Blood sugar, also known as blood glucose, plays a crucial role in our body’s energy management. It serves as a source of fuel for our cells and is regulated by the hormone insulin, which helps transport glucose from the bloodstream into cells.However, not all foods affect blood sugar levels in the same way. The glycemic response, or the change in blood sugar levels after consuming food, can vary significantly among individuals, even when consuming the same type of food. This article explores the variations in how specific foods can spike blood sugar levels in different people.
Why glycemic index only tells part of the story
The Glycemic Index (GI) is a measure used to rank how quickly and how much a carbohydrate-containing food raises blood sugar level. It is based on a scale from 0 to 100, with higher values indicating a faster and larger increase in blood sugar levels. Foods with a high GI, such as white bread and sugar-sweetened beverages, are quickly absorbed and can cause a rapid spike in blood sugar levels, while foods with a low GI, such as most fruits and vegetables, are absorbed more slowly and cause a slower, more gradual increase in blood sugar levels.
While the GI can provide a general indication of how a food may affect blood sugar levels, it is important to note that individual responses can vary widely. Several factors can influence the glycemic response of an individual to a particular food, including genetics, gut microbiota, physical activity level,stress, sleep patterns, and overall health status.
For example, a study published in the American Journal of Clinical Nutrition found that the glycemic response to white bread varied by up to 104% among individuals, with some participants experiencing a much larger increase in blood sugar levels compared to others (Wolever et al., 2018). Another study published in the European Journal of Clinical Nutrition reported that the glycemic response to a high-GI meal varied by up to 57% among healthy individuals (Meng et al., 2018).
Exploring the level of variation
Further, a study published in the journal PLOS ONE found that the glycemic response to a standardized meal varied by up to 40% among individuals, even after controlling for factors such as age, body mass index (BMI), and insulin sensitivity (Nielsen et al., 2017).
Most importantly, there were many cases where a participant would have a higher spike to one food (i.e. bananas) compared with the majority of the population and a lower spike than the majority for another food (i.e. cookies). The image below illustrates an example for two participants with high-glucose foods.
How genetics affect your blood glucose
Our genes can have an impact on how our bodies handle sugar. Scientists have found that differences in our genes can affect how our bodies process and respond to the sugar in the food we eat. Research has shown that certain genes that affect how our bodies use insulin are linked to how much our blood sugar went up after eating high-sugar foods (Ehehalt et al., 2018).
Insulin response to food is a complex process that can be influenced by various factors, including genetics, gut microbiota, hormonal regulation, and individual metabolic differences. Even if two individuals have similar insulin sensitivity rates, they may still exhibit different insulin responses to the same food due to several reasons outlined below.
Differences in gut microbiota
Your gut can have a major impact on how your bodies respond to food. Gut microbiota refers to the billions of microorganisms that live in our digestive tract. These microorganisms help break down food and can affect how our bodies absorb nutrients.
Recent research has shown that the composition of gut microbiota can vary widely between individuals and that these differences can influence insulin sensitivity and secretion. Some studies suggest that certain types of gut microbiota may lead to a more significant insulin response to certain foods, which can affect how our bodies manage blood sugar levels.
For example, studies have shown that individuals with obesity or type 2 diabetes often have a different gut microbiota composition than those without these conditions. It’s thought that the gut microbiota may contribute to insulin resistance, a condition where the body’s cells become less sensitive to insulin and are less able to use glucose for energy.
Some research has also suggested that making changes to our gut profile, such as through diet or probiotics, may help improve insulin sensitivity and blood sugar management. However, much more research is needed to fully understand the link between gut microbiota and blood sugar management.
Understanding the metabolic aspect
Lastly, each person has a unique metabolic profile that can influence their insulin response to food. Factors such as body composition, physical activity level, stress levels, and sleep patterns can all affect insulin sensitivity and secretion, leading to differences in how the body responds to specific foods. Furthermore, your overall health status, including conditions such as prediabetes, type 2 diabetes, and metabolic syndrome, can affect glycemic responses. People with pre-diabetes or diabetes often have impaired insulin sensitivity and may experience higher blood sugar levels after consuming high-GI foods compared to those with normal blood sugar regulation. Metabolic syndrome, a cluster of conditions that includes high blood sugar, high blood pressure, and obesity, can also affect glycemic responses.
Ready the study: https://www.cell.com/fulltext/S0092-8674(15)01481-6