Beta Carotene As A Source Of Vitamin A
The body can change beta carotene into vitamin A so including these sources will also help. The main food sources of beta-carotene are:
- yellow, orange and red vegetables such as carrots, sweet potatoes and red peppers
- green vegetables, such as spinach
- yellow fruit, such as mango, apricots and papaya
Biological Roles Of Vitamin A
Vitamin A is an essential micronutrient required in small amounts by human throughout the life cycle to perform multiple metabolic functions. It is important for growth and development, the maintenance of immune function and maintenance of epithelial cell integrity, good vision, reproduction as well as lipid metabolism. Vitamin A is also an important antioxidant, a property shared with vitamins E and C, respectively . New biological functions of vitamin A such as lipid metabolism, insulin response, energy balance and the nervous system are continuously being discovered.
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Vitamin A Vitamins & Supplements At Walgreens
Vitamin A is an important nutrient that promotes our health in many ways. From vision to immune health, vitamin A consumption can help protect our bodies through food sources, multivitamin, and supplements. Walgreens carries multiple over the counter options for vitamin A supplements available in stores and online.
When To See A Doctor
The symptoms of vitamin deficiency vary. Some deficiencies have no symptoms at all. In general, if you have any of these symptoms, you should contact your doctor:
- You are losing your hair.
- You feel weak.
- You are often tired, even when you get plenty of sleep.
- You have cracks in the corners of your mouth.
- You have acne-like bumps on your cheeks, upper arms, thighs, and buttocks.
- Your vision is getting worse, especially at night.
- You have dry eyes.
- You are having panic attacks.
- You have tingling or numbness in your hands and feet.
- Your gums bleed.
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B12 Recommendations For Vegans
The RDA for B12 in adults is 2.4 micrograms per day , which assumes a 50% absorption rate from the amount ingested in foods. However, higher levels may be recommended to prevent potential deficiency symptoms in vegans. Intake of higher doses does not appear to be associated with detrimental health problems.
The VNDPG recommends the following B12 guidance:
- All vegetarians, regardless of type, should periodically be screened for B12 deficiency, using either MMA or TCII assessment.
- All women considering pregnancy, and those already pregnant, should take 250 mcg/d* of a B12 supplement.
- All vegans should take 250 mcg/d* of a B12 supplement.
- All lacto-ovo vegetarians should consider taking 250 mcg/d* of B12 supplement a few times per week.
*This amount is about 100 times higher than the RDA due to the fact that only about 1% of ingested B12 from supplements is absorbed.
Norris recommends vegan adults 18 65 years old should take one of the following regimens: two doses per day of 2 3.5 mcg per serving one dose per day of 25 100 mcg per serving or two doses per week of 1,000 mcg per serving. To read his full recommendations, visit here.
|Recommended Dietary Allowances for Vitamin B12|
* Adequate Intake
What Are The Causes Of Vitamin A Deficiency
Vitamin A deficiency may be caused by prolonged inadequate intake of vitamin A. This is especially so when rice is the main food in your diet .
Vitamin A deficiency may also occur when your body is unable to make use of the vitamin A in your diet. This may occur in a variety of illnesses, including:
- Obstruction of the flow of bile from your liver and gallbladder into your gut.
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Vitamin D: Whole Foods Vs Fortified Foods
Fortified foods are meant to help boost vitamin and mineralintake. Theyre designed to add nutrients that dont naturally occur in theproduct. Sometimes iron, fiber, zinc or vitamin A is added. For instance, most milkis fortified with vitamin D and calcium is sometimes added to orange juice.
Since so few foods found in nature are good sources ofvitamin D, fortified foods provide most of the vitamin D found in the Americandiet, explains Taylor.
But she warns that some fortified foods can contain addedingredients that make the product less healthy, like sugar or hydrogenatedfats. Cows milk and most plant alternative milks are typically fortified withvitamin D, but its important to look for products with no added sugar.
Many types of yogurt and cereal are also fortified withvitamin D, but could contain excessive added sugar or saturated fat. Margarineis often fortified as well, but some products contain partially hydrogenatedoils, which should be avoided. Read labels to choose the best product for yourfamily.
How Common Is Vitamin A Deficiency
Vitamin A deficiency is unusual in high income countries. However, it is very common in low income countries where it often develops because of intestinal infections and worms, and protein-energy malnutrition.
Vitamin A deficiency is the biggest cause of preventable blindness in children worldwide. It is the most common nutritional deficiency in the world.
An increased risk of vitamin A deficiency occurs in:
- People with illnesses affecting the way food is absorbed from the gut into the body.
- People who have had weight reduction surgery.
- People who have a strict vegan diet.
- Prolonged excessive alcohol intake .
- Other forms of liver disease, as vitamin A is stored in the liver.
- Toddlers and preschool children living in poverty.
- Recent immigrants or refugees from low-income countries.
The most easily absorbed form of vitamin A is fat-soluble, and is absorbed as fat is broken down in the small bowel, so people who are on an extremely low-fat diet or are taking medication to reduce fat absorption, such as orlistat, may be at risk of vitamin A deficiency.
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Causes Of Vitamin D Deficiency
Whether you live in the northern latitudes or not, vitamin D deficiency can happen. Youre most at risk of deficiency if you are elderly, have dark skin, are obese, eat a poor diet or have a digestive disease, such as Crohns, celiac or a food allergy, that affects your absorption of nutrients.
The factor that really comes into play in the high latitudes is lack of sun exposure. Whether its due to a family history of skin cancer or because we want to avoid wrinkles, many of us expose our skin to the sun far less than previous generations did. This is mostly because science has shown us just in the last couple of decades how damaging the suns rays can actually be. Were no longer slathering our skin in baby oil for that optimal tan, er, burn! Instead, were slathering up in sunscreen.
This can translate to too little vitamin D. While sunlight doesnt actually give us the sunshine vitamin, our bodies produce it when our skin is exposed to the suns ultraviolet rays. Then our kidneys and liver work to convert the biologically inert form of vitamin D into an active form that the body can use.
Heres the catchand this brings us back to our original questionsunlight contains two types of ultraviolet rays. Ultraviolet A, or UVA, are the rays that penetrate deep and can cause wrinkles and premature aging. Ultraviolet B, or UVB, are responsible for the redness that comes with a sunburn, and are the rays that trigger the synthesis of vitamin D.
Assessing Vitamin A Status
Vitamin A status of a specific population is important to better understand health status of the community in that particular area. VAD can lead to many health consequences, with children, pregnant and lactating women known to be the prominent groups suffering from VAD in many low-income countries . Its prevalence of deficiency in a population is assessed by specific indicators/biomarkers .
Good Sources Of Vitamin A
Good sources of vitamin A include:
- fortified low-fat spreads
- milk and yoghurt
- liver and liver products such as liver pâté this is a particularly rich source of vitamin A, so you may be at risk of having too much vitamin A if you have it more than once a week
You can also get vitamin A by including good sources of beta-carotene in your diet, as the body can convert this into retinol.
The main food sources of beta-carotene are:
- yellow, red and green vegetables, such as spinach, carrots, sweet potatoes and red peppers
- yellow fruit, such as mango, papaya and apricots
Indicators To Assess Vitamin A Status
There are several indicators/biomarkers to detect VAD. The gold standard method to assess vitamin A status is through the direct measurement of liver reserves of vitamin A through biopsy, since in human, vitamin A is stored abundantly in the liver . A study in average-weight individuals for 4 months had shown that an estimated cut-off at 0.07 mol/g liver was able to protect them from any clinical signs of VAD . Unfortunately, this method is not feasible for population evaluation . Therefore, other various methods are being proposed to assess and monitor VAD based on their different aspects. The two different ways include biological and biochemical indicators . In 2010, liver reserves of vitamin A were plotted against the commonly used indicators to define the range of liver reserves associated with the specific indicators. It was later updated in 2015 as presented in Figure 1 .
The definition of vitamin A status assessed by using vitamin A indicators associated with vitamin A concentration in the liver. In 2010, 0.71 mol/g was considered adequate, but this range is considered high until more biologically meaningful data are generated.
3.1.1 Biological indicators
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What Does The Department Of Health And Social Care Advise
You should be able to get all the vitamin A you need by eating a varied and balanced diet.
If you take a supplement that contains vitamin A, do not take too much because this could be harmful.
Liver is a very rich source of vitamin A. Do not eat liver or liver products, such as pâté, more than once a week.
You should also be aware of how much vitamin A there is in any supplements you take.
If you’re pregnant or thinking of having a baby:
- avoid taking supplements containing vitamin A, including fish liver oil, unless advised to by your GP
- avoid liver or liver products, such as pâté, as these are very high in vitamin A
Women who have been through the menopause and older men, who are more at risk of osteoporosis, should avoid having more than 1.5mg of vitamin A a day from food and supplements.
- not eating liver or liver products, such as pâté, more than once a week, or having smaller portions of these
- taking no more than 1.5mg of vitamin A a day in supplements if you do not eat liver or liver products
- not taking any supplements containing vitamin A if you eat liver once a week
Having an average of 1.5mg a day or less of vitamin A from diet and supplements combined is unlikely to cause any harm.
Page last reviewed: 03 August 2020 Next review due: 03 August 2023
Special Precautions & Warnings
Pregnancy and breast-feedingLIKELY SAFEPOSSIBLY UNSAFE
Excessive use of alcohol: Drinking alcohol may increase vitamin A’s potentially harmful effects on the liver.
Anemia: People who are anemic and have low levels of vitamin A might need to take iron along with a vitamin A supplement to treat this condition.
Disorders in which the body does not absorb fat properly: People with conditions that affect fat absorption, such as celiac disease, short gut syndrome, jaundice, cystic fibrosis, pancreatic disease, and cirrhosis of the liver, are not able to absorb vitamin A properly. To improve vitamin A absorption, these people should use vitamin A preparations that are water-soluble.
A type of high cholesterol called “Type V hyperlipoproteinemia”: This condition might increase the chance of vitamin A poisoning. Do not take vitamin A if you have this condition.
Intestinal infections: Intestinal infections such as hookworm can reduce how much vitamin A the body absorbs.
Liver disease: Too much vitamin A might make liver disease worse. Do not take vitamin A if you have liver disease.
Malnutrition: In people with severe protein malnutrition, taking vitamin A might result in having too much vitamin A in the body.
Zinc deficiency: Zinc deficiency might cause symptoms of vitamin A deficiency to occur. Taking a combination of vitamin A and zinc supplements might be necessary to improve this condition.
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What Is The Treatment For Vitamin A Deficiency
The treatment for mild forms of vitamin A deficiency includes eating vitamin A-rich foods – eg, liver, beef, oily fish, chicken, eggs, fortified milk, carrots, mangoes, sweet potatoes and leafy green vegetables.
For more severe forms of vitamin A deficiency causing symptoms, treatment includes taking daily oral vitamin A supplements.
What Is The Outcome
The outcome is very good if you have a mild form of vitamin A deficiency without any symptoms. However, more severe forms may cause permanent loss of vision if treatment with vitamin A supplements is not taken at an early stage. If you have early mild eye problems, treatment can result in full recovery without any permanent loss of vision.
Severe vitamin A deficiency with severe generalised malnutrition in low income countries often leads to death.
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What Does Vitamin A Do For Your Skin
Vitamin A can have positive effects on skin, bones, and nail health. Vitamin A in the form of retinoid is often found in skin products and serums. There is evidence to suggest that retinoids reduce fine lines and wrinkles by increasing the amount of collagen protein in our skin. Collagen protein plays an important role in keeping our skin tissue and bones strong.
It is important to make sure you are getting enough vitamin A through diet or supplements. Vitamin A deficiency can cause dry skin and hair, and may also cause more serious side effects.
What Form Does Vitamin A Come In
Vitamin A comes in two forms in our diets. The first is preformed vitamin A, sometimes known as vitamin A from retinol or retinyl ester. This is found in many animal products such as liver, eggs, and fish oil. The other form of vitamin A is precursors to vitamin A, called provitamin A carotenoids, which can be found in many fruits and vegetables. The most common form of this type of vitamin A is beta carotene which is found in colorful fruits and dark leafy vegetables. Vitamin A supplements may contain either form of vitamin A, but its most common for supplements to contain preformed vitamin A with retinyl acetate or retinyl palmitate.
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Vitamin A Recommended Intake
Recommended dietary allowance represents an average daily intake that is sufficient for healthy people to meet their nutrient requirements. RDAs for vitamin A are expressed in mcg of retinol activity equivalents , although international units are used on food and supplement labels. Since the conversion of mcg RAE into IU is rather complex as it depends on the vitamin A food sources chart, this practice will soon be changed thanks to the FDAs new labeling regulations.
The recommended daily intake of vitamin A is as follows:
- from birth to 6 months400 mcg RAE
- from 7 to 12 months500 mcg RAE
- from 1 to 3 years300 mcg RAE
- from 4 to 8 years400 mcg RAE
- from 9 to 13 years600 mcg RAE
- teen boys 1418 years900 mcg RAE
- teen girls 1418 years700 mcg RAE
- adult men900 mcg RAE
- adult women700 mcg RAE
Vitamin A recommended daily intake is a bit different for pregnant women aged 1950 . Also, its different for women who are breastfeeding .
Health Benefits Of Vitamin A
- Increased Protection from Bacterial and Viral Infections – Vitamin A is essential for healthy surface linings of the eyes, mucous membranes, respiratory, urinary, and intestinal tracts, which help protect the body against infection.
- Proper Immune Functioning – Vitamin A regulates the immune system and plays a key role in making white blood cells which fight off infections in the body.
- Cancer Protection – Studies suggest beta-carotene and vitamin A lower risk of many types of cancer. This effect could mainly be from a diet high in vegetables and not from supplements. Vitamin A supplements and carotene supplements have been shown to increase risk and progression of lung cancer in smokers, or those with a high risk of lung cancer.
- Better Eye Health and Protection Against Age-Related Macular Degeneration – Oxidative stress plays a role in macular degeneration . Anti-oxidants including vitamin A, Lutein, and Zeaxanthin, are thought to play a roll in reducing macular degeneration and preserving good eye health into old age.
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Who Should Take Vitamin A Supplements
Demographics at higher risk of lack of vitamin A include:
- premature infants
- pregnant and breastfeeding women in developing countries
- people with cystic fibrosis
Also, certain medications, such as Orlistat, can affect the bodys ability to absorb fat-soluble vitamins and increase the risk of vitamin deficiency.
Those who lack vitamin A can take vitamin A tablets, but they should always consult a physician first. A healthcare professional will determine the dosage necessary to address the vitamin deficiency.