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Sabtu, 24 Desember 2011

Do Vitamins Actually Work? [Health]

Do Vitamins Actually Work?Vitamins can be a mysterious entity you put into your body on a daily basis that rarely has any noticeable effects. It's hard to gauge for yourself if it's worth the price and effort, so we put all our questions about vitamins to experts to help us differentiate between wasted cash and a helpful supplement.

Photo by Lisa Brewster.

We've asked a few experts to chime in on the importance of vitamin intake and the best practices for doing so. We have Health Coach and Dietitian Krista Lennox MA, RD, CDN, Nutritionist Andy Bellatti MS, RD, and Department of Exercise and Sports Science at the University of South Carolina Aiken's Dr. Brian Parr.

Do Vitamins Actually Work?Since we haven't arrived in a science-fiction-esque future where a pill can supply all the nutrition we need in one swallow we use multivitamins to supplement what we might be missing from our diets. As it turns out, knowing your diet's limitations is the best step to figuring out if you need a multivitamin. Krista Lennox weighs in:

For most healthy Americans under the age of 50 it is possible to meet necessary nutrient needs through diet alone. Consumption of a wide variety of colorful, nutritious food is the best way to maintain health and prevent chronic disease. With that being said, it is important to note that most Americans do not meet the recommended amount of nutrients in their diet. Through increased intake of fruits and vegetables, low fat dairy products, whole grains, and fortified foods Americans can help ensure the quality of their diet so they're more likely to meet nutritional needs.

Dr. Parr agrees:

Probably not, but maybe. If you eat a healthy diet that contains a variety of fruits, vegetables, whole grains, and low-fat dairy you likely get adequate levels of vitamins and minerals. Remember, you are supplementing your diet so you don't need a multivitamin/mineral that contains 100% (or more) of the recommended daily allowance for each vitamin or mineral. Really, the Flintstones vitamin you took as a kid would be sufficient. It may not provide great health benefits, but it also would be unlikely to cause any problems.

Andy Bellati's take is similar, but he outlines a more specific regiment instead of a multivitamin approach:

Not surprisingly, many Americans don't consume sufficient amounts of the nutrients that are easily lost during the processing of food. Approximately 3/4 of American adults don't get enough magnesium in their diet, which is a crucial mineral for blood pressure regulation, among other functions. Top sources? Spinach, potatoes, nuts, and oats.

Vitamin D deficiency is rampant. The latest research shows that current recommendations for 600 International Units a day are too low. Part of the problem is that recommendations are made solely on vitamin D's role in bone health, while newer research takes into consideration the multitude of functions vitamin D is necessary for. I urge all my clients to take 2,000 to 4,000 International Units a day. If it seems like too much, keep in mind that if you get your vitamin D from the sun, the body produces 10,000 International Units and then ceases production.

If you avoid certain types of foods, supplements might help fill in the blanks of your diet. Andy Bellati recommends a few good supplements:

I recommend vitamin B12 supplements for people who avoid animal products.

In many cases, I recommend probiotic supplements. A healthy gut is very important for overall health, and too many people wreck their gut flora (aka the friendly critters in our colon that help with immunity and nutrient absorption) with poor diets, exposure to environmental toxins, and stress. Probiotic supplements should ideally be purchased refrigerated and stored that way at home.

For individuals who do not normally eat fish or sea vegetables (two sources of DHA and EPA Omega-3 fatty acids), I recommend they supplement with either fish oils or algae oil. A consistent intake of DHA and EPA Omega-3 fatty acids (also known as "fish oil", although sea vegetables also offer them) is crucial for heart health.

Photo by Matt Reinbold.

Do Vitamins Actually Work?None of this information is really useful unless you have a way to figure out if you even need to be taking supplements in the first place. To do so, you'll need to take a close look at your diet or get a blood test with your physician to check for deficiency.

Dr. Parr notes that it's difficult to self-assess and even though supplements can work to battle deficiency, the purpose stops there. Which is to say, there aren't added benefits from taking more than your daily allowance:

Given the nature of the typical American diet, people really may not be getting enough essential nutrients like vitamins and minerals in their diet. Typically not low enough to cause deficiency symptoms, but lower levels than are recommended. In these cases, a supplement would be advised.

Andy Belatti adds that the main goal for people should be to improve the overall diet as opposed to relying on supplements:

Technically, it's smart to supplement if your diet is not high in nutrients. However, when I work with clients who consume minimally nutritious diets, my goal is to include more nutritious foods, rather than go straight for supplements. Supplements can only do so much. Popping a multivitamin every day is a moot point if your diet is high in unhealthy fats, sodium, and added sugars.

Photo by Erich Ferdinand.

It is possible to get too much of a good thing and in the case of vitamins, it's important to watch your intake. In this case, it's the fat-soluble vitamins because they're stored in your liver and fatty tissues and aren't needed typically needed on a daily basis. The water-soluble vitamins make a quick exit in your urine if you take too much, but the fat-soluble vitamins hole up as long as they can.

Dr. Parr explains how to keep your intake on the level:

Toxicity can result from very high doses and is most common with the fat-soluble vitamins A, D, E, K. Again, taking a supplement that provides less than 100% of the RDA for each vitamin and mineral is likely safe.

Krista Lennox adds:

When it comes to vitamins more is not always better, according to a recent study the nutrients most likely to exceed the tolerable upper intake levels are iron, zinc, vitamin A and niacin.

Do Vitamins Actually Work?We've all heard about pumping in certain types of vitamins and minerals when we're working out or trying to prep our bodies for a hearty workout, but does it really work? Dr. Parr doesn't think so:

In theory, some vitamins and minerals COULD improve exercise performance or health, but research into vitamin/mineral supplementation tends to show a lack of positive effect. Here are three examples:

1) Iron is an essential component in oxygen transport in the blood and muscle. Iron deficiency can impair exercise performance by lowering oxygen delivery to the muscle, an essential step in producing energy for muscular activity. In iron deficiency cases, an iron supplement can reverse the deficiency and restore exercise performance. But taking an iron supplement when you have normal iron levels would not improve performance. In fact, excess iron intake can cause liver damage.

2) I have seen several studies that report that certain vitamin supplements have no effect at reducing the risk of chronic diseases, like heart disease or cancer. In particular, high doses of vitamins A, C, E and the mineral selenium (all antioxidants) don't appear to lower the risk of chronic diseases and may actually increase the risk of death.

3) Deficiencies of certain nutrients can have a negative effect on immune function, so eating a balanced diet is essential. That said, there is no support for "boosting" the immune system by taking high doses of vitamins, minerals, or other supplements, despite the claims made by supplement companies. In fact, supplement manufacturers are not required to prove their products have any beneficial effects, so the majority of nutritional supplements have not undergone appropriate testing. For those supplements that have been tested, the results are not consistent with the claims.

If this is the case, shouldn't taking more of those vitamins improve health? I think that the answer lies in the difference between eating food that contains nutrients and taking high doses of those nutrients. Maybe the vitamins themselves cannot make up for an inadequate diet. The whole (the food people eat) is more important than the sum of its parts (the individual nutrients that make up those foods).

Photo by lululemon athletica.

Now we know that vitamin and mineral supplements work best to fill in the gaps of your diet but shouldn't be used as a supplement for eating healthy. But is the difference between a supplement and real food really that big of a deal? It turns out it is, Kristi Lennox explains:

Supplements are not intended to replace foods because they cannot provide all of the nutrients and benefits of whole foods. Whole foods are complex therefore one food can contain multiple nutrients essential for health. Fiber has been shown to reduce the risk of heart disease, type 2 diabetes and also help in weight management. Whole foods also contain naturally occurring substances which can help protect your health.

Andy Bellati agrees and expands a little:

In many cases, yes. When Vitamin E is isolated, for example, it does not work as efficiently as it does within its original food matrix. Foods high in vitamin E (mainly nuts and seeds) contain compounds that interact with vitamin E in such a way that allows it to operate efficiently.

As it turns out, vitamins can have a positive effect on your overall health, but it's best to use them exclusively as a supplement to a good diet. When you're out shopping, don't forget to buy whatever is on sale, since they're all the same. Overdosing on vitamins isn't worth much either, so if you're going to go the multivitamin route, make sure it's not providing too much of any fat-soluble vitamins or alternately, consider supplementing with just the specific mineral and vitamins you need based on your diet.

Andy Bellatti, MS, RD is a Seattle-based Nutritionist and the author of the nutrition blog Small Bites. You can follow him on Twitter at @andybellatti.
Krista Lennox MA, RD, CDN is a Health Coach and Registered Dietitian.
Brian Parr, Ph.D is an associate professor in the Department of Exercise and Sports Science at the University of South Carolina Aiken.Related Stories

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