Preventing severe COVID-19: The role of diet

Preventing severe COVID-19 is on nearly everyone’s mind given the rapid spread and persistence of SARS-CoV2. In particular, the elderly, obese, and those with Type 2 diabetes have a substantially increased risk of a severe case.

A lot of emphasis centers around public health measures such as social distancing and mask wearing. These are effective means of slowing down transmission in the public. But, they do little in preventing severe COVID-19 in the likely event of infection.

So what should you do to lower your risk of coming down with a severe case of COVID-19? A couple of studies published this past month point to changes in immune function with aging, obesity, and Type 2 diabetes as drivers of severe infection.

This gives us some lifestyle targets ripe for the plucking.

Immune decline in aging as a driver of severe COVID-19

The knowledge of immunosenescence and inflammaging provides a potential interpretation of epidemiological data underscoring the elderly as the population most sensitive to COVID-19.

As we get older, our immune function becomes impaired, a process called immunosenescence. A chronic state of inflammation often referred to as “inflammaging” emerges as the default state.

As a result, we become more susceptible to viral and bacterial infection and vaccine efficacy declines. At the same time, our risk for autoimmune diseases and chronic inflammatory conditions increase.

This pro-inflammatory state promotes SARS-CoV2 infection by increasing viral replication. Increased viral load drives more severe COVID-19 illness.

Interestingly, the 2 primary aspects of immunosenescence give SARS-CoV2 a major 1-2 punch in the elderly. First, an impaired ability to generate an adaptive immune response allows SARS-CoVs to take hold in the lungs, increasing viral load. Second, the hyperinflammatory state causes collateral damage in tissues and drives a severe course of COVID-19.

Interestingly, obesity is another major driver of a severe course of COVID-19. Evidence indicates that obesity accelerates the aging process, and leads to similar alterations in immune function.

Immune function in obesity: accelerated aging?

Obesity alters immune function in a similar way as aging, though there are differences. Both obesity and aging lead to changes in fat tissue that alter immune function. Specifically, immune cells infiltrate fat cells and amplify the inflammatory response.

Though they share some similarities, obesity and aging have independent effects on immune function. Accordingly, the combination of advanced age and obesity likely have additive effects on COVID-19 severity.

Different forms of dietary restriction have a beneficial effect on immune function. This includes:

  • Calorie restriction
  • Carbohydrate restriction
  • Protein restriction
  • Restriction of specific amino acids (Methionine, cysteine, essential amino acids)

In particular, protein and amino acid restriction improve immune function and aging by increasing antioxidant status and the integrated stress response.

Nutrient sensing pathways are a key regulator of human physiology, including immune function. In both obesity and aging, these nutrient sensing pathways become dysregulated.

While some of this comes down to age-related changes in these pathways, a good deal also comes down to behavior.

Addressing lifestyle for preventing severe COVID-19

Many common aspects of the obese and elderly lifestyle converge to promote dysregulation of nutrient sensing pathways. Addressing these variables should have a beneficial effect in the event you become infected with SARS-CoV2.

Improving lifestyle by addressing these factors has a synergistic effect on immune function and may be useful in preventing severe COVID-19 illness.


Metabolism and immune function are intertwined in a bi-directional relationship with nutrient signaling pathways at its center. Nutrient signaling pathways become dysregulated with both aging and obesity. Therefore, it’s no surprise that both obesity and aging are factors that drive severe COVID-19 illness.

Correcting these alterations in nutrient signaling likely plays a role in preventing severe COVID-19 illness. Improving circadian rhythms, decreasing calorie intake, addressing gut health, increasing physical activity, and improving sleep hygiene all have beneficial effects on nutrient signaling pathways.

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