Fat Soluble Vitamins: A, D, E and K
A nutritionally balanced diet may eliminate the need for vitamin supplementation.
Credit: Public Domain; Wikimedia CommonsUnderstanding the Basics of Vitamins
Your body requires many nutrients and minerals in just the right amount to work properly, among them 13 vitamins are essential. Four of these vitamins -- vitamin A, vitamin D, vitamin D and vitamin K -- are fat soluble vitamins.
There are two types of vitamins: water soluble and fat soluble. The body readily uses water soluble vitamins; fat soluble vitamins are stored in the fatty tissues and the liver.
With the exception of vitamin D, your body does not manufacture these essential nutrients for health. Health experts recommend obtaining the vitamins your body needs through a nutritional and balanced diet. Foods that contain the fat soluble vitamins do not lose these nutrients through cooking.
Some people choose to take vitamin supplements for various reasons. Donald Hensrud, M.D., Preventive Medicine at the Mayo Clinic[1] recommends that if you choose to take vitamin supplements, stay as close as possible to the Recommended Dietary Allowance (RDA). This will help you to avoid getting too large amounts of vitamins, especially fat soluble vitamins, and causing a vitamin toxicity.
Vitamin A
Role of Vitamin A
Like the other vitamins, vitamin A, also called retinol, performs many functions in your body. Perhaps the best known function of retinol is its aid in helping your eyes adjust to light changes. Other roles include helping your skin, eyes, mucus membranes, throat and lungs to maintain their moisture.
Vitamin A helps your body develop and maintain healthy teeth and bones.
Vitamin A Deficiency
Vitamin A deficiency is not often seen in the United States. Symptoms of low levels of this nutrient include night blindness; dry, rough skin; decreased resistance to infections; poor tooth and bone development.
Vitamin A Toxicity
Levels of vitamin A that are too high can cause birth defects and hip fractures. Mild toxicity can cause nausea and blurred vision. Higher levels can result in slowing of growth, loss of hair, bone pain and liver enlargement.
It is difficult to become toxic from vitamin A through food sources alone. Most instances of vitamin A toxicity are related to the use of vitamin supplements.
Food Sources of Vitamin A
Vitamin A fortified milk, liver, butter, dairy products, egg yolk
Orange vegetables and eggs are a good source of vitamin A
Credit: Biso; Creative Commons; Wikimedia CommonsVitamin D
Role of Vitamin D
Vitamin D is often referred to as the "Sunshine Vitamin" because the body is able to synthesize this nutrient through the action of sunlight on the skin. Vitamin D is needed for the absorption of calcium, promoting healthy bones and teeth.
Deficiency of Vitamin D
Again, deficiencies of this nutrient don't occur often in the United States. Low levels of vitamin in children produce a condition known as rickets -- long legs, slightly bowed -- and flattening of the back of the head. In adults, low levels cause weakness of both muscles and bones.
Toxicity of Vitamin D
Too much of this nutrient can lead to increased levels of calcium in the blood, decreased appetite, nausea and vomiting and slowed mental and physical growth.
Food Sources
Vitamin D fortified dairy products, fish oils, egg yolks
Sunshine
Vitamin D is one vitamin that is difficult to get enough of through diet alone, but exposure to the sun makes up the difference. Children should be exposed to 5 to 10 minutes daily of sunlight; adult sun exposure of 10 to 15 minutes three times a week should be sufficient.
Some people supplement their diets with vitamins
Credit: Public Domain; Wikimedia CommonsVitamin E
Role of Vitamin E
This vitamin plays an important role as an antioxidant; antioxidants neutralize substances called free radicals. It also functions to protect vitamins A and C and red blood cells from destruction, as well as performing the same function for essential fatty acids.
Recent research indicates that protection from heart disease and cancer from this vitamin is found in people who regularly eat antioxidant-rich fruits and vegetables rather than from taking supplements.[2] This suggests that it is the "total package" of antioxidants and other nutrients in the fruits and vegetables, along with vitamin E, that provide this protection.
Deficiency of Vitamin E
Deficiency of this vitamin is almost exclusively limited to premature infants and people who are unable to absorb fats as in cystic fibrosis, malabsorption syndromes and others.
Severe deficiency of vitamin E results mainly in neurological symptoms, including an unbalanced gait, poor coordination and muscle weakness.[3]
Toxicity of Vitamin E
High levels of vitamin E interferes with the ability of your blood to clot that can lead to hemorrhaging. People who take blood-thinning medication and/or statin drugs to lower cholesterol should consult their health care providers before taking vitamin E supplements.
Food Sources
Vegetable oil, nuts, green and leafy vegetables, eggs, avocado, whole grain products, liver
Green leafy vegetables are good sources of vitamin K.
Credit: Biswarup Ganguly; Creative Commons; Wikimedia CommonsVitamin K
Role of Vitamin K
Vitamin K plays a vital role in the ability of your blood to clot and aids in promoting bone health.
Deficiency of Vitamin K
Low levels of vitamin K lead to decreased ability of your blood to clot, leading to excessive bleeding.
Toxicity of Vitamin K
No known instances of vitamin K toxicity have been reported.[2]
Food Sources
Dark green, leafy vegetables and liver.
Bacteria in your intestines naturally produce vitamin K within your body.
Use Caution Taking Dietary Supplements
Many people wrongly assume that medications and supplements that are available over-the-counter or at health stores are safe to consume. This may not be true for everyone, depending on their particular health status and medications taken.
Supplements of fat soluble vitamins can result in toxicity in the body since these vitamins are stored in your body and not flushed out as are water soluble vitamins. Know and understand the RDA of these vitamins, adhering to them as closely as possible.
The Linus Pauling Institute[4] offers these tips: Look for supplements labeled USP-verified; this means that the product has met standards of potency, purity and quality. Take fat soluble vitamin supplements with a meal containing fat or oil.
Consult your health care provider before taking vitamin supplements and ask for the provider's recommendations.
This article is informational in nature and not intended to replace or refute information provided by health care professionals. Consult your health care provider with questions or concerns about your particular health situation or status.
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Comments
This is an excellent article with so much beneficial information that I'm bookmarking it for future reference. Thanks LLWoodard!
You're most welcome Introspective; appreciate the read.
Very useful information. Keeping a healthy balance is key to good health.
Thanks, Jack_Luca. Balance is probably a good idea for most every area of life but most assuredly good health.
Great article on the importance of vitamins. And vitamin D definitely is needed for your bone health I found that out myself. People need to have a bone density scan to find out if they have low bone density and could be at risk of fracturing bones more easy. Thanks for the helpful info.
Eileen, you've brought up an important issue in regards to bone density. Bone density scans, according to the Mayo Clinic may be recommended by your health care provider after menopause, an adult loss in height, after certain bone fractures, for anyone who has been on long-term steroid therapy, or for men who have had prostate cancer treatment.
This is a very informative article. I thought I knew much about Vitamins, but your article has educated me in areas I didn't know. I'll be bookmarking this for future reference. Thanks for sharing. Google + and posted to Facebook and Twitter.
Jeni10, I appreciate the bookmarking and shares. I'm also happy to know that you found the information helpful. If you want even further information, check out the resources in this article's bibliography.
Good, concise information lives in this article. Eating healthier surely should be the major priority versus a visit to the vitamin row in the store. a friend of mine in the health profession told me once of how big a problem toxicity from too much of one vitamin really is. Congrats on the feature article.
Kbuzz, appreciate your kind words. It seems from a theoretical standpoint that eating in a healthy manner would be a simple enough task, but the eating habits so many of us currently have have been forged over time and are a matter of habit.
I've been working towards changing my own eating habits so that they more closely follow the Mediterranean style of eating, but find it difficult some days to squeeze in at least five servings of fruits and vegetables.
Yeah, congratulations on a great feature article. This is worthy of a bookmark too for future reference.
I posted this to FB and sent a tweet too!
EGreen, I appreciate your efforts and am glad you found this information useful.
This pretty much lays down all the basics comprehensively. Thanks for sharing!
WebAddict, sometimes it seems difficult to find basic information about a topic all in one place, so rounding up this info about the fat soluble vitamins and organizing it into an easy-to-digest format was intended to be a useful reference tool. Your comment leads me to believe I met my goal.
I appreciate your read and your comment.
Great article LL! It's an informative, comprehensive, and easy-to-digest despite it being a very complex topic. Thanks for putting a great reference article together.
Thank you for reading, Miravu. I'm delighted you found it useful.
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