January 20, 2014
251 Nutrient Co-Factors [20 January 2014]
Last week I explained how the unique features of the dose-response relationship for nutrients can skew the results of nutrient intake studies towards showing no benefit. Another reason why nutrient studies often find little or no benefit is that adequate levels of cofactors are rarely ensured. Unlike drugs, nutrients work better together, and often don’t work at all without certain others. To accurately test the effect of a single nutrient on a particular process (eg bone-building), all the other nutrients required for that process must be adequately available. For example, to test the effect of calcium supplementation, all the other nutrients required for bone building must be available in adequate amounts: vitamin D, vitamin K2, magnesium, protein, and certain B vitamins. Without ensuring adequate levels of these co-factors, the study results will be meaningless and misleading.
Most nutrient studies are designed following the drug model which attempts to eliminate the effect of all other variables. But instead of eliminating the effect of cofactors by ensuring adequate levels, they are too often simply ignored. The results may be accurate for what is actually being tested – e.g. that calcium supplementation alone does not significantly increase bone formation, but to conclude that calcium is worthless would be erroneous. Instead, further studies are required to determine the optimum levels of each of the other co-factors.
The failure to consider cofactors, along with the location on the dose-response curve discussed last week, is likely responsible for the “equivocal and sometimes contradictory” vitamin D trials referred to in the Editorial “Enough is Enough: Stop Wasting Money on Vitamin and Mineral Supplements” (J Annals Int. Med, 17 Dec 2013). In one sense I agree with the authors of this editorial when they state “…further large prevention trials [of vitamins] are no longer justified.” Conducting more poorly-designed nutrient trials that are incapable of testing what they purport to be testing would not only be a waste of time and money but their erroneous conclusions may dissuade many from actions that might improve their health.
Source: Robert Heaney – Some Rules for Studies Evaluating Nutrient Effects
For more information on this or other natural health topics, stop in and talk to Stan; for medical advice consult your licensed health practitioner.