'Clinical studies on multi-vitamin requirements flawed'
Most modern clinical studies don't do baseline analysis to identify nutritional inadequacies or assess whether supplements have remedied those inadequacies - leaving your doctor not to prescribe you any multi-vitamin tablet while you may actually need one daily.
Scientists have found that 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.
"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 Balz Frei, professor and director of the Linus Pauling Institute at Oregon State University.
Vitamin or mineral supplements, or an improved diet, will primarily benefit people who are inadequate or deficient to begin with, researchers added.
But any clinical conclusion made with the available methodology is pretty much useless, the researchers added.
"These flawed findings will persist until the approach to studying micronutrients is changed. 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," added Frei.
The researchers 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, micronutrients and studies.
"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," said the study published in the journal Nutrients.
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, said the researchers, must be done with blood plasma or other measurements to verify that the intervention improved the subjects' micronutrient status along with biomarkers of health.
Other approaches are also needed that better reflect the different ways in which nutrients behave in cell cultures, lab animals and the human body.
(Posted on 31-12-2013)