1.
The impact of nutrition on COVID-19 susceptibility and long-term consequences.
Butler, MJ, Barrientos, RM
Brain, behavior, and immunity. 2020;87:53-54
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Plain language summary
The impacts of Covid-19 are being felt across the world, affecting health, healthcare and economies. Statistics from across the world are showing that the elderly, those with underlying medical conditions and under-represented minority groups are particularly vulnerable to severe complications and have a higher risk of dying of Covid-19. This opinion piece presents arguments for the importance of focusing on diet to support health resilience in general and the immune system in particular, to minimise the impact of this and future viruses. Research is presented on excessive intake of saturated fat leading to chronic activation of the innate immune system (first line, rapid defence against infection), resulting in inflammation, and associated heightened susceptibility to complications of viral infection. The standard western diet (high saturated fat, refined carbohydrates and sugars, low levels of fibre, unsaturated fat and antioxidants) has also been shown to affect the adaptive immune system (second line, delayed defence against infection), depressing its action against infection. The piece also discusses possible long-term, future impacts of those recovered from Covid-19 infection, particularly in relation to neurodegenerative diseases such as Alzheimer’s. The authors call for fresh, healthy wholefoods to be readily available and affordable to everyone in society.
Abstract
While all groups are affected by the COVID-19 pandemic, the elderly, underrepresented minorities, and those with underlying medical conditions are at the greatest risk. The high rate of consumption of diets high in saturated fats, sugars, and refined carbohydrates (collectively called Western diet, WD) worldwide, contribute to the prevalence of obesity and type 2 diabetes, and could place these populations at an increased risk for severe COVID-19 pathology and mortality. WD consumption activates the innate immune system and impairs adaptive immunity, leading to chronic inflammation and impaired host defense against viruses. Furthermore, peripheral inflammation caused by COVID-19 may have long-term consequences in those that recover, leading to chronic medical conditions such as dementia and neurodegenerative disease, likely through neuroinflammatory mechanisms that can be compounded by an unhealthy diet. Thus, now more than ever, wider access to healthy foods should be a top priority and individuals should be mindful of healthy eating habits to reduce susceptibility to and long-term complications from COVID-19.
2.
The Sleep-Immune Crosstalk in Health and Disease.
Besedovsky, L, Lange, T, Haack, M
Physiological reviews. 2019;99(3):1325-1380
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Plain language summary
The interaction between sleep and immunity is an established phenomena. This thorough review article summarises sleep changes in response to both infectious and non-infectious immune system challenges and describes the role of sleep in supporting the immune system. Details are provided of how sleep affects the innate immune system (first line, rapid defence against infection) as well as the adaptive immune system (second line, delayed defence against infection), using a feedback system which promotes host defence. Sleep is associated with reduced infection risk and can improve infection outcome and vaccination responses. Sleep deprivation is also associated with chronic, low-grade inflammation. Nutrition Practitioners wishing to support immunity can focus on sleep as a simple lifestyle measure to enhance resilience.
Abstract
Sleep and immunity are bidirectionally linked. Immune system activation alters sleep, and sleep in turn affects the innate and adaptive arm of our body's defense system. Stimulation of the immune system by microbial challenges triggers an inflammatory response, which, depending on its magnitude and time course, can induce an increase in sleep duration and intensity, but also a disruption of sleep. Enhancement of sleep during an infection is assumed to feedback to the immune system to promote host defense. Indeed, sleep affects various immune parameters, is associated with a reduced infection risk, and can improve infection outcome and vaccination responses. The induction of a hormonal constellation that supports immune functions is one likely mechanism underlying the immune-supporting effects of sleep. In the absence of an infectious challenge, sleep appears to promote inflammatory homeostasis through effects on several inflammatory mediators, such as cytokines. This notion is supported by findings that prolonged sleep deficiency (e.g., short sleep duration, sleep disturbance) can lead to chronic, systemic low-grade inflammation and is associated with various diseases that have an inflammatory component, like diabetes, atherosclerosis, and neurodegeneration. Here, we review available data on this regulatory sleep-immune crosstalk, point out methodological challenges, and suggest questions open for future research.