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How Genetics Affect Blood Sugar Spikes

Article at a Glance
  • Genetics has been observed to play a critical role in regulating blood sugar levels and the occurrence of blood sugar spikes.
  • In fact, large scale studies have shown that as much as 50% of the post-meal blood sugar response is genetic.

The human body digests and breaks down the carbs we eat, and sometimes even the protein we eat, into glucose, the preferred energy source for our cells.

Blood sugar spikes” occur when blood glucose levels rise after we consume carbohydrates. Although the spike in blood sugar levels is a natural response, excessive or prolonged spikes can harm health, especially for those with diabetes.

Although genes aren’t the whole story, genetics have been shown to play a big role in how each of us respond to eating carbohydrates.

In this article, we will explore the relationship between genetics and blood sugar spikes in detail and understand how our genes can influence our blood sugar levels. We will also discuss possible strategies that can be employed to help control blood sugar levels, especially in individuals predisposed to blood sugar imbalances due to their genetic makeup. 

Accurately measuring blood sugar spikes is elusive

Research from Stanford University School of Medicine1 shows that our traditional methods for monitoring blood sugar levels, like finger-pricking, may be missing several key spikes in glucose.

A device, called a continuous blood glucose monitor, that tracks glucose levels more closely reveals that the amount circulating in an individual’s blood often fluctuates rapidly and significantly – especially in healthy individuals after consuming certain carbohydrates.

To understand spiking, these researchers conducted a sub-study in which 30 individuals alternated between three meals: cornflakes with milk, a peanut butter sandwich, and a protein bar. To the shock of the researchers, more than half of the participants who tested as “healthy” beforehand had glucose levels similar to those of individuals who were prediabetic or diabetic.

Further research into the causes of such variations revealed that genes, the microbiome, and epigenetics were essential components to understanding dysregulation and specific foods that lead to spikes.

To focus more on genetics, I will discuss a trial that used a more in-depth approach and looked at how individuals metabolize multiple nutrient sources.

The personalized responses to dietary composition (PREDICT 1) clinical trial

The study ‘Human postprandial responses to food and potential for precision nutrition‘ published in Nature Medicine 2 is a review of the importance of understanding individual responses to food to achieve precision nutrition.

Precision nutrition is the concept of tailoring diet and lifestyle recommendations to an individual’s unique genetic, environmental, and lifestyle factors.

In the study, the authors discuss the importance of postprandial responses to food, which refer to the physiological changes that occur in the body after eating a meal.

These responses can vary greatly among individuals, even when consuming the same meal. This variability can have significant implications for health outcomes, such as weight gain, metabolic diseases, and inflammation.

This study enrolled 1,002 healthy adults, which included twins, from the United Kingdom. They were all given identical meals and then assessed for their responses to fats, carbohydrates, and protein. They tested 32 genetic mutations in several genes to see if their presence was linked to higher or lower levels of each of the nutrients.

The results showed that these mutations collectively explained approximately 9% of the observed variation in glucose and less than 1% of the variation for fat and protein, indicating that genetics had the greatest effect on glucose metabolism.

Another interesting finding was that a person’s response to the same meals was often similar and therefore predictable. This is important because it suggests that once an individual’s response to specific foods is known, their response to other foods could be determined, which allows us to take advantage of precision nutrition.

This study also determined whether a person is a high or low responder to all meals, but also that there are meal-specific responses unique to each individual. The researchers suggest that possible explanations for this include individual genetic differences in the ability to digest high-starch meals. As an example, a study published in CELL reported an example in which one participant had an exaggerated glucose response to a banana but not to a cookie, whereas the second participant had the opposite response.3

Finally, the study also highlights the use of personalized nutrition technologies, such as continuous glucose monitoring and wearable devices, as tools for assessing an individual’s postprandial responses to food. By monitoring these responses, personalized nutrition can be tailored to optimize an individual’s health outcomes.

Foods that cause spikes in your blood glucose are not what you think!

It’s widely known that consuming sugary food items such as pastries or candies can cause an increase in blood glucose levels, a possible risk factor for the nearly 50% of Americans with prediabetes or diabetes. However, it’s important to note it’s not just sweet-tasting foods that can cause this spike; even non-sweet foods that contain carbohydrates have the potential to do so.

Doughnut vs. Bagel

When making breakfast decisions, doughnuts versus bagels can be a challenging choice. Doughnuts are known for their sugar and fat content, but swapping for bagels may not be the healthiest option either. Dense carbohydrates like those found in starchy foods such as bagels can cause blood sugar to spike more than in sweet snacks like doughnuts. Therefore, while avoiding sugary food is beneficial to one’s health, it is important to also limit high-carbohydrate foods that can significantly raise glucose levels – essentially how much sugar enters your bloodstream at once.

White potatoes

These have a much higher glycemic load than other vegetables, and even more so when served warm. As an alternative to potatoes as a side dish, beans or cauliflower rice are much lower in glycemic load and offer a variety of key nutrients. Interestingly, chilled potatoes have a lower glycemic load than those served hot.

Sticky white rice

This staple food may seem innocent enough, but it can have a deceivingly high glycemic index. White rice contains very little fiber, unlike its whole-grain alternative, brown rice. Barley and farro are two more excellent alternatives that are nutrient-dense and don’t spike blood sugar levels. While whole grains are much better than refined grains, they should not be consumed in unlimited quantities since even large amounts of these can cause a drastic increase in glucose levels.

Did you know that exercise lowers blood glucose levels?

Besides the obvious ways of reducing your blood sugar, such as going low-carb, avoiding processed foods, and keeping a healthy weight, exercise, even moderate-intensity exercise can reduce your glucose levels.

The positive effects of exercise on blood sugar control have been well-documented. Studies have shown that the sensitivity of cells to insulin — a hormone used to regulate blood sugar levels — can be improved with both moderate- and high-intensity exercise.4 Furthermore, muscle cells may absorb extra sugar from the blood, thus reducing blood sugar levels.

Even when you’re exercising on an empty stomach, this could play a role in improving your blood sugar control. What’s more, increasing physical activity can aid in weight loss and provide another layer of protection against spikes in glucose levels.

Dr. Gina Leisching

Dr. Gina Leisching holds a BSc in Functional Human Biology, and Honours degree in Physiological Sciences, as well as a doctorate in human physiology from Stellenbosch University, South Africa. At Gene Food, Dr. Gina uses her expertise to provide evidence-pieces that readers may find helpful and informative.

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