Insulin is essentially the ‘key’ that opens the doors to allow glucose from the bloodstream into our cells. In the case of insulin resistance, the ‘keys' have stopped working, and some of those doors aren’t opening any more. As a result, the glucose isn’t able to get into our cells, meaning our blood glucose levels stay high: hyperglycaemia. Hyperglycaemia is damaging to nerves, blood vessels, tissues and organs. Over time this can develop into diabetes, which is also associated with an increased risk of heart attack and stroke - all good reasons to improve insulin sensitivity to ensure long-term metabolic health.
A common mediator of insulin resistance is diet. When there is an over- consumption of refined carbohydrates such as bread, pasta, and quickly absorbed sugars from things like juices, junk food and flour-based products, our cells slowly become resistant to the effects of insulin. Initially, the pancreas will just make more insulin to meet the demand, until it tires and can’t keep up. Left unchecked, this is the path to the development of insulin resistance, and potentially also metabolic syndrome and type 2 diabetes.
High insulin levels are a warning sign, as is the development of central obesity, fatigue after meals, sugar and carb cravings, high blood pressure and increasing inflammation.
Central adiposity is also an important mediator of insulin resistance. As a metabolically active endocrine organ, fat secretes hormones and inflammatory cytokines
such as IL-6 and TNF- α. TNF-α has been shown to be part of the causation pathway for insulin resistance. Insulin resistance is intrinsically an inflammatory condition. Elevated levels of inflammatory cytokines can predict future weight gain, which then further contributes to insulin resistance. Hyperglycaemia leads to glycation, a process where a sugar molecule binds to a protein or a fat, which in turn leads to the formation of advanced glycation end-products (AGEs). AGEs are highly inflammatory, further adding to the picture of inflammation that drives insulin resistance.
It is also important to understand the impact of lifestyle choices on blood sugar regulation. Chronic stress is associated with the development of insulin resistance, and research shows that even partial sleep deprivation over one night can cause and increase in blood sugar levels.
Better sleep habits are an effective and important way to regulate cortisol levels. Physical inactivity is also a risk factor, with research indicating that as little as 30 minutes of moderate walking three to seven days per week for six months can alone reverse insulin resistance.
Patients understanding of sugar is often limited to the idea that the obvious sources of sugar like coca cola or chocolate bars are the only thing causing their insulin resistance. Educating clients on the effect of refined carbohydrates on blood sugar, as well as give them lists of foods that fall into this category, and ideally, providing them with suitable alternatives, should be a priority when discussing insulin resistance with a patient.
Out-of-date ideas about which foods will keep your blood sugar in check are still common, with many patients believing that wholemeal bread, store-bought granola and oatmeal are healthy choices, whilst in reality, the effect these foods have on blood sugar can be catastrophic for those with insulin resistance.
In addition to improving sleep quality, reducing weight and reducing stress, there are several other ways to improve insulin sensitivity. Exercise is known to increase insulin sensitivity, with both cardio and resistance training offering benefits lasting up to 48 hours after exercising.
Increasing the amount of soluble fibre in the diet is associated with improved insulin sensitivity, as well as with lowering cholesterol and reducing appetite.
Increasing dietary polyphenols and antioxidants has been associated with improved sensitivity to insulin, though fruit should be limited to 2 or three servings a day, ideally of lower- sugar fruit such as berries and citrus fruits. Low-glycemic carbs are best, and refined carbohydrates should be avoided. Other foods associated with improved insulin sensitivity include cinnamon, green tea and apple cider vinegar.
A personalised approach that combines both dietary interventions and lifestyle elements is key, because the mediators of insulin resistance can vary significantly from patient to patient.
Insulin resistance may be preceded by changes in liver and cholesterol panels. Blood pressure and triglyceride levels may be high, even before HbA1c is affected.
The Basic Metabolic Bloodspot Test is a simple bloodspot test that can identify blood sugar dysregulation markers and assess cholesterol breakdown.
The panel includes fasting insulin, high sensitivity CRP, as well as HbA1c, triglycerides, and cholesterol markers.
The GENIE Test is another option to assess insulin resistance. GENIE is a transcriptomics test that considers 20 different categories of gene expression. The second category of the report covers genes relating to insulin resistance, including IGF1R, IGF2BP2, IGF2R, IGFLR1 and IRS2, which all play a role in mediating the control of various cellular processes by insulin. The test also includes genetic expression of cytokine activity such as that for TNFa.
Finally, The Cleveland Heart Lab Metabolic Test gives a well-rounded picture of the level of inflammation (Lp-PLa2, hdCRP and OxLDL), as well as lipids (including ApoB/ApoA1 ratio), and metabolic markers including insulin, HbA1c, TMAO and Adiponectin, among many other useful markers.
If you’d like further advice on choosing the right test for your client, we’re a happy to help - drop us an email here.