A higher intake of vitamins A, D and E is linked to a lower prevalence of respiratory complaints according to a new analysis of long-term survey data.
The UK study, in the BMJ Nutrition Prevention & Health looked at the association between vitamins A, D and E from diet and supplements and the prevalence of self-reported respiratory complaints.
Vitamins A, C, D and E support immune function and may help in the prevention of acute, respiratory complaints according to a recent review.
We know that nutrition is a key factor in the prevention of disease - and we know that malnutrition contributes to increased mortality from disease.
"Globally, there has been an emerging trend of pandemics affecting the respiratory system,
which has culminated most recently in the severe acute respiratory syndrome coronavirus 2019 outbreak. Current efforts to tackle the pandemic rely on managing associated symptoms and providing standard supportive nutritional care, with a substantial burden on
the National Health Service"
The research team, from London, Cambridge and Nagasaki in Japan, call for an urgent exploration of how vitamin intake could affect the incidence and severity of acute, respiratory complaints.
"This understanding is critical to developing short-term and long-term public health nutrition recommendations to help tackle respiratory complaints and reduce burden on healthcare systems."
The study used information from 6115 adults in the UK who participated in the 2008–2016 National Diet and Nutrition Survey Rolling Programme (NDNS RP). The researchers looked at dietary and supplemental intake of vitamins, adjusting for "relevant confounders" such as age, sex, BMI, smoking status, household income and total energy intake.
Respiratory complaints were self-reported symptoms such as breathlessness, weak chest, collapsed lung and damage from pneumonia.
Overall, there were 33 cases of respiratory complaints reported. These tended to be reported by older people who were less likely to say whether they were taking any vitamins or supplements.
As none of the adults with respiratory complaints reported taking vitamin C, the researchers were unable to come to any conclusions about this vitamin.
For vitamins A, E and supplemental vitamin D, however, there was a clear correlation with a reduction in respiratory complaints. This adds to the current scientific debate about the effect of vitamin D status on respiratory health and whether supplemental vitamin D is more effective for maintaining adequate levels:
"It is estimated that around a fifth of the general population in the UK have low vitamin D, and over 30% of older adults aged 65 years and above do not achieve the recommended nutrient intake."
"Our findings are consistent with the hypothesis that supplementation is critical to ensuring
adequate vitamin D status is maintained and potentially indicate that intake of vitamin D from diet alone cannot help maintain adequate vitamin D status."
Overall, the researchers conclude that:
"Intake of vitamin A and E from diet and supplements, and vitamin D from supplements,
show strong evidence of association with lower self-reported prevalence of respiratory complaints..."
It's important to highlight that this study looked at the link between vitamin intake from diet and supplements, with the incidence of respiratory complaints as defined in the NDNS. The authors advise that "...no inferences should be made with regard to the current COVID-19 pandemic."
These associations are not causal, but given what we know about how these nutrients contribute to respiratory health, it's hardly a surprise.
While the media focuses on vaccines and antibodies, ensuring you eat enough nutrient-dense foods that contain vitamins A, C and E, and supplementing with vitamin D is one of the safest and most accessible things you can do right now to look after your immune system.
Almoosawi S, Palla L Association between vitamin intake and respiratory complaints in adults from the UK National Diet and Nutrition Survey years 1–8 BMJ Nutrition, Prevention & Health 2020; bmjnph-2020-000150. doi: 10.1136/bmjnph-2020-000150
Calder PCNutrition, immunity and COVID-19 BMJ Nutrition, Prevention & Health 2020;3:doi: 10.1136/bmjnph-2020-000085