All About Vitamin A: Recommended Intake, Sources, and Supplements
This article will focus on Vitamin A, its function, food sources, drug interactions, and government regulation of labeling. There is also some personal opinion thrown into the mix (sorry, I can't stop myself!).
Vitamin A is primarily classified as a "fat soluble" vitamin, but can also be a "water soluble" vitamin, depending if it originates from an animal source (food from animals) or a plant source (foods from plants).
So if Vitamin A is both fat soluble and water soluble, what exactly does that mean for my body? How do I tell the difference?
The label must list all of the ingredients and whether they are from animal or plant sources.
Vitamin A from an animal source is fat soluble, and is absorbed much easier and quicker than Vitamin A from a plant source. It also stays in the body longer. Vitamin A is stored in your liver and fatty tissues, and needs fat in order for the body to use it effectively.
Vitamin A from a plant source is water soluble. It can be consumed daily and will wash out of the body each day with body fluids.
- It is not necessary, nor is it advised by most medical professionals, to consume fat soluble vitamins every day.
- Taking mega-doses of fat soluble vitamins can cause toxicity because the dose stays in the body for a long period of time.
I remember it this way to keep from getting confused:
Animal fat = fat soluble Vitamin A
- Water the plants - water soluble Vitamin A
Abbreviations From National Institute of Health (NIH)
UL (Tolerable Upper Intake Level) - this is the safest amount that won't risk overdose/toxicity
DV (Daily Value) -this is the recommended amount based on 2000 calorie diet. This is sometimes the same as RDA
RDA (Recommended Dietary Allowance) & AI (Adequate Intake) - this is the amounts you need to stay healthy and avoid nutritional deficiencies. These are determined according to age groups and gender.
Dietary Supplements Are Big Business
According to several National Health and Nutrition Examination Surveys (NHANES):
- "the percentage of the U.S. population, ages 20 and over, who used at least one multivitamin/multimineral product increased from 30% in the NHANES study of 1988 to 1994.
- It went up to 39% in the NHANES study conducted from 2003 to 2006, with use more common among women than men."
You would think that a business that big would have some kind of regulation, especially since we, as consumers, rely on the FDA to protect us regarding the safety of our foods and drugs.
Nope, we are on our own because vitamins and supplements are not considered food and they are not considered drugs, even though people take them religiously for their general good health.
Forms of Vitamin A
Vitamin A is normally measured in International Units (IU), although some labels measure it in micrograms (mcg).
Vitamin A comes in two forms: (see photos for food sources)
- Retinol - (a pre-formed Vitamin A)
- Carotenoids - (a pro-formed Vitamin A or provitamin)
According to the CDC, to be considered a dietary supplement, the product must contain three or more vitamins.
But it does not have to have any minerals added to the composition.
Why You Need It and Recommended Dosage
Most people, when they think about Vitamin A, think about their eye health. It is true that Vitamin A helps your eyes adjust to changes in light. Therapeutic doses have been shown to assist with the treatment of night blindness.
But it is also important for skin, bone and teeth growth and development, the reproductive system (producing sperm), and regulating the immune system.
Vitamin A keeps your mucous membranes moist - skin, eyes, mouth, nose, throat and lungs. It is an important antioxidant that regulates the immune system, and studies say it is important in the prevention of certain types of cancer.
Vitamin A, in the form of beta-carotene, is the best to choose. For skin, topical retinol is best.
It is very easy to get too much Vitamin A (retinol) from your supplements. But it is possible to get too little as well.
3,000 micrograms of preformed Vitamin A is more than three times the Recommended Dietary Allowance, and some publications consider this to still be safe.
However, conservative thinking says that this high dose increases the risk of hip fractures and can interfere with the benefits of Vitamin D, which often accompanies Vitamin A formulas.
Beta-carotene (preformed Vitamin A) is not considered toxic at high levels and some people believe it reduces their risk of cancer.
Smokers should avoid high doses of stand alone Vitamin A (without added vitamins and minerals) because some recent trials linked high doses with increased lung cancer risk.
Beta-carotene should not be taken as a stand alone supplement. It should always be accompanied by other supplements in a formula.
Men = 900 micrograms of retinol (equal to 3,000 IU)
Women - 700 micrograms of retinol (equal to 2,333 IU)
Food Sources for Carotenoids (provitamin A)
All dietary supplements must have this disclaimer on the label:
“This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Food Sources for Retinol (pre-formed Vitamin A)
Who Regulates the Vitamin & Supplement Industry?
After extensive reading on this subject, the answer I arrived at is: No one.
The official National Institute of Health (NIH) answer is that there is no government oversight because dietary supplement manufacturers are not drug manufacturers.
The supplement companies probably enjoy that status because that means they have no one but the consumer to answer to regarding the quality of their products.
- So therefore - in my opinion - the wolves are guarding the hen house.
Studies show that most of us take vitamins and supplements daily. I wonder how many people take them "just in case" they are not getting enough in their diet ...
In October 1994, Senator Orrin Hatch's creation of Dietary Supplement Health and Education Act of 1994 ("DSHEA") and President Bill Clinton's signing it into law, was a lot of pomp and circumstance that ended up creating yet another government agency (most likely with prime office space in Washington DC) that still sits and twiddles its thumbs, having no real job to perform and even less of a job description.
In an excerpt (i.e. gibberish) from the FDA's website which explains the latitude given to the dietary supplement companies:
- Before 1994, dietary supplements were subject to the same regulatory requirements as were other foods. (In other words, there was very little or no regulations.)
- This 1994 law only addressed the safety and labeling of dietary supplements.
- Under DSHEA, each company continues to be responsible for determining that the dietary supplements it manufactures or distributes are safe. Any representations or claims made about them must have adequate evidence to show that they are not false or misleading. This is why labels are devoid of claims or cures, or even giving consumers an inkling of what the product is used for.
- Dietary supplements do not need approval from FDA before they are marketed.
- A company does not have to provide the FDA with their evidence that supports the safety or effectiveness of their products, except in the case of introducing a new dietary ingredient. In this case, it is required by law that it be reviewed for safety data and other information before going on the market. If the new ingredient was in our food supply or existed before October 1994, whether or not it was previously added to a supplement, it is not considered new and is a recognized food substance.
Are dietary supplements considered food?
Since we consume and digest dietary supplements, should they be considered a food?
Language On Label
A supplement cannot make a claim to affect the structure or function of the body, a claim of general well-being, or a claim of a benefit related to a classical nutrient deficiency disease.
It can claim to "support," "promote," or "help fight."
In June, 2007, the FDA published comprehensive regulations called Current Good Manufacturing Practices which focused on practices that ensure the identity, purity, quality, strength and composition of dietary supplements.
- These "Practices" also governed what information should be on the label, an acceptable language so the average consumer could understand it, and the recommended dosages. (in other words: LABELING)
To date, most labeling is vague.
It pays to be an informed consumer and know what product you are looking for before you get to the store.
Are they drugs?
Since we use dietary supplements to self-treat a variety of body functions/dysfunctions, should they be considered a drug?
Warning: Vitamin A and Prescription Interactions
The New Law Was All About The Labels
Since this multi-billion industry is primarily a self-care industry, proper labels were deemed more necessary to address than the actual regulation of the products. A well funded government study yielded the types of information we see today on our dietary supplement labels.
Paraphrased from www.cdc.gov:
- A dietary supplement must be labeled as a dietary supplement. (a real no-brainer)
- The label must give the consumer enough information to make informed decisions about products. However, the label cannot say precisely what body system the product will cure or treat. It can only use words like "help build" or "promotes good."
- The label must very clearly disclose the ingredients in the supplement as well as in the capsule or tablet composition (i.e. gluten free, sugar free, etc.)
- The label must make known the safety information - interactions, contraindications, and possible side effects and adverse reactions.
- The label must give understandable directions for use, including proper doses and frequency of doses.
- The label must have the name of the manufacturer, production location and batch numbers
- The label must be of a unique design so that consumers can distinguish the product from other self-help products.
- The label must have this disclaimer: “This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease” if the supplement bears a claim to affect the structure or function of the body (structure/function claim), a claim of general well-being, or a claim of a benefit related to a classical nutrient deficiency disease."
Under the Dietary Supplement Health and Education Act of 1994, supplements are mainly unregulated and do not require proof of effectiveness or safety in order to market the products as a supplement.
Symptoms of Vitamin A Deficiency
Commonly associated with malnutrition, it is rare to see a Vitamin A deficiency (xerophthalmia) in the United States.
Because Vitamin A is stored in the liver and fatty tissues, deficiency can take as long as two years to manifest in the body.
Symptoms of Deficiency:
- Night blindness
- Dry, rough skin
- decreased resistance to infections
- poor tooth development
- slower bone growth for age group.
Best Supplements To Take With Vitamin A
Symptoms of Vitamin A Toxicity
Toxicity presents in patients more than deficiencies and some supplement formulaes have very high doses of Vitamin A which is not complemented by enough of the other vitamins and supplements in the dose.
The label must say that the majority of Vitamin A is beta-carotene.
- dry, itchy skin
- loss of appetite
High doses of Vitamin A over short periods of time can lead to dizziness, blurred vision, slower growth and possibly hip fractures. When pregnant, high doses have been associated with severe birth defects.
Function Of Foods Rich In Vitamin A
Dr. Oz talks about his vitamin intake
Questions & Answers
© 2014 Rachael O'Halloran