Metabolic syndrome describes the combined effect of abdominal obesity, high glucose, high cholesterol and high blood pressure. Over a five to ten year period, these factors double the risk of developing cardiovascular disease and quintuple the risk of developing type 2 diabetes. Lifestyle factors, such as a poor diet and physical inactivity are common causes, however there are many others. Within psychiatry, psychotic disorders and the medications used to treat them are also attributable. For these patients, an important question arises; is metabolic syndrome inevitable or can lifestyle interventions, such as a plant baseddiet, be used to lessen the impact on the health?
There are a number of psychotic disorders, the most common being schizophrenia. In its chronic state, it’s association with metabolic syndromewas originally thought to be due to the use atypical anti-psychotic medications, such as olanzapine. Increased hunger, cravings for high sugar foodsand decreased satietylead to the consumption of more processed foodand those with high sugar and fat content. This is compounded by less favourable eating patterns and physical inactivity.
Interestingly, in a recent lecture that I attended by Dr Adam Joiner, consultant psychiatrist, new evidence was presented suggesting the disorder itselfis also implicated. A recent systematic review and meta-analysiswas highlighted showing that at first presentation of psychosis, levels of serum triglycerides are high. Interestingly, triglycerides are known to cause glucose dysregulation, which is a feature of type 2 diabetes.This could suggest shared biological mechanisms behind schizophrenia and metabolic syndrome. Additionally, cholesterol levels (total cholesterol and low-density lipoprotein) were also found to be low at this early stage. The rise in cholesterol throughout the disease course could therefore be modifiable and more importantly, amenable to intervention.
To combat the multi-factorial concept of metabolic syndrome in psychotic disorders, it is important that lifestyle factors, such as diet and physical activity are addressed. The National Institute of Clinical Excellence (NICE) recommends that these are monitored at each annual review, alongside weight, waist circumference and serum glucose and lipids. Early interventions aimed at patients with first presentation of psychosis are recommended, with a key focus on prevention.Healthy Active Lives(HeAL) is an example of a UK initiative challenging the perception that poor physical health is inevitable and focuses on lifestyle factors at every possible opportunity.
There is ongoing research into the optimum diet to prevent metabolic syndrome in psychotic disorders. The DASH diet(Dietary approaches to stop hypertension) has been widely researched, and consists of fresh fruit and vegetables, whole grains and lean meats. Whole food plant-based diets, with little or no animal products are also gathering research interest and have been shown to significantly reduce weight, cholesteroland insulin resistance. This effect is only evident in healthy plant-based dietsi.e. not those consisting of nutrient sparse, processed foods and has recently been shown to be independentof energy intake restriction and physical activity.
The emerging knowledge base is promising for the health of people with psychotic disorders. However, there are limitations of the research itself and its clinical application. Research participants are often not blinded to the lifestyle intervention being studied, which can cause performance biasand act as motivationfor behavioural change. Long term behavioural change is uncertain, owing to the loss of incentive and lack of accountabilityand it is also argued that factors intrinsicto serious mental illness, such as social isolation and fatigue, are important. This is not to say, though, that these factors impose an absolute barrier to lifestyle interventions in psychotic disorders.
So I ask the question again, is metabolic syndrome in psychotic disorders an inevitability? Or can evidence based, appropriately timed lifestyle interventions prevent or at least slow the development of metabolic syndrome? The life expectancy of people with schizophrenia and other serious mental health illnesses is currently 20 years lessthan the general population and in my opinion, this warrants a change in current practice.