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Most studies on vitamins are flawed by poor methods says identifying research

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Most large, clinical trials of vitamin supplements, including some that have concluded they are of no value or even harmful, have a flawed methodology that renders them largely useless in determining the real value of these micronutrients, a new analysis suggests. You can check out the study online, The study or its abstract, published this month in the journal Nutrients, is "Myths, Artifacts, and Fatal Flaws: Identifying Limitations and Opportunities in Vitamin C Research," which is available online since December 16, 2013. Or Download PDF Full-Text. These flawed findings will persist until the approach to studying micronutrients is changed, says a December 30, 2013 news release, "Most clinical studies on vitamins flawed by poor methodology."

Many projects have tried to study nutrients that are naturally available in the human diet the same way they would a powerful prescription drug. This leads to conclusions that have little scientific meaning, even less accuracy and often defy a wealth of other evidence, said Balz Frei, in a new review published in the journal Nutrients, Volume 5, Issue 12. Balz Frei is a professor and director of the Linus Pauling Institute at Oregon State University, according to the news release.

These flawed findings will persist until the approach to studying micronutrients is changed, Frei said in the news release. Such changes are needed to provide better, more scientifically valid information to consumers around the world who often have poor diets, do not meet intake recommendations for many vitamins and minerals, and might greatly benefit from something as simple as a daily multivitamin/mineral supplement. People are concerned whether they're overdosing on supplements or whether they're deficient, and many can't afford testing or supplements, or they don't have access to affordable healthier foods.

Needed are new methodologies that accurately measure baseline nutrient levels, provide supplements or dietary changes only to subjects who clearly are inadequate or deficient, and then study the resulting changes in their health

Tests must be done with blood plasma or other measurements to verify that the intervention improved the subjects’ micronutrient status along with biomarkers of health. And other approaches are also needed that better reflect the different ways in which nutrients behave in cell cultures, lab animals and the human body.

The new analysis specifically looked at problems with the historic study of vitamin C, but scientists say many of the observations are more broadly relevant to a wide range of vitamins, micro nutrients and studies. “One of the obvious problems is that most large, clinical studies of vitamins have been done with groups such as doctors and nurses who are educated, informed, able to afford healthy food and routinely have better dietary standards than the public as a whole,” said Frei, an international expert on vitamin C and antioxidants, according to the news release.

Flawed findings on micronutrients and vitamin/mineral deficiencies among people

Vitamin or mineral supplements, or an improved diet, will primarily benefit people who are inadequate or deficient to begin with, OSU researchers said, according to the news release. But most modern clinical studies do not do baseline analysis to identify nutritional inadequacies and do not assess whether supplements have remedied those inadequacies. As a result, any clinical conclusion made with such methodology is pretty much useless, they said.

“More than 90 percent of U.S. adults don’t get the required amounts of vitamins D and E for basic health,” Frei said, according to the news release. “More than 40 percent don’t get enough vitamin C, and half aren’t getting enough vitamin A, calcium and magnesium.

Smokers, the elderly, people who are obese, ill or injured often have elevated needs for vitamins and minerals

“It’s fine to tell people to eat better, but it’s foolish to suggest that a multivitamin which costs a nickel a day is a bad idea.” Beyond that, many scientists studying these topics are unaware of ways in which nutrients may behave differently in something like a cell culture or lab animal, compared to the human body. This raises special challenges with vitamin C research in particular.

“In cell culture experiments that are commonly done in a high oxygen environment, vitamin C is unstable and can actually appear harmful,” said Alexander Michels, an LPI research associate and lead author on this report, according to the news release. “And almost every animal in the world, unlike humans, is able to synthesize its own vitamin C and doesn’t need to obtain it in the diet. That makes it difficult to do any lab animal tests with this vitamin that are relevant to humans.”

Some studies understate the value of vitamin supplements

Even though such studies often significantly understate the value of vitamin supplements, the largest and longest clinical trial of multivitamin/mineral supplements found a total reduction of cancer and cataract incidence in male physicians over the age of 50. It suggested that if every adult in the U.S. took such supplements it could prevent up to 130,000 cases of cancer each year, Frei said, according to the news release. Looking for the study's statistics? Click here to load and display the download statistics.

“The cancer reduction would be in addition to providing good basic health by supporting normal function of the body, metabolism and growth,” he said. “If there’s any drug out there that can do all this, it would be considered unethical to withhold it from the general public. But that’s basically the same as recommending against multivitamin/mineral supplements.”

On another note not from this study, have you ever wondered how people might check to see whether supplements are safe before they buy them? What consumers would like is a reliable, validated source that doesn't charge them a fee to find out whether a product is safe and what ingredients are in the product. It would be better still to also know from where the ingredients came.

How many people first check with the non-profit United States Pharmacopeia, also known as USP to see whether any nutritional supplements they buy is USP verified?

If you walk through a local health food store or shop online, how do you know for sure that what's on the label is what's in the container? Since the FDA doesn't regulate dietary supplements, there are sources where you can see voluntarily regulated nutritional supplements by checking to see whether the supplements have the USP label on them. It's known as the USP Verified Mark that's on the package. How do you know whether the dietary, nutritional supplement you'd like to buy is safe?

There's the non-profit United States Pharmacopeia, also known as USP. It has been around since 1820, and has a voluntary regulation program where manufacturers of dietary supplements can have their ingredients verified. Since it's voluntary, not all manufacturers of nutritional supplements are marked as "USP Verified." If you're looking for USP free forums, see the site, User Forums Open for Registration.

Also courses are given by USP around the world. You also can check out the website explaining the courses and/or meetings. Check out the free online courses, such as Medicines Compendium eLearning Course-NEW: Self-paced eLearning. Yes, it's free, and with 30-days unlimited access.

Here's where you can find information on USP Dietary Supplement Standards

On the website of the U.S. Pharmacopeial Convention you also can find links to information on Dietary Supplements, Reference Standards, Verification Services, Food Ingredients, and Resources. You can check out the Dietary Supplements Compendium and the Development Process.

You can check out the video, "What to Look for When Choosing Dietary Supplements," (June 2012). To help manufacturers, suppliers, and regulators safeguard the dietary supplement supply, USP provides documentary standards and reference materials for determining product and ingredient identity, strength, quality, and purity. Check out the site, "Education on Dietary Supplement Verification."

These standards help limit the introduction of potential adulterants and contaminants, and serve as a widely acknowledged quality benchmark in the buying and selling of dietary supplement products and their ingredients in the global marketplace. In addition to its standards, USP offers third-party, independent verification services for dietary supplement finished products and dietary ingredients, according to the USP's website.

How do you check out your dietary supplements before you buy them? See, Dietary Supplement Tools and Resources. You also can view Sample DSC Admissions Criteria Safety Review. Or read the USP Catalog. Before you buy a supplement, you might want to check out the Safety Data Sheets for USP Reference Standards Available as a Free Resource.

USP's Relationship with Dietary Supplements

Since its beginning in 1820, USP has been concerned with the standardization of botanicals and minerals, evidenced by the content of the first USP, which contained mostly botanicals and other natural drugs. In 1930, USP formed the Vitamin Advisory Board, which established the first pharmacopeial assays and Reference Standards for Vitamin A and D, and by 1942, USP had established monographs for all vitamins recognized at that time. In 1975, USP acquired the National Formulary (NF), which primarily features specifications for excipients commonly used in pharmaceuticals and dietary supplements. Check out the USP Catalog.

In 1990, the USP Convention adopted a resolution calling for standards on dosage forms containing combinations of vitamins and minerals, leading to the development of a separate "Nutritional Supplements" section in the USP–NF. After the passage of the Dietary Supplements and Health and Education Act in 1994, this section was expanded significantly and renamed "Dietary Supplements" with the addition of many new monographs for botanical and non-botanical dietary ingredients and dietary supplement articles.

With the purchase of the Food Chemicals Codex (FCC) in 2006, USP once again added to its portfolio of standards relevant to dietary supplements. Considering the changing needs of a growing global dietary supplement industry, USP published the USP Dietary Supplements Compendium (DSC) in 2009, with the intention of providing a comprehensive resource for dietary supplement manufacturers, suppliers, and regulators. The DSC combines the "Dietary Supplements" section and other relevant monographs from USP–NF with monographs from the FCC.

Today, USP offers nearly 800 monographs in the DSC and more than 200 Reference Standards for use in the development and testing of dietary supplements. In addition, the USP Verified Mark, the symbol awarded by USP to dietary supplement products that meet the stringent criteria of its voluntary Dietary Supplement Verification program, has appeared on more than 400 million supplement labels, notes the organization's website. Check out the Meeting Observer Form for Non-members.

Help Develop USP Standards

Again this year, USP staff will travel to locations around the world. At each stop, the organization will present one-day, free seminars to discuss timely issues regarding USP initiatives and how to use available USP resources to your advantage.

Seminar topics include:

  • USP Publications
  • Pharmacopeial Forum Redesign
  • Reference Standards Development
  • Hot Topics:
    • Heavy Metals/Elemental Impurities
    • Biotechnology and Biologics
    • Food Ingredients
    • Performance Verification Testing
    • Harmonization Process
  • Opportunities to Get Involved with USP

All events include a Q&A session and take-home materials. Lunch will be provided.

Register now for a USP User Forum near you. Or check out the site, "Education on Dietary Supplement Verification." Forums are in the USA or in Europe.

The forums in the USA include the following:

User Forum Raleigh, NC

February 11, 2014

FCC/DSC User Forum Anaheim, CA

March 5, 2014

If you're traveling to Europe or Israel, check out the European or Israel forum dates:

User Forum Barcelona, Catalonia, Spain

January 21, 2014

User Forum Basel, Switzerland

January 29, 2014

User Forum Tel Aviv, Israel

February 13, 2014

User Forum London, England

March 6, 2014

User Forum Frankfurt, Germany

March 13, 2014

User Forum Ljubljana, Slovenia

June 5, 2014



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