Covid-19, why are obese people more at risk?

Article by Solongevity Research
While the main predisposing factor for the development of severe forms of Covid-19 is old age, obesity comes next. How comes? What do these two conditions have in common? Both appear to reduce the body’s ability to fight infection by weakening the immune system and promoting inflammation. The point is made in an article published in Nature (in the Features – Collection section, ‘Nutrition, immunity and a global pandemic’, in collaboration with another journal in the same group, European Journal of Clinical Nutrition and Nutrition & Diabetes).

Age, the biggest risk factor for any disease

Ageing and its consequences are a much-studied phenomenon. It is easy to see why: old age is linked to a variety of diseases, many of which, if you dig deeper, turn out to have an inflammatory basis. Although there is still much to be uncovered, scientists have produced enough evidence to be reasonably sure that as time passes, the immune system changes, becoming less active in some ways and hyper-reactive in others. As a result, it is no longer as efficient at fighting infection.

Obesity, an accelerator?

Experts believe that obesity may accelerate the ageing of the immune system. While adipose tissue normally plays an anti-inflammatory and protective role, when it becomes too much it can become dysfunctional, secreting hormones and other chemical signals that instead promote what is called a chronic low-grade inflammatory state. A condition similar, in fact, to that which develops with the passing of the years and which increases the risk of developing disorders such as cardiovascular diseases, autoimmune diseases, tumours, etc. Thus, it is no coincidence that a high body mass index is associated with.

Obesity seems to accelerate the ageing of the immune system

Three possible mechanisms

How chronic low-grade inflammation is promoted by excess adipose tissue is still under investigation, but there are several hypotheses. Some experts think that the overload of nutrients within adipocytes (fat cells) causes intercellular stress that initiates an inflammatory cascade. Others believe that adipose tissue becomes hypoxic and, in the absence of oxygen, activates inflammatory mechanisms. A third possibility is that immune system cells (macrophages) infiltrate the overabundant adipose tissue and try hard to get rid of the dying parts. This generates toxicity, triggering a cascade of reactions that contribute to the body’s chronic inflammatory state. Obesity, however, is considered a risk factor for Covid-19 not only because of its contribution to chronic inflammation. In fact, being overweight is very often associated with type 2 diabetes and respiratory difficulties, which in turn expose people to an increased risk of Sars-Cov-2 infection complications.

The role of nutrition

Our diet also contributes to low-grade chronic inflammation. According to an article published in 2019 in the journal Nutrients, the diet of Western countries (high-income) has been enriched in sugars and fats and depleted in complex carbohydrates, fibre and micronutrients: an unhealthy combination that promotes so-called chronic metabolic inflammation and alters the gut microbiota, increasing the production of toxins. Obesity also predisposes to altered intestinal permeability. This means that more toxins pass from the gut into the bloodstream, inducing a further inflammatory response. The Mediterranean diet, rich in foods containing antioxidants, polyphenols and omega-3 fats, can help reduce chronic inflammation linked to obesity.

Excess adipose tissue could trigger an inflammatory cascade

Eating well is therefore essential for everyone and can help reduce the damage caused by age-related problems and being overweight. The Mediterranean diet is still considered the best, because it provides antioxidants, polyphenols and omega-3 that work to reduce inflammation. These are molecules that have been shown to be effective and have even been studied as ingredients in food supplements to support the immune system and reverse chronic inflammation processes.

Losing weight keeps us safe

Adjusting our diet and exercising (even moderate exercise, such as a 20-minute walk) can not only help to decrease chronic low-grade inflammatory status, but also help to maintain a healthy weight or lose excess weight. According to Andrew Greenberg of the Jean Mayer USDA Human Nutrition Research Center on Aging, “even losing 5 to 10 per cent of weight really helps a person improve their metabolic profile”.

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