Most of us associate blood glucose (or ‘blood sugar’) with diabetes, but does it matter if you’re not diabetic? Should fit and healthy people still keep an eye on their blood glucose levels? According to the science, the answer is a resounding yes.
In this blog, we’ll look at how even slightly elevated blood glucose levels or brief spikes can harm your health and longevity (regardless of whether you have diabetes), and discuss how you can keep your glucose metabolism in optimal condition.
Why glucose levels matter
Glucose is found in almost all food and drink. It’s your primary source of cellular energy, powering muscles, neurons, metabolism and everything in between. Your body is naturally pretty good at keeping glucose levels within the normal range (70-100 mg/dL or 3.9-5.6 mmol/L), but just being within the healthy (i.e. non-diabetic) range isn’t necessarily optimal for health and longevity. In the long term, even slightly elevated glucose levels negatively impact a huge range of physiological processes and worsen age-related decline, as we’ll discuss in this blog.
It’s not just about your overall blood glucose levels. Even if you are not diabetic and your overall average glucose levels are in the normal range, we are all capable of spiking our blood glucose to a momentary high after eating a specific food. Recent research is highlighting just how harmful these spikes can be is in the long term, even if your average glucose levels are still normal. Regular glucose spikes cause cardiovascular damage and increase the risk of premature death [1, 2], with evidence suggesting they’re actually MORE harmful to blood vessels than continuously elevated levels . It’s also been shown that this kind of damage occurs in many people who have normal baseline blood glucose .
Glucose metabolism and brain aging
Recent research has highlighted the central role that glucose plays in healthy brain aging. High blood glucose - both over an extended period and in the short-term spikes described above- damages small blood vessels in the brain and leads to vascular dementia , and type 2 diabetes patients are known to have a significantly increased risk of Alzheimer’s disease . Another study found that young adults who are at a high risk of developing Alzheimer’s disease due to genetic abnormalities show disrupted glucose metabolism across various brain areas, highlighting the importance of maintaining healthy glucose metabolism at any age .
Glucose metabolism and AGEs
Another harmful consequence of elevated glucose is the accumulation of advanced glycation end products (AGEs). AGEs are formed when excess glucose in the blood binds to proteins, fats or DNA through a process called glycation. They bind to receptors (RAGEs) found throughout the body and appear to trigger chronic disease and age-related decline . In fact, the AGE-RAGE interaction has been implicated in almost all aspects of the aging process, including degeneration of the brain, skin, cardiovascular system, kidneys, eyes and pancreas and muscles .
Glucose metabolism and quality of life
The health of your glucose metabolism has an acute effect on your day-to-day life too. Elevated blood glucose increases the risk of depression  and regular glucose spikes are associated with low mood . High amounts of glucose also impact the balance of your gut microbiome and circulating hormones, leading to further negative mood impacts [12, 13, 14], and glucose dysregulation has recently been shown to cause sleep disturbances . Controlling your glucose levels and minimizing glucose spikes will also reduce sugar cravings and overall hunger [16, 17].
Glucose metabolism and vision
Excess glucose in the bloodstream causes damage to the walls of blood vessels. The smaller the blood vessel, the more damage the sugar molecules can cause, and so the tiny blood vessels in the eyes are particularly at risk. Even slightly elevated blood glucose levels (still well below the levels associated with diabetes) are linked to an increased risk of retinopathy, which can lead to blindness [18, 19]. Glucose dysregulation also plays a role in macular degeneration, another cause of age-related vision loss .
Challenge yourself to optimize your glucose metabolism
This month, we’re encouraging you to optimize your blood glucose by trying out our science-backed tips below:
- Do light exercise after meals: Light exercise after eating reduces the size of glucose spikes by up to 25%, with the most benefits coming from a 30-minute walk or longer .
- Implement an intermittent fasting regime and regular extended fasts of over 24 hours: This greatly benefits glucose metabolism by allowing your body’s glucose control mechanism to regularly rest and reset [22, 23].
- Break your fast with protein or fat, then have carbs later: Eating protein or fat followed by carbohydrates results in far smaller glucose spikes than the other way round [24, 25], and eating a high protein, low carbohydrate breakfast results in less hunger later in the day .
- Engage in regular cold exposure: Cold exposure - through cold plunges or winter swimming, for example - improves glucose metabolism by increasing insulin sensitivity .
- Assess the health of your glucose metabolism with a continuous glucose monitor (CGM): Wearing a CGM enables you to measure your average blood level as well as the magnitude and frequency of glucose spikes, which can help you determine the effect of particular foods or aspects of your lifestyle on your blood glucose.