Sugar and Your Immune System

We all know too much sugar is bad for us. Sugar promotes obesity, diabetes, heart disease, tooth decay, skin aging, and a host of other ailments. It increases the risk of depression, rheumatoid arthritis, and kidney failure, just to name a few. And, concerning especially during cold and flu season, eating sugar suppresses the immune system.

Or does it?

Is Flu Season Made Worse by Sugar?

Doctors and scientists agree with all but the last point. For many years (since the 1970s), the prevailing belief has been that sugar suppresses the immune system for several hours after consumption. It seemed mighty unfortunate that flu season aligned with a period of increased sugar consumption (starting with an abundance of Halloween candy and lasting throughout Christmas and New Year festivities). Are people more apt to get the flu during this time simply because everybody is binging on sweets and unhealthy carbs, resulting in lowered immunity?

While that certainly seems to make sense, it doesn’t tell the full story. 

The Immune System is Complex

Sugar does indeed impact the immune system. It affects the entire body. We can’t say that it is the main determinant of whether you will come down with something, though. The 1973 study was compelling and likely has truth to it, but as most studies go, it was also limiting in what it could test to replicate the complexities of the human body.

But we do now have reason to believe that after you get sick, sugar appears to act in different ways. Which means condemning sugar as “immune system enemy #1” may be too much of a generalization.

“Starve a Fever, Feed a Cold”?

In 2016, researchers at Yale conducted an eye-opening study on mice that led the researchers to conclude sugar can be either harmful or helpful depending on what type of infection it is up against. 

  • For the bacterial infection, sugar was lethal to the mice.
  • For the viral infection, sugar helped the mice survive

In the mice, the bacteria needed to be starved of sugar in order to activate their bodies’ fasting metabolism that allowed the body to recover. However, the virus required the exact opposite, needing glucose to equip the body to function appropriately. 

While a single study conducted on mice cannot be blindly applied to humans, it does raise important questions about the role of sugar on our immune systems. What you eat controls what nutrients are available to your cells, and sometimes cells need glucose. The old saying “starve a fever, feed a cold” may have a little truth to it.

Sugar: Just What the Doctor Ordered…?

That doesn’t mean when you have the flu (a viral infection), you should only eat bowls of ice cream covered in chocolate syrup. Unhealthy sugars are going to be unhealthy even when you’re sick. Sugar (glucose) also comes from fruits, veggies, and carbs — so a bowl of chicken noodle soup or some applesauce (without added sugar!) could be just what your body needs.

When you’re sick, it’s generally best to rely on your body’s own signals. If you’re hungry, eat. If you’re not, don’t. Drink lots of fluids, like water and green tea, and rest.

Eat Smart All Year Long

Good nutrition keeps us from getting sick and allows our bodies to recover from sickness faster. 

While we can’t say for sure exactly whether or how sugar suppresses our immune systems, we can say with confidence that people with healthier lifestyles (including their diets) get sick less often and recover faster from illness than those that don’t. So, even during the festive holiday season when it’s so easy to indulge in carb-loaded dinners, sweet potato pies, and mugs of hot chocolate, try to remember that moderation is key.

If you do find yourself sick this time of year, In and Out Express Care is here for you. Stop by one of our four urgent care clinics in Hampton Roads to feel better fast!