Getting higher dosages than the upper safe daily dose of 3,000 mcg can be dangerous. Especially, for pregnant women and elderly people, as it increases the risk of birth defects and osteoporosis, respectively. Chronic intake of supplements, or consumption of foods high in retinol, such as beef liver and fish oil, may lead to vitamin A toxicity!
What does vitamin D do to the body?
Vitamin A is a fat-soluble vitamin. Most of it is stored in the liver.
Above all, vitamin A is well-known for its key role in vision. In fact, vitamin A helps absorb light in the retinal receptors, and it supports the normal functioning of the cornea.
Besides vision, vitamin A is necessary for good immune function, reproduction, and the normal functioning of the heart, lungs, kidneys, and other organs.
What’s the recommended daily dose?
It’s a bit tricky to set a recommended daily dose for vitamin A. Actually, vitamin A is absorbed in different rates, depending on the dietary source.
Whatever the source, the body converts all dietary forms of vitamin A into retinol.
Actually, there are two forms of vitamin A; preformed vitamin A (retinol) and provitamin A carotenoids. Retinol is much more bioactive than carotenoids, though.
First, vitamin A from dietary supplements containing retinyl esters (a form of retinol), and vitamin A from animal source foods has the highest bioavailability. Retinol is easily metabolized by the body.
On the other hand, 1 mcg of supplemental beta-carotene is equivalent to 0.5 mcg of retinol. Beta-carotene (or provitamin A carotenoid) isn’t absorbed as effectively!
Moreover, beta-carotene from food is absorbed even less. 1 mcg of dietary beta-carotene is equivalent to 0.083 mcg of retinol. It’s 12 times less bioactive than retinol!
Other types of carotenoids, such as alpha-carotene or beta-cryptoxanthin are even 24 times less bioactive than retinol.
Actually, the recommended daily dose for vitamin A is referred to retinol. That’s what the RAE (Retinol Activity Equivalents) stands for.
|1–3 years||300 mcg RAE||300 mcg RAE|
|4–8 years||400 mcg RAE||400 mcg RAE|
|9–13 years||600 mcg RAE||600 mcg RAE|
|14+ years||900 mcg RAE||700 mcg RAE|
Practically, teens and adults need a daily vitamin A dose of:
- 900 mcg from retinol supplements, or
- 900 mcg from animal source foods (beef liver, fish oils) or
- 1,800 mcg from beta-carotene supplements, or
- 10,800 mcg from plant-based foods.
Only pregnant and lactating women need higher vitamin A doses of 770 mcg RAE and 1,300 mcg RAE, respectively.
What’s the upper safe dosage for vitamin A from supplements?
We should be really careful about our vitamin A intake. Vitamin A is a fat-soluble vitamin. Hence, the body stores excess amounts. This may lead to toxicity! Thus, we shouldn’t exceed the upper safe dosage for vitamin A, unless your physician has advised you otherwise.
In most cases, vitamin A toxicity may occur due to the overconsumption of animal source foods rich in retinol (beef liver and fish oil), and dietary supplements. Actually, the upper safe dosage for vitamin A is 3,000 mcg.
On the contrary, getting high amounts of beta-carotene, either from supplements, or food, is considered safe. It’s less bioactive.
What supplement dose is safe?
We should be pretty careful about the consumed vitamin A dose from supplements. It shouldn’t exceed the maximum daily intake!
But, the dose of vitamin A varies significantly! There are vitamin A supplements containing doses of 7,500 mcg. This dose is 833% of the recommended daily intake and 250% of the upper safe dose for adults!
You shouldn’t take so high dosages, without consulting your physician.
Better prefer vitamin A supplements with doses of 1,500 mcg, which is half the maximum safe dose.
Adverse effects of extremely high vitamin A dosages from supplements
Chronic intakes of higher vitamin A doses than the recommended intake may lead to increased intracranial pressure, dizziness, nausea, headaches, skin irritation, pain in joints and bones, liver damage, birth defects, and even death.
Also, chronic high dosages of vitamin A may cause reduced bone mineral density, and increased fracture risk! This is particularly important for older people. Especially women, who are at increased risk of osteoporosis.
Moreover, pregnant women and women planning to become pregnant should avoid excess vitamin A intake in the retinol form, which is commonly found in vitamin A supplements, and animal source foods, such as beef liver, and fish oil. Retinol doses higher than the maximum safe dosage seem to increase the risk of birth defects and may harm the fetus.
On the contrary, extremely high beta-carotene doses of 30,000 mcg a day, or diets high in carotenoid-rich foods for long periods are not associated with vitamin A toxicity!
Above all, consult your physician before taking supplements or drastically changing your diet.
Should I take vitamin A supplements?
Actually, vitamin A deficiency is rare. Healthy people who follow a well-balanced diet probably don’t need to take vitamin A supplements.
Can I get too much vitamin A from diet?
In fact, beef liver contains extremely high amounts of preformed vitamin A. It may cause adverse effects. You should avoid its regular consumption. Additionally, fish oil is pretty high in retinol. High amounts could cause toxicity.
Milk and egg contain smaller amounts of preformed vitamin A as well.
Practically, you can’t exceed the maximum safe dosage for vitamin A from food. Just avoid eating beef liver and consuming high amounts of fish oil.
Certainly, you could eat high amounts of plant-based foods rich in vitamin A. Plants contain carotenoids, which don’t cause vitamin A toxicity. Actually, there isn’t a maximum safe dose for carotenoids!