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Covid-19: death rate is 0.66% and increases with age, study estimates

BMJ 2020; 369 doi: https://doi.org/10.1136/bmj.m1327 (Published 01 April 2020) Cite this as: BMJ 2020;369:m1327

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Re: Covid-19: death rate is 0.66% and increases with age, study estimates

Dear Editor
Making nutrition a priority to help reduce risk of infections and death during the coronavirus pandemic

The risk of fatality from COVID-19 is dramatically higher among older people, particularly those over 80 years and those with chronic disease comorbidities [1]. Many people who develop COVID-19 and other respiratory tract infections are not only older but also immunocompromised [2].

One factor that affects immune responses with increased age is reduced serum levels of 25-hydroxyvitamin D (25(OH)D), the biomarker used to assess risk of vitamin D deficiency and suboptimal dietary intakes. The seasonality of many viral infections, especially in cold weather in winter, is associated with low 25(OH)D concentrations as a result of limited exposure to sunlight. The metabolism and actions of vitamin D are well known. Vitamin D3 is produced in the skin and plays a key role in the immune systems, the highly complex mechanisms in the body that are designed to help protect people against a host of infectious agents, including bacteria and viruses. People who are self-isolating or unable to go outside into the sunshine, people living in regions impacted by air pollution, people who are malnourished, overweight or obese and those with low baseline 25(OH)D concentrations are likely to have weakened immune systems and functions and be at increased risk of viral infections.

Healthy eating and maintaining and improving nutritional status are vital to keep the body in top condition—both physical and mental. The healthiest meals include plenty of vegetables, fruits and wholegrain cereals, beans and other legumes and smaller portions of meat. Other nutrient-dense foods include dairy products, eggs, fish (particularly oily fish as a source of the essential omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)), nuts and seeds.

Only a few foods contain vitamin D and, in these unprecedented times, eating a varied and balanced diet becomes even more challenging. Of particular concern are the key micronutrients that support the immune system. These essential nutrients are not only vitamin D but also vitamin A (including beta-carotene), the B vitamins (folate, vitamins B6, B12), vitamin C and the essential minerals and trace elements iron, copper, zinc and selenium. In the case of vitamin D, the UK Government advice [3,4] to take a daily supplement of at least 10 µg/day of vitamin D will help to ensure healthy vitamin D status. As stated previously, older people and critically ill patients have a very high prevalence of vitamin D deficiency and suboptimal vitamin D levels, which are associated with greater illness severity, morbidity and mortality. A safe use of 25 micrograms of vitamin D3 (1000 IU) per day as a food supplement could be an important and inexpensive way to improve nutritional status of older people, and to act as an adjuvant therapy for many disease states.

Although messages about the importance of a balanced diet and a healthy active lifestyle underpin nutrition and health advice to the public, there is now a need to give evidence-based scientific advice to people at all stages of life, including during pregnancy, childhood and adolescence as well as old age, about the need to maintain and enhance the micronutrient density of the diet and about the role of food supplements as sources of essential nutrients. All the specific nutrients mentioned have authorised European Union health claims for their contributions to the normal functioning of the immune system based on scientific assessments carried out by the European Food Safety Authority [5]. It is not surprising that deficiencies and suboptimal intakes of essential nutrients like vitamin D will lead to impairments of the immune functions, particularly for those over 60 years of age who may have lost their senses of smell and taste, and appetite, have low energy intakes, follow restrictive diets such as vegetarianism and veganism, or have limits on physical and outdoor activities. The use of some pharmaceutical drugs such as antibiotics, anti-hypertensive, anti-inflammatory and endocrine drugs can lead to lower serum 25(OH)D concentrations.

Surveys of nutrient intake and nutritional status in the UK demonstrate chronic shortages of several micronutrients and not only suboptimal intakes of vitamin D. In 2019, the publication of the UK National Diet and Nutrition Survey [6], conducted on behalf of Public Health England and the Food Standards Agency, stated that there was a downward trend in intakes of most vitamins and minerals over a nine-year period for many age/sex groups. The data demonstrated a sustained worsening of the diet, particularly among the lower income groups. Many people have intakes lower than the Lower Reference Nutrient Intakes, where the risk of deficiency is high, particularly if sustained over a period of time.

Poor nutritional status and low intakes of essential nutrients are evident not only in the general population but also in various care and clinical settings. Even mild micronutrient deficiencies and depletion of micronutrient stores in the body over weeks can lead to general fatigue and reduced resistance to infections.

No one knows how long the public health and safety measures, such as social distancing, self-isolation and thorough handwashing will be needed to reduce exposure to the virus and to slow the spread of this disease. Now is the time to raise awareness about the associations between nutrition and health. In times of emergency, public health measures to reduce risks of infections and death should include messages about the role and benefits of the essential micronutrients for the immune system. Their contribution to the resilience of the population to the COVID-19 pandemic, particularly vitamin D supplementation to raise 25(OH)D to optimal serum levels, should have higher priority for both patients, all medical and care home staff as well as the general population.

References
1. Mahase E. Covid-19: death rate is 0.66% and increases with age, study estimates. BMJ 2020; 369: m1327
2. Grant et al. Evidence that vitamin D supplementation could reduce risk of influenza and COVID-19 infections and deaths. Nutrients 2020; 12: 988
3. The SACN report Vitamin D and Health is available at: https://www.gov.uk/government/publications/sacn-vitamin-d-and-health-report
4. The new government advice on vitamin D is available at: https://www.gov.uk/government/news/phe-publishes-new-advice-on-vitamin-d
5. European Commission EU register on nutrition and health claims. Available online at https://ec.europa.eu/food/safety/labelling_nutrition/claims/register/pub...
6. National Diet and Nutrition Survey report available at: https://www.gov.uk/government/statistics/ndns-time-trend-and-income-anal...

Competing interests: No competing interests

14 April 2020
David P. Richardson
Scientific consultant and nutrition scientist
Visiting professor, University of Reading, School of Chemistry, Food and Pharmacy
School of Chemistry, Food and Pharmacy, University of Reading, PO BOX 224, Whiteknights, Reading RG6 6AP