How diabetes causes the immune system’s defence against infection to malfunction

Shortly after the SARS-CoV-2 virus started its rapid spread around the world, one of the first conclusions drawn was that those individuals with co-morbidities, particularly diabetes, were at far greater risk of developing severe infection. COVID-19 aside, diabetes, which occurs when a person’s pancreas doesn’t produce enough insulin to control the amount of glucose, or sugar, in their blood, is a chronic condition. In December 2021, the International Diabetes Federation published the 10th edition of their Diabetes Atlas which stated that diabetes ranks among the top 10 causes of mortality globally. This article by Dr Hassina Kajee of The Noakes Foundation looks at a healthy immune system’s three levels of defence against infection and explains how patients with Type 2 diabetes have malfunctions in all of them. Fortunately, there’s a sparkling silver lining. In BizNews interviews with Professor Tim Noakes and Dr Mark Cucuzzella, Dr Tro Kalayjian and Dr Eric Westman, (both interviews embedded below), all four trailblazing experts definitively stated that Type 2 diabetes is reversible. – Nadya Swart

Diabetes and its effect on the immune system

By Dr Hassina Kajee*

The pandemic of diabetes has slowly and steadily increased as human beings overload our bodies with unnaturally and excessively high levels of carbohydrates.

For many years, Prof Noakes and The Noakes Foundation, as well as many professionals all over the world, including Dr Neville Wellington and myself locally along with team Eat Better South Africa and more recently Nutrition Network, have spent many hours trying to increase awareness globally with an aim to prevent new cases and reverse existing cases of Type 2 Diabetes. Prof Noakes has and continues to donate his personal funds and much of his private time towards this goal. When we founded the Nutrition Network, it was in order to continue on this pathway of global education and networking. When we founded Eat Better South Africa, it was in order to convert that education to a practical way of life for those who aspire to better health and to continue to empower through education. We believe in the intelligence of the public and continue to maintain that prevention is better than cure.


A healthy immune system is our best defence against infection. A healthy immune system is one in which all components of the system function optimally. The healthy immune system starts with strong and intact physical barriers. The next level of the immune system is our first line soldiers and defenders. Those cells and chemicals that keep us safe and start attacking and defending as soon as a barrier is breached by an organism. The third line of defence in a healthy immune system consists of cells that are specific to targeting the organism that is being faced. When the body faces an organism that it has previously faced, the response is specific and swift. However, when the body faces an organism that is novel, as is the case with SARS-CoV2, the body must take more time to make antibodies specific to that virus. Hence the need for an optimally functioning immune system.

Unfortunately, patients with Type 2 diabetes have malfunctions in all three levels of the immune system. Not only that, but obesity and Type 2 diabetes are pro-inflammatory conditions that worsen the severity and clinical expression of symptoms of COVID-19.


It is well known that prolonged uncontrolled blood glucose results in extremely harmful by-products called ‘advanced glycation end products’ (AGEs) and other products that are associated with oxidative stress. This can and does result in small vessel damage and damage to nerves that causes disruption of the first immune barrier. The side effects of diabetes due to build-up of these products are well known as diabetic neuropathy (diabetic foot), diabetic retinopathy, diabetic nephropathy.

Diabetes can also result in multiple defects in both the second and third line of defence in the immune system. These defects include abnormalities in macrophages, neutrophils, natural killer cells (NKCs), cytokines, complement, as well as T and B-cell dysfunction.


In addition, diabetes and obesity are chronic inflammatory states that result in many pro-inflammatory genes, growth factors and harmful modulators being switched on.

The good news is that many of these defects normalise as the blood sugar normalises. We see these improvements routinely when people adopt a low carbohydrate diet. They’re routinely reflected as a lower hs-CRP which is a great indicator that inflammation is lowering. We see this improvement routinely in our patients enrolled in The Eat Better South Africa program.

If you are already on a well formulated low carbohydrate diet, I would like to encourage you to continue to do your very best to eat for the health of your body.

If you are struggling to stay on plan, I hope this information will encourage you to get back on plan. Try to do your very best to use this time to improve your health and support your own ‘built-in’ artillery. If you look after your body, it will look after you.

Wishing you the very best in this time and beyond.

References (click title to view article):

*Dr Hassina Kajee is co-founder and Medical Director of The Noakes Foundation ‘Eat Better South Africa’ program. She turned her clinical practice towards chronic disease prevention after years of practising ‘palliative’ chronic medicine at the tertiary level where she headed up the High Care Unit at Groote Schuur Hospital. 

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