Using Nutritional Markers to Personalize Health and Guide Policy
The 2015 Dietary Guidelines Advisory Committee (DGAC) identified a healthy diet as one higher in vegetables, fruits, whole grains, low- or nonfat dairy, seafood, legumes, and nuts; moderate in alcohol (among adults); lower in red and processed meat; and low in sugar-sweetened foods and drinks and refined grains.” The challenge is that the terms higher, moderate, and lower are relative. Should I buy this bar or that one? Should I buy this meal or that one? Which is the better food choice?
In an editorial, Cespedes and Hu advocate for standardizing dietary patterning methodologies to guide food and nutrition policies. It is probable this letter was partially stimulated by an expert report condemning the usefulness of self-reported food intake to guide policy.
In reality, there is only one objective, science-based approach to develop nutrition policy. The only approach is to use nutrition status assessment. Policy should be guided by the percentage of the population who do not meet a criterion of sufficiency, defined as a serum 25-hydroxyvitamin D3 concentration ≥50 nmol/L (20 ng/mL) for bone health. As an individual, it doesn’t interest me to know if my vitamin D requirements are one of the lowest or highest of that measured in a few people when setting an Estimated Average Requirement (EAR) and extrapolated to a Recommended Dietary Allowance (RDA). Thus, objective measures of nutritional status fulfill policy making needs and, more importantly, provide individuals with the information they need to adjust dietary practices.
There is no doubt that 25(OH)D3 concentrations can be changed by dietary intake. When 25(OH)D3 concentrations are below 75 nmol/L, every microgram of vitamin D consumed will increase 25(OH)D3 concentration by 2 nmol/L. By measuring status, one can determine how much more vitamin D should be consumed to reach 75-80 nmol/L. To improve vitamin D status, one should worry more about the type of vitamin D (ergocalciferol or cholecalciferol) than the source (food or supplement). Knowing vitamin D status, individuals can make informed dietary decisions and bureaucrats can make science-based changes to policy.
Such an approach can be applied to other micronutrients. Measuring vitamin B12 status in pregnant women can be used to improve metabolic status of children. Low-cost, simplified urinary collections can accurately measure sodium intake. Regional and national differences in red blood cell phospholipid concentrations of eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) concentration, the omega-3 index, may explain differences in cardiovascular heart disease. Rather than discussing the pros and cons of dietary patterns, i.e. the Mediterranean diet, isn’t it more valuable to know that omega-3 index of countries ranges from <4% to 9%. Do you know where your community, or yourself, stand on the continuum?
My final example. Lutein and zeaxanthin are concentrated in the fovea of the eye and found in the brain. Their intake may partially explain the health benefits of eating fruit and vegetables. Adding lutein and zeaxanthin to the Age-Related Eye Disease (AREDS) formulation, provided an additional 10% reduction in the risk of age-related macular degeneration (AMD). The amounts of lutein and zeaxanthin found in breast milk and infant formula vary. Macular pigment optical density (MPOD) is a time- and dose-dependent measure of their intake.
Cespedes EM, Hu FB. Dietary patterns: from nutritional epidemiologic analysis to national guidelines. 2015 Am J Clin Nutr doi: 10.3945/ajcn.115.110213
Dhurandhar NV, Schoeller D, Brown AW, Heymsfeld SB, Thomas D, Sorensen TIA, Speakman JR, Jeansonne M, Allison DB, and the Energy Balance Measurement Working Group. 2014 Int J Obesity doi: 10.1038/ijo.2014.199
Whiting SJ, Bonjour J-P, Payen FD, Rousseau B. Moderate amounts of vitamin D3 in supplements are effective in raising serum 25-hydroxyvitamin D from low baseline levels in adults: A systematic review. 2015 Nutrients doi: 10.3390/nu7042311
Adaikalakotwswari A, Vatish M, Lawson A, Wood C, Sivakumar K, McTernan PG, Webster C, Anderson N, Yajnik CS, Tripathi G, Saravanan P. Low maternal vitamin B12 status is associated with lower cord blood HDL cholesterol in white Caucasians living in the UK. 2015 Nutrients doi: 10.3390/nu7042401
Wang C-Y, Carriquirry AL, Chen T-C, Loria CM, Pfeiffer CM, Liu K, Sempos CT, Perrine CG, Cogswell ME. Estimating the population distribution of usual 24-hour sodium excretion from timed urine void specimens using a statistical approach accounting for correlated measurement errors. 2015 J Nutr doi: 10.3945/jn.114.206250
Wagner A, Simon C, Morio B, Dallongeville J, Ruidavets JB, Haas B, Laillet B, Cottel D, Ferrieres J, Arveiler D. Omega-3 index levels and associated factors in a middle-aged French population: the MONO LISA-NUT study. 2015 EJCN doi: 10.1038/ejcn.2014.219
Secondary analyses of the effects of lutein/zeaxanthin on age-related macular degeneration progression AREDS2 Report No 3. 2014 JAMA Opthalmol doi: 10.1001/jamaopthalmol.2013.7376
Costa S, Giannantonio C, Romagnoli C, Barone G, Gervasoni J, Perri A, Zecca E. Lutein and zeaxanthin concentrations in formula and human milk samples from Italian mothers. 2015 EJCN doi: 10.1038/ejcn.2014.282
Loughman J, Nolan JM, Beatty S. Impact of dietary carotenoid deprivation on macular pigment system and serum concentrations of lutein and zeaxanthin. 2012 Br J Nutr doi: 10.1017/S0007114512004461