One year after the onset of the Covid-19 pandemic, the shock, scare and nasty surprise on the Covid-diabetes link have not disappeared. What has changed is the wealth of new research bringing to light fresh investigations and new evidence every day. So where are we now? Here are some of the latest updates to help you make sense of the complex science.
Polyphenols to the rescue
It is believed that diabetes is caused by a complex interplay of environmental, nutritional and genetic factors. Hence, dietary strategies are at the forefront of research. In recent years, the action of polyphenols on diabetes has been in the spotlight.
Polyphenols are micronutrients widely found in a large variety of fruits, nuts, spices, vegetables and herbs. The growing interest is related to the recognition of polyphenols as abundant components of our diet with beneficial antioxidant roles in a range of diseases: cancer to diabetes, heart disease to neurodegenerative diseases and many others. In particular, they have been found to have preventive and therapeutic potentials for diabetes. It seems, polyphenols not only reduce the risk but also delay the development of the disease.
It was in January that the journal Integrative Physiology published a study on the impact of polyphenols-based diet in elderly and obese patients of Covid-19. The researchers found that a high intake of polyphenols may have a protective effect on patients with Covid-19 and prevent disease progression.
The research on coronavirus has brought to light the link between old age, obesity and inflammation: how that increases substantially the vulnerability of the elderly population and those with co-morbidities, such as obesity, diabetes, respiratory system diseases, hypertension and cardiovascular disease. The data presented by the study reinforce the hypothesis that polyphenols might have the potential for inflammation prevention and, therefore, for the treatment and/or management of patients with viral infections, such as SARS-CoV-2.
The dangers of obesity
In a review article published on January 21, 2021, in Nature, researchers from Germany focused on obesity, hyperglycaemia and Covid-19. The researchers posited key points.
First, that obesity has emerged as a strong and independent determinant of severe Covid-19. In addition, visceral obesity seems to increase the risk of complications.
Secondly, diabetes is not only an established risk factor for severe Covid-19, there is emerging evidence that hyperglycaemia (high blood sugar) among people in the non-diabetic and diabetic range also strongly predicts severe Covid-19.
The researchers sound out several warnings: to begin with, since the SARS-CoV-2 virus targets organs and tissues that are relevant for cardiometabolic health, there could be an increased incidence of cardiometabolic diseases in the wake of the pandemic.
Cardiometabolic conditions mean, a person’s chances of having a heart attack or stroke, when one or more of the following risk factors are present: high blood pressure, diabetes, high LDL (“bad”) cholesterol, low HDL (“good”) cholesterol, high triglyceride levels and excess fat around the waist.
Weight loss and improvement in metabolic health might help people cope better with Covid-19. Understanding how diet and nutritional status modify the immune response could help explain why Covid-19 takes the divergent course in different people and improve patient outcomes. What’s more, they warn, the linked mechanisms between obesity and hyperglycaemia can also negatively affect the efficiency of a SARS-CoV-2 vaccine.
The four conditions
In February 2021, researchers at the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University, US, published a study in the Journal of the American Heart Association (JAHA) with insights to reduce the impact of Covid-19.
In the modelling study, the researchers estimated that of the 906,849 total Covid-19 hospitalisations as of November 18, 2020, in the US, two-thirds (64%) were attributable to at least one of four pre-existing conditions: 30 per cent obesity, 26 per cent hypertension, 21 per cent diabetes and 12 per cent heart disease.
Each of the above conditions is strongly linked to a heightened risk of severe Covid-19 infection. And, hence, might have been prevented. The study found that people might have been infected but not faced a severe enough infection to require hospitalisation.
“While newly authorized COVID-19 vaccines will eventually reduce infections, we have a long way to go to get to that point,” writes Dariush Mozaffarian, lead author and dean of the Friedman School. The findings call for interventions to determine whether improving cardiometabolic health will reduce hospitalisations, severe illness and death from Covid-19.
Changes in diet quality alone, even without weight loss, rapidly improve metabolic health within just six to eight weeks, point out the researchers. Hence, it is crucial to test such lifestyle approaches for reducing severe Covid-19 infections, both for this pandemic and future pandemics likely to come.
The model estimates that age also plays a role. For instance, about eight per cent of hospitalisations among patients 50-years-old or younger are attributable to diabetes, while the disease accounts for about 29 per cent of hospitalisations among those over 65. Obesity has been found to be equally detrimental across all age groups.
The bottom line is: doctors need to educate people who may be at risk for severe Covid-19 and promote preventive lifestyle measures—from the improved dietary quality and physical activity to improve overall cardiometabolic health.
The bright side of the pandemic
Lockdowns and lifestyles during the pandemic were an issue of enormous concern to doctors the world over. An increase in sedentary behaviour, anxiety and emotional stress, along with limited appointments with physicians had an adverse impact on people with underlying co-morbidities, considered more vulnerable to Covid-19.
A few studies, however, found an unexpected “bright side” in people with diabetes during the pandemic. Behavioural changes improved blood glucose control, they reported. In an observational study conducted in Paris on 1,378 people with type 1 diabetes, in the age bracket of 35 and 56 years, the researchers looked at differences in glycaemic control (using Flash Glucose Monitoring) for 38 days, as they collected behavioural information, lifestyle modifications, and current treatments.
They observed an improvement in glycaemic control on average during the lockdown. Younger adults with higher HbA1C showed an improvement as they reduced food intake, snacking, started exercising and also lost weight during the lockdown. Bars were closed, and the decrease in alcohol intake helped improve glycaemic control. The study was published in Diabetes Care (Potier, L. et al, Dec 2020)
“The studies can help guide people in the importance of lifestyle modifications and how these changes can improve their health,” writes L.M. López in a review article in Diabetes in Control, an online resource for medical professionals. Calling it “The Bright Side Of Having Diabetes During COVID-19,” she writes: “It is vital to our diabetic population to control what they eat, when they eat, how much they eat, and to know how to monitor their blood glucose before and after eating.”
Eating patterns, physical activity, and constant blood glucose monitoring were found crucial in improving the health of people with diabetes during the pandemic.