What Does Eating Sugar Do to Your Health and Immunity?

This time of year is a marker of sorts: it’s the beginning of a holiday season full of sweet temptations and loads of comfort foods, coupled with the start of cold and flu season. This year, though, the cold and flu season is different from any other we’ve known because of the additional threat of COVID-19, with experts already advising us to “hunker down” through the next few months. But what does the season of sweets and treats have to do with the cold and flu season, or more specifically, how you weather cold and flu season? It all has to do with blood sugar.

When most people think of blood sugar dysfunction, they think of type-2 diabetes, but that is just the end result of many years of chronically elevated blood sugar. There’s a spectrum of blood sugar dysfunction, and the damage to your body starts even when your blood sugar consistently stays at the high end of “normal.” Simply put, high blood sugar is very bad for your health.

Eating Sugar and Your Immunity

Good Health & Immunity Start with Balanced Blood Sugar

Keeping blood sugar, or glucose, balanced is so important to health that our bodies have a tightly regulated system to ensure levels stay within a narrow range. When you eat sugary foods and simple carbohydrates (like bread, pasta, or french fries), they are rapidly digested and converted into glucose, leading to sharp spikes in blood sugar. The pancreas responds by releasing a surge of insulin, which directs the glucose into cells and lowers blood sugar levels back to a normal range. When sugar and/or refined carbs are occasionally consumed in small amounts, this is an effective system. But when these types of foods are regularly consumed, the body is constantly fighting to keep blood sugar levels in a normal range by continually pumping more insulin into the bloodstream. Overtime, the cells stop responding to insulin (i.e., insulin resistance), the first step toward developing type-2 diabetes. This leads to chronically elevated blood sugar and insulin levels, which damages proteins in the body and leads to major inflammation and oxidative damage, underlying factors in almost all chronic diseases. In fact, chronically elevated blood sugar increases the risk for type-2 diabetes, Alzheimer’s, depression, cardiovascular disease, and even some types of cancer. 1 2 3 4 5 6 7 8 It also leads to a poorly functioning immune system.

Keeping your blood sugar levels in a healthy range determines how well your immune system is able to mount an attack against all types of pathogens, whether viral or bacterial. Chronically high blood sugar causes major dysfunction in both innate and adaptive immunity, and research has found that some viruses and bacteria are “better nourished and become more virulent” in the presence of high blood sugar, which provides them with a better environment to cause infection in the first place.And we have seen with COVID-19 that people with type-2 diabetes are at an increased risk for severe illness or even death.10 11 12 13 14 Even if you are an overall healthy person, if you eat sugar when you are sick, or are first starting to feel sick, that sugar will undermine your immune response, in part because glucose blocks vitamin C from entering your cells, and vitamin C is a critical immune-supportive nutrient, especially during acute infection.15 When you maintain healthy blood sugar levels, you also support the optimal functioning of your immune system.

How to Achieve Healthy Blood Sugar Balance…You Are What You Eat

The good news is that you are in charge of your own blood sugar! Blood sugar is directly related to what you eat, so by shifting away from a diet built on a foundation of grains, starchy fried foods like potato chips and french fries, sugary sodas and coffee drinks, and baked goods and sweets, to a lower carb diet built around an abundance of low-starch vegetables, healthy fats, and protein, you can get your blood sugar under control, and keep it that way. Most of us eat an excessive amount of carbohydrates—more than our bodies need, or can handle, which causes dramatic spikes in glucose and insulin. To maintain healthy blood sugar aim to get between 100 and 150 grams of carbs each day (the average American eats between 350 and 600 grams of carbs each day, mostly in the form of refined, processed sugars and grains).16 17 If you work to get the majority of your carbs from non-starchy vegetables and a small amount of higher-carb foods like beets, potatoes, and carrots, you will easily fall into this range. Add in healthy fats and a small amount of protein each meal, and you’re on your way to healthy blood sugar balance. When you approach eating in a way that maintains healthy blood sugar balance, then an occasional indulgence—sweet treats included—shouldn’t be a problem.

Supplements for Blood Sugar & Immune Support

While diet is vital for maintaining healthy blood sugar balance, there are also some key supplements that will give you extra support. The advantage of these supplements is that many of them are foundational nutrients that, in addition to maintaining healthy blood sugar balance, will promote overall health and immune competence, as well as reduce inflammation and oxidative damage in the body.

B-complex vitamins

This family of vitamins is intricately tied to cellular energy production via their role in metabolizing carbohydrates and complex sugars. When you eat an excess of grain-based carbs your body quickly burns through the B vitamins to keep up, which can drastically deplete levels. When these important cofactors are missing, blood sugar imbalances can occur. A B-complex vitamin is a foundational supplement that also supports general health, overall immune competence, and mental wellbeing.18


This important mineral plays a key role in regulating insulin activity and cellular glucose uptake, and low magnesium levels can worsen insulin resistance. Additionally, low magnesium intake has been associated with the development of type-2 diabetes and metabolic syndrome, while supplementation with the mineral has been shown to improve fasting and post-prandial glucose levels (glucose levels after eating) and insulin sensitivity, as well as decrease markers of inflammation in those with prediabetes. It is estimated that at least half of all Americans don’t get enough magnesium through diet, making supplementation necessary.19 20


This mineral is essential for normal carbohydrate metabolism and research has found that supplemental chromium has significant beneficial effects on HbA1c (a marker of long-term blood sugar levels) and glucose and insulin levels. Chromium also plays a role in modulating the immune response, that is, it ensures that the immune system neither under- or over-reacts to pathogens.21 22


Another important mineral for blood sugar balance, zinc plays a role in insulin signaling, helping to regulate blood glucose levels. One trial showed that zinc supplementation lowered blood glucose and cholesterol levels in prediabetics, as well as reduced the number of people who progressed to full-blown diabetes.

A meta-analysis of 32 studies, involving 1,700 participants, concluded that zinc supplementation can improve blood glucose control in both prediabetic and diabetic patients. Zinc is also a critical mineral for both innate and adaptive immune system function and even moderate deficiencies can increase the risk of viral infection.23 24 25 26

Alpha-lipoic acid

One of this antioxidant’s important roles in the body is to support insulin function and research has shown that supplementation significantly decreases fasting glucose, insulin, insulin resistance, and HbA1c in diabetics in a dose-dependent manner, that is, higher doses led to more significant decreases (daily doses ranged from 300 to 1,200 mg). It’s also been found to reduce triglycerideand LDL cholesterol levels, and through its powerful antioxidant actions, reduce oxidative damage caused by chronically high blood sugar.27 28


Research has shown that the plant extract berberine lowers fasting glucose and insulin levels, post-prandial glucose, HbA1c, and triglycerides. It improves insulin resistance, inhibits glucose production in the liver, and stimulates the breakdown of glucose. Berberine also has anti-inflammatory, antioxidant,and antimicrobial properties and supports mitochondrial health, another key component for overall health. 29 30 31 32 33

One of the most important things you can do for both your short-term and long-term health is to get your blood sugar under control. It is absolutely vital for your body to be rooted in health and to remain resilient against infection. And it’s in your power to do it—aim to eat a low-carb diet most of the time so you can enjoy those moments of indulgence, and incorporate some key supplements that will give you the extra support you need over the long term. Do this and you’ll increase your chances of staying healthy and vibrant, not just through the winter months, but for years to come.

References available upon request.