Healthy Food & Healthy Living by Dr. Ayala

Does a healthy diet reduce the risk of severe Covid-19?

I haven’t written about Covid for a while. Frankly, I was hoping to move on to other health topics by now – we’ve been living under this shadow for almost two years. But Covid-19 is still a central health matter, and many of its mysteries remain unsolved.

One of the most puzzling issues is the incredible variability in disease severity, age notwithstanding. Underlying medical conditions, such as hypertension and diabetes predict a higher likelihood of severe disease, as does obesity, but there’s a lot that can’t be explained by that.

Could nutrition inform some of this disparity? Poor diet is linked with the severity of other infectious diseases. Sound nutritional status supports immunity, lowers the chance of severe, out-of-control inflammation, and malnutrition causes immune deficiency.

This question remains relevant for this pandemic. Although vaccination is the most effective way to prevent severe disease and hospitalization, breakthrough infections are possible and ameliorating those is vital – we’re not completely done protecting ourselves, even with two shots. 

This question is also crucial for other infectious diseases known and yet to come.

Diet and the pandemic

A new study in the journal Gut looks at data from almost 600,000 people in the UK and the US, who were followed from March to December of 2020 by the smartphone based Covid-19 Symptom Study. All participants’ diet was assessed before the study began.

During follow-up almost 32,000 people had Covid-19 infections.

Healthy plant-based diets were associated with lower risk of contracting the disease and of severe Covid-19.

Poor diet quality was associated with lower socioeconomic status, as you might imagine. Healthy behaviors tend to cluster and people who eat healthy may sign on to other health-promoting measures. 

But the association remained strong even after accounting for other healthy behaviors, social determinants of health like education disparities, income inequality, housing insecurity, healthcare access, social isolation, food insecurity, unemployment, public safety etc., and the steps taken to prevent virus transmission such as mask wearing as well as the rates of transmission of Covid-19 in the community.  The authors conclude that: “The joint association of diet quality with socioeconomic deprivation was greater than the addition of the risks associated with each individual factor, suggesting that diet quality may play a direct influence in COVID-19 susceptibility and progression. Our findings suggest that public health interventions to improve nutrition and poor metabolic health and address social determinants of health may be important for reducing the burden of the pandemic.”

Another study of about 3000 health workers from France, Germany, Italy, Spain, UK, and the US showed that those on a plant based or pescatarian diet had lower odds of moderate to severe disease after taking into account other health characteristics, with the vegetarians among the group showing a 73 percent lower chance of moderate to severe illness, and the pescatarians with 59 percent lower odds of significant manifestations.

Again, removing every confounder is impossible, but we already have so many reasons to invest in healthy diets – personally with our own decisions and with public health interventions that increase access and education about the importance of eating well. This isn’t just the Covid-19 pandemic: Poor diets are a risk factor for a long list of chronic diseases, from heart disease to diabetes to cancer.

Dr. Ayala

Does food affect susceptibility to Covid-19?

Six months into the Covid-19 pandemic, and the astonishing variability in disease severity remains an enigma. The same virus causes an infection so mild in some that it passes without notice, yet in others it manifests catastrophically. While older age clearly increases the risk for severe disease and death, at times younger people also need intensive care, and a whole host of underlying conditions are presumptive risk factors.

According to the WHO, the CDC and other leading health agencies, conditions that make a person more likely to suffer severe Covid-19 include cardiovascular disease, diabetes, lung disease such as asthma and COPD, hypertension, obesity and history of smoking, among others.

Unfortunately, underlying health conditions are common. According to modeling recently presented in the Lancet about one in five people worldwide are at increased risk of severe Covid-19, due to underlying health conditions, and 4 percent of those infected worldwide would require hospitalization. The situation in the US is even more concerning: 60 percent of Americans have an underlying condition. Even young adults ­– late teens to late twenties – in the US are more vulnerable than one might imagine. A new study by UCSF researchers, in the Journal of Adolescent Health predicts that 32 percent of young adults are at risk of severe Covid-19 based on risk factors.

But although time goes in only one direction, and not every underlying disease can be reversed, many risk factors are highly modifiable. And since it looks like we’re in for a long battle it’s time to step up our efforts.

Eating to support immunity and measured inflammation

Our knowledge of Covid-19 is evolving, but it’s safe to assume that a sound nutritional status supports immunity, and lowers the chance of severe, out-of-control inflammation.

More importantly, many of the chronic diseases, which put us at risk of severe Covid-19, can be mitigated by a healthy diet. A healthy diet supplies us with all the essential nutrients – malnutrition causes immune deficiency – and also promotes health, reduces undue inflammation, and lowers the risk of chronic diseases.

There are many ways to eat healthy. There’s one particular diet pattern, however, that’s clearly not good, and it’s unfortunately popular, inexpensive and prevalent. The Western diet, characterized by excessive consumption of highly processed, sugary and fatty foods, refined grains and cured and red meats, and low intake of fruits and vegetables, is associated with impaired blood sugar and insulin, metabolic disease and obesity. It’s linked with inflammation and many chronic diseases, including diabetes and heart disease, even in people with normal weight.

One example of a healthy diet – one I’m especially fond of due to its flavor and ease of preparation – is the Mediterranean diet. It’s characterized by high intake fresh whole foods, fruits and veggies, fiber and only moderate intake of other foods; it’s associated with lower incidence of chronic diseases. Any diet that emphasizes fresh plant-based foods such as vegetables and fruits, whole grains, legumes, and nuts may improve the inflammatory response, fight insulin resistance and metabolic disorders.

An interesting new paper in ACS Chemical Neuroscience looks at the correlation between herb and spice consumption and Covid-19 cases, deaths and recovery in 163 countries. It found that countries with lower consumption of spices per capita had a higher number of deaths per million citizens as a result of Covid-19, and more importantly, that the recovery rate was higher in nations with higher consumption of spices. Could ginger, turmeric, garlic, clove and thyme help fight infections? The authors cite studies that support the notion that “herbs and spices are well-known to boost immunity,” perhaps due to their antiviral, antioxidant and anti-inflammatory actions.

Or perhaps, people from countries that utilize large amounts of spices simply cook more from scratch, rely less on highly processed foods, and therefore just have better diets.

Now, more than ever, healthy eating habits should be a top priority; they may reduce our susceptibility to severe Covid-19 and its complications. Now, more than ever, is the time for cooking simple meals from scratch, and filling half the plate with veggies. Spices and herbs will enhance the flavor of the dish, add to its nutritional value, and maybe even help with fighting illness.

Dr. Ayala