Wow, Measuring Nutritional Status is Insightful
Stephen Colbert once said “Facts matter not at all. Perception is everything. It’s certainty.” This was the premise of a very successful satirical television program, The Colbert Report. As a person, I enjoy satire and humor. As a scientist, I am troubled when perception trumps fact.
Two-time Nobel laureate, Linus Pauling, was a leader in many fields. He championed vitamins to maintain optimal health and prevent disease. His motto was having the ‘right molecules in the right concentration’ although antioxidant nutrition seems to not matter today. Part of the perception arises from reviews assessing treatment (placebo versus supplement) rather than nutritional status.
Although oxidative stress is thought to underlie many chronic diseases, progress has been slowed by the a broad portfolio of biomarkers and a lack of consensus. Yet without biological measurements of nutritional and oxidative status, the impact of nutrient supplementation on health outcomes cannot be determined.
In an excellent study, Solomon evaluated serum concentrations of functional vitamin B12 (cobalamin, Cbl) and its metabolites - methylmalonic acid (MMA) and homocysteine (HCys) - measured in older, community-dwelling individuals over 12 years. Subclinical vitamin B12 deficiency, elevated MMA and HCys in patients with low serum Cbl, has been associated with neurocognitive disorders. Increased exposure to oxidative stress in older subjects was associated with functional Cbl deficiency and ageing. Most importantly, the vitamin B12-oxidative stress risk interactions were observed in individuals who were not vitamin B12 deficient.
Health professionals rely upon accurate diagnosis – a combination of experience and clinical tests – to identify and subsequently treat nutrient deficiencies. The majority of people are not deficient but they aren’t necessarily eating a balanced diet. To understand nutrient-outcome relationships, more studies with biological data like today’s main citation by Solomon are needed.
By understanding the impact of having a nutritional status along the continuum of ‘slightly better than deficient’ to ‘meeting a criterion of adequacy’, nutrition guidance and policy can be guided by facts, not perception.
Solomon LR. Functional cobalamin (vitamin B12) deficiency: role of advanced age and disorders associated with increased oxidative stress. 2015 EJCN doi: 10.1038/ejcn.2014.272
Carmel R. How I treat cobalamin (vitamin B12) deficiency. 2008 Blood J doi: 10.1182/blood-2008-03-040253
Dalle-Donne I, Rossi R, Colombo R, Giustarini D, Milzani A. Biomarkers of oxidative damage in human disease. 2006 Clin Chem doi: 10.1373/clinchem.2005.061408