Dr Dan McCartney, dietitian, lecturer in Human Nutrition and Dietetics and Programme Director of the Human Nutrition and Dietetics programme at TU Dublin and Trinity College Dublin, joins Laura to discuss the vitamins and minerals many of us simply aren’t getting enough of — and why that matters for our health.
Drawing on Ireland’s national food intake data, Dan reveals striking levels of inadequate intake across essential nutrients including vitamin B6, folate, vitamin C, vitamin A, zinc, magnesium and selenium. At least half of the Irish population have inadequate intakes of magnesium and selenium, while more than 40% have inadequate vitamin C intakes.
Laura and Dan also discuss the European Food Safety Authority (EFSA) and proposals to lower or restrict the levels of certain vitamins and minerals available through supplements. Dan questions the rationale for reducing these levels when nutrient intakes are already low, discussing proposed levels for vitamin D, as well as restrictions affecting magnesium and the importance of vitamin C. He explains why he believes a restrictive, one-size-fits-all European approach may not meet the nutritional needs of the Irish population.
They also explore whether some recommended daily amounts are focused more on preventing severe deficiency than achieving optimal health, including vitamin C recommendations based around preventing scurvy and vitamin D recommendations historically centred on bone health rather than immune function.
The conversation returns to Dan’s early research into vitamin D and COVID-19, before moving into nutrition and immunity, healthy ageing, dementia, pregnancy and epigenetics — and why the nutritional choices we make today can influence our health decades into the future.
Half the population are falling short on key nutrients
Dan discusses inadequate intakes of magnesium, selenium, vitamin B6, folate, vitamin C, vitamin A and zinc in Ireland.
Why are nutrient intakes so low?
Poor diet quality, low fruit and vegetable intake, low wholegrain consumption and highly refined diets.
EFSA and proposed supplement restrictions
Laura and Dan discuss EFSA and proposed European changes affecting vitamin and mineral supplements, including vitamin D and magnesium, and why Dan is concerned about further restrictions.
Are recommended intakes actually optimal?
Dan questions whether some guidelines focus on preventing severe deficiency rather than supporting optimal health.
Vitamin D, immunity and COVID-19
Dan revisits the research that led him and Dr Declan Byrne to propose a link between vitamin D deficiency and severe COVID-19 in 2020.
Nutrition across a lifetime
From pregnancy and epigenetics to ageing and cognitive health, Dan explains why nutrition today can affect health decades later.
Optimisation of Vitamin D Status for Enhanced Immuno-protection Against Covid-19
Dan and Declan Byrne, Irish Medical Journal, 2020
Vitamin D Deficiency and ARDS after SARS-CoV-2 Infection
Faul et al., Irish Medical Journal, 2020
Autocrine vitamin D signaling switches off pro-inflammatory programs of TH1 cells
Chauss et al., Nature Immunology, 2022
Nutrition, immunity and COVID-19
Philip Calder, BMJ Nutrition, Prevention & Health, 2020
European vitamin D supplementation trials, meta-analysis
Rupprecht et al., Nutrients, 2023
00:00 — Cold open
02:07 — Meet Dr Dan McCartney
04:03 — Vitamin D and COVID-19
06:10 — The 2020 research
13:49 — Why vitamin D levels run low
19:08 — Vitamin D and immunity
32:00 — Ireland’s nutrient inadequacies
34:02 — Poor diet quality
35:09 — Zinc, magnesium and selenium
37:24 — Are nutrient guidelines out of date?
38:03 — Scurvy vs optimal health
45:48 — EFSA and proposed supplement restrictions
46:24 — Vitamin D supplement levels
50:11 — Magnesium restrictions
51:03 — Nutrition guidelines for Ireland
54:35 — Primates and vitamin D
55:51 — Ageing and dementia
57:39 — Pregnancy and epigenetics
1:02:43 — Why good habits compound
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