Around one million people in the UK have undiagnosed type 2 diabetes (T2D); 42% of people with T2D do not receive annual health checks; and the NHS spends at least £10 billion annually on diabetes – equivalent to 10% of its budget – with 80% spent on treating complications (Whicher et al, 2019). However, as the Parliament of Western Australia (2019) reports, T2D ‘can go into remission and it need not be a life-long progressive chronic illness. Some practitioners argue it is reversible.’ Such reversal can be attained through low-carbohydrate or carbohydrate restricted diets. Thus, Hallberg et al (2019), for example, note that before insulin's discovery in 1921 low-carbohydrate diets were commonly prescribed for diabetes, and low-carbohydrate diets can reduce reliance on anti-glycaemic medications like insulin while conferring improvements in glycated haemoglobin (HbA1c), weight, inflammation and cardiovascular risk factors (Athinarayanan et al, 2019; Unwin et al, 2019).
T2D and depression
But what about the mental aspects of T2D? Adams et al (2022) cite evidence showing that depression is more common among individuals with T2D than those without T2D, and that insulin therapy is associated with increased risk for depressive symptoms in T2D. While acknowledging that carbohydrate restriction can treat T2D effectively, Adams et al (2022) investigated how its long-term impacts influenced depressive symptoms. They explored changes in depressive symptoms over 2 years among 262 primarily non-depressed T2D patients participating in a continuous remote care intervention that emphasised carbohydrate restriction. Subclinical depressive symptoms reduced over the first 10 weeks, with these reductions maintained for up to 2 years. Further, increased frequency of blood ketone concentrations that indicated adherence to a low-carbohydrate diet ‘predicted decreases in depressive symptoms’ (Adams et al, 2022). Addressing concerns that restrictive diets might exert potential negative impacts on quality-of-life factors such as mood, the authors concluded that their results ‘support positive rather than negative long-term impacts of closely monitored carbohydrate restriction on depressive symptoms’ (Adams et al, 2022).
Psychological impact of T2D
When Mantantzis et al (2019) undertook a systematic review and meta-analysis to evaluate the relationship between acute carbohydrate ingestion and mood, their findings challenged ‘the idea that carbohydrates can improve mood and might be used to increase the public's awareness that the “sugar rush” is a myth, inform health policies to decrease sugar consumption, and promote healthier alternatives.’
This view is endorsed by Southport-based chartered clinical and health psychologist Dr Jen Unwin (Twitter @jen_unwin), who has addressed the challenge of food addiction (Unwin, 2021) and helped organise an international conference on Food Addiction on 20 May 2022 in Bristol, under the auspices of the UK's Public Health Collaboration (https://phcuk.org/phc-conference-2022/).
What is her experience of the psychological impact of T2D on the patients she deals with? T2D, Dr Unwin told Practice Nursing, is often linked with psychological difficulties such as ‘foggy brain’, low energy and low mood: ‘The question is whether the T2D is causing these issues or whether there is a third common denominator? In our work in primary care helping people to reverse their T2D drug-free, we have focused on supporting people to lower the sugar and refined carbohydrates in their diets, just like the patients studied by Adams et al (2022).’ Dr Unwin has seen some remarkable transformations in terms of mental health from this intervention, ‘including people coming off medications such as antidepressants and reporting improved memory, energy and mood. There is plenty of evidence now for the damaging effects of sugar and processed foods on the brain.’
One mechanism directly linked to mood, explains Dr Unwin, relates to dopamine: ‘Sugar consumption leads to the release of high concentrations of dopamine in the brain. Dopamine is linked to motivation, and the brain responds to high concentrations of dopamine by “down regulating” dopamine receptors. Less dopamine becomes available over time if this process is repeated. There is a similar process at play for serotonin, the “feel-good” neurotransmitter. A vicious cycle can ensue of cravings, sugar consumption and worsening mood.’
‘Some patients experience a significant improvement in their mental health in tandem with an improving HbA1c.’
T2D and mental health in primary care
Somerset GP Dr Campbell Murdoch (Twitter @CampbellMurdoch) is a clinical advisor to the Royal College of General Practitioners and co-founder and medical director of the Preventative Healthcare Group (www.preventativehealthcare.co.uk/). He explains that physical and mental health are linked, and that T2D diabetes isn't just a problem of blood glucose and physical health: ‘Depression can be a contributor and a consequence too. Effective management of T2D needs to take a biopsychosocial approach. In my GP work some patients experience a significant improvement in their mental health in tandem with an improving HbA1c. I think this is due to a combination of the sense of hope and control they gain when they make effective lifestyle changes, as well as a possible direct benefit of the physiological changes on their mental health.’
What advice would Dr Unwin give health professionals working in primary care in relation to how they deal with the psychological aspects of T2D on their patients? ‘I would start by informing patients that sugar, refined carbohydrates, and ultra-processed foods upset the balance of the motivation and happiness chemicals in the brain. Encourage patients towards a real food diet with good protein and healthy fats.’ Dr Unwin also emphasises that changing how we eat can be difficult in today's food environment, but the effects can be dramatic: ‘Some form of regular support can really help, and there are plenty of resources available. It's a hopeful message to patients that they can both improve their T2D and feel better psychologically by making some changes to their daily routine.’
Finally
With a mounting evidence base that supports the effectiveness of lifestyle changes and low-carbohydrate diets in addressing the challenges of T2D, it is interesting that Adams et al (2022) cite evidence not only suggesting that intensive medication treatment for T2D may have a negative effect on patient mood and well-being, but also that ‘intensive treatments are often less preferred by patients who commonly value reduced need for medication as an outcome of successful diabetes management.’ It seems that an era of effective medication-free T2D management is approaching.