In the wake of the current and unprecedented COVID-19 pandemic, on 20th March 2020, the Director-General of the World Health Organization (WHO) emphasised the importance of appropriate diet and lifestyle measures including adequate nutrition to protect the immune system. This is of course not a substitute for adherence, first and foremost, to key public health and medical advice on prevention. However, as vast sections of society spend more time at home, it provides an opportunity to focus on strengthening the four lifestyle pillars of sleep, mind, exercise and diet. To elaborate on diet and nutrition, particularly given the variable quality of online information, we have put together a 10-point summary as general guidance:
1 The Coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2) is highly transmissible and can be potentially lethal. Hence any strategies that can prevent or mitigate respiratory infection risk and strengthen overall immunity are critical at this time.
2 Poor nutrition, due to either insufficient dietary intake of key nutrients or a poor overall diet quality, can compromise immune function and increase overall infection risk.
3 Micronutrients, commonly known as vitamins and minerals, are required in small quantities but are critical for health and pivotal in strengthening the immune system.
4 Multiple micronutrients are essential for good immune function, particularly vitamins A, C, D, E, B2 (riboflavin), B6 (pyridoxine), B12 (cobalamin) and B9 (folic acid) and minerals iron, selenium, zinc, magnesium and copper, and these are found in a variety of foods that form part of a balanced diet in line with national guidelines.
5 There are a variety of foods rich in vitamins and minerals (see below), in particular fruit and vegetables, which can be fresh, tinned or frozen.
6 In the United Kingdom, as an example, several micronutrient deficiencies are prevalent as the Government’s National Diet and Nutrition Survey (2019) demonstrates widespread inadequacy in the intakes and/or status of vitamin D, vitamin A (retinol), folate and selenium across the UK population and in specific age groups. This is likely to be mirrored more widely across multiple countries.
7 Certain individuals are at greater risk of micronutrient deficiency; this includes women of childbearing age, particularly pregnant and lactating women, infants and toddlers, children, adolescents (particularly females), older adults, obese individuals, and the critically ill, plus individuals with inflammatory bowel disease and other chronic inflammatory and malabsorptive conditions.
8 In many high risk groups, a balanced diet alone may not be sufficient to meet these requirements and deficiencies can contribute to impaired immune function. This can be due to a variety of factors affecting intakes, absorption and also due to increased utilisation of micronutrients during times of infection. In such cases, the immune system can be supported by micronutrient supplementation particularly to help correct deficiencies.
9 As a key example from the UK, Vitamin D supplementation is recommended at 10 micrograms a day, as per guidelines. The average diet provides less than half of this amount.
10 Overall, whilst COVID-19 is causing inevitable distress to one and all, aside from the impact of the viral illness itself, prevention through social distancing and staying at home can affect both mood and feelings. This may cause depression, anxiety, loneliness and irritability. During these testing times, it is important to remember that eating well, staying hydrated, thinking positively, sleeping adequately and staying active will contribute to both physical and mental wellbeing.