Christmas is here! The scent of cinnamon, saffron, and cardamom  wafts from the kitchen. Christmas is the holiday of bright, warm colors; red, green, yellow, and multitude of sparkling things. The sights and smells we surround ourselves with make us feel a bit like donning a warm knitted sweater and getting cosy in the corner of the couch with a cup of tea and a book.

But that’s an understatement, because what you’re really doing in the kitchen is more like knitting small microscopic sweaters for all of your 40 trillion intestinal bacteria, which, after all, need some Christmas love too. They’ve been working hard all year!

The strong flavors and warm colors of cinnamon sticks, ginger, mustard, and cloves are the perfect tools for your intestinal bacteria’s own little versions of Santa’s workshop, in which they produce the many healthy substances that your body needs; hormones that control your mood, neurotransmitters that help maintain a strong immune system through the cold season, and fatty acids that prevent inflammation.

It’s no wonder that we’re attracted to tasty herbs, fruits and vegetables with bright colors, since these are the ones that have the greatest impact on our bodies. Lab analysis has shown that all herbs can be included in a group of plants containing the greatest number of antioxidants. Our ancestors did not have any labs, but they figured it out anyhow, and for centuries they’ve used herbs as natural remedies.

Short Christmas-quiz: What’s most healthy: a light green or a red apple? Answer: a red apple.

The explanation is, of course, that the healthy polyphenols live inside color itself.

Test yourself in the store. Do you choose white cabbage or red cabbage? Iceberg lettuce or kale? Let the color guide you. The stronger the color the better. Much of the color is usually displayed on the external surface, or skin. So by all means eat the skins, and don’t peal off too many layers of onion. A large part of the nutrition will be lost that way. The skin also contains insoluble fibers that provide good energy to intestinal bacteria, while the pulp provides soluble fibers that will help to keep your stomach on the right track throughout Christmas, which can sometimes be a challenge. Usually, not everything on the table is healthy.

When you look at nature, you obviously see lots of green plants. The explanation for the green color is chlorophyll, and when it disappears in the fall, it turns into all those other sparkling colors, like red, orange, and yellow. The colors were waiting there all along, behind the green.

Autumn colors are dominated by yellow xanthophyll like lutein, orange beta carotene, and red antocyanine. When we suggest a diet involving vegetables, we should remember that it’s not only green vegetables that contain healthy nutrition. The various other colors of vegetable are all full of nutrition too.

But what about garlic then? It’s white, but good anyway, right? Yes – and the explanation for that lies in the fact that the light color is typical for onions. The substances, such as the flavonols quercetin and kaempferol, have a white or creamy color. If you choose red onions you’ll also get red antocyanine.

So, one good tip is: Eat all the colors of the rainbow! And don’t forget the gray scale.

This is a guest post. The opinions expressed are the writer’s own.