Mismatch Between DRIs and Nutrient Values on Many Nutritional Supplements Labels: What it Means to the Consumer

The current post builds on the previous most recent post on this blog, entitled, “Getting your advice on nutrition for optimum health from your doctor’s emergence rooms is not a good idea”. It all boils down to optimum health from optimum nutrients intake. It also expands the conversation on views presented in one other post on this site entitled, “Nutrition and Health: Dissecting The Complexity - Is nutrition science up to the task?”

Dietary Reference Intakes (DRIs) developed jointly by Canadian and American scientists, are new nutrient values which represent a significant departure from the former Recommended Dietary Allowances (RDAs) for the United States and Recommended Nutrient Intakes (RNIs) for Canada, National Academies Press (US), (2003). In the past, RDAs and RNIs were the primary values available to U.S. and Canadian health professionals for planning and assessing diets of individuals and groups. The new DRIs represent a more complete set of values. They were developed in realization of the growing and diverse uses of quantitative reference values and the availability of more advanced approaches for dietary planning and assessment purposes.

However, from my own personal observation, a number of  DRIs do not match what you would observe on supplements labels from many health food store. DRIs are much lower and in some instances by far much lower than what would be indicated on the supplement label in the health food store. Of course it is logical to question why nutritional supplements manufacturers would make a pill, capsule or tablet of such high level nutrient content, expecting the consumer to attempt to cut the pill into pieces which meet the DRIs nutrient content measurements. Certainly the answer is elsewhere. This mismatch informs us that most likely there is something developers of DRIs are still missing in the new emerging knowledge of nutrition science, that is better understood by nutritional supplements manufacturers. To that effect, advice on nutrition and health based on DRIs may be misleading. A classic example is that of vitamin C, presenting RDAs of 90 mg/day for adult men and 75 mg/day for adult women, where as most vitamin C supplements have a value content of 500mg per tablet.

The value of a nutrient matters in planning diets for individuals or groups. A mismatch of DRIs and current supplements values found on labels, especially where there are claims of safe and more effectiveness with higher intake levels, brings some confusion to consumers and at the same time raises thought provoking questions as to the appropriateness, adequacy and reliability of the methodology used to establish the DRIs and the validity of the outcome. This has been captured in Hickey and Roberts (2004) books “Ridiculous Dietary Allowance: An open challenge to the RDA for vitamin C” and “Ascorbate: The Science of Vitamin C”, who pointed out that the DRIs for vitamin C and of cause other nutrients have not been established on evidence-based scientific methodologies. They argue that DRIs for vitamin C were designed to cure the acute deficiency disease, scurvy and not for other functions it is known for, i.e.,  the preventive and/or therapeutic role in most chronic noncommunicable diseases, which are largely diet-related.

A report by the National Academies of Sciences, Engineering, and Medicine, (2017), on guiding principles for developing DRIs based on chronic diseases, does not dispute assertions by Hickey and Roberts (2004), on inadequacies of methodological approaches to establish DRIs and their subsequent use in intervention against chronic diseases. In fact developers of the DRIs acknowledge that traditionally, a major consideration in the DRI process has been nutritional adequacy, i.e., for nutrients deemed nutritionally essential for normal physiological functioning), and therefore the scientific literature is reviewed by the DRI committee to determine the most appropriate indicator of adequacy that will be used to set the requirement for the nutrient, whereby possible indicators of adequacy could include prevention of signs or symptoms of a nutrient deficiency disease, biomarkers of the nutrient’s function (e.g., activity of an enzyme that uses the nutrient as a cofactor), and biomarkers of body stores of the nutrient.

Currently, in contrast to the previous method of establishing U.S. RDAs and Canadian RNIs, the current DRI process, which began in the early 1990s also incorporates consideration of chronic diseases. With this comes emerging challenges and issues in the process of establishing DRIs with the goal of gathering ideas for improving the process in the future and as scientific knowledge expands. The challenges include finding appropriate methodological approaches as currently it is an issue of expert panels of specialist from various fields: nutrition, epidemiology, toxicology, etc., which calls into question issues of an evidence-based process. It is pretty much work in progress, and currently the use of DRIs for planning and assessing diets for individuals and groups is unlikely to be of any significant value for intervention approaches to chronic diseases.

The bottom line:
DRIs could be of value in prevention and treatment of classic nutrition deficiency diseases.
DRIs are currently not yet up to the task on prevention and/or treatment of nutrition-related chronic noncommunicable diseases.
Mismatch between DRIs values and nitritional values found on labels of nutritional supplements brings some confusion to the consumer, and at the same time raises question on whether any nutritional advice information, derived from the DRIs, is of any value or may be misleading to the consumer.



Ref.: 

1. Hickey, S and Roberts, H (2004).  Ridiculous Dietary Allowance: An open challenge to the RDA for vitamin C. Available at: file:///E:/Ridiculous%20Dietary%20Allowance%20-%20A%20Challenge%20to%20the%20RDA%20for%20Vitamin%20C.pdf 

2. Hickey, S and Roberts, H (2004). Ascorbate: The Science of Vitamin C. Available at: https://www.dougcookrd.com/wp-content/uploads/2018/09/Ascorbate-The-Science-of-Vitamin-C.pdf 

3. Institute of Medicine (US) Subcommittee on Interpretation and Uses of Dietary Reference Intakes; Institute of Medicine (US) Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. Dietary Reference Intakes: Applications in Dietary Planning. Washington (DC): National Academies Press (US); 2003. 2, Using Dietary Reference Intakes in Planning Diets for Individuals. Available from:  https://www.ncbi.nlm.nih.gov/books/NBK221374/ 

4. Institute of Medicine (2003). Dietary Reference Intakes: Applications in Dietary Planning. Washington, DC: The National Academies Press. https://doi.org/10.17226/10609.

5. National Academies of Sciences, Engineering, and Medicine, (2017). Guiding principles for developing Dietary Reference Intakes based on chronic disease. Washington, DC: The National Academies Press. doi: https://doi. org/10.17226/24828.