Majority of Vitamin Supplements Studies Flawed, Researcher Says

The majority of large, clinical trials of vitamin supplements suffer from flawed methodology and should not be trusted, according to a new study published in the journal Nutrients.

According to Balz Frei, director of the Linus Pauling Institute at Oregon State University, many studies attempt to study nutrients naturally available in the human diet the same way as a prescription drug, leading to "conclusions that have little scientific meaning, even less accuracy and often defy a wealth of other evidence," Oregon State University wrote in a statement.

Moreover, Frei says, the situation is not liable to improve until the a new approach for studying micronutrients is instituted. Accurate measurements are needed to measure baseline a person's nutrient levels. Subsequent supplements or changes to one's diet should only be given to those who are deficient, with studies focusing on the resulting changes in health. 

"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 expert on vitamin C and antioxidants.

In order to fully understand a supplement's effects, tests with blood plasma or other measurements must be conducted, he argues.

"More than 90 percent of US adults don't get the required amounts of vitamins D and E for basic health," Frei said. "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."