The Truth About Cold & and Flu Season (It’s Not What Most People Think)

Every year like clockwork, once fall turns into winter, people start saying the same thing: “Cold and flu season is here.”
But what if it’s not the season itself that’s making people sick?

In my experience, there are two major factors that get overlooked every single year — and they line up almost perfectly with when people start feeling run down.

Less Sun = Less Vitamin D = Weaker Immunity

As the days get shorter, we naturally spend less time in the sun. This matters more than most people realize.

Vitamin D plays a major role in immune function. It helps regulate how the immune system responds and supports the body’s ability to fight off viruses. When vitamin D levels drop, the immune system simply doesn’t work as efficiently.

This is one of the biggest reasons people tend to get sick more often in the winter — not because cold weather causes illness, but because we’re no longer getting the sunlight our bodies rely on. In northern states especially, it can be extremely difficult to maintain healthy vitamin D levels through sunlight alone during fall and winter.

The Sugar Spike No One Talks About

The second factor lines up perfectly with the calendar: Halloween through Christmas.

This is the time of year when kids — and adults — consume the highest amount of sugar all year. Candy, desserts, baked goods, holiday treats… it adds up quickly.

What many people don’t realize is that sugar directly weakens the immune system. High sugar intake can suppress the activity of white blood cells for hours after consumption. When sugar intake is frequent — day after day — the immune system stays in a weakened state.

When you combine:

• Less vitamin D from reduced sunlight

• Increased sugar intake from the holidays

You end up with the perfect setup for weakened immunity.

It’s Not About Fear — It’s About Awareness

This isn’t about avoiding holidays or never enjoying treats. It’s about understanding what’s actually happening in the body so you can support it better.

Simple habits can make a real difference:

• Supporting vitamin D levels during fall and winter

• Being mindful of daily sugar intake, not just special occasions

• Supporting immune health before symptoms show up

Cold and flu season isn’t random. When you look at the patterns, it starts to make a lot more sense than we’re usually told.

Supporting Vitamin D Levels

If you’re looking for a simple way to support healthy vitamin D levels during the fall and winter months, Dr. Bergman’s recommended Vitamin D supplement is available both in our Advanced Health clinic and on our website. This is the form we trust and use ourselves.

You can find it here:
https://advancedhealthmed.com/products/vitamin-d3-serum-liquid-vitamin-d-oil-drops-for-adults-liquid-vitamin-d3-5000-iu-sublingual-vit-d3-liquid-0-43-fl-oz

As always, if you have questions about supplementation or want guidance on what’s right for you, we’re happy to help.