women?
Although adequate vitamin A is important for fetal development,
excessive intake early in pregnancy may increase the risk of fetal
abnormalities.
Therefore, pregnant women and breastfeeding mothers should y
special attention to their total intake (daily intake of food and health
products should not exceed 5,000 IU) to avoid harmful consequences.
In addition, synthetic forms of vitamin A (commonly used in
high-dose supplements for formal medical treatment) may cause serious birth
defects in fetuses and should therefore be avoided. Related forms include
acitretin, bexarotene, isotretinoin, and tazarotene
What is the recommended amount of vitamin A?
According to the recommended dietary allowance standards set by
the Institute of Medicine (IOM):
Children
0 to 6 months: 400 mcg daily
7 to 12 months: 500 mcg daily
Children
From 1 to 3 years: 300 micrograms daily
From 4 to 8 years: 400 micrograms daily
From 9 to 13 years: 600 micrograms daily
Pikes
Teenagers and adults
Males aged 14 years and over: 900 micrograms daily
Women aged 14 years and over: 700 micrograms daily
(For women, it can increase to 770 micrograms during pregnancy
and 1,300 micrograms during breastfeeding)
1 microgram is equivalent to 3.33 IU of vitamin
Conclusion
Vitamin A, a fat-soluble vitamin containing retinol and
beta-carotene, is crucial for cell growth, differentiation, and immune
function.
It has numerous benefits for children, especially those
suffering from inflammation, pigmentary infections, diabetes, and cataracts.
Vitamin A can reduce the risk of pneumonia, retinal
degeneration, diabetes, and pancreatic cancer.
It also promotes the health of young children, reduces morbidity
and mortality, and reduces the incidence of pancreatic cancer.
However, side effects of vitamin A supplements include nausea,
headaches, hair loss, fatigue, and severe liver damage.
Long-term use may increase osteoporosis and hip fractures.
Pregnant women, children, and those with poor liver and kidney
function should consult medical staff before taking vitamin A supplements.
It is important to be cautious with low blood pressure,
blood-clotting disorders, concurrent use of high-dose vitamin A and
tetracycline antibiotics, orlistat and cholesterol-lowering medications.
Vitamin A is found in beef, animal liver, eggs, cod liver oil,
dairy products, whole milk, and cheese. Excessive intake early in pregnancy may
increase the risk of fetal abnormalities.
Pregnant women and breastfeeding mothers should limit their
daily intake to 5,000 IU. Synthetic forms of vitamin A should be avoided.