Hard facts and misfits: essential ingredients of public health nutrition research

Abstract

Policy decisions and the practice of public health nutrition need to be based on solid evidence, developed through rigorous research studies where objective measures are used and results that run counter to dogma are not dismissed but investigated. In recent years, enhancements in study designs, and methodologies for systematic reviews and meta-analysis, have improved the evidence-base for nutrition policy and practice. However, these still rely on a full appreciation of the strengths and limitations of the measures on which conclusions are drawn and on the thorough investigation of outcomes that do not fit expectations or prevailing convictions. The importance of ‘hard facts’ and ‘misfits’ in research designed to advance knowledge and improve public health nutrition is illustrated in this paper through a selection of studies from different stages in my research career, focused on the nutritional requirements of resource-poor populations in Africa and Asia.

Biochemical Markers of Calcium and Bone Metabolism during and after Lactation in Ugandan Women with HIV on Universal Maternal Antiretroviral Therapy

“…( 39 , 40 ) However, the benefits of vitamin D supplementation in individuals with good vitamin D status are unknown, and unexpected long‐term effects of calcium supplementation in African women and children have been reported. ( 41 ) Thus, further studies are needed to explore mechanisms in more detail and to investigate whether the use of TDF‐based ART by African women during pregnancy and lactation has long‐term consequences for the bone health of the mother and for the growth of the child. In particular, clinical endpoint data will be required to determine the implications of the findings of this study and to guide consideration of potential interventions.…”

Micronutrient malnutrition across the life course, sarcopenia and frailty

“…The final symposium of the conference covered measures used to address issues relating to micronutrient deficiency, and this included the approaches to development and setting of dietary reference values that provide guidance on the daily intake of micro and macro nutrients required to meet the needs of the majority of the population. Professor Hilary Powers, summarised how dietary recommendations are developed and implemented (18) and Professor Ann Prentice highlighted that policy decisions and the practice of public health nutrition need to be based on "solid evidence developed through rigorous research studies where objective measures are used to determine their relevance" (19,20) . Prof Prentice also noted the relevance of sexual dimorphism on recommendations for micronutrients as they are influenced by body size or macronutrient intake.…”

Effects of maternal calcium supplementation on offspring blood pressure and growth in childhood and adolescence in a population with a low-calcium intake: follow-up study of a randomized controlled trial

“…The Gambia, West Africa, has high rates of adult hypertension and stroke, in both urban and rural communities [ 13 , 14 ]. Prenatal nutrient restriction and accelerated growth after periods of growth faltering in early life are common [ 15 , 16 ]. In an RCT in rural Gambia, a population with a low-calcium intake (300–400 mg/d), a maternal supplement of 1500 mg Ca/d from 20 wk gestation to term had no significant effect on maternal blood pressure, birth outcomes, or infant growth [ 17 , 18 ] and no apparent effect on offspring blood pressure at 7 y of age [ 19 ].…”