Approaches to setting dietary reference values for micronutrients, and translation into recommendations

Micronutrient malnutrition across the life course, sarcopenia and frailty

Micronutrient malnutrition, the deficiency of vitamins or minerals, impacts on physical and mental health, in clinical and general populations, across the life course. In older western populations the high prevalence and impact of micronutrient malnutrition is less well recognised. Low- and middle-income countries are experiencing the 'double burden of disease' where malnutrition coexists alongside the non-communicable diseases of aging, obesity, type 2 diabetes and cardiovascular disease. Held in December 2020, the Winter Conference of the Nutrition Society was designed to cover new areas of research and concern in micronutrient malnutrition across the life course. Common themes arising from the conference were: 1) The continuing high prevalence of micronutrient malnutrition across the life-course, in diverse populations, in high, middle and low-income countries. 2) That multiple deficiencies of micronutrients frequently exist. 3) The primary cause of deficiency is poor quality diets, of low diversity, low in micronutrient dense foods. 4) Clinical conditions, medications for common non-communicable diseases, and environmental conditions, interact with and exacerbate the effects of poor diet quality. 5) Understanding of the mechanistic effects of micronutrients is still emerging. 6) Micronutrients are necessary for maintaining immune function, which has importance for the COVID-19 epidemic. 7) Better biomarkers are needed detect and understand the effects of deficiency. 7) Dietary recommendations need to be updated regularly. Further research is needed in all these areas. Comprehensive public health and government approaches to ensure access and affordability of good quality foods to populations of all ages, particularly during the ongoing COVID-19 epidemic, are crucial.

Sex differences in requirements for micronutrients across the lifecourse

For many people, micronutrient requirement means the amount needed in the diet to ensure adequacy. Dietary reference values (DRV) provide guidance on the daily intake of vitamins and minerals required to ensure the needs of the majority in the population are covered. These are developed on estimates of the quantity of each micronutrient required by the average person, the bioavailability of the micronutrient from a typical diet and the interindividual variability in these amounts. Sex differences are inherent in the requirements for many micronutrients because they are influenced by body size or macronutrient intake. These are reflected in different DRV for males and females for some micronutrients, but not all, either when data from males and females are combined or when there is no evidence of sex differences. Pregnancy and lactation represent times when micronutrient requirements for females may differ from males, and separate DRV are provided. For some micronutrients, no additional requirement is indicated during pregnancy and lactation because of physiological adaptations. To date, little account has been taken of more subtle sex differences in growth and maturation rates, health vulnerabilities and in utero and other programming effects. Over the years, the MRC Nutrition and Bone Health Group has contributed data on micronutrient requirements across the lifecourse, particularly for calcium and vitamin D, and shown that supplementation can have unexpected sex-specific consequences that require further investigation. The present paper outlines the current issues and the need for future research on sex differences in micronutrient requirements.