According to the Mayo Clinic, A balanced diet can provide all the vitamins and minerals you need (in other words you don't need to take a vitamin). If you're generally healthy and eat a wide variety of foods, including fruits, vegetables, whole grains, legumes, lean meats and fish, you don't likely need dietary supplements. If you want assurance that you're getting all the vitamins and minerals you need, stick with dietary supplements that contain no more than 100 percent of the Daily Value (DV) for any given nutrient.
Although there's little conclusive evidence that dietary supplements in general help prevent disease, fish oils or other specific supplements may be beneficial for some people. Talk to your doctor about which supplements and which doses might be appropriate for you. Be sure to ask about possible side effects and interactions with other medications.
With all the Vitamin D talk lately, my vitamin curiosity is peaked. I mean sure, the American Academy of Pediatrics (AAP) makes this new recommendation doubling the recommended amount of vitamin D children should be taking. But, how much of a vitamin does your body really absorb? And before answering that question, why do we even need vitamins? Aren't they in the food we eat? And, are liquid vitamins better than pills?
What exactly is a vitamin? Well, a vitamin is any of a group of organic substances essential in small quantities to normal metabolism.
Okay, that wasn't much help. Let's try our trusty Wikipedia; A compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet.
Eureka!!
Now, the bigger question...what makes a vitamin a vitamin? According to the Wikipedia vitamin article, vitamins are classified by their biological and chemical activity, not their structure. Thus, each "vitamin" may refer to several vitamer compounds that all show the biological activity associated with a particular vitamin. Such a set of chemicals are grouped under an alphabetized vitamin "generic descriptor" title, such as "vitamin A," which includes the compounds retinal, retinol, and many carotenoids. Vitamers are often inter-converted in the body. The term vitamin does not include other essential nutrients such as dietary minerals, essential fatty acids, or essential amino acids, nor does it encompass the large number of other nutrients that promote health but are otherwise required less often.
But where do vitamins come from? Apparently people were using vitamins well before we even knew what they were. The most well known use of food for vitamin replacement is probably the discovery that citrus could prevent scurvy (this led to the "limey" nickname for sailors). However there is evidence all the way back to Egypt that people ate certain foods to help cure maladies like night blindness. But it was the discovery of the link between citrus and scurvy that, in part, led to the use of vitamins as we know them today!
Throughout the early 1900s, the use of deprivation studies (giving one group a substance and NOT giving it to a second group to see what happens) allowed scientists to isolate and identify a number of vitamins. Initially, lipid from fish oil was used to cure rickets in rats, and the fat-soluble nutrient was called "antirachitic A". The irony here is that the first "vitamin" bioactivity ever isolated, which cured rickets, was initially called "vitamin A", the bioactivity of which is now called vitamin D. What we now call "vitamin A" was identified in fish oil because it was inactivated by ultraviolet light. In 1931, Albert Szent-Györgyi and a fellow researcher Joseph Svirbely determined that "hexuronic acid" was actually vitamin C and noted its anti-scorbutic activity. In 1937, Szent-Györgyi was awarded the Nobel Prize for his discovery. In 1943 Edward Adelbert Doisy and Henrik Dam were awarded the Nobel Prize for their discovery of vitamin K and its chemical structure.
Now, there are two types of vitamins. There are water-soluble vitamins and fat-soluble vitamins. Water-soluble dissolve easily in water and fat-soluble dissolve easily in fat. Simple enough, right? Well, while most of the vitamins you need are obtained from the food you eat, some vitamins are produced by your body. For example, microorganisms in the intestine—commonly known as "gut flora"—produce vitamin K and biotin, while one form of vitamin D is synthesized in the skin with the help of natural ultraviolet in sunlight. Our bodies can also produce some vitamins from precursors they consume. Examples include vitamin A, produced from beta carotene, and niacin, from the amino acid tryptophan.
Now that we know what vitamins are and where they come from the question is, why do we need them? Well, the foods we eat in this day and age tend to be on the slim side when it comes to nutritional value. That's why you have food companies touting the nutritional information in the foods they make. (The first thing that comes to MY mind is Total cereal.) So, if your diet consists mainly of fast food, or you never eat any fruits and vegetables, it is generally recommended that you take a multivitamin every day. And as more research is done on the effects of vitamins on the body the recommendations change over time.
According to a Mayo Clinic article on dietary supplements, If you're generally healthy and eat a wide variety of foods, including fruits, vegetables, whole grains, legumes, lean meats and fish, you likely don't need dietary supplements.
However, if you can't or don't eat enough healthy foods, or can't or don't eat a variety of healthy foods, you may need a daily dietary supplement. Dietary supplements may be appropriate if you:
Talk to your doctor or a dietitian about which supplements and what doses might be appropriate for you. Be sure to ask about possible side effects and interactions with other medications.
So, you take the Recommended Daily Allowance (RDA) of Vitamin A. But, how much of that vitamin is really absorbed by your body? I have talked to several people about this and the consensus is that your body does NOT absorb all of the vitamin or mineral. But, is that really true? The answer is surprisingly complex. Apparently it's not as simple as needing water or fat to dissolve and absorb their respective vitamins. Many vitamins need help to be absorbed into the body and some vitamins prevent others from being absorbed. The best thing to do is do some research on the particular vitamin or mineral you are concerned with.
On to the next question...which is better, liquid vitamins or solid (pill) vitamins? People can argue either way. The fact remains that those vitamins that are fat-soluble will not be absorbed until they are in the intestines whether they are already in liquid form when they enter the stomach or not. From what I have been able to find, there is no real difference between the two so I would go with what you prefer if you take a vitamin.
So, what's the bottom line? According to the Mayo Clinic (and probably your doctor or pediatrician) you only need a multivitamin if you are pregnant or if you don't eat a complete diet. But, with merging studies on the positive and negative effects of particular vitamins and minerals (like Calcium and Vitamin D), your doctor may recommend that you take specific ones. But should you be worrying that you aren't getting all the vitamins and minerals you need? Probably not. But if you're unsure take a vitamin! There sure are plenty to choose from!
More information:
The Office of Dietary Supplements (TONS of good information here from the National Institutes of Health)
Dietary Supplements (vitamins, herbs, etc.) Fact Sheets
Dietary Guidelines for Americans
Dietary Reference Intakes: A Risk Assessment Model for Establishing Upper Intake Levels for Nutrients
From the Food and Drug Administration (FDA)
Vitamins and Minerals and where you can find them:
October 16, 2008
Vitamins - A Quick Guide
blog comments powered by Disqus
Subscribe to:
Post Comments (Atom)
